# Wastegate Actuator Spring Mod



## Marcus_Aurelius (Mar 1, 2012)

I have been asked countless times about my wastegate actuator spring mod. I think it's time to make a thread about it that I could link people to; and at the same time have a place to discuss things with some of the guys in the 1.8T technical forums that are starting to catch up.

The purpose of this, is to increase the holding capacity of the wastegate flap by increasing the actuator spring rate. This can also be achieved by buying an aftermarket actuator, but why do all that when you can get the same results or better for a couple of dollars and 10 minutes of your time? The spring mod also allows you to tailor the final spring rate to the boost that you run, while you are stuck with preset rates with the aftermarket units (the fact that it is reversible in 1/2 a minute is also appealing). 

Do not confuse this mod with cranking the preload of the actuator by adjusting the rod screw. *Preloading the actuator is a bad idea because it considerably reduces the travel of the wastegate flap, and causes high EGTs on top of reduced efficiency.*

In my case, boosting anything past 25 psi blew the wastegate flap open at WOT, even without an actuation pressure signal coming from the N75 (a condition AKA as wastegate creep). So to remedy the situation, I added 2 external pull springs rated at 7lbs each (you may want less spring rate and one spring, if you are running less boost and there is less pressure in the hot side). The result is a tested 27-28 psi cracking pressure at rest. Being that I run upward of 30 psi, I am considering adding another small 3 lbs spring to bump the initial cracking pressure to about 30 psi.

Do you need this mod? IMO, as long as you run boost that are considerably higher than stock, the answer is yes. The stock actuator is designed for, and does a fine job around, stock pressure. Increase your boost with a flash and you are generating hot side pressure that is outside the range that the stock actuator was designed for. Once that wastegate creeps open at WOT because the actuator rate is exceeded, you are wasting valuable energy (exhaust pulses) that could be used to spin the turbine wheel harder and generate boost/power. Some will say, why bother if I can hold the desired boost without it? Well, you are not operating at full potential efficiency because you're wasting/bypassing some of the energy your engine/turbo is working hard to produce. Another sign of an overworked/weak actuator is the car's inability to hold boost to redline. The small frame turbos will always struggle up top and have some boost taper, but not the fall-off-a-cliff profile that is associated with an inappropriately sprung wastegate actuator.

*This is the best and cleanest pic I've seen of the spring mod (picture borrowed from 96AAAjetta :beer*






*This what it looks like in my car. One end is hooked to the actuator rod and the other to the vacuum nipple on top of the actuator. The other pic is the regulated pressure rig I used to test the intitial cracking pressure but a simple hand pump with a gauge could do *





















The picture below is borrowed from Peter139 (my pix are down momentarily). It shows a single spring added to the actuator.










Another borrowed picture, this time from Boulderhead's build thread! (just as a backup in case my pics are down again )


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## Marcus_Aurelius (Mar 1, 2012)

Reserved for springs rates, part # and better pictures

Help brand spring assortment part #59001 (use the smaller spring)

Home depot brand, use one or the two small 5lbs springs (the bigger ones aren't preloaded as well as the small ones, and are a better match for our OEM KKK turbo actuators)






















*The only good picture I was able to snap of the hook on the actuator nipple side (it's really tight in there)*















*Some more of that side*
























I rest a washer on the rod nut to give the spring a good spot to rest on, and prevent them from sliding over the nut.





















*This what your spring hooks should look like before installing it, I like to crush them a bit so they have no chance of coming out. This is a year old spring with many heat cycles and I usually refresh them once every racing season but they will last a lot longer *


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## 96AAAjetta (Jul 7, 2008)

I like where this is going and will deff be keeping an eye on this thread. I remember seeing this info somewhere else and have been looking for it but haven't been able to find it till now.


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## PLAYED TT (Oct 17, 2010)

opcorn:


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## All_Euro (Jul 20, 2008)

I did this quite a while back after reading one of your posts... simple, inexpensive & works really well.

*Thanks :thumbup:*


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## 1.8 skeet skeet (Aug 11, 2004)

Well how do you do it man?


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## warranty225cpe (Dec 3, 2008)

Good stuff. I felt a nice difference when I went with the forge WG with the stiffer spring (thanks Sparti)


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## Cryser (Sep 9, 2009)

Found this on an evo site and found it to be very true, gives a good difference between adjusting the Wastegate arm length and using external springs 



honki24 said:


> I'll letcha know, I just did that today. I'll log tomorrow. Anyone had the spring pop off or snap due to heat cycling? I'm a bit concerned about that happening.
> 
> Actually... I wasn't going to do this but yep... Imma unload my thesis now:
> If the spring is a linear spring (which is most common) then foce doesn't increas dramatically with deflection. This means that adjusting the eyelet on the WGA arm adds pretention to the spring which assures initial cracking pressure is adiquate, but does not actually increase force put on the arm. Adjusting the eyelet also decreases the flapper stroke, which means the maximum boost limiting ability is decreased. This isn't a problem unless it is over-adjusted. The only real advantage that might come from adjusting the eyelet (WGA arm length) would be cracking pressure, which means higher boost spike. The decreased flapper stroke gives the turbo the ability to hold higher boost... because less exhaust gasses escape. Adding the external spring actually sounds quite genius to me because it basically increases the spring's entire curve.. not just an initial pressure.
> ...


 Did this mod on my jetta and found I was able to uncrank my wastegate from what I had it and still able to hold a good amount of boost to redline. Also uncranking the wastegate allowed the car to drive much more civilized around town. Overall I have found using this mod to increase wastegate spring pressure is much more suitable then changing the wastegate arm because of the fact that changing the wastegate arm also begins to limit the ability for the car to control boost. This mod doesn't have that downside, you car can still fully control boost yet it has the increase spring tension.


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## Marcus_Aurelius (Mar 1, 2012)

Cryser, I'm glad the mod helped and I see that you found the thread even before I got a chance to finish the how to and link you to it. 

To add to what you are saying, cranking the adjustable rod not only screw up the ability to control boost spikes but it has a much more negative effect. With flap stroke or travel reduced, when there is actually a pressure signal from the N75 or boost controller asking the flap to open in order to reach a boost target, the flap only opens at a reduced percentage (less volume bypassed) and create high EGTs. Steve AKA Spartiati documented this in one of the technical forum thread, and having an EGT probe housing, he registered the issue and also power loss. 

I don't want to make this thread about cranking rods adjustment as it is highly undesirable IMO. The spring mod however, allows you to retain full flap travel but also increase the ability to fight premature wastegate creep and make more boost/power efficiently. 

The only warning I have with the spring mod is that it should not be used a way to control boost. Upper boost limit should be controlled by a boost controller. Besides that there are only positives and most people don't know how much stronger their car can get with this simple mod, until they tried it. I'm hoping this will help others that will follow the lead :beer:


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## Cryser (Sep 9, 2009)

yeah I'm still messing with uncranking my wastegate because of the mod. But so far I have uncranked it a significant amount and still hold more boost in the top end then I ever did with it basically fully cranked. At the moment I'm still having problems with partial throttle boost at above 50% pedal I get a big spike and some "surging/bouncing" off boost but that has been going down as I slowly uncrank the gate more and more. 

I'm almost back to stock location and still holding more boost in the top end then I ever did with my WG almost fully cranked. I'm just trying to find that delicate balance between un cranking and allowing the ECU to adjust for boost :laugh:


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## RabbitGTDguy (Jul 9, 2002)

going to chim in on this here as Max and I have talked about things many times before and this indeed does work and achieve what most are after as long as you know what you are getting into and the implications for doing it. 

When I was setting up my Stg 3 WMI with Max here...we went this route. I need to pull more sustained boost at higher RPM's and overall. To accomplish this, I did it a bit differently than Max but did have a good result from it. Instead of using the above springs I remember that I had some long return/assist springs from a recent rear drum/brake job I had done on my own Jeep (though, this type of spring is common to most drum setups). It has a "eyelit" at one end and a hook at the other. To use. I simply slightly heated that eyelit end so that I could bend the eyelit to 90 degrees and fit it around the acuator rod end and then the hook end easily grabbled the acutator mount itself. Pretty slick. It worked flawlessly... 

Then came the FORGE acutator...I bought one this winter...installed this spring. After the nightmarish install (it wasn't really that bad...just a pain for such an small part). I am currently running the "yellow" spring which is the next up from the stock green one they put in it. 

I have to say, I can attest to the preloading of the spring and the associated consequences of doing so recently as well. 

I set the acuator as you should (and many don't) but closing the flapper, applying 7psi or so to the acuator, and then setting the "preload" on the acuator from there. There truly is a "sweet spot" to this acutator and it is NOT by adding preload. I had it slightly in too much and I had surging everywhere. It was horrible. boost would sky rocket so fast and made things spooky scary and also that couldn't have been healthy for the turbo either. While it was exihilarating...it was also useless. 

I made a few adjustments the other night and took ALL the preload off the flapper and it feels SO much better. As a matter of fact, since I'm pushing near the levels of boost as Max discusses, I believe that with proper tuning that I could handle the blue spring or the red one to achieve my goals for now (before a BT or FT build). The wategate spring really SHOULD be the end all when it comes to adjustment at the wastegate itself because it really should match the level of boost you are wanting to run...think about how the stock acutator settings work. The same thinking should be applied on the aftermarket approach as well. This isn't to be done by "cranking" the wastegate though. 

What you achieve through the spring mod is more linear and smooth in action. Easily achieveable with the stock acutator as mentioned above or through the ability to "tune" an acutator like the FORGE unit. (I didn't buy mine new...trust me...wouldn't have thought it worth it if that was the case...was "like new" though....but not "like new price"  ). I'm really edging towards trying to source a blue spring and giving it a go because this is what the car really needs to hold all the boost as long as you can. Set correctly....no surge...just smooth power/good build with better top end hold and as long as you have the mods and the know how to hold it...your golden. 

Max, you'll find this interesting. Bought the "Road and Track" buyer's guide for the original TT where they discuss the K04 in part of it. Now...whether it is fact or fiction...but they claimed at the time that the TT with the K04 was capable of producing a max of 29psi with the K04. Makes me want to talk to the engineers and still keeps me playing with this unit. I still can't make that jump to the other side of the fence do to the less laggy/low end fun/torque and driveability that the K04 gives. I wouldn't want to lose that! 

By the way...emailed you. Package should arrive soon. You decide what its worth to you and we can work from there. I emailed you info about things though. 

Joe


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## 1.8 skeet skeet (Aug 11, 2004)

Where do you buy the springs? Im going to give this thing a try :thumbup:


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## Marcus_Aurelius (Mar 1, 2012)

1.8 skeet skeet said:


> Where do you buy the springs? Im going to give this thing a try :thumbup:


 Home depot - autoparts store - hardware store etc. 

The autoparts store have an assortment under the Help brand, use the heaviest spring. The home depot carries an assortment too that has two springs that are perfect. I like going to a local Ace hardware because they have a big spring selection and the rates and other specs are available. 



*The home depot one, the two big springs are perfect for the job*


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## Cryser (Sep 9, 2009)

^ 

using those exact springs I'm using. Think it ended up being 6 bucks from home depot. 

Although I'm using the 2 smaller ones rather then the 2 bigger ones as I didn't want to add that much more spring tension. Although I have the smaller one stretched pretty far to reach, I'm wondering if using the bigger ones, not stretched as far might work better. 

only time and testing will tell =)


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## 1.8 skeet skeet (Aug 11, 2004)

Marcus_Aurelius said:


> Home depot - autoparts store - hardware store etc.
> 
> The autoparts store have an assortment under the Help brand, use the heaviest spring. The home depot carries an assortment too that has two springs that are perfect. I like going to a local Ace hardware because they have a big spring selection and the rates and other specs are available


 Thanks man I really appreciate it! Im going to home depot tomorrow opcorn:


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## Cryser (Sep 9, 2009)

so I backed off my wastegate arm even more today, I think I have it at stock location(based on the patina on the actuator arm rod). Reset my ecu boost adaptations and everything(removed the battery for 10 mins) and I can tell ya, damn what a difference. The ability for the car to actually control boost is fully restored. Yet I can still hit 22-23PSI going up hill. Drove the car around in all sorts of loads and it's adapting nicely, still giving me a bit of surging at about 50%-70% throttle but it's nothing you can feel, just see it bouncing on the boost gauge and that is starting to target in. I'm gonna log tomorrow because the car feels a lot more powerful in the lower boost regions and my thoughts are that the ecu isn't pulling as much timing because of the reduced EGTS. The sound of the turbo also is MUCH better so I'm excited to get some logs and see if my estimations are true. 

This truly is a MUCH better way to increase spring tension over cranking the **** out of the wastegate. A mod like this allows increased tension while still allowing the ecu to control boost properly. Spool up isn't as violent and because of that the car doesn't fight itself to control boost, before with my cranked wastegate I was basically limited to 10-25% throttle and full throttle. It's nice to be able to take off from a light at an "aggressive" pace without having to go full throttle and not look like a 16yr ricer trying to impress everyone around me.


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## 1.8 skeet skeet (Aug 11, 2004)

Just installed the springs! But its so hot and humid out I don't feel like taking her out of the garage  I will let you guys know how it goes :thumbup:


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## Cryser (Sep 9, 2009)

I was right, a lot less timing pull a negligible loss in airflow(-1g/s). There was actually more airflow past 5500 because of boost being held longer and the ecu has adapted quite nicely to the car returning a full pedal range. Much better way to hold boost longer


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## 20psi now (Feb 26, 2009)

I know this is off topic and NOT to thread jack, but you 225 guys might want to check your EGT probe at the turbo. Every time i get down there it back out a few threads and need to be tighted back up. I Would like to try this spring mod but I hold 14psi from 2500-6500 :laugh:.


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## warranty225cpe (Dec 3, 2008)

I wonder how much spring tension I would need since I have the stiffer forge already.


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## Marcus_Aurelius (Mar 1, 2012)

Cryser said:


> ^
> 
> using those exact springs I'm using. Think it ended up being 6 bucks from home depot.
> 
> ...


 The two smaller ones might be better than the bigger ones if they are short enough to be under tension at rest. I haven't used this assortment with the TT but did so once with an EVO. If you test both just report your results but for the time being I will update the second post to recommend the springs you are using. Thanks for the contribution!


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## Marcus_Aurelius (Mar 1, 2012)

1.8 skeet skeet said:


> Just installed the springs! But its so hot and humid out I don't feel like taking her out of the garage  I will let you guys know how it goes :thumbup:


 :thumbup: let us know your results


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## Marcus_Aurelius (Mar 1, 2012)

warranty225cpe said:


> I wonder how much spring tension I would need since I have the stiffer forge already.


 You may or may not need any... only testing can determine that since you already have uprated spring rate. It all going to depend on the amount of boost that you run, more boost = more pressure in the hot side to prematurely crack the flap open. You can test your initial cracking pressure with the Forge unit and internal spring installed. That will tell if the color spring you run is enough or appropriate for the boost you're running. Just make sure you don't have excessive preload on that actuator rod, I still believe that it played a major role on your turbo failing. Preload and reduced flap travel is evil IMO because of the heat and stress that's put on components (much higher EGT indicates it).


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## 1.8 skeet skeet (Aug 11, 2004)

Marcus_Aurelius said:


> :thumbup: let us know your results


 I think it feels great!! You can totally feel a difference at the end of gears. The turbo doesn't fall on it face at upper RPM's like it use too


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## jason bouchard (Aug 25, 2005)

wow , nicely done. . . I think I will be trying this soon. . . 

I am having problems with my wastegate holding pressure (checked line) 
I think its the canister


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## nuff said (Nov 22, 2011)

*testing cracking pressure*

I am wondering how to test the wastegate cracking pressure. Please chime in anyone .I assume 
I would tap into the wastegate line, with a gauge ,and under the car,slowly pressurise the line,keeping a close eye on both pressure,and the wastegate,when the car is not running. Does this sound correct? Also,should the cracking pressure be about the samne as the max boost you run?


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## Marcus_Aurelius (Mar 1, 2012)

nuff said said:


> I am wondering how to test the wastegate cracking pressure. Please chime in anyone .I assume
> I would tap into the wastegate line, with a gauge ,and under the car,slowly pressurise the line,keeping a close eye on both pressure,and the wastegate,when the car is not running. Does this sound correct? Also,should the cracking pressure be about the samne as the max boost you run?


 To test the cracking pressure, simply hook the hose going to the actuator to a regulated air compressor with a gauge hooked up. While watching the gauge, slowly increase the pressure with the regulator until the rod start to move and you have your cracking pressure. The old bike hand pump trick would work also, just use one with built in pressure gauge. 

As far as ideal spring tension or cracking pressure, you want it to be a few psi under the Max boost that you run. Your goal is to eliminate the wastegate being blown open too much without a N75 or MBC actuation signal. If you put your cracking pressure at the boost you're running, you're basically running at wastegate pressure and have no real control over boost. For example, when I ran 33 psi, I had 20 psi cracking pressure and also tried 25 psi cracking pressure, had plenty of control over boost with both but 25 psi cracking pressure offered the best performance. 

Think of it this way, the OEM actuator naturally cracks at 5-6 psi and that's conservatively designed to work in concert with a stock boost of 13 psi; increase the boost x psi over stock calls for at least x psi more actuator tension :beer:


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## nuff said (Nov 22, 2011)

*Wastegate Spring Mod Results*

Thanks for your reply Marcus Aurelius. I got under the car and installed some springs ,testing as I went along. I ended up trying 18 psi cracking pressure. My boost was running at 22 psi. I have set everything up previously for quickest boost response. After driving today and testing it these 
are the results; 
My wastegate takes much longer to open once cracking pressure is met, so say I want to pass someone,there is now that hesitation before it gets going. The good side is I am now boosting 25 psi,a 3 psi improvement. I got on it ,on the freeway in 5th gear and after the slight hesitation ,the car accelerated like a rocket ship. It actually surprised me. It felt like it was accelerating expotentially faster.Even though I only got on it for a few seconds ,the boost gauge seemed to be super glued at 25 psi and felt as if I could go to redline(set at 7200rpm) and have nearly no drop off. I cannot decide which I prefer. Without the springs ,the car feels like it pulls harder ,immediately,but a few seconds later ,would not keep up with the car if the springs were in. I wish there was a way to have both the instant response and the improved acceleration at the top end......Thanks for your write up on this mod..


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## Cryser (Sep 9, 2009)

Wanted to post an update. Currently I am using 3 of the smaller springs with the wastegate rod actually looser then stock. My cracking pressure is around 15PSI, this has allowed me to run a stage 2 eurodyne map(only edit on my side is swapped to using LAMFA map(power enrichment) rather then LAMBTS(full load lambda) other then that completely off the shelf tune. Everything runs great, getting my eurodyne cable back this week and I'm throwing my stroker bottom end on with the stock turbo for now, so I'll get to see how just a displacement increase effects things before the PPT .72 A/R 71r goes on =) 

Again to sum up the thread, THIS is the PROPER way to increase wastegate spring tension while still allowing your ecu to actually control boost, better MPG, better response, better power then just cranking the actuator rod and effectively limiting you ability to control boost. My car now has a nice full range of power, still holds 21PSI around max boost, 14PSI at redline. Rubberbandness of the car is gone a lot more fun to drive around town.


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## Marcus_Aurelius (Mar 1, 2012)

nuff said said:


> Thanks for your reply Marcus Aurelius. I got under the car and installed some springs ,testing as I went along. I ended up trying 18 psi cracking pressure. My boost was running at 22 psi. I have set everything up previously for quickest boost response. After driving today and testing it these
> are the results;
> My wastegate takes much longer to open once cracking pressure is met, so say I want to pass someone,there is now that hesitation before it gets going. The good side is I am now boosting 25 psi,a 3 psi improvement. I got on it ,on the freeway in 5th gear and after the slight hesitation ,the car accelerated like a rocket ship. It actually surprised me. It felt like it was accelerating expotentially faster.Even though I only got on it for a few seconds ,the boost gauge seemed to be super glued at 25 psi and felt as if I could go to redline(set at 7200rpm) and have nearly no drop off. I cannot decide which I prefer. Without the springs ,the car feels like it pulls harder ,immediately,but a few seconds later ,would not keep up with the car if the springs were in. I wish there was a way to have both the instant response and the improved acceleration at the top end......Thanks for your write up on this mod..


 With everything else in check, you should not have any hesitation resulting from the spring mod. All you're really doing is increase the wastegate actuator pressure holding capacity to reduce the wastegate being blown open under loaded exhaust pressure. The increase in boost achieved and sustained should be the only things that you get from doing this. 

I am pretty sure your hesitation or flat feeling right at onset (peak boost) is from something else. Maybe the ecu is dumping timing due to heat from the extra boost pressure; it could also be something else but definitely not a result of the mod. I would look at AFR, IAT, timing corrections, and even misfires to see what's causing the flat spot.:beer:


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## Marcus_Aurelius (Mar 1, 2012)

Cryser said:


> Wanted to post an update. Currently I am using 3 of the smaller springs with the wastegate rod actually looser then stock. My cracking pressure is around 15PSI, this has allowed me to run a stage 2 eurodyne map(only edit on my side is swapped to using LAMFA map(power enrichment) rather then LAMBTS(full load lambda) other then that completely off the shelf tune. Everything runs great, getting my eurodyne cable back this week and I'm throwing my stroker bottom end on with the stock turbo for now, so I'll get to see how just a displacement increase effects things before the PPT .72 A/R 71r goes on =)
> 
> Again to sum up the thread, THIS is the PROPER way to increase wastegate spring tension while still allowing your ecu to actually control boost, better MPG, better response, better power then just cranking the actuator rod and effectively limiting you ability to control boost. My car now has a nice full range of power, still holds 21PSI around max boost, 14PSI at redline. Rubberbandness of the car is gone a lot more fun to drive around town.


 Thanks for the update! :thumbup: 

Switching to LAMFA over LAMBTS sounds interesting, I remember asking my buddy DougLoBue for the reason for the preference for full load lambda in the community. What are your findings? 

I also can't wait to hear your thoughts on the increased displacement on a stock snail, keep us posted :beer::beer::beer:


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## RoTTirocket (Feb 8, 2007)

Wow great read. Will def have to do this since I found out my whole waste gate is literally loose, just wiggling around back there. Thread jack: Any tips for getting back there to remove the waste gate and install the new one? So tight!


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## Marcus_Aurelius (Mar 1, 2012)

RoTTirocket said:


> Wow great read. Will def have to do this since I found out my whole waste gate is literally loose, just wiggling around back there. Thread jack: Any tips for getting back there to remove the waste gate and install the new one? So tight!


 Remove the turbo outlet pipe, hose and strut tower bar and the metal shield behind the valve cover. Then bear hug the motor from the top so you could reach everything. It's not that bad with everything out of the way.


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## nuff said (Nov 22, 2011)

*update;wastegate spring mod result*

I have now had the wastegate spring mod in for 2 weeks.I experimented with a few different spring tensions to find the best combination. One of the good results was uncranking my 
previously cranked wg.It is now back to stock position.I now have better drivability,less flutter,and 3 psi more power. All for a couple bucks....Excellent mod thanks to Marcus A.


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## Marcus_Aurelius (Mar 1, 2012)

nuff said said:


> I have now had the wastegate spring mod in for 2 weeks.I experimented with a few different spring tensions to find the best combination. One of the good results was uncranking my previously cranked wg.It is now back to stock position.I now have better drivability,less flutter,and 3 psi more power. All for a couple bucks....Excellent mod thanks to Marcus A.


 :thumbup::thumbup::thumbup:


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## Chuckmeister87 (Nov 10, 2009)

I'm guessing there might be a slight change needed for those of us running K03s?


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## Marcus_Aurelius (Mar 1, 2012)

Chuckmeister87 said:


> I'm guessing there might be a slight change needed for those of us running K03s?


 Not really, same principle, almost identical internal wastegate with external actuator and rod etc. 

Simply carry the mod as seen in the thread!


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## tt_kcalb_nevar (Feb 26, 2010)

I'm having my turbo rebuilt today and was wondering if this mod would help to fix my stuck waste gate problem (boost drops while under throttle from 18psi to 12 psi, or only climbs up to 12-15 psi and you can hear a loud movement of air). I will be adding the same springs as Marcus used. I have also looked for a stock replacement waste gate for my car but couldn't find a stock unit, only the upgraded Forge model. Anyway, if anyone knows where I would be able to get a replacement waste gate or suggest something else, I would greatly appreciate it! 

Thanks Again.,


:beer:


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## Marcus_Aurelius (Mar 1, 2012)

tt_kcalb_nevar said:


> I'm having my turbo rebuilt today and was wondering if this mod would help to fix my stuck waste gate problem (boost drops while under throttle from 18psi to 12 psi, or only climbs up to 12-15 psi and you can hear a loud movement of air). I will be adding the same springs as Marcus used. I have also looked for a stock replacement waste gate for my car but couldn't find a stock unit, only the upgraded Forge model. Anyway, if anyone knows where I would be able to get a replacement waste gate or suggest something else, I would greatly appreciate it!
> 
> Thanks Again.,
> 
> ...


Hey bud, try giving FrankenTurbo Doug a try! He may have an OEM actuator for you. Did you go with a standard rebuild or are you upgrading the internals while you're at it?


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## tt_kcalb_nevar (Feb 26, 2010)

Marcus_Aurelius said:


> Hey bud, try giving FrankenTurbo Doug a try! He may have an OEM actuator for you. Did you go with a standard rebuild or are you upgrading the internals while you're at it?


I kept it pretty standard actually since the turbine and compressor were all in good shape. The rebuild kit from gpopshop does include an upgraded 360* thrust bearing and few other small upgraded bits, but I guess its geared more towards reliability than anything else. I figure my new (read: properly functioning) ecu with an apr tune and rebuilt turbo, should hold me over for a while before I go FT or BT.

Thanks for the tip, I just sent FT an email, I just need the actuator and exhaust housing and Ill be good to go! Hate driving the silverado daily...


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## Chuckmeister87 (Nov 10, 2009)

I bought the springs last night from Home Depot. Put them on today. I have to say it was the quickest and easiest mod I've done to the car, besides removing the back seats.

I've noticed some changed since the mod:
- improved response time from the car:thumbup:
- no more wind noise coming from the missing grommet in my firewall (I could hear something leaking boost before):thumbup:
- boosting spikes to 25psi on my 20psi tune:thumbdown:


I'm not sure how good spiking to 25psi will be for my old car, so I'm going to get a boost controller to take care of the issue.

Thanks for the info, Marcus. Changing the $7 springs periodically and paying for a boost controller is a good investment after deciding to run higher boost. :beer:


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## Marcus_Aurelius (Mar 1, 2012)

Chuckmeister87 said:


> I bought the springs last night from Home Depot. Put them on today. I have to say it was the quickest and easiest mod I've done to the car, besides removing the back seats.
> 
> I've noticed some changed since the mod:
> - improved response time from the car:thumbup:
> ...


Yes Chuck, get a boost controller and cap the boost ceiling where it should be according to the flash. Then enjoy increased efficiency across the board for $10. :thumbup:


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## WiKKiDTT (Aug 13, 2009)

tt_kcalb_nevar said:


> I kept it pretty standard actually since the turbine and compressor were all in good shape. The rebuild kit from gpopshop does include an upgraded 360* thrust bearing and few other small upgraded bits, but I guess its geared more towards reliability than anything else. I figure my new (read: properly functioning) ecu with an apr tune and rebuilt turbo, should hold me over for a while before I go FT or BT.
> 
> Thanks for the tip, I just sent FT an email, I just need the actuator and exhaust housing and Ill be good to go! Hate driving the silverado daily...


I have a brand new actuator that I will sell u for $20.00 oem k04.


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## tt_kcalb_nevar (Feb 26, 2010)

WiKKiDTT said:


> I have a brand new actuator that I will sell u for $20.00 oem k04.


Thanks WiKKiDTT, but I already purchased one from Doug at FRANKENTURBO.

:beer:


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## Marcus_Aurelius (Mar 1, 2012)

WiKKiDTT said:


> I have a brand new actuator that I will sell u for $20.00 oem k04.


Hey bud, PM coming your way about the stuff you were inquiring about in the other thread, and I'll take the actuator from you (I have an experiment in mind). :beer:


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## Chuckmeister87 (Nov 10, 2009)

Marcus_Aurelius said:


> Hey bud, PM coming your way about the stuff you were inquiring about in the other thread, and I'll take the actuator from you (I have an experiment in mind). :beer:


Report your findings even if they fail. The info may give inspiration to others.


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## Marcus_Aurelius (Mar 1, 2012)

Chuckmeister87 said:


> Report your findings even if they fail. The info may give inspiration to others.


Will do Sir!


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## ttwsm (Feb 27, 2011)

Every experiment where you learn something is a success! :beer:


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## Chuckmeister87 (Nov 10, 2009)

ttwsm said:


> Every experiment where you learn something is a success! :beer:



Very much so.:beer:


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## WiKKiDTT (Aug 13, 2009)

Marcus_Aurelius said:


> Hey bud, PM coming your way about the stuff you were inquiring about in the other thread, and I'll take the actuator from you (I have an experiment in mind). :beer:


Pm me ur email. Tried to respond to you but it says your message box is full


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## Marcus_Aurelius (Mar 1, 2012)

WiKKiDTT said:


> Pm me ur email. Tried to respond to you but it says your message box is full


Measage box cleaned up, you can PM me back!


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## WiKKiDTT (Aug 13, 2009)

Pm sent


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## tt_kcalb_nevar (Feb 26, 2010)

Hey guys, I bought the springs from home depot and now Im a bit unsure of which to use. I have an APR tune and with a boost controller Im running between 21 to 25psi, which spring(s) should I use and should I use both of them? 

thanks! 

:beer:


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## Chuckmeister87 (Nov 10, 2009)

tt_kcalb_nevar said:


> Hey guys, I bought the springs from home depot and now Im a bit unsure of which to use. I have an APR tune and with a boost controller Im running between 21 to 25psi, which spring(s) should I use and should I use both of them?
> 
> thanks!
> 
> :beer:


 
Use the two big ones and one of the small ones. You might find it easier to slightly open the ends of the springs with a pair of pliers. I had to blindly hook them over the WG and pull them back to the washer I had over the bolt. It's a piece of cake as long as you can feel things out


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## Arnolds64 (Nov 13, 2009)

*Did this on another car.*

I wondered if anyone had done this little mod. I did it back in 1985 on a New POS Dodge Daytona Turbo coupe. Broke every mechanical part under warranty. Once rebuilt at the dealership it was a good car. Took it from 7lbs to 9! Wow! But there was obviously more power that it produce. It had a fuel shut off or sensor or something. If it went higher than 9 it would just shut down. Seem to remember it messed with the throttle response some making it a little less torquey on the lowend. Old Garret T-3 vacuumed operated waste gate on those. Different tech and era so this must be different with our cars but not to much. I know these are crude mods but if they work, they work. Kinda like if you do your own port work on a certain Air cooled beetle and a forum crowd tells you that unless you have a flow bench and a CNC machined you will lose power and screw it up. Well let me tell ya, car gained a ton of power. Forum racers kill me! Real modders get greasy and actually have the balls to do the unconventional. Then you have guys say, Why is your car so much faster than theirs with the same mods? You don' t let them in on your secret sauce. 

By the way this is OK with 225 or AMU crowd isn't it?


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## Marcus_Aurelius (Mar 1, 2012)

Arnolds64 said:


> I wondered if anyone had done this little mod. I did back in 1985 on a POS Dodge Daytona Turbo coupe. Took it from 7lbs to 9! Wow! But there was obviously more power. It had a fuel shut off or sensor or something. If it went higher than 9 it would just shut down. Seem to remember it messed with the throttle response some making it a little less torquey on the lowend. Old Garret T-3 vacuumed operated waste gate on those. Different tech and era so this must be different with our cars.
> 
> By the way this is OK with 225 or AMU crowd isn't it?


 Many have successfully tried on run on in their TT in this thread (including myself and Cryser that documented his results on a VW). You must have had some kind of safeguard or something on your old Dodge to prevent proper operation and induce fuel cut. This simply increases hotside efficiency by increasing allowable wastegate pressure before it gets naturally bleed by the flap cracking open. On any car running boost levels above stock this is a great mod and has no negative effects (as long as boost ceiling is capped via software or hardware and not allowed to go uncontrolled). :beer:


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## Marcus_Aurelius (Mar 1, 2012)

tt_kcalb_nevar said:


> Hey guys, I bought the springs from home depot and now Im a bit unsure of which to use. I have an APR tune and with a boost controller Im running between 21 to 25psi, which spring(s) should I use and should I use both of them?
> 
> thanks!
> 
> :beer:


 At 21-25 psi I'd suggest something like an extra 7-10 lbs of spring tension (maybe a single 7lbs springs or two 5lbs ones). This will greatly improve hotside efficiency and leave you with a healthy 6-7 psi window of boost control. Whatever spring assortment you buy should have the spring rates listed... :thumbup:


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## Chuckmeister87 (Nov 10, 2009)

Marcus_Aurelius said:


> At 21-25 psi I'd suggest something like an extra 7-10 lbs of spring tension (maybe a single 7lbs springs or two 5lbs ones). This will greatly improve hotside efficiency and leave you with a healthy 6-7 psi window of boost control. Whatever spring assortment you buy should have the spring rates listed... :thumbup:


 
I just reread your first post to see you were running 3 springs because you wanted to hold 30psi. Took some springs off and I dont spike to 25psi anymore. Go figure


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## tt_kcalb_nevar (Feb 26, 2010)

Thanks for the tips guys! I used the large (8lbs) and small(5lbs) spring that comes in that Home Depot pack. I have it spike and hold at 25 all day long, i spiked to 27 psi on the test drive before I adjusted my mbc.

Turbo lag is almost nonexistent, the car feels like its supercharged! It also feels strong all the way to redline! Doesn't fall flat on its face anymore!:thumbup:


:beer::beer::beer:


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## Marcus_Aurelius (Mar 1, 2012)

Nice, not bad for less than $20 and 10 min of your time! :beer:


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## tt_kcalb_nevar (Feb 26, 2010)

Marcus_Aurelius said:


> Nice, not bad for less than $20 and 10 min of your time! :beer:


Actually the springs cost $7 ! 

Honestly, what a great mod! Keep up the good work Marcus_Aurelius! 

Beers on me if youre ever in LA!


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## peter139 (May 4, 2005)

how safe is this mod? is it possible to blow your engine?
Mine runs stock 13psi(180bhp), if i increase it to 18psi or 20 psi will it kill my engine in time?


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## Marcus_Aurelius (Mar 1, 2012)

peter139 said:


> how safe is this mod? is it possible to blow your engine?
> Mine runs stock 13psi(180bhp), if i increase it to 18psi or 20 psi will it kill my engine in time?


Honestly, if you're asking these questions it may not be thing for you to attempt. Essentially, this mod is intended to increase internal wastegate efficiency *when you're running boost levels that are above stock.* 

Adding spring tension is intended to help the OEM actuator that becomes too weak when turbine pressure are elevated above what the stock actuator spring can efficiently control. *This should not be used as a method of boost control and boost ceiling should always be capped accordingly to match the tune (a MBC is the easiest way) * If you're running a stock tune with stock boost levels, the stock actuator is more than capable of handling the hotside pressure generated (that is what it was designed for). Simply adding actuator spring rate with nothing else done to the car is dangerous because boost won't be properly controlled, fueling requirements won't be meet for the increased boost and you'd probably hit limp mode once you passed the boost limits preset in the ECU (these get raised once a car get a remap). So, NO this is not for your application.


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## peter139 (May 4, 2005)

Ok i understand, but if the actuator spring is worn(like mine), the waste gate will open much early than it should open. 
So if we do this mod, will my boost increase? With this mod the spring rate will be more than stock so i was asking if this mod is dangerous for the engine (ignition and fueling will stay stock)


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## Marcus_Aurelius (Mar 1, 2012)

peter139 said:


> Ok i understand, but if the actuator spring is worn(like mine), the waste gate will open much early than it should open.
> So if we do this mod, will my boost increase? With this mod the spring rate will be more than stock so i was asking if this mod is dangerous for the engine (ignition and fueling will stay stock)


With this mod, unless you only add a very soft spring just to offset the lost of tension of said worn actuator, it will increase boost levels (boost ceiling). So, with nothing to cap the boost where it should be, it will be dangerous for the motor. If you want to do it, buy/make a cheap ball and spring boost controller to cap the boost where it should be.


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## steve-o 16v GLI (Jun 26, 2005)

Hey max what boost are you seeing at redline? Im curious what the ko4 can do when pushed like your setup. Im currently running a single spring and it allowed me to get 15psi at redline vs the prev 12-13. It was def. a noticable difference when driving.:thumbup::beer:


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## Marcus_Aurelius (Mar 1, 2012)

I'm spiking 36-37 psi and holding about 25 psi nowadays. :beer:


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## 1fast2liter (Apr 4, 2005)

i tried cranking my wastegate today about half the length of the threads left...maybe boost a little faster and maybe a 1psi spike more.. it does seem to hold boost better above 5000rpms.. but i am wondering i think i am gonna try a 5 pound spring... marcus do the packages say what pond they are on them? i would love to see 21psi and hold about 17 better yet spike 21 and hold that to..lol... gonna find directions on making a mbc and try this spring too. 



i also went in and adjustable main fuel add by +3% but when logging my timing pull it was a tad higher went from 0-3 before fuel adding to 0-5 wonder if the ecu is adding timing based on the more fuel and compensating for the added timming on its own? used unisettings to add fuel also added 5ms to o2 sampling rate to and upped idle speed by 70rpms... i am hopping that this spring mod will give me what i am looking for till i go bt. also no home depo here just Menards.


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## Arnolds64 (Nov 13, 2009)

*Just did it.*

I put the single 7 lb spring to be conservative. I am running an APR 91 flash without a boost gauge so I thought I should be careful. Really can feel less lag or re-spool between shifts and pulls to a much higher rpm level than before. So 2 of the large Home Depot Springs will be safe? As someone here says the Software will control boost level? 

GREAT! So Marcus Arellius is Max or I am not reading into this right?


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## Marcus_Aurelius (Mar 1, 2012)

1fast2liter said:


> i tried cranking my wastegate today about half the length of the threads left...maybe boost a little faster and maybe a 1psi spike more.. it does seem to hold boost better above 5000rpms.. but i am wondering i think i am gonna try a 5 pound spring... marcus do the packages say what pond they are on them? i would love to see 21psi and hold about 17 better yet spike 21 and hold that to..lol... gonna find directions on making a mbc and try this spring too.
> 
> 
> 
> i also went in and adjustable main fuel add by +3% but when logging my timing pull it was a tad higher went from 0-3 before fuel adding to 0-5 wonder if the ecu is adding timing based on the more fuel and compensating for the added timming on its own? used unisettings to add fuel also added 5ms to o2 sampling rate to and upped idle speed by 70rpms... i am hopping that this spring mod will give me what i am looking for till i go bt. also no home depo here just Menards.


 Couple things here: 

1) Cranking the wastegate is not good practice. You are seeing increased timing pull even with 3% fuel added, it could be that the increased EGT associated with a cranked wastegate is the culprit. Usually, although up to a point, adding fuel cools down cyl charge and keep the ECU happy. The proper way of bumping hot side efficiency is by adding spring rate, not preloading/cranking the crap out of the actuator rod (honestly, Audi/VW would have serve this community better with no adjustments on the actuator). 

2) Add some springs until you can hold the desired boost pressure. Make sure you do this in conjunction with a MBC to cap boost ceiling, and logging of timing corrections since you are playing with fuel and timing in the adaptation channels. 

3) Adding sampling rate on your O2 can be a blessing and a curse. I would leave that alone as there is nothing to be gained from it. 

4) I'd suggest you post some logs that includes IAT, actual timing, timing corrections etc. so I can help you get this running perfectly.


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## Marcus_Aurelius (Mar 1, 2012)

Arnolds64 said:


> I put the single 7 lb spring to be conservative. I am running an APR 91 flash without a boost gauge so I thought I should be careful. Really can feel less lag or re-spool between shifts and pulls to a much higher rpm level than before. So 2 of the large Home Depot Springs will be safe? As someone here says the Software will control boost level?


 What are you doing without a boost gauge? You just found your next project (I'm serious about that)! 

Doing things blindly is asking for trouble, the software will attempt to control boost, but that doesn't mean that it'll succeed. The OEM hardware in charge of boost control (N75) struggles enough without additional hardware variables, so don't trust it. 

Your proper course of action should be to get a boost gauge --->install a MBC ----> add spring incrementally till the desired effect is reached. 



Arnolds64 said:


> GREAT! So Marcus Arellius is Max or I am not reading into this right?


 Who's Max? 

J/K, at this point pretty much everyone had it figured out. Let's just say that Marcus is Max reloaded!


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## Arnolds64 (Nov 13, 2009)

*Gauge!*



Marcus_Aurelius said:


> What are you doing without a boost gauge? You just found your next project (I'm serious about that)!
> 
> Doing things blindly is asking for trouble, the software will attempt to control boost, but that doesn't mean that it'll succeed. The OEM hardware in charge of boost control (N75) struggles enough without additional hardware variables, so don't trust it.
> 
> ...


 Yeah I have it I have it I just have not had time to put it in. So I guess this is a good reason to do it now!! Hey I like the DV and the LCA's Marcus. LOL! You da man. Hey just don't sell anything here again. We all need you dude! We know where to go to get stuff and most everyone else.


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## 1fast2liter (Apr 4, 2005)

The added fuel and timing comments were done before a cranked the wastegate..... but i understand that... why am i loosing boost thru tje nut though.. i am not getting any over boost codes as i never see over 20psi

Sent from my Motorola Electrify using Tapatalk 2


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## 1fast2liter (Apr 4, 2005)

2 springs. And trying to figure out when i added a mbc to it taking out the n75 how its still dumping boost.. sounds like its coming thru the dv but i got the yellow spring and 2 shims in

Sent from my Motorola Electrify using Tapatalk 2


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## Arnolds64 (Nov 13, 2009)

*DV*



1fast2liter said:


> 2 springs. And trying to figure out when i added a mbc to it taking out the n75 how its still dumping boost.. Sounds like its coming thru the dv but i got the yellow spring and 2 shims in
> 
> sent from my motorola electrify using tapatalk 2


 get max's dv. It is great. Got one and so much faster than the forge.


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## 1fast2liter (Apr 4, 2005)

Itr wouldnt matter whatone i have their is nothing wrong with mine. Its been tested

Sent from my Motorola Electrify using Tapatalk 2


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## Arnolds64 (Nov 13, 2009)

*Gauge.*



Arnolds64 said:


> get max's dv. It is great. Got one and so much faster than the forge.


 Going to try to install the gauge tonight. I tell you with only one large exact spring you showed from Home Depot it is amazing. Way less lag at shifts like it had before and no nose over after 5500. Drives much more like a NA engine. This is probably the biggest change aside the APR 91 octane flash so far in performance. 

I still get some flutter and have for awhile letting off the throttle between shifts. Should I worry Max? Have your DV.


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## Marcus_Aurelius (Mar 1, 2012)

Arnolds64 said:


> Going to try to install the gauge tonight. I tell you with only one large exact spring you showed from Home Depot it is amazing. Way less lag at shifts like it had before and no nose over after 5500. Drives much more like a NA engine. This is probably the biggest change aside the APR 91 octane flash so far in performance.
> 
> I still get some flutter and have for awhile letting off the throttle between shifts. Should I worry Max? Have your DV.


 Glad you like the improvement! 

If the flutter noise is at low load and part throttle, there is nothing to be alarmed about. If it's at WOT shifts however, I'd be concerned. When was the last time you sealed your boost/vacuum leaks? It's a never ending battle with these cars and leaks, at least with a gauge you'll be able to tell right away when they pop.


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## Arnolds64 (Nov 13, 2009)

*Flutter.*



Marcus_Aurelius said:


> Glad you like the improvement!
> 
> If the flutter noise is at low load and part throttle, there is nothing to be alarmed about. If it's at WOT shifts however, I'd be concerned. When was the last time you sealed your boost/vacuum leaks? It's a never ending battle with these cars and leaks, at least with a gauge you'll be able to tell right away when they pop.


I am pretty sure it is only at low rpm and low load I hear it. Yah I pressure checked it when I borrow you checker after i got your DV several months ago and it was doing it after I put it on. Fixed some leaks then. I am pretty sure there is no flutter on WOT Shifts. Gotta go somewhere where this is wall on the highway so I can hear it better. LOL!
Still without Gauge - Toilet flush fix tonight, leaky. Seriously. LOL! Aw the life of a home owner.


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## mk2riceeater (Sep 6, 2007)

*Springs too long?*

Hey, ive got a ko3s and the exact springs shown on this post and it seems like the bigger springs are too long and wont fit with any tension...im running the 2 smaller springs at the moment, do you have any idea where i could anchor the actuator spring side elswhere?


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## Marcus_Aurelius (Mar 1, 2012)

mk2riceeater said:


> Hey, ive got a ko3s and the exact springs shown on this post and it seems like the bigger springs are too long and wont fit with any tension...im running the 2 smaller springs at the moment, do you have any idea where i could anchor the actuator spring side elswhere?


I am not sure if I posted that before but the two smaller springs in the Home Depot assortment are perfect for our turbo. Their shorter length guarantees that they are under tension or preloaded at rest. The larger ones would need to be hooked somewhere else to put proper tension on them on our cars. :beer:


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## mk2riceeater (Sep 6, 2007)

*Victory!!*



Marcus_Aurelius said:


> I am not sure if I posted that before but the two smaller springs in the Home Depot assortment are perfect for our turbo. Their shorter length guarantees that they are under tension or preloaded at rest. The larger ones would need to be hooked somewhere else to put proper tension on them on our cars. :beer:


You my friend are a godsend! This is by far the best mod ive done to my car, im now seeing 20+ lbs of boost on the regular compared to my 16-18 i was getting before i installed the springs. Im guessing my wastegate is worn out? I dont know what it was but shes cruisin now! :beer: thank you!!


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## Marcus_Aurelius (Mar 1, 2012)

mk2riceeater said:


> You my friend are a godsend! This is by far the best mod ive done to my car, im now seeing 20+ lbs of boost on the regular compared to my 16-18 i was getting before i installed the springs. Im guessing my wastegate is worn out? I dont know what it was but shes cruisin now! :beer: thank you!!


Your wastegate actuator is not worn out. The hot side pressure associated with the above-stock 16-18 psi produced was overcoming the stock actuator spring. What you did with the mod is give the stock unit some "helper spring" to help it achieve better hot side efficiency (also producing higher boost on the cold side).

Glad you enjoy the mod! :beer:


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## mk2riceeater (Sep 6, 2007)

Why is it that some people do not experience this problem?


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## Marcus_Aurelius (Mar 1, 2012)

mk2riceeater said:


> Why is it that some people do not experience this problem?


Everyone that increases boost pressure on an OEM spec actuator does! 

The reason why it's not a well known issue is because people usually force the turbo to work harder (spin faster creating heat related inefficiency) to reach boost targets. When people see that they can meet boost targets, they assume that OEM actuator with stock springs are fine and can do the job at any boost level. What they are not realizing is that wasted exhaust pulses from a wastegate flap cracking open prematurely means less energy to spin the turbine and less boost made. With an actuator that matches the pressure target, and not bleeding precious exhaust pulses, more boost is created on the cold side at loads remaining constant. (One of the main reason, there is so much boost taper on flashed cars with OEM spec actuators). :beer:


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## Chickenman35 (Jul 28, 2006)

Marcus_Aurelius said:


> Everyone that increases boost pressure on an OEM spec actuator does!
> 
> The reason why it's not a well known issue is because people usually force the turbo to work harder (spin faster creating heat related inefficiency) to reach boost targets. When people see that they can meet boost targets, they assume that OEM actuator with stock springs are fine and can do the job at any boost level. What they are not realizing is that wasted exhaust pulses from a wastegate flap cracking open prematurely means less energy to spin the turbine and less boost made. With an actuator that matches the pressure target, and not bleeding precious exhaust pulses, more boost is created on the cold side at loads remaining constant. (One of the main reason, there is so much boost taper on flashed cars with OEM spec actuators). :beer:


And pity the poor guys running an AEB. We have a 7 psi actuator spring vs 10 psi for the TT225 ( and possibly some 180HP GTI's ). Talk about taper at high RPMS!! 

I'm running a MBC and can run 18 psi right up to about 5,000 rpm. By 6,500 rpm my boost has tapered right off to 7 psi because the flapper is being forced open by the exhaust gases. Gonna try the spring Mod, but I have an Longie A4 and there is just no room to get at things easily.


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## mk2riceeater (Sep 6, 2007)

Its deffinately worth trying to get too no matter how hard it is to access.. Night and day with the results!!:thumbup:


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## All_Euro (Jul 20, 2008)

I've been enjoying this mod for quite some time now but today I decided to see what the cracking pressure of my stock actuator really is - without springs. I was expecting 7 psi… try 4 

I added 17.4 lbs of spring pressure to the 4 lbs the wastegate has... so there's about 21.4 lbs of preload. I'm running a 3.0 bar MAP sensor so that leaves 8.6 psi to play with.

Because of the available spring rates - my actuator looks like it's being attached by Dr. Octopus 









Results… car is nice any snappy now & on a quick little test my K03 hit 28 psi in 3rd gear & 30 psi in 4th.

Those of you with a keen eye will notice I'm missing one of the three turbo to manifold bolts too :beer:


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## mk2riceeater (Sep 6, 2007)

*Nowwww*

Ok so i just installed a 3inch downpipe today which is an amazing difference, but i just noticed that i spike to almost 25lbs with not limp mode probably due to my programming but im also seeing jumpy boost at WOT... Its weird and i have never witnessed that before...do you think my ecu has to adapt to the new exhaust or what? Im not too worried as to ive read people talk about boost surging issues before but this is the first time ive seen it...pleasssse input!:beer:


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## steve-o 16v GLI (Jun 26, 2005)

All_Euro said:


> I've been enjoying this mod for quite some time now but today I decided to see what the cracking pressure of my stock actuator really is - without springs. I was expecting 7 psi… try 4
> 
> I added 17.4 lbs of spring pressure to the 4 lbs the wastegate has... so there's about 21.4 lbs of preload. I'm running a 3.0 bar MAP sensor so that leaves 8.6 psi to play with.
> 
> ...


Man I hope you dialed that boost down a bit. 30psi on a ko3 Blew one after only running 25psi for maybe a yr. And why not replace that bolt before you went and bought springs to mod your wastegate.:screwy:


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## All_Euro (Jul 20, 2008)

steve-o 16v GLI said:


> Man I hope you dialed that boost down a bit. 30psi on a ko3 Blew one after only running 25psi for maybe a yr. And why not replace that bolt before you went and bought springs to mod your wastegate.:screwy:


Haha - I'm boosting 30 on purpose. I've been running 22-26 psi for 2+ years now; no issues aside from exhaust leaks… and a corroded compressor wheel.

The exhaust leak is a priority, no worries there - the housing threads are toast, not the bolt. Going to try tapping the housing to the next bigger size. Until then - there is still less of a leak than when the wastegate was blowing open from part throttle onwards. Plus, I'm not driving around at 30 psi all the time - just because I can now 

As far as this spring mod goes, I've been doing this for quite some time now… &… it makes a night and day difference :thumbup:


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## Marcus_Aurelius (Mar 1, 2012)

All_Euro said:


> I've been enjoying this mod for quite some time now but today I decided to see what the cracking pressure of my stock actuator really is - without springs. I was expecting 7 psi… try 4
> 
> I added 17.4 lbs of spring pressure to the 4 lbs the wastegate has... so there's about 21.4 lbs of preload. I'm running a 3.0 bar MAP sensor so that leaves 8.6 psi to play with.
> 
> ...


Nice!

I have been doing some testing with a few hybrid actuators. Stock looking but with increased internal spring rate (same as the external spring mod without the external contraption). I am even playing with dual porting to help boost increase the overall spring rate (that way a soft spring can be used instead). Some very interesting stuff and I will send you a tester unit when I have everything finalized. :beer:




steve-o 16v GLI said:


> Man I hope you dialed that boost down a bit. 30psi on a ko3 Blew one after only running 25psi for maybe a yr. And why not replace that bolt before you went and bought springs to mod your wastegate.:screwy:


Besides what All_Euro said, there is no real "limit" besides what the turbo can physically compress from the energy a ailable in the turbine. My car is the perfect example, I've been reliably pressurizing way more boost with it than the norm (30+) for years now. All_Euro also runs a more advanced setup than most with pre-turbo water injection etc.


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## Marcus_Aurelius (Mar 1, 2012)

mk2riceeater said:


> Ok so i just installed a 3inch downpipe today which is an amazing difference, but i just noticed that i spike to almost 25lbs with not limp mode probably due to my programming but im also seeing jumpy boost at WOT... Its weird and i have never witnessed that before...do you think my ecu has to adapt to the new exhaust or what? Im not too worried as to ive read people talk about boost surging issues before but this is the first time ive seen it...pleasssse input!:beer:


You would have to tell us more about your boost profile than "Jumpy". What does it do exactly from onset to redline?


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## 20v master (May 7, 2009)

Well I bought the springs. Then I realized how cramped it is behind a 180Q charge piping with the strut bar in the way. :laugh: I miss being able to reach everything like on my BT setup.  Anyways, ordering a boost gauge and pod soon so I can get to tuning the boost curve. On another note, holy horrible timing on a standard chip, stock OEM single SMIC, intake and TIP. I was rather depressed after logging it last night.


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## Marcus_Aurelius (Mar 1, 2012)

20v master said:


> On another note, holy horrible timing on a standard chip, stock OEM single SMIC, intake and TIP. I was rather depressed after logging it last night.


Yeah, I've seen zero advance on final timing BTDC on stock mapping in the summer. The combination of astronomical IATs due to a heat-soak prone SMIC, and hot coolant temp, makes for the depressing final timing (after correction). Water injection in your future I see!


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## 20v master (May 7, 2009)

Marcus_Aurelius said:


> Yeah, I've seen zero advance on final timing BTDC on stock mapping in the summer. The combination of astronomical IATs due to a heat-soak prone SMIC, and hot coolant temp, makes for the depressing final timing (after correction). Water injection in your future I see!


I'm leaning that way. Ambient temp was ~75*F, coolant went from 90* to 95*C and IAT went from 45* to 79*C in a single 4th gear pull. Max advance was 14* BTDC with a torque spike of 9*. So sad.


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## l88m22vette (Mar 2, 2006)

45-79?


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## Marcus_Aurelius (Mar 1, 2012)

^^^ 113-174 IAT on 75 ambient is pretty hot sounding indeed.


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## All_Euro (Jul 20, 2008)

Marcus_Aurelius said:


> Nice!
> 
> I have been doing some testing with a few hybrid actuators. Stock looking but with increased internal spring rate (same as the external spring mod without the external contraption). I am even playing with dual porting to help boost increase the overall spring rate (that way a soft spring can be used instead). Some very interesting stuff and I will send you a tester unit when I have everything finalized. :beer:


That sounds pretty sweet... this should give more precise adjustment... and the dual chamber design should react quicker, no? - OEM appearance doesn't hurt either :thumbup:

I'm game to help with some testing. What I will do then is install your actuator and, while the turbos out, pull my compressor housing off for an inspection of the comp wheel. We'll be able to tell from its colour if the W/M was hitting it or not :beer:


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## steve-o 16v GLI (Jun 26, 2005)

Sent you another pm max. Need some w/m injection advice.


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## Marcus_Aurelius (Mar 1, 2012)

steve-o 16v GLI said:


> Sent you another pm max. Need some w/m injection advice.


Replied!


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## Twopnt016v (Jul 5, 2009)

Will be picking up springs and installing before I leave work tomorrow. I've been sleeping on this mod for too long. :beer: :wave:


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## Marcus_Aurelius (Mar 1, 2012)

Twopnt016v said:


> Will be picking up springs and installing before I leave work tomorrow. I've been sleeping on this mod for too long. :beer: :wave:


Let us know your findings Matt! :beer:


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## Twopnt016v (Jul 5, 2009)

Marcus_Aurelius said:


> Let us know your findings Matt! :beer:


Well I tossed 2 big springs on the hybrid's wg actuator and pulled out of the shop and didn't really get on it hard and immediately started spinning the tires in the first and second gear.
The car feels way better, feels like the "rubberband effect" is gone. Every part of the power band feels stronger, throttle response feels better, the whole nine yards. The springs on the wg coupled with the lightning fast recovery time of the madmax diverter make for a vicious combo.:thumbup:
Once again... Madmax for the win!
Just broke down and ordered a 3" 42dd turbo back race setup. I've been wanting it but was having hard time letting go of the 2.5 milltek. The milltek was quality and quiet but is hindering what I'm trying to do. I am still fighting that misfire issue but it comes and goes. I put a back pressure tester on the 2.5 and was seeing some back pressure and I'm afraid the cat matrix is breaking up. Once the 3" goes on if the misfires continue I will be pulling the AEB head for further inspection. I've never chased something for so long EVER! I may end up putting the the small port back on but will dread it as I am 100% sold on the big port on a KKK frame hybrid with WMI and some gangster timing timing advance. 
Thanks again for all the input, advice and knowledge you kick down to myself and the rest community Max! You are one of the main reasons I still lurk around here. Your the peoples champ:thumbup::beer:


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## toy4two2 (Feb 6, 2012)

*photos*

NAPA has some great pictures of the turbo actuator I found, should help you guys know what you are looking for

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=NECXTT2T512_0378820043


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## RadRacer513 (Nov 1, 2010)

Is a MBC necessary for this mod? I'm chipped, spiking 21psi but it drops fast to around 14psi at redline. I don't want to raise my boost, I just want it to hold longer. Will the stock N75 and all handle it if I just add one or two springs to the WG? Or should I invest in a MBC first?


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## Chickenman35 (Jul 28, 2006)

RadRacer513 said:


> Is a MBC necessary for this mod? I'm chipped, spiking 21psi but it drops fast to around 14psi at redline. I don't want to raise my boost, I just want it to hold longer. Will the stock N75 and all handle it if I just add one or two springs to the WG? Or should I invest in a MBC first?


Nope. Mod works fine with N75.


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## All_Euro (Jul 20, 2008)

I've been using stock n75's with this mod - no issues.

If you run into overboost problems for some reason then you can plumb in a MBC either for just the overboost or for total boost control and get rid of the n75 altogether.


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## Marcus_Aurelius (Mar 1, 2012)

Personally, I think it's a "hit or miss" thing! Some car's N75 controls it without a problem (especially when you're not stepping too far outside boost parameters). Other cars have their N75 doing temper tantrums and not really keeping boost control consistent. My car for example, once the springs were installed, would not control boost as it should with the N75 alone. I had to at least run an MBC in tandem with the N75 to regain total boost control. I don't run the N75 anymore because a standalone MBC is much better for adjustability and consistency, and if you're doing this mod it's not a bad idea to have a MBC ready just in case the N75 is overwhelmed. :beer:


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## All_Euro (Jul 20, 2008)

Last week I ordered a Forge Unos MBC... hopefully I get it this week. The n75 has worked well for me but I'm interested to compare the two.

The way I got around the 22psi boost limit with my setup is to use a 3.0bar MAP... but the standard 2.5bar MAP (that my tune was written for) will yield better fuel & ignition timing trims... so hopefully MBC driveability is as good or better :beer:


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## Marcus_Aurelius (Mar 1, 2012)

All_Euro said:


> Last week I ordered a Forge Unos MBC... hopefully I get it this week. The n75 has worked well for me but I'm interested to compare the two.
> 
> The way I got around the 22psi boost limit with my setup is to use a 3.0bar MAP... but the standard 2.5bar MAP (that my tune was written for) will yield better fuel & ignition timing trims... so hopefully MBC driveability is as good or better :beer:


What 3bar MAP are you running? Is it from another Vag application and plug and play? 

I am not concerned with the effect a 3 bar pressure sensor will have on fueling or timing, I can easily correct that with a little tuning. It would be really nice for me to be able to record boost profile with RPM and everything else that VCDS does. Any info would be greatly appreciated!


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## Atomic Ed (Mar 19, 2009)

All_Euro said:


> The way I got around the 22psi boost limit with my setup is to use a 3.0bar MAP... but the standard 2.5bar MAP (that my tune was written for) will yield better fuel & ignition timing trims... so hopefully MBC driveability is as good or better :beer:



OK, now you've peak my interest! How did you utilize the 3.0 bar MAP to get past the 22 psi boost limit? I tried that on my TT and no luck. BUT, I was runnig REVO software at the time.

Do tell how it's done!


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## l88m22vette (Mar 2, 2006)

Can't be done, not enough programming to read anywhere past the stock MAP limit...there is a thread on id27 but I can't find it right now...


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## Atomic Ed (Mar 19, 2009)

l88m22vette said:


> Can't be done, not enough programming to read anywhere past the stock MAP limit...there is a thread on id27 but I can't find it right now...


That's what I tought. But I know Eurocode Tuning in CA used to talk about how they were able to move past the 22 psi limit on their tunes. I'm still hopefull someone can crack the code to get us there.

I'd like to read that thread if you can find it. I'll look too.


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## Marcus_Aurelius (Mar 1, 2012)

Atomic Ed said:


> That's what I tought. But I know Eurocode Tuning in CA used to talk about how they were able to move past the 22 psi limit on their tunes. I'm still hopefull someone can crack the code to get us there.
> 
> I'd like to read that thread if you can find it. I'll look too.


I would like the read that thread as well! 

I wouldn't say it can't be done since the 8bit map that limits the ECU readings to 2500 mbar can be recoded/rescaled just like any other ECU maps (APR did it with their stage 3 BT files for the TT). It's been said that some of the A4/S4 guys have worked a way around it as well . I haven't confirmed the info and apparently the ones who did it aren't looking to share (I don't blame them). 

A bit of searching reveals that plugging the 3 bar sensor (part # 038906051C) works but the ECU isn't using it past the 2500 mbar limit. I just need All_Euro to confirm that his setup is or isn't reading past 22.5 psi in the ECU. To me, even if the 3 bar can't be effectively used to tune boost and fueling, just the fact that it can be read to its full potential would be a huge step forward (being able to log boost with other ECU parameters is a valuable tool).


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## All_Euro (Jul 20, 2008)

Hey guys - I just got home and will see what other info I can find for you… but let's get right to the point!

Our cars are limited to 22psi because the 5volt MAP sensor that our ECU's are programmed around are 2.5bar… and that's their limit. TDI's run 3.0bar MAP's - I got mine from Mark @ Malone Tuning but I'm sure ECS and many other places will have them on hand too.

The ECU reads the boost on the 0-5volt scale… it doesn't know what MAP sensor you have hooked up to it. It just assumes it's the 2.5bar unit.

Roughly speaking - wastegate springs, a n75J and a 3.0bar MAP sensor gets me to 30psi. If you want to boost more just get a 3.5 bar MAP sensor


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## l88m22vette (Mar 2, 2006)

I was under the impression that you had to recode/scale the ECU settings to make it work, and that yes APR did it a long time ago. Found the thread, with another thrown in (you can see this has been referenced before )

MAP sensor upgrade?

Using 2.5bar map sensor...

PS: I hope everything discussed was wrong and that we can just plug a better one in :thumbup:umpkin: Is that spike or sustained?


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## toy4two2 (Feb 6, 2012)

*just finished this mod*

wow guys! I put on two of the big Home Depot springs, wasn't too hard with the strut tower bar off.

Power definetly held better, peaking at 22 psi on my APR 91 Tune! Falls back to around 17 psi, is that the N75 reducing it, maybe a Manual Boost Controller will fix that..

Not all good though, today, day 2, I had to SLAM on the gas to get across a 4 lane intersection with traffic coming... mash it and BOOOOOM!

Scared the *($)@ out of me! I pulled over and I blew the stock hose and clamp off the intake manifold form the driver side intercooler. I thought I blew the engine it was like a gun shot.

Amazing power, I went and bought some T-Bar Hose Clamps to repalce those junk stockers. I'm also now getting misfires when I hit 22psi according to VAGCOM, I suspect the spark plugs are original 80k or coils, might also be my stock 710N diverter valve even though its 2 weeks old.

Thanks for this mod, it should be in the FAQ :heart:


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## All_Euro (Jul 20, 2008)

l88m22vette said:


> I was under the impression that you had to recode/scale the ECU settings to make it work, and that yes APR did it a long time ago. Found the thread, with another thrown in (you can see this has been referenced before )
> 
> MAP sensor upgrade?
> 
> ...



Haha, ya that first threat kind of seems familiar 

To have everything running properly the tune should be written for all the actual hardware being used...but this is the way I've gotten around the 22psi limit without a MBC or custom tune.

I'm running a stock K03 so the 30psi is just a spike at this point


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## All_Euro (Jul 20, 2008)

Toy4two2, great to hear about the snappy results... & that you made it through the intersection!

This mod is just helping you weed out the weak links in your system


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## Atomic Ed (Mar 19, 2009)

All_Euro said:


> Haha, ya that first threat kind of seems familiar
> 
> To have everything running properly the tune should be written for all the actual hardware being used...but this is the way I've gotten around the 22psi limit without a MBC or custom tune.
> 
> I'm running a stock K03 so the 30 psi is just a spike at this point


So I gather that you're not holding 30 psi? That would be in line with my experience. I still have my 3 bar MAP on the car. It seems it's main function is to throw you into limp mode if you exceed 22 psi, which with my build and Maestro tune, I don't need to worry about spiking above 22 psi.

I think the key is somewhere in the ecu torque value tables (and probably many other tables), but I'm so much an amateur in this area that I'm not going to play with it. I'll leave it to those the have the skills....Well, maybe after I convert to a wideband ecu.


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## Atomic Ed (Mar 19, 2009)

toy4two2 said:


> I'm also now getting misfires when I hit 22psi according to VAGCOM, I suspect the spark plugs are original 80k or coils, might also be my stock 710N diverter valve even though its 2 weeks old.


Replace your coils and plugs. Also, open up and check your ignition and injector harnesses for corrosion. I'm replacing both of mine now. They were toast.


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## jettasmooth (Aug 7, 2002)

I've got a question is regards to this mod on an AEB setup with a K04 (TT225) turbo. I have no problems with stumbling or open throttle, but it seems that there is no intermediate boost control unless I am at WOT. My car through the pedal response goes from 5-7psi all the way until the throttle is completely depressed, and then jumps to 22-25psi final. I would really like to have more of a part throttle response which would allow the boost to be between 10-12psi before hitting WOT. Would this spring mod take care of the partial throttle response? I had liked the throttle feel when I just ran the Greddy Profec-B instead of the N75, but the ECU did not like the partial throttle adjustment that was occurring through the EBC solenoid and so it would misfire and hit fuel cutoff limp mode unless I was at WOT. Can anyone chime in on this? I'm currently back to running the stock N75.


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## 20v master (May 7, 2009)

jettasmooth said:


> I've got a question is regards to this mod on an AEB setup with a K04 (TT225) turbo. I have no problems with stumbling or open throttle, but it seems that there is no intermediate boost control unless I am at WOT. My car through the pedal response goes from 5-7psi all the way until the throttle is completely depressed, and then jumps to 22-25psi final. I would really like to have more of a part throttle response which would allow the boost to be between 10-12psi before hitting WOT. Would this spring mod take care of the partial throttle response? I had liked the throttle feel when I just ran the Greddy Profec-B instead of the N75, but the ECU did not like the partial throttle adjustment that was occurring through the EBC solenoid and so it would misfire and hit fuel cutoff limp mode unless I was at WOT. Can anyone chime in on this? I'm currently back to running the stock N75.


Sounds like your WG arm is possibly sticking? You'd need to log requested vs actual boost to get a better idea of what is causing the problem.


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## jettasmooth (Aug 7, 2002)

20v master said:


> Sounds like your WG arm is possibly sticking? You'd need to log requested vs actual boost to get a better idea of what is causing the problem.


I can't log requested vs. actual. I don't have a MAP sensor. I have an AEB ECU.


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## 20v master (May 7, 2009)

jettasmooth said:


> I can't log requested vs. actual. I don't have a MAP sensor. I have an AEB ECU.


Didn't check your vehicle list. That sucks. The AEB ECU is the worst of all 1.8T ECU's, and yes I know it's the easiest to do the Mk3 swap with.


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## Marcus_Aurelius (Mar 1, 2012)

jettasmooth said:


> I've got a question is regards to this mod on an AEB setup with a K04 (TT225) turbo. I have no problems with stumbling or open throttle, but it seems that there is no intermediate boost control unless I am at WOT. My car through the pedal response goes from 5-7psi all the way until the throttle is completely depressed, and then jumps to 22-25psi final. I would really like to have more of a part throttle response which would allow the boost to be between 10-12psi before hitting WOT. Would this spring mod take care of the partial throttle response? I had liked the throttle feel when I just ran the Greddy Profec-B instead of the N75, but the ECU did not like the partial throttle adjustment that was occurring through the EBC solenoid and so it would misfire and hit fuel cutoff limp mode unless I was at WOT. Can anyone chime in on this? I'm currently back to running the stock N75.


This almost sounds like your boost regulation valve (N75) duty cycle has one of these weird profiles that are common with 1.8t tuners (GIAC old files had some ballz but are watered down nowadays). The "rod safe" philososophy that is really a "cover my ass" tactic, usually have a flat curve all the way passed peak TQ and then Jumps in a non-linear fashion to 90-95% to get the turbine wheel going. The lack of transition and smoothing in the wastegate control is probably what gives you this screwed up boost profile where there is nothing (supposedly to save rods) and then bam full duty cycle. 

Other means of wastegate/boost control would cure this (that is what you experienced with your EBC), but may also interfere with the ECU preset control limits if they are not raised in the files. You can talk to your tuner about raising them limits if you want to get rid of the limitation that is the N75 (that would allow an EBC or MBC to take over the wastegate duties without limp mode). Another way to approach this is with a diode that clamps the pressure signal to a preset voltage and the ECU never reads an exceeded pressure limit to call for protection (limp mode). 

The spring mod will help but not do much especially in the region where the N75 is sending full pressure signal to the actuator to "protect rods". I would still investigate the possible mechanical issues pointed out by Adam (boost leaks also come to mind)... but if everything is in good mechanical order, the N75 profile is what's raining on your party.


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## warranty225cpe (Dec 3, 2008)

20v master said:


> Sounds like your WG arm is possibly sticking?


That was my first thought. Sounds like the wastgate isn't closed all the way when building boost (I'm dealing with a similar issue. Slow to build boost because the position of the door/flap isn't allowing you to build boost, until the output of the turbo compensates for the leak. (At least that's what IM finding)


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## All_Euro (Jul 20, 2008)

Does anyone know for *sure* which of these is the latest Forge Unos MBC?

Pic from Fogrge's website…









Pic of MBC sent to me…









Thanks :thumbup:


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## jettasmooth (Aug 7, 2002)

I appreciate the replies. I don't think that the wastegate is sticking, especially since the problem goes away with the use of the EBC, except the fueling is now incorrect at partial throttle and causes limp mode. Also, diode mod won't work since I don't have a MAP sensor to clamp. The AEB's only have control through throttle position, MAF, 02 sensors, and IAT.

I agree with the above post in regards to the N75. It does appear that the N75 is protecting any boost over 7-8psi unless I am WOT. At WOT, the car is insanely quick to spool, and can be controlled if I start low in the RPM range (under 2000 rpm). It does seem that maybe the tuner has built in a control to protect the low RPM boost increase, but I feel that it actually makes the car less driveable and may actually make it easier to bend rods by not allowing a smooth throttle response by not feathering the boost pressure across the throttle position. I have already engaged conversation with the tuner, so it sounds like they are very open to helping out. I'll respond back here with more information once I talk with them further. My thought is similar to what was stated above. I would like to see if they can increase fueling across the partial throttle range to make sure it will not hit limp mode while running moderate boost (12-15psi) at partial throttle.

Thanks for the feedback. Any other suggestions are welcome.


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## warranty225cpe (Dec 3, 2008)

All_Euro said:


> Does anyone know for *sure* which of these is the latest Forge Unos MBC?
> 
> Pic from Fogrge's website…
> 
> ...


Yours is the new one. I've got the same one and was curious enough to call Forge and ask. The guy said he's worked there for 5 years, and has never seen the flat top version.


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## All_Euro (Jul 20, 2008)

warranty225cpe said:


> Yours is the new one. I've got the same one and was curious enough to call Forge and ask. The guy said he's worked there for 5 years, and has never seen the flat top version.


Haha - thanks :thumbup: I wrote Forge this morning and they're responded already...

"_The top picture is the old unit and the lower on in the box is the newer one.


regards,

Angel Robles
www.forgemotorsport.com
[email protected]
ph: 407-447-5363
fax: 407-447-5361_"


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## VWstung (Dec 19, 2010)

Glad I came in here!!!!
Im always complaining about all the different boost noises my car makes!!!

225 has the Uni stage 1+ tune 21 psi and 2 weeks later clutch started slipping in 6th and 5th...

Clutch would slip and the car would sense the load change and open the waste gate.

Thanks to this thread I now know the higher psi is also keeping the valve open :facepalm:
I'm so sick of hearing the undetectable boost leak

In a nut shell in some gears my car seems faster at 80% throttle and at 100% I hear the gate opening and it feels just a lil slower....

Will go grab 1 or 2 springs and try it out :thumbup:


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## VWstung (Dec 19, 2010)

Just some extra info here.
This is what it takes to comfortably reach the wastegate,
Remove Strut Bar
Remove Charge Pipe









Here is what I have on my car:
Full Emissions delete
Unitronic Stage 1+ Tune (22 psi)
Forge 007 DV with Yellow spring
Stock N75

Now I have some questions,
Just like Max said I used 2 of the large springs from Home Depot.









Although I don't have a boost gauge, I'm fairly certain the 2 springs did nothing 
Car feels exactly the same but more importantly I still hear my Wastegate loud and clear opening and letting air out 

Should I add 1 more big spring?


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## Marcus_Aurelius (Mar 1, 2012)

It has been reported that the two smaller springs in the kit will work better for our actuator. They are shorter in length than the big ones and have more tension at rest (better preload). So the smaller ones will add more rate increase throughout the travel. (I thought it was mention somewhere in the thread but will edit the first post to reflect the findings).

On another note, have you tested for leaks and made sure that you actual wastegate is seating properly and not sticking open (not unusual)?


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## VWstung (Dec 19, 2010)

Yes I will swap the 2 larger for the 2 smaller springs tomorrow. I did notice there wasn't much tensions with the larger ones.

Do you mean boost leaks or exhaust wastegate leaks?

As far as boost is concerned everything is up to par, I have a Vag-com graph of everything;
Rpm's < Pedal position < Misfires < Compressed Mbar < Intake temps 

Although this hose is starting the creep down on me.










I really have no way of testing the wastegate seal, Just gonna try the different springs in hopes the higher tension will keep it closed


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## VWstung (Dec 19, 2010)

Well I ended up putting on all 4 springs both big and small.

Noticed a small difference but can still hear the wastegate open at times.

I would like to hook a boost gauge up and see whats happening


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## 20v master (May 7, 2009)

VWstung said:


> I would like to hook a boost gauge up and see whats happening


That's what you should have done to begin with.


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## All_Euro (Jul 20, 2008)

A boost gauge is crucial really… it took me a while to install one too though 

Your stock WG holding capacity may be pathetic ( as in 4-5psi ) to begin with so if that's the case you'll naturally need more spring pressure. What's the combined pressure of the springs you've attached compared to target boost? Load up to within 5-10 psi of max boost.

Also, if the two springs are too long - wrap them around the back of the WG so they're under better tension :thumbup:


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## VWstung (Dec 19, 2010)

Well the combined tension of the 4 added springs should be........
.....Correct me if I'm wrong but,
2 big springs 7+7=14
2 small springs 5+5=10 
So added 24lbs for a 22psi tune

But I will say the springs don't seem to be fully extended so maybe the springs are only using half of the lbs they are rated for??? 

Need a boost gauge to see what I'm spiking, holding, and losing at higher rpm's
Then go from there?

Instead of adding more springs, is there another point to hook the springs to other then the vacuum nipple??
Thanks everybody :wave:


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## Marcus_Aurelius (Mar 1, 2012)

Boost gauge, boost gauge, boost gauge! Unhook all the springs, get the gauge and get a baseline and then start adding springs. If you are adding rate and nothing happens you either have:

- a huge leak (vacuum, or pressure side)
- faulty or sticking wastegate/actuator
- a major restriction downstream of the turbo (clogged cat converter)
- failing/failed turbo


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## Kacz07 (Mar 4, 2012)

Sorry for the noob question, but does the MadMax DV mitigate this issue in any capacity (early cracking of WG)?


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## 20v master (May 7, 2009)

Kacz07 said:


> Sorry for the noob question, but does the MadMax DV mitigate this issue in any capacity (early cracking of WG)?


No, totally separate.


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## Arnolds64 (Nov 13, 2009)

*Boost Gauge in and numbers.*

Peaked at about 23 and settled in at 20 up to almost the red line. One spring only. Got some room with an APR 91 Flash tune you think? Small Spring added to get 25 psi?


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## 20v master (May 7, 2009)

Arnolds64 said:


> Peaked at about 23 and settled in at 20 up to almost the red line. One spring only. Got some room with an APR 91 Flash tune you think? Small Spring added to get 25 psi?


Logged IAT, timing advance, and timing correction? You are using 91 octane or that's what your software is?


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## Marcus_Aurelius (Mar 1, 2012)

Like Adam said, logging IAT, timing, and corrections will tell you what the car can safely take in terms of boost increase. Two more things that would help tremendously is to have an idea of your AFR curve and IDC.


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## 20v master (May 7, 2009)

Marcus_Aurelius said:


> Like Adam said, logging IAT, timing, and corrections will tell you what the car can safely take in terms of boost increase. Two more things that would help tremendously is to have an idea of your AFR curve and IDC.


I'm awaiting a boost gauge so I can do this also, but after looking at my IAT's and timing advance, there won't be much to gain as timing pull will only go up with more boost. Max won't give full blessing, but I'm still leaning towards an FMIC and low temp thermostat before touching the boost.


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## Marcus_Aurelius (Mar 1, 2012)

20v master said:


> I'm awaiting a boost gauge so I can do this also, but after looking at my IAT's and timing advance, there won't be much to gain as timing pull will only go up with more boost.


My take:
Say you add the springs and cap boost ceiling (MBC, EBC or ECU controlled) where they are right now, 
you may be surprised to see that the temps and timing pull remain intact. To meet boost request on flashed car with an actuator that is bleeding/bypassing exhaust pressure, the turbo is forced to spin faster than it needs to (moving operating conditions away from the central efficiency islands of the compressor map). This unwanted pressure bypass can reduce hotside efficiency over 50% if you push things like I do. Since turbine and compressor wheels are attached and constantly at a 1:1 ratio, that's a lot of RPM added on the compressor side to generate the same pressure. The result (because of the higher rpm operation) is a lot higher turbo outlet air temperature.

When you install the springs, if done right, you can reduce the hotside bypass to a very low percentage. This should effectively put a lot less stress on the compressor side of things and bring you back towards ideal efficient islands. (Just be sure to cap boost ceiling where it needs to be for the fueling supplied). :beer:



20v master said:


> Max won't give full blessing, but I'm still leaning towards an FMIC and low temp thermostat before touching the boost.


We're starting to know and understand each other very well! 

Thermostat=yay
FMIC=Nay

I might have brushed on this for others but for you a more in-depth explanation of my position is in order. Firstly, the TT bumper was never designed with a FMIC in mind. Most FMIC I've seen, have a great percentage of their core blocked by the bumper (removing the crash bar does nothing but help fitment since the bumper skin has a rather wide center beam that goes across its width). Unless you come up with a strategy to bring sealed fresh airflow across the entire core, a FMIC will remain a big ugly chunk of inefficiency in my eyes.

The second problem is probably even more difficult to digest, if like me, you look at intercooling as a sub-system that also needs to play nice with other components. Yes, reducing IAT is nice, but if that means making the coolant sub-system even more inefficient than it already is, something is wrong with the overall approach. Also worth mentioning is the coolant also has the burden of cooling the oil. So by cutting the coolant efficiency in the name of cooler air charge, you'll unfortunately increase oil temp as a byproduct. 

IMO, there are many other efficient ways to improve IAT that doesn't involve hurting other things. Upgraded SMICs, chemical cooling, AWIC, are all viable options. But if you have to have a FMIC, some serious shrouding and bumper hacking, as well as radiator and oil cooler upgrades will need to be part of the plan. Otherwise it will not get my seal of approval when compared to the alternative options.


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## 20v master (May 7, 2009)

I have a brand new 13 row Mocal unit ready and able.  This would just be on my 180Q DD, so no road racing or auto-x. More than anything, I just want to install the small port SEM manifold, which would mean swapping throttle side, which means FMIC in my line of thinking. :laugh: Yes, I'm aware of the front bumper and airflow limitations, hence the thermostat and potentially the 3 row radiator. Since this is the lowly 180Q, a big/thick FMIC core isn't needed. I just like the simplicity of air to air, don't want chemical cooling on my daily driver, sidemount upgrade won't work with the throttle flip, etc etc. Now the AWIC would fit with the plan, but you'd have to devote some time to helping me source the parts for a solution.  Either way, the 180hp AWP is where I got my 1.8T roots, and I got the stock turbo to a low 13 second 1/4 mile in FWD trim, well before a lot of the options on the market became available. My current setup is much too slow for my tastes, so I'm trying to keep it as simple as possible and uncork some of the potential. First comes the boost gauge, then I'll tinker with the springs on the WG, then see where the IAT/timing pull ends up before I decide anything. :beer:


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## Marcus_Aurelius (Mar 1, 2012)

20v master said:


> I have a brand new 13 row Mocal unit ready and able.  This would just be on my 180Q DD, so no road racing or auto-x. More than anything, I just want to install the small port SEM manifold, which would mean swapping throttle side, which means FMIC in my line of thinking. :laugh: Yes, I'm aware of the front bumper and airflow limitations, hence the thermostat and potentially the 3 row radiator. Since this is the lowly 180Q, a big/thick FMIC core isn't needed. I just like the simplicity of air to air, don't want chemical cooling on my daily driver, sidemount upgrade won't work with the throttle flip, etc etc. Now the AWIC would fit with the plan, but you'd have to devote some time to helping me source the parts for a solution.  Either way, the 180hp AWP is where I got my 1.8T roots, and I got the stock turbo to a low 13 second 1/4 mile in FWD trim, well before a lot of the options on the market became available. My current setup is much too slow for my tastes, so I'm trying to keep it as simple as possible and uncork some of the potential. First comes the boost gauge, then I'll tinker with the springs on the WG, then see where the IAT/timing pull ends up before I decide anything. :beer:


Good to see you have a plan for elevated coolant and oil temperatures. My question is: why does swapping throttle body side excludes the use of SMICs in your line of thinking? Why not upgrade to a dual SMIC setup and enjoy a decent percentage of charge cooling without taxing the oil and coolant?
You should have the cross tube installed in your car, and I have my SMIC/hoses/brackets on the used stock pile. So, you're basically 90% ready for the SEM/TB swap. Later on, you could just upgrade the passenger SMIC with a larger more efficient Tyrol unit, since that's the one that takes a beating and usually loose all its efficiency from the heat soak.

If you chose to go AWIC, cloning my setup is a cake... the leg work is already done! To be honest, I don't see why you have chemical cooling off the table when AWIC is still an option. A water injection setup can be super DD friendly if built with that in mind. All you need is a decent size trunk mounted tank (3-4 gal), tune to run on straight H20 like I do, and appropriately sized nozzles (I have custom nozzles made for that purpose, so you're golden). Water is cheap, a 4 gallon tank would give you a nasty range before needing to refill (maybe every 3-5 tanks of gas).

You have a lot of good options, and IMO due to the front end design on the TT, FMIC is the least appealing one! :beer:


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## 20v master (May 7, 2009)

Marcus_Aurelius said:


> My question is: why does swapping throttle body side excludes the use of SMICs in your line of thinking? Why not upgrade to a dual SMIC setup and enjoy a decent percentage of charge cooling without taxing the oil and coolant?


Because of the layout of the stock charge piping, the passenger SMIC on the single IC 180 setup has the inlet on the bottom and outlet on the top to feed the passenger side throttle. I'd either need custom piping out of that SMIC outlet to reach the second driver's side SMIC to complete the throttle side swap, or I'd need custom piping from turbo outlet to the inlet of the 225 style passenger side SMIC with the inlet on the top. The second option would allow use of all the OEM piping from the first core to the throttle. However, it would be much easier to have the 180 style OEM piping remain in place to the pancake pipe, then have a custom pipe into a FMIC core and finish the rest to the driver's side throttle. We know the dual SMIC's aren't the most efficient, nor is the piping layout (bends, reductions, etc.). Again, we are talking about my daily driver, so it's not going to get beat on often or for long. The thermostat and oil cooler would satisfy my concerns there. 

As for water injection, a 3-4 gallon tank is going to eat up a lot of the already small hatch space. I do take this car out of town for weekend trips with my lady which requires luggage room. Also, what do you do about sub freezing temps when running straight water? My garage is detached from the house and isn't heated.  Water injection would be the best and easiest way to achieve cooler IAT's and more timing advance, but doesn't solve the problem of routing charge piping to use the SEM and driver's side throttle, so the manifold and chemical cooling are seperate upgrades in the grand scheme.....

All that leads me to believe I should just copy your AWIC setup, get the lower IAT's along with shorter charge piping route for less pressure drop, and the added flow of the manifold upgrade without affecting oil/coolant temps. What fluid are you using in your AWIC setup (same concerns of freezing temps)? Would you mind putting together a parts list with approximate prices and posting it in your AWIC thread or emailing it to me? :beer: So many options......all in the name of turning up the boost! 

...then again, I could just install the K04-02x setup from my 225 donor car, which would make the dual IC upgrade much easier. Decisions decisions.


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## crzygreek (Jul 8, 2005)

Home Depot doesn't carry these in Canada :banghead::banghead:
When I'm back in the US i'll drop in and get a couple of sets... Ah the joys of not living in the States :screwy:


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## 20v master (May 7, 2009)

Well I added one small spring yesterday while changing out my valve cover. The midrange is definitely stronger after the boost spike, but my timing curve got worse (less advance). So upgrades are needed as thought to the charge cooling system.


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## Marcus_Aurelius (Mar 1, 2012)

20v master said:


> Well I added one small spring yesterday while changing out my valve cover. The midrange is definitely stronger after the boost spike, but my timing curve got worse (less advance). So upgrades are needed as thought to the charge cooling system.


Ok, I am going to transfer our last few post about charge cooling in my dedicated cooling thread so we can get into the specifics of the options available to you and keep it on more topic. :beer:


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## VWstung (Dec 19, 2010)

Got another dumb question,
Does adding tension to help keep the was wastegate closed effect the normal operation of the n75 trying to open the gate at boost? Or is that why you don't add more tension then your tune was made for???

Also I have a full emissions delete, would it be beneficial, or more predictable to delete the n75 and put in a ball and spring "forge unos" mbc so everything (DV & Wastegate) are 100 analog and are easier to adjust spikes and whatnot?


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## Marcus_Aurelius (Mar 1, 2012)

This was posted in a different thread showing logged differences before and after the spring mod. I thought it belonged in here for future references. (Thanks for sharing Tony!)



Boulderhead said:


> After reading a good bit on here I ran across a great thread started by a fellow named Max. Seems that the wastegate on our stock setups can greatly benefit from a couple hardware spring provide to keep up with software tune. The extra pressure blows the wastegate open and forces the turbo to work even harder to maintain requested boost when under hard acceleration.
> 
> http://forums.vwvortex.com/showthread.php?5700226-Wastegate-Actuator-Spring-Mod
> 
> ...


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## Gonzzz (Apr 27, 2010)

Pictures are down


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## Marcus_Aurelius (Mar 1, 2012)

Gonzzz said:


> Pictures are down


I'm over my limit for hosted pictures in photobucket. I'm trying to delete as many old posts in from years ago on various forums, so newer ones can reappear. If not I'll re-post new ones from a different host (I should be a bit under my quota for imageshack ).


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## crzygreek (Jul 8, 2005)

Found what I think to be the equivalent spring that is sold by Lowes (now in Canada!). Will update with pictures and data this weekend after the install :thumbup:


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## 20v master (May 7, 2009)

Well I got my boost gauge installed, and running off the N75 and software, I spike to 20-21, hold 19, then taper off. I'll get a proper boost request and actual log tonight hopefully, but at ~5500 my boost is dropping to 9 psi. I've seen the throttle close some on my Torque logs, but want to log with VAG COM for a better idea of what's going on, and hopefully how to stop it since it's like hitting a wall of no acceleration when the boost drops/cuts out. :thumbdown:


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## Marcus_Aurelius (Mar 1, 2012)

20v master said:


> Well I got my boost gauge installed, and running off the N75 and software, I spike to 20-21, hold 19, then taper off. I'll get a proper boost request and actual log tonight hopefully, but at ~5500 my boost is dropping to 9 psi. I've seen the throttle close some on my Torque logs, but want to log with VAG COM for a better idea of what's going on, and hopefully how to stop it since it's like hitting a wall of no acceleration when the boost drops/cuts out. :thumbdown:


Get more logs to confirm what's going on! But if the flap is still being blown open even with one spring, time to add a second one (just cap the added spike with a boost controller). A small frame turbo will naturally taper in the upper revs due to design inefficiencies (lack of flow, especially on the turbine side) but spiking 21 to hold 9 is not normal. My guess is that you are still overwhelming the actuator and bleeding/bypassing precious exhaust pulses when you need it the most. I would also look into the health of your DV, these suckers are notorious for venting pressure as well!


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## 20v master (May 7, 2009)

Marcus_Aurelius said:


> Get more logs to confirm what's going on! But if the flap is still being blown open even with one spring, time to add a second one (just cap the added spike with a boost controller). A small frame turbo will naturally taper in the upper revs due to design inefficiencies (lack of flow, especially on the turbine side) but spiking 21 to hold 9 is not normal. My guess is that you are still overwhelming the actuator and bleeding/bypassing precious exhaust pulses when you need it the most. I would also look into the health of your DV, these suckers are notorious for venting pressure as well!


It's not the DV nor is it blowing open the WG flapper. The reason I know this is because it doesn't do it in lower gears or even during bursts in upper gears that cross 5500 rpms, only on long single gear pulls like you'd do for a data log, and when it happens it's obvious and instant. If it was blowing open the WG, it would do it every time at that rpml. It doesn't taper to 9 psi after the torque spike, it tapers and holds 17 psi from 4500 rpms to 5500 rpms in the log I did yesterday where it either vents boost or closes the throttle. I'll know more after a quick 115/118/003 log. :thumbup:

Sent you an email BTW.


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## Currancchs (Feb 24, 2011)

Thanks for the tip Max! Used one of the small Home Depot springs in the two-pack with large and small springs (~5 lbs.) on my '01 AMU 225 TT w/APR Stage 2. Went from peaking @~18.5 psi and holding 14 to redline in ~32 degree weather to peaking @ 20.5 and holding ~18 psi in the same conditions. Car feels a lot less peaky as well. Vag-Com shows an estimated torque increase of ~15 ft-lbs. Small rise in timing pull, but could have been a coincidence (went from 0-3 degrees pulled to 3-6 degrees pulled on two cylinders, the others were still 0-3, but I had gotten on it a few times before checking, was checking AFR (through wideband) and boost through Vag-Com before doing a full run to check timing pull).


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## 20v master (May 7, 2009)

Well with one spring added to my K03S 180Q, it feels faster (I didn't have a boost gauge before I installed the spring), but it limps out at 5500-5700ish rpms dropping boost down to 9 psi until you lift off the gas. MAF readings aren't excessive (peaking at low 180's), the boost matches requested boost pretty closely, and there is timing pull but nothing excessive (less than 6*). However, the single SMIC isn't cutting it as IAT's shoot up ~40*C in a single 4th gear pull and keep climbing while at WOT. I was hoping I'd be able to add a second spring without any other changes, but I'll probably take the spring off this weekend to log and see how it behaves with no modifications to the boost control/WG.


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## RadRacer513 (Nov 1, 2010)

Any chance you're hitting limp mode?

Sent from my x10 using Tapatalk 2


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## SigfridR (May 2, 2012)

*spring mod, boost spike*

I did the spring mod last weekend but used a spring I found in my garage. It felt like 5 to 10 lbs at best. Most likely not too smart on my part though. I checked by manually opening the waste gate without the spring and then with the spring. I was getting about 21 psi boost spike before, tapering to 15 with an APR stage 1 tune, turbo back & K&N panel filter. After the spring, I am getting 25 psi spike and tapering to 17 or maybe 18. Spool is improved, drivability is also improved but I assume 25 psi is not good for an APR stage 1 and I need a manual boost controller. 
Any recommendations on which manual boost controller is the best to manage spikes and gentle on the wallet?
What target spike should I shoot for with an APR stage 1?

I think I need to tinker with this a bit more to get the right results. I also ordered a TIP just in case my stock hose is collapsing and causing some upper RPM boost loss.
I am highly optimistic. Thanks for this Marcus. The forum is great because of people willing to share.

Sigfrid


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## 20v master (May 7, 2009)

RadRacer513 said:


> Any chance you're hitting limp mode?
> 
> Sent from my x10 using Tapatalk 2


That's exactly what's happening.  With the added spring on the WG, limp mode has become 8-9 psi instead of 5 psi.


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## peter139 (May 4, 2005)

I tested my stock actuator, manual with a compressor. Mine already opens at 0,55bar. 
Does that mean that my acuator is worn? (180fwd)
With the spring it opens much later, it's a good update.


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## Gonzzz (Apr 27, 2010)

peter139 said:


> I tested my stock actuator, manual with a compressor. Mine already opens at 0,55bar.


I believe that is the crack pressure on the stock actuator based on what I have seen on the stock files and my experience (both confirm this).


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## Marcus_Aurelius (Mar 1, 2012)

RadRacer513 said:


> Any chance you're hitting limp mode?
> 
> Sent from my x10 using Tapatalk 2


Very good catch! The same thing happened with someone else's car, we chased our tails looking for a leak (even did an MBC swap) until the light bulb went on. He was on limp mode at 15 psi with a couple of springs installed.

*Anyone with this mod, if you go into limp, your wastegate pressure will be the sum of all the springs (internal + external(s). * With all the different mappings/software available (from stock to the various stages and their different boost limits) it is safe to say that a N249 bypass/delete is also a good idea with this mod. So, a MBC to cap boost ceiling, and a N249 bypass to avoid limp, and a boost gauge should be the supporting mods for the spring upgrade. (This is even more important to K03 users as their ECU preset boost limits tend to be more conservative than similarly staged K04 mapping).


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## Marcus_Aurelius (Mar 1, 2012)

SigfridR said:


> I did the spring mod last weekend but used a spring I found in my garage. It felt like 5 to 10 lbs at best. Most likely not too smart on my part though. I checked by manually opening the waste gate without the spring and then with the spring. I was getting about 21 psi boost spike before, tapering to 15 with an APR stage 1 tune, turbo back & K&N panel filter. After the spring, I am getting 25 psi spike and tapering to 17 or maybe 18. Spool is improved, drivability is also improved but I assume 25 psi is not good for an APR stage 1 and I need a manual boost controller.
> Any recommendations on which manual boost controller is the best to manage spikes and gentle on the wallet?
> What target spike should I shoot for with an APR stage 1?
> 
> ...


Personally, I don't see 25 psi spike being too much on a 225 TT, but I'm sure others will see that as extreme. Those who have been part of the community long enough will tell you that the old GIAC files used to run 25 psi, and they used to run laps around their competition at the time. The tuners have since started to play it safe to cover themselves and even GIAC went numb with their newer files. Log timing corrections, IDC, and IAT and you'll get a pretty good idea of what's going on.

As far as MBC, they are not created equal, so you'll get what you pay for! Regardless, stay away from bleed type MBC and look for something with several springs available for the unit (no one size fit all crap). Also get the largest barrel possible, my personal recommendation is the Forge UNO MBC, Grimspeed also make something similar.


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## Marcus_Aurelius (Mar 1, 2012)

20v master said:


> That's exactly what's happening.  With the added spring on the WG, limp mode has become 8-9 psi instead of 5 psi.


Adam, I looked at your logs and nothing really jumped out except that IAT needs some help. Even your corrections were within the acceptable range. You should look into bypassing the N249 or a clamping the pressure sensor (diode mod) and report. :beer:


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## 20v master (May 7, 2009)

Marcus_Aurelius said:


> Adam, I looked at your logs and nothing really jumped out except that IAT needs some help. Even your corrections were within the acceptable range. You should look into bypassing the N249 or a clamping the pressure sensor (diode mod) and report. :beer:


Haven't fooled with diodes in years (BT since 06 :laugh so I'd have to order them, but the direct boost/vac source to the WG is planned for this weekend to take the N75 out of the mix. 

Edit: N249 controls secondary air injection/kombi valve, did you mean N75?


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## Marcus_Aurelius (Mar 1, 2012)

20v master said:


> Haven't fooled with diodes in years (BT since 06 :laugh so I'd have to order them, but the direct boost/vac source to the WG is planned for this weekend to take the N75 out of the mix.
> 
> Edit: N249 controls secondary air injection/kombi valve, did you mean N75?


N249- Diverter Valve Control Solenoid

Basically gives the ECU a way to control boost by opening and bleeding pressure via the the 710N (or aftermarket conventional DVs). That is the ECU secondary mean of boost control after the wastegate solenoid (N75). The N249 is often used whenever the ECU senses an overboost or pressure deviation situation that is outside the preset limit written on the file. The N249 does so by storing vacuum in that weird plastic tank and using that vaccum to open the DV whenever the ECU calls for it. (I used to trick mine by removing the plastic tank and there would be no vacuum available to open the DV when the ECU wanted to spoil the fun). 

Bypassing the N249 or completely taking it out of the loop is one solution (also get better, crisper, unmolested signal to your DV). Clamping the pressure sensor is another option, the ECU will never find out that you were boosting more than it is expecting (I'm not a fan of this because the pressure signal is also referenced in fueling, load calc, TQ calc, and is a back up for a failing MAF). :beer:


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## 20v master (May 7, 2009)

Stupid VW solenoid names. But yes, I just delete the vac reservoir on the valve cover. :thumbup:


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## Boulderhead (Oct 21, 2012)

*Boost / Vacuum vs DV / WG*

Hi guys, hope you don't mind if I ask this here. I have applied the WG spring mod and have been quite pleased. I also played around with different DV spring tensions, spacers, and the direction of the DV (forge piston driven). 

The reason we throw the springs on the WG is to keep it from blowing open on us when even a slightly modded car asks for more... Is the same true for our diverter valves? 

I know that excess pressure left in the system from the spinning turbo and sudden increase in vacuum from a quickly closed throttle plate combine forces to dump excess pressure. However if we create more Boost pressure than the DV spring can handle will it just blow open like the waste gate? 

I believe the reason for flipping the direction of DV is to provide a safety net incase of a vacuum leak is present which could cause the DV to not crack fast/long enough.. creating excess back pressure on the turbo? With the DV flipped does it make sense I should also run a stiffer spring (Blue rated for 23-30 PSI) in the DV to keep the turbo from blowing it open under full load in high gears.. or am I just over thinking? 

Thanks folks eace:


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## Arnolds64 (Nov 13, 2009)

*Boost Gauge on and Springs.*

Well Boys and Girls I finally got my Boost Gauge on and at the time I had one spring on it. Would spike at about 22lbs and then upper R's it would hold at about 17. Added another large Spring and now it spikes to about 25 and holds at about 20. I think I am good. Runs really strong. 

So Marcus is this pretty conservative and will be no long term issues? Of course as long as I drive it sanely that is? I do a have an APR 91 tune.


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## Marcus_Aurelius (Mar 1, 2012)

Boulderhead said:


> Hi guys, hope you don't mind if I ask this here. I have applied the WG spring mod and have been quite pleased. I also played around with different DV spring tensions, spacers, and the direction of the DV (forge piston driven).
> 
> The reason we throw the springs on the WG is to keep it from blowing open on us when even a slightly modded car asks for more... Is the same true for our diverter valves?
> 
> ...


 I think you're kind of blending two unrelated things here. The actuator (a valve similar to a DV but works on positive pressure) an the DV (works mainly on negative pressure) are similar in operation but one is on the hotside/turbine side and the other works on the charge/compressor side. 

With the wastegate actuator mod, we are stopping *exhaust* pulses from opening the gate and bleeding precious energy that could be used to create boost by the compressor wheel. The reason for this is the internal spring in the stock actuator was not designed to handle the hotside pressure that we generate with higher boost demand with a chip. However, all this action remains on the hotside or exhaust side. 

With the DV, which is to be technically correct a compressor bypass valve, we aim at diverting/bypassing excess pressure in the charge pipe when the throttle plate is shut or close to being shut. However, when boosting which require zero bypass, the valve can become overwhelmed depending on the boost and bleed pressure. That is the reason we upgrade to higher sprung units and valves that have better internal sealing. The "reversing to pull orientation" (no pressure acting against the diaphragm plate/piston) is an attempt to mitigate weak springs that would normally be blown open by the positive pressure in the system when normally boosting (zero bypass required). There is also some positive pressure from the vacuum nipple that help equalize pressure above and under the diaphragm/piston, helping at keeping a seal. However, the pressure trying to force the valve open is much higher than the little counteracting action happening from the vacuum nipple. So, to prevent the DV to open under boost, when bypass isn't required, we need to go higher in spring rate or reverse the valve (running an oversized diaphragm/piston diameter also help because a lighter spring can be used to hold a constant pressure). 

In your case, you need to test to find the ideal spring that will hold the valve shut under boost. This may not be a specific spring but a combination of a spring and some shims. When I messed with a Forge diaphragm valve (I believe warranty uses it in his car now) a yellow spring with a two militer custom spring worked best; the spring alone was too soft and the next spring up was too stiff. Maybe you can try that on yours. :beer:


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## Chickenman35 (Jul 28, 2006)

> When I messed with a Forge diaphragm valve (I believe warranty uses it in his car now) a yellow spring with a two militer custom spring worked best; the spring alone was too soft and the next spring up was too stiff.


 Was that supposed to be a Forge Piston DV? I didn't know that Forge made diaphragm valves?? 

Two militer custom spring?? WTF is a milter? :laugh: 

Is that supposed to read " Two millimeter custom *shim*?  

Late night? :beer:


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## Marcus_Aurelius (Mar 1, 2012)

Chickenman35 said:


> Was that supposed to be a Forge Piston DV? I didn't know that Forge made diaphragm valves??
> 
> Two militer custom spring?? WTF is a milter? :laugh:
> 
> ...


 Yes, Forge did make diaphragm based valves with their conventional shell (it's probably the best valve they ever made, and probably don't make anything diaphragm based anymore). 

I was trying to write millimeter (mm) sorry! Another typo from not having time to read my own post before sending, and not knowing/caring how to set spell check on this forum.


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## Boulderhead (Oct 21, 2012)

*Muchas Gracias*

Hi Max, thanks for the detailed reply, that makes great sense. :thumbup: 

I did run some tests last weekend logging block 115 (graphs in my thread), although they weren't as controlled or complete as one would like.. (lost a screw and got dark) Supposed to be in the mid 40's and sunny here this weekend so perhaps I will start fresh and test a variety of spring / shim loads. 

Any other blocks helpful in this case? Have a great weekend all :beer:


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## Cryser (Sep 9, 2009)

Also remember the DV has that top port that allows pressure to work against the pressure, much like an external wastegate has the top port for electronic boost control. If you have ever handled an external wastegate you'll notice the spring rates for what is 23-30 PSI is MUCH heavier then the blue spring provide by forge for the same PSI range. The springs in DV aren't really do THAT much to keep the valve closed as the pressure from that top port is. The springs are more for the return action of closing the valve after a shift, the do offer SOME tension against the pressure in the tube. But a DV relies much less on the spring tension to hold itself shut and more on the top port, where as a wastegate relies much more on the spring tension to hold itself shut. In the case of an internal wastegate where there is only 1 port, the spring tension is in fact all you have, hence the need for this mod. Applying this type of mod to a DV could actually stop it from working properly and cause more damage then good. 

Swapping the orientation of a DV isn't recommended and produces that horrible tweety bird getting punched sound anyway, I did it was literally 1 shift pulled RIGHT over and switched it back :laugh:


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## Boulderhead (Oct 21, 2012)

Cryser said:


> Applying this type of mod to a DV could actually stop it from working properly and cause more damage then good.
> 
> Swapping the orientation of a DV isn't recommended and produces that horrible tweety bird getting punched sound anyway, I did it was literally 1 shift pulled RIGHT over and switched it back :laugh:


 Hey man, correct me if I am wrong, but isn't the tweedy bird noise just the piston of the DV slamming open and shut rapidly (spring force fighting against excess boost) as there isn't any or enough vacuum to hold the piston open at that point when the boost is trying to escape. Shouldn't this be possible in either orientation with a piston driven valve just because of the physics? 

In regards to spring tension of the DV I logged block 115 with different springs and with a Green spring in (weakest) I couldn't meet the pressure the ECU was asking for. Interestingly enough.. the more spacers I had in, the farther off target I was with the green spring (last two graphs in my thread).


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## Marcus_Aurelius (Mar 1, 2012)

Cryser said:


> Also remember the DV has that top port that allows pressure to work against the pressure, much like an external wastegate has the top port for electronic boost control. If you have ever handled an external wastegate you'll notice the spring rates for what is 23-30 PSI is MUCH heavier then the blue spring provide by forge for the same PSI range. The springs in DV aren't really do THAT much to keep the valve closed as the pressure from that top port is. The springs are more for the return action of closing the valve after a shift, the do offer SOME tension against the pressure in the tube. But a DV relies much less on the spring tension to hold itself shut and more on the top port, where as a wastegate relies much more on the spring tension to hold itself shut. In the case of an internal wastegate where there is only 1 port, the spring tension is in fact all you have, hence the need for this mod. Applying this type of mod to a DV could actually stop it from working properly and cause more damage then good.


 Hey Cryser, you're one of the guys that has knowledge that I respect in these forums! However, I have to disagree there... and I'll explain my position. The top chamber does have some pressure acting to keep the valve shut, but that action is secondary to the spring tension from what I have gathered through years of hands-on experience with DVs. The pressure from vacuum nipple on the top, is not nearly as strong as the one acting at the bottom trying to push the valve open - and the spring is what makes up for the difference. If your theory was the case, all DVs would rock soft springs and there would be no need for different spring rates to control different boost pressure (all that would be needed, is a spring that can return the mass of the diaphragm plate or piston back to its seat). 

I've heard what you're saying before, but what is forgotten to be taken into consideration with that train of thought, is that there is also dynamic pressure differentials in practice. In real life, the throttle plate isn't always fully open or closed. In pressure differentials situations (difference in pressure before and after the not-fully opened throttle plate), the pressure acting to push the valve open can be very high, while the plenum pressure (post-TB) almost nonexistent. I'll use an extreme to illustrate, but it shows that the spring is the main factor in a DV ability to hold pressure/boost. Think about going uphill in high gear but at part throttle (say 35%), the load generated are high and boost is pretty substantial. However, behind the throttle, the pressure where the DV vacuum port happen to be located, is super low in comparison (obviously because the throttle plate is only partially open). In situations like the one described, the spring is the only force helping to hold the valve shut - use a soft spring and all the pressure made would be bleed/bypass resulting in very poor performance. Many of our normal operating dynamic conditions reflect some of that pressure differential described above, all of them pointing towards the conclusion that in a DV, the spring action is primordial in sealing the valve. 

Another hole in the theory is that the spring main role is to return the diaphragm plate (or piston) to the closed position. If that was the case, you'd see DV designed with very soft pull springs in the bottom chamber (only acting as return springs). Take the Madmax DV for example there is an external relief hole vented to the atmosphere for that very purpose, it helps evacuate positive pressure trapped in the top chamber and allow the valve to shut back relatively quicker. Much like you'd find in a MBC, or internal wastegate actuator, this strategically placed hole allows boost to be vented out when going back into vacuum. This allow much faster reaction speed or recovery than what the spring alone can do at helping the valve return to full sealed position. 

As usual, things aren't always black or white and the gray area is often bigger in practice. The internal spring in a DV has many functions, including returning to sealing position, but allowing the valve to remain seal under boost is its main one (at least much more so than counteracting vacuum nipple pressure) :beer:


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## Cryser (Sep 9, 2009)

Good Call Marcus, never really though of the scenarios you presented and I can see how my line of thinking is flawed in those situations. The thing that always puzzled me was that a spring rated for 23 PSI for a DV is no where even close to a spring rated for say 10 PSI on an external wastegate. 

That always lead me to believe the top port was always more important then the actual spring. That coupled with the fact that it seems 1 spring fits a very wide range of boost levels and the number one reason for a DV not opening/working correctly a poor "signal" to that top port, my mind just sorta passed that off as the main factor of the DV working against the pressure of the pipe and the spring taking a secondary roll. But I can see how that line of thinking is flaw in all but a racing/WOT situation. :beer: 

I've always found, in my experience, unless I'm going for a very aggressive style set up to go 1 step down in spring rate from what the manufacturer recommends when setting up a DV. Unless your at the very outer limits of the spring range this always seemed to hold boost just fine but give a much more civil, streetable ride.


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## Azierus (Nov 17, 2007)

So I have a bit of a problem and I was hoping anyone could chime in with some good advice. About a week ago I installed my eurojet fmic. Car has revo stg 2, 42draft 3in tb w/cat, forge 007 and tsi coils. When I accelerate partial throttle the boost spikes to 20-21 pis then drops. I can hear turbo flutter and the car stumbles. If I mash the pedal the boost will only go to 5psi and hold. But if i slightly let go of the pedal and re apply pressure the boost surges up to 20-21 and drops back down. Ive been over all of my piping checking for boost leaks, i dont know what more to do. Ive replaced the the n75 with a new stock version and tried different springs in the forge dv. Maybe its my wastegate? any help would be nice :beer:


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## Boulderhead (Oct 21, 2012)

*Fuel Trims Lean?*



Azierus said:


> If I mash the pedal the boost will only go to 5psi and hold. But if i slightly let go of the pedal and re apply pressure the boost surges up to 20-21 and drops back down. Ive been over all of my piping checking for boost leaks, i dont know what more to do. Ive replaced the the n75 with a new stock version and tried different springs in the forge dv. Maybe its my wastegate? any help would be nice :beer:


Start simple and begin eliminating your doubt of what is the issue by getting some good data.

Do you own or have access to a VagCom.. If so, what do your fuel trims look like (Block 32)? Check your engine for a Partial throttle for "Lean intermittent Multiplicative". The intermittent code will give you the soft limp mode that you describe (boost limited to 5 psi). You aren't stuck in limp as you indicated boost will jump to 20 psi under partial so that sounds like an intermittent issue for now.

I battled a similar problem for weeks before replacing my MAF after some extensive data logging and help from the folks around here. Do you have any MAF logs running 2nd or 3rd gear from 2500 RPM up to redline?

Hope that helps!


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## Azierus (Nov 17, 2007)

Boulderhead said:


> Start simple and begin eliminating your doubt of what is the issue by getting some good data.
> 
> Do you own or have access to a VagCom.. If so, what do your fuel trims look like (Block 32)? Check your engine for a Partial throttle for "Lean intermittent Multiplicative". The intermittent code will give you the soft limp mode that you describe (boost limited to 5 psi). You aren't stuck in limp as you indicated boost will jump to 20 psi under partial so that sounds like an intermittent issue for now.
> 
> ...


No I dont  I need to get in contact with some people but have been so busy with work that I only have time on the weekend. And even then, i dont feel like doing anything lol. MAF was replaced about 4 months ago. What I find odd is that it only started doing this after the fmic install. It ran perfect before. I had a similar issue before and it ended up being the coupler from the stock side mount to the pancake pipe. This time its far worse.


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## Boulderhead (Oct 21, 2012)

*Rich / Lean*

I would get some data before anything else.. as you could be running rich or lean. 

Since you mention a recent FMIC, my guess is you are actually running rich and have a boost leak on the charge side of the turbo. Lean would be the result of unmetered air getting in via vacuum leak, or faulty MAF reading lower than what is passing through.

Cheers,
Tony


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## Kacz07 (Mar 4, 2012)

Did I miss instructions on install? I have a tubular exhaust manifold. Better to come from top or bottom?


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## Boulderhead (Oct 21, 2012)

Kacz07 said:


> Did I miss instructions on install? I have a tubular exhaust manifold. Better to come from top or bottom?


Have a gander at the first post... Pop strut tower brace off, and intake or stock air box and come from top.


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## All_Euro (Jul 20, 2008)

All_Euro said:


>


Installed this on the weekend... I've been resistant to try a MBC because of the part throttle drive-ability issues that so many people report. Max is right - this one shines... and I'm not just referring to the polished finish 

The Forge Unos delivers *better* part throttle response than the n75. It came with two springs... a light and a heavier option. The light spring gave me 10-12 psi in 3rd & the heavier spring nets me 28psi... so I suppose that's the only thing - I've lost a couple pounds of boost. Unless Forge sells a heavier spring I think I'll make a shim or two to put under the current one.

Either way - seems to be a great MBC overall :thumbup:


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## Marcus_Aurelius (Mar 1, 2012)

All_Euro said:


> Installed this on the weekend... I've been resistant to try a MBC because of the part throttle drive-ability issues that so many people report. Max is right - this one shines... and I'm not just referring to the polished finish
> 
> The Forge Unos delivers *better* part throttle response than the n75. It came with two springs... a light and a heavier option. The light spring gave me 10-12 psi in 3rd & the heavier spring nets me 28psi... so I suppose that's the only thing - I've lost a couple pounds of boost. Unless Forge sells a heavier spring I think I'll make a shim or two to put under the current one.
> 
> Either way - seems to be a great MBC overall :thumbup:


You can shim it, get a slightly stiffer spring! I can't remember but I think in mine I only extended the stiff spring (pull it outward from its extremities to make it longer and increase the preload) to get 30+ psi. Try that first before going crazy looking for springs or shims! :beer:

As I said before, best ball and spring MBC money can buy! (Forge really nailed this!):thumbup:


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## warranty225cpe (Dec 3, 2008)

All_Euro said:


> Installed this on the weekend... I've been resistant to try a MBC because of the part throttle drive-ability issues that so many people report. Max is right - this one shines... and I'm not just referring to the polished finish
> 
> The Forge Unos delivers *better* part throttle response than the n75. It came with two springs... a light and a heavier option. The light spring gave me 10-12 psi in 3rd & the heavier spring nets me 28psi... so I suppose that's the only thing - I've lost a couple pounds of boost. Unless Forge sells a heavier spring I think I'll make a shim or two to put under the current one.
> 
> Either way - seems to be a great MBC overall :thumbup:


There are only 2 springs offered with the UNOS. I have both, and have experienced the same thing. Like max said, give the spring a little tug and extend it a little.


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## peter139 (May 4, 2005)

I installed last week also a forge unos mbc. The design and construktion of this product is very nice.

Did first the cheap spring mod, but my spring snapped 2 times. (see pic on page 1)
The spring mod rides smoother, but the Forge unos mbc is better to adjust.


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## Slimjimmn (Apr 8, 2006)

I did this with my stock ko3s. Installed the biggest spring and it now boosts 15psi! Eek. Anyway I dialed down my mbc to attempt to lower the boost to12 again with no luck. The partial throttle drivability is amazing but I don't want the 15psi just want to give my old wastegate a help with boost. I am going to try the medium spring from the kit and see what happens tomorrow. 

















FYI I believe I have a wastegate flap jamming inside the exhaust housing intermittently or a misfire. The wastegate operates fine by hand though.


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## RadRacer513 (Nov 1, 2010)

I did this mod last weekend. Mid range is awesome now and the car is a whole new beast. It did put me into limp mode a few times, so I'm debating on taking the spring off vs a mbc. Also, under 5psi it almost seems like the cars struggling, but get it over that and it really comes alive

Sent from my x10 using Tapatalk 2


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## Marcus_Aurelius (Mar 1, 2012)

peter139 said:


> The spring mod rides smoother, but the Forge unos mbc is better to adjust.





RadRacer513 said:


> I did this mod last weekend. Mid range is awesome now and the car is a whole new beast. It did put me into limp mode a few times, so I'm debating on taking the spring off vs a mbc.


Guys, I feel the purpose of the mod is getting lost here! *This isn't suppose to be a mean of raising or controlling boost ceiling*. You get increased boost throughout the range (because of increased hotside efficiency), but it's not meant to be used as a boost controller or replace one. In fact, from the get go, I recommended using this in conjunction with a boost gauge and a MBC to control the boost ceiling where it's suppose to be set at...

Done properly, with a MBC, this gives you increased exhaust/hotside efficiency throughout, where stronger boost (cold side) comes as a byproduct but regulated in its ceiling with a boost controller. With a proper cap on boost, there will be no limp, no worries, just a stronger operating turbocharged motor. :thumbup::thumbup:


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## Slimjimmn (Apr 8, 2006)

I installed the large spring and it spikes 15 psi. I closed my mbc that's set inline with the stock n75 and still spikes 15. 
I installed just the small spring and going to drive tomorrow and see how it works. I believe the large spring was too Much tension for a stock ko3s with stock tuning.


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## Kacz07 (Mar 4, 2012)

I performed this mod and in conjunction with the MM DV, boost recovery is so much better and I'm definitely holding more boost and longer through the rev range. I have to put on my 3" exhaust (will be turbo back) and anticipate a dyno close to 290awhp DJ with a fat torque curve. I will likely bring it to RT Tuning in Lansdale, PA.

I have noticed the car takes longer to cool down, likely because of the tubular manifold runs pretty hot. I have the low profile engine bay trim, but I think I need a radiator upgrade.


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## Marcus_Aurelius (Mar 1, 2012)

Slimjimmn said:


> I installed the large spring and it spikes 15 psi. I closed my mbc that's set inline with the stock n75 and still spikes 15.
> I installed just the small spring and going to drive tomorrow and see how it works. I believe the large spring was too Much tension for a stock ko3s with stock tuning.


I'll be the bigger person and help you despite calling me an "idiot" out of nowhere before! And for no apparent reason, because when everybody in the 1.8t technical called you out, you had nothing to show for it! Ironic isn't it you're trying the idiot's mod and he's still looking to help you?

Anyway let's move on, to be able to get to your 12 psi boost ceiling, you can't have your total wastegate actuator rate higher than 12 psi (total actuator spring rate = OEM internal sping rate + added external rate). A MBC has no control over wastegate duty under the total actuator rate. For example, say your factory actuator (unmodified) is 5 psi cracking pressure, with a MBC you can't lower boost under 5 psi. That is the reason why limp mode is 5 psi AKA matching OEM actuator rate (anyone who does the mod, their new limp pressure is whatever their total rate is increased to).

In your case, you have to find a spring soft enough to bring your total actuator rate to 12 psi. So if your OEM internal spring is a 5 psi like it should, look for a 7 psi spring and you'll be good to go. (The ideal way would be to hook up a compressor regulated signal to the vacuum line going to the actuator. Pressurize until you get movement on the rod and that is your total actuator cracking psi). :beer:


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## Slimjimmn (Apr 8, 2006)

After installing the small spring last night Marcus I drove it today and its boosting 12psi as before but the partial throttle response is as good as the heavy spring. 
I knew you have to find the right spring for application. In my case the small spring works perfect. I would assume that when chipped it may need a heavier spring due to more boost pressing he wastegate open.


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## Slimjimmn (Apr 8, 2006)

And Marcus, I have limited tuning knowledge for turbo applications as I have always run N/A accept for my ok mk3 2.0t I owned for 6 months before the dash started on fire from a p/o poor wire job in the rats nest relay box. 
I have plenty of automotive diagnostics experience though. Just learning the other side of tuning as I go. A majority 98% on vortex have limited knowledge of anything other then bolt on this bolt on that. Having threads like this allows people to actually learn something other then bolting on a turbo back gives more power.


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## Marcus_Aurelius (Mar 1, 2012)

Slimjimmn said:


> And Marcus, I have limited tuning knowledge for turbo applications as I have always run N/A accept for my ok mk3 2.0t I owned for 6 months before the dash started on fire from a p/o poor wire job in the rats nest relay box.
> I have plenty of automotive diagnostics experience though. Just learning the other side of tuning as I go. A majority 98% on vortex have limited knowledge of anything other then bolt on this bolt on that. Having threads like this allows people to actually learn something other then bolting on a turbo back gives more power.


:thumbup::beer:


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## RadRacer513 (Nov 1, 2010)

Marcus_Aurelius said:


> Guys, I feel the purpose of the mod is getting lost here! *This isn't suppose to be a mean of raising or controlling boost ceiling*. You get increased boost throughout the range (because of increased hotside efficiency), but it's not meant to be used as a boost controller or replace one. In fact, from the get go, I recommended using this in conjunction with a boost gauge and a MBC to control the boost ceiling where it's suppose to be set at...
> 
> Done properly, with a MBC, this gives you increased exhaust/hotside efficiency throughout, where stronger boost (cold side) comes as a byproduct but regulated in its ceiling with a boost controller. With a proper cap on boost, there will be no limp, no worries, just a stronger operating turbocharged motor. :thumbup::thumbup:


I completely understand the point of this mod. I just didn't expect it to raise the boost ceiling to the point of putting me into limp mode everytime I try to have fun with the car . I'm looking into a mbc in parallel with the n75 for an overboost solution; this way I can cap boost to a safe level, and still have good mid-range power from this mod


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## 20v master (May 7, 2009)

RadRacer513 said:


> I completely understand the point of this mod. I just didn't expect it to raise the boost ceiling to the point of putting me into limp mode everytime I try to have fun with the car


Have you logged requested vs actual? It may not be the boost level causing the limp mode. For example, on my chipped 180Q, the boost curve with one spring added to the WG matches requested perfectly, but IAT's climb so fast that it puts me in limp mode during long extended pulls. Short bursts don't do this. Just something to think about, as IAT's, injector duty cycle, MAF values too high, etc etc can all cause limp mode.


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## Boulderhead (Oct 21, 2012)

*Spring is "Magic"*

Hi folks, please correct me if I am off target with this comment, but.. the ONLY purpose of this mod is to increase hot side efficiency (as others pointed out). This is done by raising the stock cracking pressure of the waste-gate which is not high enough for our modded cars. 

This means the turbo doesn't have to work as hard to create the higher pressure the ECU requests as the WG stays closed longer. 

The ECU is responsible for controlling the boost ceiling NOT the spring.. Proof is in the pudding as I recently swapped a tuned ECU out for a stock one (spring was on with both test cases) and the spring doesn't do a damn thing to raise the boost levels.



20v master said:


> Have you logged requested vs actual?


:thumbup:


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## 20v master (May 7, 2009)

Boulderhead said:


> the spring doesn't do a damn thing to raise the boost levels.


....unless you are attempting to run boost levels that create enough backpressure in the exhaust manifold that it blows open the WG flapper. THEN the spring will help you weak system run the boost you are desiring. Otherwise, no, the spring doesn't do anything if you aren't attempting to run boost levels that high, which you shouldn't be doing without a full exhaust upgrade, approriate charge cooling, and monitoring of your EGT's.


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## Boulderhead (Oct 21, 2012)

Thanks mate.. still making sense of the forced induction world  This entire community is great and keeps the learning fun! Im working with off the shelf flash tune for now and have a lot more reading to do before I get to tinkering much with the powertrain like some of you have. :beer:


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## 20v master (May 7, 2009)

Boulderhead said:


> Thanks mate.. still making sense of the forced induction world  This entire community is great and keeps the learning fun! Im working with off the shelf flash tune for now and have a lot more reading to do before I get to tinkering much with the powertrain like some of you have. :beer:


Yeah, off the shelf tunes won't gain anything from this. The gains come when you try to turn the boost up past what the hardware is capable of, but chip tunes usually stay within those limits. For example, I don't think Audi engineers or the software guys at APR meant for Max to be able to run 35psi on his stock actuator and their software. :laugh:


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## Slimjimmn (Apr 8, 2006)

My boost spike went from 12 to 15 with a spring added. 
Took the spring off spiked at 12

Put a softer spring on spikes 15


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## tedgram (Jul 2, 2005)

Will have to try that my waste gate seems to be opening at 3000 RPM @ 25# of boost.


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## All_Euro (Jul 20, 2008)

RadRacer513 said:


> I completely understand the point of this mod. I just didn't expect it to raise the boost ceiling to the point of putting me into limp mode everytime I try to have fun with the car . I'm looking into a mbc in parallel with the n75 for an overboost solution; this way I can cap boost to a safe level, and still have good mid-range power from this mod


I went with the Forge Unos and cut the n75 out of the equation - couldn't be happier with the results :thumbup:


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## RadRacer513 (Nov 1, 2010)

20v master said:


> Have you logged requested vs actual? It may not be the boost level causing the limp mode. For example, on my chipped 180Q, the boost curve with one spring added to the WG matches requested perfectly, but IAT's climb so fast that it puts me in limp mode during long extended pulls. Short bursts don't do this. Just something to think about, as IAT's, injector duty cycle, MAF values too high, etc etc can all cause limp mode.


No I haven't. But, shouldn't iats be similar, if not lower, assuming same boost levels? The compressor is working more efficiently now, which means less heat, so a slightly cooler charger? I say slightly for a reason, I doubt you'll see anything significant, but possibly an overall smaller temperature change through out the powerband?



20v master said:


> Yeah, off the shelf tunes won't gain anything from this. The gains come when you try to turn the boost up past what the hardware is capable of, but chip tunes usually stay within those limits. For example, I don't think Audi engineers or the software guys at APR meant for Max to be able to run 35psi on his stock actuator and their software. :laugh:



I'd disagree here. I have no idea who tuned my car (previous owner had it done, wasn't aware of of when I purchased it), but my car feels stronger now. Since the boost level is raised above stock, the cracking pressure of the wastegate should be raised too. It'll make running higher boost easier on the compressor, and should allow for a nicer boost curve throughout the whole RPM range . Just get a mbc to keep it from spiking too high and causing limp mode 
Sent from my x10 using Tapatalk 2


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## 20v master (May 7, 2009)

RadRacer513 said:


> No I haven't. But, shouldn't iats be similar, if not lower, assuming same boost levels? The compressor is working more efficiently now, which means less heat, so a slightly cooler charger? I say slightly for a reason, I doubt you'll see anything significant, but possibly an overall smaller temperature change through out the powerband?
> 
> *No, you won't see lower IAT's from this. In theory, maybe. In practice, no. *
> 
> ...


If your ECU wasn't able to meet requested boost without WG mods, then yes you'll make more power after doing this. The condition of everyone's WG on their 12 to 6 year old 1.8T's isn't going to be the same. My car feels stronger too, but I'm not spiking any higher, am right inline with requested boost, and still hitting limp mode (from IAT's IMO). Since the spring is so easy to remove, logging boost before and after isn't hard to do. The problem lies in that more boost doesn't always equal more power.

In fact, the more that I think about it, I had no problem spiking to 25 psi and slowly tapering from there to 14 psi at 7200 on my original K03S setup with nothing more than a Boostvalve ball and spring MBC. Condition of the WG is the variable. Just like with external WG's, you can only run so much on a WG designed for a lower amount of boost/cracking pressure. As Max keeps saying, this isn't meant to be a boost controller or raise boost to moderate levels. This is to overcome a weak WG spring rate that is bleeding off exhaust.


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## Marcus_Aurelius (Mar 1, 2012)

tedgram said:


> Will have to try that my waste gate seems to be opening at 3000 RPM @ 25# of boost.


At 25 psi of boost, your wastegate is getting blown open right at boost onset, and making the entire power range a big inefficient event on the exhaust side (aka hotside). Try and you'll have a much stronger running car throughout! :thumbup:


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## VWstung (Dec 19, 2010)

Finally put in a boost gauge
Have 2 small springs on and peak @ 25, wastegate blows open, then holds 20 with unitronic "22 psi" tune

May get a unos mbc and add 1 more spring.

What you guys think?


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## Marcus_Aurelius (Mar 1, 2012)

20v master said:


> If your ECU wasn't able to meet requested boost without WG mods, then yes you'll make more power after doing this. The condition of everyone's WG on their 12 to 6 year old 1.8T's isn't going to be the same. My car feels stronger too, but I'm not spiking any higher, am right inline with requested boost, and still hitting limp mode (from IAT's IMO). Since the spring is so easy to remove, logging boost before and after isn't hard to do. The problem lies in that more boost doesn't always equal more power.
> 
> In fact, the more that I think about it, I had no problem spiking to 25 psi and slowly tapering from there to 14 psi at 7200 on my original K03S setup with nothing more than a Boostvalve ball and spring MBC. Condition of the WG is the variable. Just like with external WG's, you can only run so much on a WG designed for a lower amount of boost/cracking pressure. As Max keeps saying, this isn't meant to be a boost controller or raise boost to moderate levels. This is to overcome a weak WG spring rate that is bleeding off exhaust.


I agree with what you're saying here Adam, but at the same time understand where the other argument is coming from as well. The thing that needs to be noted is that being able to have actual boost meet request doesn't necessarily means things are optimal on the exhaust side. It means you're able to spin your compressor wheel in a different region (specifically in different efficiency islands on the compressor map) that usually means lower efficiency and more heat. The discrepancy in heat gain or loss (registered by the IAT) seen by different people with different setup is clear to me, and dependent of two factors:

1) How far out of the ideal compressor efficiency region you're operating (simply put how much boost you're asking the peanut-size compressor to pressurize)

2) How efficiently you're able to cool down the air charge before reaching the plenum-mounted IAT sensor. 

In my car for example, with a pretty efficient charge cooling strategy - at 28 psi and up, without any spring added I can still force the turbo to boost to the moon (like I usually do ). However, both on paper and in practice, zero additional spring *always* results in higher IAT (peak and average). 

On the other end of the spectrum, a K03 powered 1.8t with a single SMIC, may already be at the limit of charge cooling efficiency and always see IAT rise from more boost (regardless of slightly better hotside efficiency, resulting in less demand on the compressor). The 225TT with double the cooling capacity of a 180, and not forcing things like I do, as I suspect do not see any IAT taxing as you are. 

Regardless of the setup, there is a nice improvement throughout from better hotside efficiency!


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## RadRacer513 (Nov 1, 2010)

While we're talking about efficiency, has anyone done this mod with preturbo water injection?

Sent from my x10 using Tapatalk 2


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## Marcus_Aurelius (Mar 1, 2012)

RadRacer513 said:


> While we're talking about efficiency, has anyone done this mod with preturbo water injection?
> 
> Sent from my x10 using Tapatalk 2


What are you looking for? I run this mod and pre-turbo injection, so I might be able to answer your questions (besides that, I think All_Euro is the only one with that odd combo).


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## RadRacer513 (Nov 1, 2010)

Marcus_Aurelius said:


> What are you looking for? I run this mod and pre-turbo injection, so I might be able to answer your questions (besides that, I think All_Euro is the only one with that odd combo).


Just curious if anyone else was; I'm debating on doing it. Have wmi setup for post IC right now, and am debating on switching to preturbo, or maybe both. How are you running your setup? What size nozzle? What mix, psi, progressive/standard, turn on point, etc. How long and how much of a difference did it make? Just trying to figure out if it'll be beneficial for a daily car, or just keep it the way it is now. If I did the switch, it would be a 35cc nozzle @150psi, replace my n75 with a mbc, and probably try to squeeze a few more psi from my k03s. Pm me if you'd rather not clutter this thread. Just looking for specifics of other people's setups and what benefits they saw really

Sent from my x10 using Tapatalk 2


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## Marcus_Aurelius (Mar 1, 2012)

RadRacer513 said:


> Just curious if anyone else was; I'm debating on doing it. Have wmi setup for post IC right now, and am debating on switching to preturbo, or maybe both. How are you running your setup? What size nozzle? What mix, psi, progressive/standard, turn on point, etc. How long and how much of a difference did it make? Just trying to figure out if it'll be beneficial for a daily car, or just keep it the way it is now. If I did the switch, it would be a 35cc nozzle @150psi, replace my n75 with a mbc, and probably try to squeeze a few more psi from my k03s. Pm me if you'd rather not clutter this thread. Just looking for specifics of other people's setups and what benefits they saw really
> 
> Sent from my x10 using Tapatalk 2


I run custom 25cc/min nozzles at 60 psi base pressure (both direct port and pre-turbo). At the pressure that I run my nozzles, they flow about 35 cc/min each. Although I have a progressive setup, it is set to go to max pressure from the get-go. I don't go with the progressive BS because I don't see why anyone wouldn't want to use all the pressure available to them at all time :screwy:. I run straight water when racing and during the summer because of the superior cooling properties over a mix (use a small 25% mix of alcohol to prevent freezing in the winter). 

As far as results from pre-turbo injection alone, I can't give a verdict yet. I don't like giving a yay or nay on something until I can measure it as a single variable. Once I can test it "on" and "off" on the dyno, I'll report. What I can tell you from using it, is that pre-turbo doesn't show any measurable change in IAT (recorded at the plenum mounted OEM sensor), but shows a gain in Mass Airflow and boost pressure throughout the entire rev range. :beer:


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## RadRacer513 (Nov 1, 2010)

How much boost are you running with your setup? K03s? And I figured iats wouldn't change much, hence me thinking of doing a dual nozzle setup. Preturbo would just to be to increase the efficiently of the already overdriven, tiny K03

Sent from my x10 using Tapatalk 2


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## Marcus_Aurelius (Mar 1, 2012)

RadRacer513 said:


> How much boost are you running with your setup? K03s? And I figured iats wouldn't change much, hence me thinking of doing a dual nozzle setup. Preturbo would just to be to increase the efficiently of the already overdriven, tiny K03
> 
> Sent from my x10 using Tapatalk 2


On my OEM K04-02X powered car, I peak at 35-37 psi depending on the gear. More info on the setup can fe found here:

http://forums.vwvortex.com/showthre...Charge-Cooling-quot-a-different-approach-quot

and here:

http://forums.vwvortex.com/showthread.php?5788526-Chronicles-of-a-track-TT&p=80140256#post80140256


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## RadRacer513 (Nov 1, 2010)

Marcus_Aurelius said:


> On my OEM K04-02X powered car, I peak at 35-37 psi depending on the gear. More info on the setup can fe found here:
> 
> http://forums.vwvortex.com/showthre...Charge-Cooling-quot-a-different-approach-quot
> 
> ...


I've already read your threads, nice setup. You were the one who got me interested in preturbo injection . How much for one of your nozzles?

Sent from my x10 using Tapatalk 2


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## rickysantana (Nov 29, 2009)

.


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## Joey GTI (Aug 8, 2011)

Marcus_Aurelius said:


> Home depot - autoparts store - hardware store etc.
> 
> The autoparts store have an assortment under the Help brand, use the heaviest spring. The home depot carries an assortment too that has two springs that are perfect. I like going to a local Ace hardware because they have a big spring selection and the rates and other specs are available.
> 
> ...


i have the exact same kit from home depot. did you use both smaller springs? or just one? i have a apr stage II tune @ 15psi now.


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## Gonzzz (Apr 27, 2010)

This mod is the *shit*


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## warranty225cpe (Dec 3, 2008)

JohnnyLlama said:


> This mod is the *shit*


Totally! nice to see a thread that doesnt contain "more low", or "#becauseracecar" :laugh:


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## Joey GTI (Aug 8, 2011)

Love the idea of this mod! I just jacked up my car in my driveway and put both the smaller springs on. And did about 4 pulls feels like it pulls harder but in 2nd it still dropped off and also in 3rd and it always falls back to 10psi not 15psi what my cars boost is tuned for. Should It make a difference if I had my boost gauge tapped into my fpr?


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## charles_3 (Apr 6, 2009)

Did this and every gear spikes at 21 and holds at 16 psi big difference then before 

Sent from my ADR910L using Tapatalk 2


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## 20v master (May 7, 2009)

Joey GTI said:


> Love the idea of this mod! I just jacked up my car in my driveway and put both the smaller springs on. And did about 4 pulls feels like it pulls harder but in 2nd it still dropped off and also in 3rd and it always falls back to 10psi not 15psi what my cars boost is tuned for. Should It make a difference if I had my boost gauge tapped into my fpr?


Not the best place to tap for boost but won't hurt anything if your connections are good. If it's dropping to 10 psi, that's because you're hitting limp mode and 5 psi of base WG pressure plus springs is giving you the 10 psi. When you add springs to the WG, your WG boost level goes up.


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## Joey GTI (Aug 8, 2011)

20v master said:


> Not the best place to tap for boost but won't hurt anything if your connections are good. If it's dropping to 10 psi, that's because you're hitting limp mode and 5 psi of base WG pressure plus springs is giving you the 10 psi. When you add springs to the WG, your WG boost level goes up.


well i know its not a limp mode ive delt with limp(9psi)and hard limp(5psi) before. its bleeding off after 5k rpm ive been told by numerous apr tuned people that its not normal to bleed off like that. but have also been told its because the turbo cant hold higher boost levels than stock because of its size which would be why it bleeds back to stock 10psi. why is it not the best spot? it shows boost levels. and it bled off to 10 psi before the springs...


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## 20v master (May 7, 2009)

Joey GTI said:


> well i know its not a limp mode ive delt with limp(9psi)and hard limp(5psi) before. its bleeding off after 5k rpm ive been told by numerous apr tuned people that its not normal to bleed off like that. but have also been told its because the turbo cant hold higher boost levels than stock because of its size which would be why it bleeds back to stock 10psi. why is it not the best spot? it shows boost levels. and it bled off to 10 psi before the springs...


It's not the best spot because if you develop a leak at one of your connections, it's then affecting your fuel pressure. People use vague terms to describe turbo operation, and "it can't hold boost because of it's size" is pretty vague. Plenty of people run more than 10 psi to redline on K03's. I always had my K03 setup dialed in to hold 14 psi to 7K rpms, so you either have a leak, a weak WG actuator, or another issue somewhere.


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## Joey GTI (Aug 8, 2011)

20v master said:


> It's not the best spot because if you develop a leak at one of your connections, it's then affecting your fuel pressure. People use vague terms to describe turbo operation, and "it can't hold boost because of it's size" is pretty vague. Plenty of people run more than 10 psi to redline on K03's. I always had my K03 setup dialed in to hold 14 psi to 7K rpms, so you either have a leak, a weak WG actuator, or another issue somewhere.


i know that all the connections are ok at the fpr. and i figured that the turbo size wasn't the issue seeing that people are holding higher boost on stock turbos. it was just something i had been told. it probably is a leak ill have random fluctuations in vac at idle sometimes that's why i had planed on doing the SAI/N249/PCV/EVAP Delete. to see if that helps at all.


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## feche (Feb 7, 2013)

hi, i am from Argentina and we haven´t Home Depot here, so i must find other springs, could anybody put the size and working load from the small springs? i cant see it well in those 2 photos. THANKS!!!


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## All_Euro (Jul 20, 2008)

feche said:


> hi, i am from Argentina and we haven´t Home Depot here, so i must find other springs, could anybody put the size and working load from the small springs? i cant see it well in those 2 photos. THANKS!!!


Welcome 

Even small springs can be rated quite high; so just make sure the place you buy them from also lists the rate of those particular springs. How much you pre-load the wastegate will be customized to your hardware and tune, etc. :thumbup:


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## feche (Feb 7, 2013)

i have APR stage 2 98oct, in my 2.0TSI Scirocco MK III, thanks for the advice! put to buy the springs herei need the sizes and load of this springs


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## cmann1290 (Feb 28, 2011)

was wondering what spring tension i should use for running like anywhere from about 15-25 psi


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## vtraudt (Mar 1, 2010)

*Boost swing - wastegate spring pressure too low?*

I installed a larger turbo (still KKK based, but more like an RS4) on my 1.8T (mine is longitudinal, AEB, but shouldn't matter for this discussion).

My setup: high flow exhaust manifold, 3" DP, FMIC, Giac PC16 (written for K04), 31lb, 3 bar, N75).

I have THREE (3) cars setup this way. ALL 3 show a boost swing of 4-5 psi when loaded up, around 2800-3400 rpm when boost goes over 10 psi. Frequency around 1-2 Hz.

I have tried: 
a) putting a restrictor in the line to the actuator
b) disconnecting the N75 (4 psi on 2 cars, 7-8 psi on one car, I think it has a stronger spring in the actuator)
c) disconnecting wastegate line (boost to 25 (or more?) psi)

Since i cannot modify the Giac tune: what other methods can i apply to get rid of the boost swing?

Do I need a WG actuator with higher spring load? 

Should I try to either reduce or increase the restriction (the stock N75 has a build in restrictor in the connector to the compressor housing)?


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## 20v master (May 7, 2009)

vtraudt said:


> I installed a larger turbo (still KKK based, but more like an RS4) on my 1.8T (mine is longitudinal, AEB, but shouldn't matter for this discussion).
> 
> My setup: high flow exhaust manifold, 3" DP, FMIC, Giac PC16 (written for K04), 31lb, 3 bar, N75).
> 
> ...


What exactly is it that you are calling a "boost swing?"


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## vtraudt (Mar 1, 2010)

Boost swings at 1-2 Hz with 4 psi or so amplitude. For example between 14-18 psi, 2 times per second.

Obviously, the tune/wastegate/N75 fail to keep the boost constant (ca. 2800-3200 rpm range; not below, not above; does not occur under 10 psi).


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## 20v master (May 7, 2009)

vtraudt said:


> Boost swings at 1-2 Hz with 4 psi or so amplitude. For example between 14-18 psi, 2 times per second.
> 
> Obviously, the tune/wastegate/N75 fail to keep the boost constant (ca. 2800-3200 rpm range; not below, not above; does not occur under 10 psi).


Not sure how or even why you are measuring things in Hz, but that up and down boost under load is typically called "surging" on a 1.8T is a byproduct of variance in N75 valves (unless you've adjusted WG arm threaded nut position to an extreme. Have you tried using a MBC to verify it's the boost control solenoid (N75)?


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## vtraudt (Mar 1, 2010)

Hertz (official short: Hz) is the proper unit for frequency.
The swinging does not occur with N75 disconnected (goes to 4 psi (8 psi respectively on the one car with stronger spring in the actuator) and stays there. Also not with WG line disconnected (boost stable, from 0 to 20 psi (only depends on right foot).


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## 20v master (May 7, 2009)

vtraudt said:


> Hertz (official short: Hz) is the proper unit for frequency.
> The swinging does not occur with N75 disconnected (goes to 4 psi (8 psi respectively on the one car with stronger spring in the actuator) and stays there. Also not with WG line disconnected (boost stable, from 0 to 20 psi (only depends on right foot).


I'm a mechanical engineer, I'm well aware what a Hertz is (1 cycle/second), yet I've never seen anyone that wasn't in automotive production/developement actually measure anything in Hertz. I'm assuming you use frequency by trade and estimated 2-4 seconds since you didn't answer how you measured it.  Now you say it does not swing with N75 disconnected. You mean electrically unplugged? If so, the valve diverts to open and you're running off your WG alone, which is why you see a stable 4 psi. With the WG line disconnected, you can't have stable boost, as you aren't getting boost to hold stable at one level over the rpm range. With no pressure applied to WG ever, you make infinite boost, like you said controlled by your foot. You need to install a cheap ball and spring manual boost controller (MBC) to see if you have an issue with your WG above moderate boost levels (which I doubt but it's possible). The MBC should give you flatline boost if set between 15-20psi. If all your hardware is okay, then the N75 is the cause of your surging, which is very typical of 1.8T's.


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## vtraudt (Mar 1, 2010)

Probably a good idea to put an MBC in and set at pressure above boost swing occurring (say 18 psi).
If it does NOT swing: N75 needs different calibration (1 is brand new OEM, 2 are original OEM).
If it does swing: ??? Turbo itself causing the swing?


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## Marcus_Aurelius (Mar 1, 2012)

^^^ vtraudt, at the 1- 2Hz frequency that the boost is oscillating, you're most likely experiencing compressor surge. This is very common on hybrids or turbos where the compressor and housing are not well matched. Compound this with all the charge piping restrictions and head flow limitations (even bottle necks after the exhaust ports will have an effect) and your compressor wheel has no choice but to partially stall - recover - partially stall again - recover again. This process will repeat itself until the motor is spinning fast enough (upper revs) to ingest the air and not have the compressor wheel work so hard. The root of the problem is the wheel/housing combo, but requesting a certain pressure from it too early sends it right in that surge range. You could request less pressure in that range as a half-ass fix. Increasing flow overall will help too (removing restrictions) and increasing the head flow capacity (large port head, porting, etc). However, until the compressor wheel/housing combo is changed, the problem will remain (anything will just move the range where it's happening, that's why you don't notice it with the N75 removed and no wastegate actuator signal). 


The wastegate, when blowing open from too much hotside pressure, stays open throughout. There is no yo-yo effect that I have recorded with the exhaust wheel speed. :beer:


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## vtraudt (Mar 1, 2010)

Marcus-A: that is very well a possibility.
Can I confirm 'surging' by running an MBC set to 18 psi (above the 'surge pressure') and take the N75 out of operation for a test?
Surging would then occur as well if compressor/turbo related (and not N75/tune/wastegate spring), correct?


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## 20v master (May 7, 2009)

vtraudt said:


> Can I confirm 'surging' by running an MBC set to 18 psi (above the 'surge pressure') and take the N75 out of operation for a test?
> Surging would then occur as well if compressor/turbo related (and not N75/tune/wastegate spring), correct?


Correct. I didn't get into compressor surge because most people don't understand it. Do you even have a compressor flow map for your turbo? Is it an off the shelf turbo (you mentioned RS4, those are K04's) or is it wheels put into original OEM housings? I'd still test the MBC to eliminate the N75. It's a very common problem, and very easy to test this way compared to changing turbos and all other efficiency improvements Max mentioned.


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## Marcus_Aurelius (Mar 1, 2012)

vtraudt said:


> Marcus-A: that is very well a possibility.
> Can I confirm 'surging' by running an MBC set to 18 psi (above the 'surge pressure') and take the N75 out of operation for a test?
> Surging would then occur as well if compressor/turbo related (and not N75/tune/wastegate spring), correct?


That is correct! I would do the test with a ball and spring MBC and test at various pressures (say 5, 10, 15, then move to your real life 18, 20, 22, 24 psi target range), that way you could more or less gauge your surging range pressure ratio.


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## Marcus_Aurelius (Mar 1, 2012)

20v master said:


> Correct. I didn't get into compressor surge because most people don't understand it. Do you even have a compressor flow map for your turbo? Is it an off the shelf turbo (you mentioned RS4, those are K04's) or is it wheels put into original OEM housings? I'd still test the MBC to eliminate the N75. It's a very common problem, and very easy to test this way compared to changing turbos and all other efficiency improvements Max mentioned.


Yeah, it's probably rs4 internals swapped into a K04-02x carcass. I entertained doing this at some point myself but none of the KKK wheels seemed a perfect match for our housing. Yes, they'll flow more but at a cost. The real thing would be to have properly casted clone-style housing to match those existing wheel sizes... but at that point it would make no sense when you can just can just go with something else that is more modern.


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## vtraudt (Mar 1, 2010)

Marcus_Aurelius said:


> The real thing would be to have properly casted clone-style housing to match those existing wheel sizes.


In one of the cars, I am actually running a 'properly matched' OEM RS4 cold side (housing and wheel). Also see next post a far as the 'wrong wheel/housing' goes with respect to the boost swing....


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## vtraudt (Mar 1, 2010)

Just got back from test run with wastegate air disconnected (N75 cannnot open the wastegate): Runs perfectly smooth, no boost swing whatsoever. 

This effectively eliminates the turbo/wheel housing discussion.

The swing is only caused by the interaction between Giac tune, N75 and wastegate/wastegate actuator.

This confirms (checking on my notes) the same experience I had on the other car (non voluntarily; the hose from the N75 to the wastegate actuator had a crack!): Boosting to the moon, NO NONE NADA boost swing. Fixed, and swinging like in the good old 30's.

I don't have an old spare N75, otherwise I would also try: the N75 has a build in restrictor that I could 'play' with (try larger or smaller).


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## Marcus_Aurelius (Mar 1, 2012)

Before we move forward, when you say wastegate actuator air signal disconnected, is it with the line capped? Or left open to build boost unrestricted (to the moon)?


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## vtraudt (Mar 1, 2010)

vtraudt said:


> I don't have an old spare N75, otherwise I would also try: the N75 has a build in restrictor that I could 'play' with (try larger or smaller).


Since turbo is clearly ruled out, I could try swapping in the N75 from my 2.7T. 
I seems no one really knows the difference between the various versions/part number (including 'race N75'). I would suspect the electro-mechanical part is all the same (all it has to do is open/close at varioius frequencies), and the only/main difference might be the orifice (restrictor)?

Does anyone no the specifications (for example restrictor diameter, flow over frequency, etc) of the various Audi/VW N75 valves?


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## vtraudt (Mar 1, 2010)

Marcus_Aurelius said:


> Before we move forward, when you say wastegate actuator air signal disconnected, is it with the line capped? Or left open to build boost unrestricted (to the moon)?


WG actuator line pulled off, not capped (no air going to the actuator). Yes, this is bleeding some air off the compressor housing if N75 is in no power state.


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## SteveCJr (Aug 3, 2008)

Glad I found this thread, just took a couple hours and read through it all. Will be doing this asap. Not sure how I missed it the first time:banghead:

Thanks Max:beer:


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## Marcus_Aurelius (Mar 1, 2012)

SteveCJr said:


> Glad I found this thread, just took a couple hours and read through it all. Will be doing this asap. Not sure how I missed it the first time:banghead:
> 
> Thanks Max:beer:


It's a pretty neat mod when done right. Report your results when you're done. :beer:


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## vtraudt (Mar 1, 2010)

vtraudt said:


> WG actuator line pulled off, not capped (no air going to the actuator). Yes, this is bleeding some air off the compressor housing if N75 is in no power state.


Comparing 2 aftermarket N75: one with a bit of leak on the 'long leg', the other tight (as it is supposed to be): the 'slight leak' results in higher boost, but does not control boost as smooth. The 'tight' one regulates smooth, but caps boost at lower psi.

Both as expected: the 'leak' may be large enough to reduce flow/pressure to the wastegate, thus not fully opening the WG (higher boost).


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## SteveCJr (Aug 3, 2008)

Got this done this morning. It took me roughly 45 minutes from tare down to back together. I'm sure if I had to do it again it would be closer to 25 minutes. I think the hardest part was finding out the hard way the easy way to put the spring on is by hooking it over the end of the WG first then stretching it over the rod end. At first i was hooking it over the rod end because I could see it. Then trying to stretch it over the top of the WG. Ended up losing a small spring down into the engine bay.

As for results. Before the spring I was slowly spiking to 20 psi where I could hear the whoosh sound and inevitably taper down to about 15-16. After the spring I noticed it builds much much faster and will now spike to 25 psi, but it will still taper down to the same amount. And I can still hear what I believe is the WG still opening. It just sounds louder now.

My N249 is still installed and that will be the next thing to go once I find a good write up. I Believe the valve is what might be causing my WG to creep open. I do have a boost machine and I will try to tone it down to 20 psi and see what happens. 25+ might be a bit much for my apr 93 tune.

Had limited time to play around with it today as I had to sleep before work tonight. I'll keep you guys updated.


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## SteveCJr (Aug 3, 2008)

It just dawned on me i remember reading that the large spring from home depot was a bit too long to get the enough tension on it. Since I lost one of the smaller springs into the abyss of my engine bay. I went with one small and one large. Maybe i'm not getting enough tension with it like that?

First and second gear I will overboost and the engine stumbles a bit kinda like a misfire. But doesn't the CEL flash when it misfires or trips limp mode? I'm not seeing any CELs. 3rd - 6th is fine.


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## [email protected] (May 14, 2009)

If anyone is looking for a good place for springs, try McMaster. You can spec out what you need.

http://www.mcmaster.com/#extension-springs/=mpvwpf


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## max13b2 (Jul 24, 2007)

I see most everyone is using the home depot spring set. Anyone using the Help! spring? If so which one in the assortment did you use and how is it? Or should I just return this set and pick up the home depot brand?


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## Boulderhead (Oct 21, 2012)

max13b2 said:


> I see most everyone is using the home depot spring set. Anyone using the Help! spring? If so which one in the assortment did you use and how is it? Or should I just return this set and pick up the home depot brand?


Brand of manufacturer really doesn't matter.. You just need to pay attention to how much additional pre-load you are adding. A good thing to do is measure how much pressure it currently takes to move the WG arm... And then measure / test again after adding your spring(s).

You do this by disconnecting the line from your N75 to the waste gate and supplying a pressure source to the line opening which hooks into the N75.

If you have an air compressor that lets you dial in the pressure this is pretty easy to do. Adding two of the larger HD springs required an additional 8 psi of pressure from the air compressor to move the WG arm in my scenario for a cracking pressure around 15 lbs.

Hope that helps :beer:


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## Alec's TT (Jan 28, 2013)

*Help*

Huh ha! I did this and it worked! Went to Walmart at 3 am, bought a screen door spring, cut it into 1/3's, welded a washer on 1 piece and installed. Instant wg pressure of 10 psi! Driving through town not bad! Way faster spool etc, out in the country, 1st, 2nd topped about 24 psi'ish. Gauge only goes to 20psi. Then 3rd gear, Whooooooo bang somewhere around probably 30-35 psi "gauge buried" i blew a boost hose off my fm. So I went home and installed my ball and spring mbc just like http://i130.photobucket.com/albums/p276/superman_006/parralle.jpg and i was able to cap boost at 22psi perfect! But even in parallel it drives at part throttle just like only using a mbc. What can cause such an awful part throttle?

This is the mbc i have. I only payed like $8 for mine though

http://www.ebay.com/itm/Universal-M...Parts_Accessories&hash=item5af17beff3&vxp=mtr


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## Marcus_Aurelius (Mar 1, 2012)

Alec's TT said:


> Huh ha! I did this and it worked! Went to Walmart at 3 am, bought a screen door spring, cut it into 1/3's, welded a washer on 1 piece and installed. Instant wg pressure of 10 psi! Driving through town not bad! Way faster spool etc, out in the country, 1st, 2nd topped about 24 psi'ish. Gauge only goes to 20psi. Then 3rd gear, Whooooooo bang somewhere around probably 30-35 psi "gauge buried" i blew a boost hose off my fm. So I went home and installed my ball and spring mbc just like http://i130.photobucket.com/albums/p276/superman_006/parralle.jpg and i was able to cap boost at 22psi perfect! But even in parallel it drives at part throttle just like only using a mbc. What can cause such an awful part throttle?
> 
> This is the mbc i have. I only payed like $8 for mine though
> 
> http://www.ebay.com/itm/Universal-M...Parts_Accessories&hash=item5af17beff3&vxp=mtr


I would get a better MBC (Forge Unos is my recommendation)! 

This is like a boost valve or whatever it's called replica. They do not work that well at keeping equilibrium a part-throttle, and on/off throttle is like an on/off switch. I've build many MBCs like that from angle blocks, and what I learned from doing so is that there is a lot more to it than that. Things like the size of the angle block used, the spring length, weight of the ball (lighter ceramic balls make a world of a difference, and most importantly the size of the relief hole in relation to the angle block size, will make or brake how the MBC behave overall. It takes a lot of trial and error to get right and the Unos from Forge got it right (anything from ball to canister and relief hole sizing). :beer:


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## All_Euro (Jul 20, 2008)

Marcus_Aurelius said:


> I would get a better MBC (Forge Unos is my recommendation)!...


I'll second that motion!

I had to be _the world's most reluctant person_ to even use a MBC... but after switching to the Unos it's hard to even think about using anything else


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## 18T_BT (Sep 15, 2005)

http://www.amazon.com/Forge-Motorsport-UNOS-MBC/dp/B008RJIVEI

I prefer the EBC's but that's because I want to control it from inside the cabin, plus with a switch you can have a high and low setting :thumbup:


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## All_Euro (Jul 20, 2008)

18T_BT said:


> http://www.amazon.com/Forge-Motorsport-UNOS-MBC/dp/B008RJIVEI
> 
> I prefer the EBC's but that's because I want to control it from inside the cabin, plus with a switch you can have a high and low setting :thumbup:


That makes sense - a lot of people like to switch between high and low settings.

I like to keep it simple I suppose... one setting... set at the max... but I drive like a grandma


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## Alec's TT (Jan 28, 2013)

So in parallel it should drive like normal? I used a Turbo XS MBC today and it still drove the same way. Part throttle, pulls like a train then let off and epc light. :/ Im up for buying an expensive one if a few more people confirm they work! Thanks

Edit: Also can they be mounted in cabin or is that to much air line to fill? The forge one says it can be dash mounted.


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## RadRacer513 (Nov 1, 2010)

I think part throttle driveability is affected by this mod. Before, your waste gate would open at 5psi; now it's opening later, so the turbo spools a little more than before and you have a slight boost spike, compared to before. Shouldn't be much, but you will see a slight difference. Maybe I'm wrong, but that makes sense to me...

Sent from my Inspire 4G using Tapatalk 2


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## VWstung (Dec 19, 2010)

Max, am I missing something?
Took the rusted springs off after a season and with the stock actuator I still hit 24/25psi triggering fuel cut!!!

I know Unitronics has a pretty vicious boost spike but what the deal, 
hope this isnt permanent.... It's acting as if the springs are still in place.


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## racin2redline (Sep 25, 2008)

VWstung said:


> Max, am I missing something?
> Took the rusted springs off after a season and with the stock actuator I still hit 24/25psi triggering fuel cut!!!
> 
> I know Unitronics has a pretty vicious boost spike but what the deal,
> hope this isnt permanent.... It's acting as if the springs are still in place.


Try pulling the battery it will clear all adaptations



Sent from my postoffice using a carrier pigeon


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## rains (May 30, 2008)

great thread :thumbup:


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## RadRacer513 (Nov 1, 2010)

Ordered springs from McMaster Carr. This is my car in limp mode 










Sent from my Inspire 4G using Tapatalk 2


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## Marcus_Aurelius (Mar 1, 2012)

RadRacer513 said:


> *I think part throttle driveability is affected by this mod*. Before, your waste gate would open at 5psi; now it's opening later, so the turbo spools a little more than before and you have a slight boost spike, compared to before. *Shouldn't be much*, but you will see a slight difference. Maybe I'm wrong, but that makes sense to me...


 Interesting diagnostics, especially without any testing to base your conclusions from...



RadRacer513 said:


> Ordered springs from McMaster Carr. This is my car in limp mode


Now that you're about to try it, you're in for a big surprise.


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## 20v master (May 7, 2009)

RadRacer513 said:


> I think part throttle driveability is affected by this mod. Before, your waste gate would open at 5psi.....


Based on my experience, it isn't. And the WG only opens WITH 5 psi of pressure applied to it, not any time you have 5 psi in the manifold. The ECU/N75 determine when the WG gets that 5 psi, it's not under all conditions.


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## racin2redline (Sep 25, 2008)

I'm hopefully going to pick up a hallman pro RX with the ceramic ball later. Curious to see how my part throttle is going to be. Also a while ago i picked up a resistored plug from IE i know it fits in the plug for the N75 i wonder if i could use that instead of leaving it plugged in? 


Sent from my postoffice using a carrier pigeon


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## warranty225cpe (Dec 3, 2008)

racin2redline said:


> I'm hopefully going to pick up a hallman pro RX with the ceramic ball later. Curious to see how my part throttle is going to be. Also a while ago i picked up a resistored plug from IE i know it fits in the plug for the N75 i wonder if i could use that instead of leaving it plugged in?
> 
> 
> Sent from my postoffice using a carrier pigeon


Why not just leave the N75 plugged in electrically and cap off the ports?


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## racin2redline (Sep 25, 2008)

warranty225cpe said:


> Why not just leave the N75 plugged in electrically and cap off the ports?


Idk i figured if its not doing anything and i could resistor it out why not. No point really lol 


Sent from my postoffice using a carrier pigeon


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## RadRacer513 (Nov 1, 2010)

Marcus_Aurelius said:


> Interesting diagnostics, especially without any testing to base your conclusions from...
> 
> 
> 
> Now that you're about to try it, you're in for a big surprise.


I've already tried it. Been driving with this mod for many months now. Definitely a great mod to do. This video above was showing how my limp mode, which should be 5psi, holds a solid 9psi because of the increased spring pressure.




20v master said:


> Based on my experience, it isn't. And the WG only opens WITH 5 psi of pressure applied to it, not any time you have 5 psi in the manifold. The ECU/N75 determine when the WG gets that 5 psi, it's not under all conditions.


I realize the n75 controls the boost signal to the waste gate and it doesn't always see the manifold pressure. Otherwise we wouldn't be able to boost past the waste gate pressure...my response about part throttle driveability was in response to the previous post about using a MBC...consider this: you start accelerating, which builds boost. Normally the n75 would bleed a little boost to the waste gate to allow it to open and give you a smoother boost curve. So, 5psi gets to the waste gate, and the computer expects it to crack open...but it doesn't because you're springs raised the cracking pressure to 10psi. This is why I think part throttle driveability can be affected. This should cause a steeper, harsher boost curve. However, I also believe that the computer adapts, and you as well, to the point that this change is negligible. So, I guess what I'm trying to say is, it can affect it, but give it some time and you and the car will adapt. So, whoever was trying to run a MBC with the n75 and saying part throttle sucked, try it out for a week first, then report back 


Sent from my Inspire 4G using Tapatalk 2


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## 20v master (May 7, 2009)

RadRacer513 said:


> So, whoever was trying to run a MBC with the n75 and saying part throttle sucked, try it out for a week first, then report back


My comment was in response to just the additional actuator spring. Yes, adding a cheap ball and spring MBC without a proper vent will result in poor part throttle driveability, and this is well documented since the days when the Boostvalve first hit the 1.8T forum. :laugh:


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## racin2redline (Sep 25, 2008)

Just went to the shop where i thought they would have the boost controller an of course out of stock. Does anybody know if the forge mbc is a ceramic ball? 


Sent from my postoffice using a carrier pigeon


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## RadRacer513 (Nov 1, 2010)

20v master said:


> My comment was in response to just the additional actuator spring. Yes, adding a cheap ball and spring MBC without a proper vent will result in poor part throttle driveability, and this is well documented since the days when the Boostvalve first hit the 1.8T forum. :laugh:


Shouldn't if the MBC is ran in parallel with the n75 though, correct?

Sent from my Inspire 4G using Tapatalk 2


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## 20v master (May 7, 2009)

RadRacer513 said:


> Shouldn't if the MBC is ran in parallel with the n75 though, correct?
> 
> Sent from my Inspire 4G using Tapatalk 2


It's not as drastic, but still no where near as smooth as OEM/N75 control only.


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## warranty225cpe (Dec 3, 2008)

racin2redline said:


> Just went to the shop where i thought they would have the boost controller an of course out of stock. Does anybody know if the forge mbc is a ceramic ball?


Yes, the ball in the UNOS is ceramic 


RadRacer513 said:


> Shouldn't if the MBC is ran in parallel with the n75 though, correct?


I was thinking about running the Unos in paralel with the N75, but Gonzo said it would make the part throttle worse instead of better (not sure thats possible). With the N75 controlling boost instead of the Unos, everything is MUCH smoother. But tbh, I kinda miss the slam of tq I had when using the Unos.


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## 20v master (May 7, 2009)

warranty225cpe said:


> But tbh, I kinda miss the slam of tq I had when using the Unos.


Which is why Max doesn't use one. Also why he's attempting to go to WG only. :thumbup:


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## warranty225cpe (Dec 3, 2008)

20v master said:


> Which is why Max doesn't use one. Also why he's attempting to go to WG only. :thumbup:


I might go back to it if I can fix part throttle with it.


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## Doooglasss (Aug 28, 2009)

warranty225cpe said:


> I might go back to it if I can fix part throttle with it.


Have Gonzo soften your accelerator pedal map


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## RadRacer513 (Nov 1, 2010)

Hmmmm. I don't see why having it ran in parallel would cause any issues...guess I need to get one and try it 

Sent from my Inspire 4G using Tapatalk 2


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## warranty225cpe (Dec 3, 2008)

DougLoBue said:


> Have Gonzo soften your accelerator pedal map


Lol, I texted him that. He said "poppycock".


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## racin2redline (Sep 25, 2008)

Just put my UNOs in. Running it straight with the n75 out of the loop. I tried resistoring it out... it didnt work put me in limp which i thought was odd but i guess the ECU needs feed back from the n75. 
Where are people mounting the boost controller I'm looking for a good spot to put it 


Sent from my postoffice using a carrier pigeon


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## Boulderhead (Oct 21, 2012)

racin2redline said:


> Just put my UNOs in. Running it straight with the n75 out of the loop. I tried resistoring it out... it didnt work put me in limp which i thought was odd but i guess the ECU needs feed back from the n75.
> Where are people mounting the boost controller I'm looking for a good spot to put it
> 
> 
> Sent from my postoffice using a carrier pigeon


 When I added my MBC I was constantly hitting limp for overboost issue when in lower gears. I left my N75 plugged in with the vacuum ports capped. After 2 weeks I pulled the MBC and put the N75 back in.


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## racin2redline (Sep 25, 2008)

Boulderhead said:


> When I added my MBC I was constantly hitting limp for overboost issue when in lower gears. I left my N75 plugged in with the vacuum ports capped. After 2 weeks I pulled the MBC and put the N75 back in.


 Im running a giac flash. on the n75 ( both the stock c and the j valve ) it was spiking almost 30psi and going into limp after 4500rpms. I got the MBC to put a cap on it now i see about 25psi steady and i still have around 17- 20 by redline. Still stock exhaust also retaining the n249 with the vacuum canister deleted. 


Sent from my postoffice using a carrier pigeon


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## Boulderhead (Oct 21, 2012)

racin2redline said:


> Im running a giac flash. on the n75 ( both the stock c and the j valve ) it was spiking almost 30psi and going into limp after 4500rpms. I got the MBC to put a cap on it now i see about 25psi steady and i still have around 17- 20 by redline. Still stock exhaust also retaining the n249 with the vacuum canister deleted.
> 
> 
> Sent from my postoffice using a carrier pigeon


 Have you logged request versus actual pressure? Hitting 30psi with N75 in the mix seems like there may be a failure relieving excess pressure (clamped down WG arm, pinched hose going to actuator). I am not sure about the tune.. but for my APR flash, ECU requests tapering boost in all gears with lower limits in lower gears. That is why the MBC was still causing me to hit limp (over boost, max pressure exceeded) if I wanted to go WOT. 

Maybe we should move this to another thread as we are steering in a different direction?


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## VWstung (Dec 19, 2010)

So has anybody had problems with the forge unos not holding a steady psi?

So a quick background is a full emissions delete, uni tune, forge dv with the yellow spring?

I had 2 springs on the wastegate then recently had a problem with over boost and the car hitting 25psi and then jerk... So I took them off but the problem continued 

So I decided to get rid of the n75 (clearly wasn't controling the boost) and replace it with the forge unos mbc,
Now my system is completely analog. 

At first had the lighter spring but that maxed out at 15psi. 
Put in the heavier spring and gave it 5 turns. 
Goes up to 22/23 psi but then sputters between 20-22 psi and sounds like a flat tire. 

It's deff not a boost leak.

Can't fiqure it out....


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## warranty225cpe (Dec 3, 2008)

VWstung said:


> So has anybody had problems with the forge unos not holding a steady psi?
> 
> So a quick background is a full emissions delete, uni tune, forge dv with the yellow spring?
> 
> ...


Try heavier spring with just 1 click then increase from there. Make sure the bleed port isn't clogged on the UNOS.


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## VWstung (Dec 19, 2010)

Originally I started with only 1 click, It was at 16 psi (where the softer spring left off)

I did read something about how the anodizing can clog the ports a bit. Suppose I can take it apart again a really look at it. 

Also the heavier spring had a harder time seating then the softer spring.


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## VWstung (Dec 19, 2010)

Well I took it apart again and it was clean as can be. 
Reseated the spring and made sure the 2 screws were tight. 
Still having the same problem only at WOT. 

Maybe I need to hook up a misfire counter even though I don't have any fault codes....


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## tedgram (Jul 2, 2005)

Started Wastegate Actuator Mod with a 22# and 6# spring. Spiking over 30# gauge go's no higher, Hit limp in first gear. Replaced 22# spring with another 6# spring spiking to 27# then drops to 23#. Before pressure was dropping to 9# wastegate was blowing open.. Car drives real nice. Time trials this week end, will turn boast machine up to see if I can keep pressure at 27#. May add another 6# spring. Thanks Max :thumbup:


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## Marcus_Aurelius (Mar 1, 2012)

tedgram said:


> Started Wastegate Actuator Mod with a 22# and 6# spring. Spiking over 30# gauge go's no higher, Hit limp in first gear. Replaced 22# spring with another 6# spring spiking to 27# then drops to 23#. Before pressure was dropping to 9# wastegate was blowing open.. Car drives real nice. Time trials this week end, will turn boast machine up to see if I can keep pressure at 27#. May add another 6# spring. Thanks Max :thumbup:


:beer:


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## Tim Dog (Sep 20, 2004)

SO I picked up the springs from HD and I guess before I install them I'll order a unos mbc from forge. I'm doing this to see if it resolves my surging or fluttering I get right at 5lbs on part throttle. Goes away with more or less throttle. My question is if I use the mbc should I continue to use the n75J or eliminate it? And if I eliminate it do I leave it plugged in and cap the ports on it? All my car info is in my sig.:thumbup:


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## tedgram (Jul 2, 2005)

I still have my stock N75 in the system. After some additional tunning I'm spiking to 30 psi and holding 27 psi and the car is running even smoother.


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## Tim Dog (Sep 20, 2004)

tedgram said:


> I still have my stock N75 in the system. After some additional tunning I'm spiking to 30 psi and holding 27 psi and the car is running even smoother.


 With or without a mbc? And which springs are you using?


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## Marcus_Aurelius (Mar 1, 2012)

tedgram said:


> I still have my stock N75 in the system. After some additional tunning I'm spiking to 30 psi and holding 27 psi and the car is running even smoother.


 :thumbup:


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## Kiyokix (Dec 16, 2005)

Most awesome thing ever.... :thumbup: 

I'm only running a single spring right now that I picked up at Ace today. I picked up a few springs of various strengths (didn't list them sadly for the ones I bought), I went with the heavier of the two types for the first test. It's not a HEAVY spring, I'd say somewhere around 7-10lbs or so. The other springs I bought are maybe 4-5lbs. 

Using the single spring as a first test, and I may have lucked out lol? Tune is for 22lbs (Gonzo Stg2+) and she shoots right up there PRONTO without spiking to a higher number. Holds 21-22lbs until around 4k then by 5k is around 16-17lbs finally settling to 14-15lbs when I let off at 5600rpm. 

I don't have a sexy TIP yet so I'm sure it'll be even more amazing once I get one, also running the stock intercooler for now. Super curious how it'll feel with some nice cool night air to drink up. Also might try adding one of the weaker springs tomorrow as well to see if anything changes. 

:beer::beer: 

Kei


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## Marcus_Aurelius (Mar 1, 2012)

Kiyokix said:


> Most awesome thing ever.... :thumbup:
> 
> I'm only running a single spring right now that I picked up at Ace today. I picked up a few springs of various strengths (didn't list them sadly for the ones I bought), I went with the heavier of the two types for the first test. It's not a HEAVY spring, I'd say somewhere around 7-10lbs or so. The other springs I bought are maybe 4-5lbs.
> 
> ...


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## Kiyokix (Dec 16, 2005)

Marcus_Aurelius said:


> I'd suggest staying with the single heavy spring for now (unless you logged and make sure you have enough fuel supply, safe AFR, and acceptable IDC). The reason for me to say this because there is always a risk of exceeding the fuel capacity if going too extreme, and exceeding the limits of boost control set in the ECU (putting you into limp and forcing you remove some of the safeguard in place to protect the motor). :beer:


 I'm certainly not looking for any more boost of course, I'm just curious whether or not the holding would get any better (unlikely with the small k03s turbo I think) or not. As far as fueling is concerned, in order to get a Gonzo Stage 2+ tune you have to have a 4bar pressure regulator instead of the stock 3 bar. 

I haven't hooked up the vagcom to look at any numbers yet, I definitely don't want to get a stupid spike putting me into limp mode lol, done that before don't need to do it again. (did it on my old APR 93 tune) 

I'm so far very happy with this little mod overall. With the rain today I doubt I'll be doing anything with it, but I'll probably swap back to the N75 F valve I've been running since I bought the car last month. I just had to find out if the J valve I had was actually good (thankfully it is). 

Thanks again :beer: 

Kei


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## Marcus_Aurelius (Mar 1, 2012)

Kiyokix said:


> I'm certainly not looking for any more boost of course, I'm just curious whether or not the holding would get any better (unlikely with the small k03s turbo I think) or not. As far as fueling is concerned, in order to get a Gonzo Stage 2+ tune you have to have a 4bar pressure regulator instead of the stock 3 bar.
> 
> I haven't hooked up the vagcom to look at any numbers yet, I definitely don't want to get a stupid spike putting me into limp mode lol, done that before don't need to do it again. (did it on my old APR 93 tune)
> 
> ...


 :thumbup:


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## Tim Dog (Sep 20, 2004)

Tried the two larger springs over the past week. Definitely better performance out of the turbo. Pulls strong, peaking up and past 25lbs and can hold pretty steady anywhere from 15-20lbs. Unfortunately I'm still getting that pulsing around 5lbs when I'm at part throttle. Thinking maybe I should switch out to the two smaller springs?


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## toy4two2 (Feb 6, 2012)

I ran the WASM for about 12000 miles. Cooked my stock turbo, at least that is what my tuner PURE MS said likely was the cause of the bearing going out, now sounds like a dentists drill. Not definitive, but def think it put more stress on the turbo and shame on me for not properly logging. I run a APR 91 tune but was spiking b/w 27-30 psi, it was insane, then held 17-20 to around 5500. The only reason I got away with it for 12000 miles IMHO was b/c I had a small boost leak, once that was fixed I was breaking traction in second flying around corners hill climbing and thats when the spikes started.. car was loads of fun though 

if I were to do it all over again, instead of using two spring, I would have just used one of the big ones from HD, I don't think my wastegate ever opened with two of the big springs 

At least now I have a new F23 turbo about to go in, no springs this time, just a Forge Wastegate Actuator and Gonzo Stage 3 tune.


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## RadRacer513 (Nov 1, 2010)

toy4two2 said:


> I ran the WASM for about 12000 miles. Cooked my stock turbo, at least that is what my tuner PURE MS said likely was the cause of the bearing going out, now sounds like a dentists drill. Not definitive, but def think it put more stress on the turbo and shame on me for not properly logging. I run a APR 91 tune but was spiking b/w 27-30 psi, it was insane, then held 17-20 to around 5500. The only reason I got away with it for 12000 miles IMHO was b/c I had a small boost leak, once that was fixed I was breaking traction in second flying around corners hill climbing and thats when the spikes started.. car was loads of fun though
> 
> if I were to do it all over again, instead of using two spring, I would have just used one of the big ones from HD, I don't think my wastegate ever opened with two of the big springs
> 
> At least now I have a new F23 turbo about to go in, no springs this time, just a Forge Wastegate Actuator and Gonzo Stage 3 tune.


If you did it right, it shouldn't have cooked the turbo. If anything, the turbo is more efficient now, which should cause it to last longer...maybe, like you implied, you had too much spring that it cooked the turbo....

Sent from my Inspire 4G using Tapatalk 2


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## Marcus_Aurelius (Mar 1, 2012)

RadRacer513 said:


> If you did it right, it shouldn't have cooked the turbo. If anything, the turbo is more efficient now, which should cause it to last longer...maybe, like you implied, you had too much spring that it cooked the turbo....
> 
> Sent from my Inspire 4G using Tapatalk 2


Correct! When done properly, the mod actually relieves some of the stress from unnecessary over-spinning the turbo when the gate is cracking open prematurely. I don't think that running two springs was the cause of this particular bearing failure. I have ran double that amount of spring tension for much longer and pushing a lot more boost, my turbo is barely broken-in after 13 years. He had loss vacuum to his DV (mentioned in another thread) and likely had caused his compressor to stall and kill the bearings. The only other thing I can think to cause bearing failure on these very robust CHRAs is running bad, improper grade, dirty, or hot oil temp... but what do I know.


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## toy4two2 (Feb 6, 2012)

Marcus_Aurelius said:


> Correct! When done properly, the mod actually relief some of the stress from unnecessary over-spinning the turbo when the gate is cracking open prematurely. I don't think that running two springs was the cause of this particular bearing failure. I have ran double that amount of spring tension for much longer and pushing a lot more boost, my turbo is barely broken-in after 13 years. He had loss vacuum to his DV (mentioned in another thread) and likely had caused his compressor to stall and kill the bearings. The only other thing I can think to cause bearing failure on these very robust CHRAs is running bad, improper grade, dirty, or hot oil temp... but what do I know.


is true for two weeks the line under my intake manifold sprung a leak and my DV would do the CHA CHA CHA on lift. Likely part of the problem. For oil I was running Mobil 1 0W-40 always topped up. Just repeating what the well respected Audi tuner in town told me.


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## Slimjimmn (Apr 8, 2006)

Ok so I finally got around to properly installing this on my stock chip ko3s. 
At first I just put the spring on and it boosted to 15psi and went in limp mode. So...
Took the medium spring and backed the wastegate nuts off 8 turns and locked them. Then installed a washer, the spring, another washer, a nut and tightened it down. Then installed another nut to lock the first nut. 
Wow does this make a difference. I guess my 150k stock wastegate spring must have lost a lot of tension over the years. Te car actually holds 11.5 psi now all the time and every time. It also spools a lot quicker happy of my results. 
I guess I figure that the wastegate just couldn't keep the flap closed when I put my chipped comp in last year and it's why it was surging at 21psi. I still felt that after putting the stock computer back in and I don't feel it anymore. 
Hope to take a cruise this weekend with some buddies and see how it works in the curvy roads.


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## Marcus_Aurelius (Mar 1, 2012)

Slimjimmn said:


> Ok so I finally got around to properly installing this on my stock chip ko3s.
> At first I just put the spring on and it boosted to 15psi and went in limp mode. So...
> Took the medium spring and backed the wastegate nuts off 8 turns and locked them. Then installed a washer, the spring, another washer, a nut and tightened it down. Then installed another nut to lock the first nut.
> Wow does this make a difference. I guess my 150k stock wastegate spring must have lost a lot of tension over the years. Te car actually holds 11.5 psi now all the time and every time. It also spools a lot quicker happy of my results.
> ...


Let us know how it performs in the twisties. :beer:


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## Slimjimmn (Apr 8, 2006)

Performance was good today!
Definitely reminded me of driving the gti 1.8t back in 02-03-04 new at the dealer. Power to redline that doesn't really taper off. 
Iirc I counted 12threads to the end of the rod from the outer nut. 

Anywho it was fun until I was 80miles from home in bum f nowhere (yes town of 312 people called Hokah) this happened 









Flatty
Good thing my spare was a-ok and not flat lol. Had to stay about 50 and slow


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## All_Euro (Jul 20, 2008)

I had my turbo out and was doing some more porting work on the hot-side so I decided to retire Doctor Octopus (post#88) and try something new - drilled into the wastegate bracket at a couple mounting spots that would allow free spring travel and slight tension in the closed position. Springs are now uprated so I only need two...







*Edit:* since these stock actuators only open for part of the possible wategate range and I'm relying on spring tension - I've just added one turn of preload instead of the standard three. There seems to be about 20* of wastegate rotation left on the table with these stock actuators unfortunately...


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## warranty225cpe (Dec 3, 2008)

I actually shortened a few springs today. Since you can't mount springs on the Forge inlet nipple, the springs have to be shorter. I zip tied one around the base of the forge.


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## Marcus_Aurelius (Mar 1, 2012)

All_Euro said:


> I had my turbo out and was doing some more porting work on the hot-side so I decided to retire Doctor Octopus (post#88) and try something new - drilled into the wastegate bracket at a couple mounting spots that would allow free spring travel and slight tension in the closed position. Springs are now uprated so I only need two...
> 
> 
> 
> ...


Nicely done! This approach is almost like what C. Bell had diagramed in 'Maximum Boost' for a cleaner, more secure way of going about it (not that the random hook thing doesn't work well). 

Unfortunately, short of using a taller actuator canister that allows for more rod travel, we're stuck with low opening angle on the internal gate/door.


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## All_Euro (Jul 20, 2008)

Marcus_Aurelius said:


> Nicely done! This approach is almost like what C. Bell had diagramed in 'Maximum Boost' for a cleaner, more secure way of going about it (not that the random hook thing doesn't work well).
> 
> Unfortunately, short of using a taller actuator canister that allows for more rod travel, we're stuck with low opening angle on the internal gate/door.



Thanks - cool idea to wind in a second spring inside the wg caninster... I think I'll pick up a copy of that book! I do have a second wg actuator... might be worth experimenting with...

Ya, the original way of attaching springs served me really well - great mod :thumbup:


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## 2.0t mk2 (Dec 23, 2007)

Im not sure ift his spring mod will help me but I have a 3076r with a internal wg set at 16psi and im running a manual boost controler and when I turn it up the boost wants to fall off in high rpm


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## tedgram (Jul 2, 2005)

Sure it will help. Sounds like your waste gate is being blow open. What do you consider high RPM?


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## 2.0t mk2 (Dec 23, 2007)

4500+


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## racin2redline (Sep 25, 2008)

Sticky?


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## 20psi now (Feb 26, 2009)

Max I have to ask, Why not just drill a hole and weld in a 38mm flange and use a external wastegate? IT would not be hard for someone that can tig a flange on and would it not provide more controle over boost, creep, and or holding presser in the upper RPM .


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## Marcus_Aurelius (Mar 1, 2012)

20psi now said:


> Max I have to ask, Why not just drill a hole and weld in a 38mm flange and use a external wastegate? IT would not be hard for someone that can tig a flange on and would it not provide more controle over boost, creep, and or holding presser in the upper RPM .


That's exactly what I'm doing on my hybrid build, externally gated with atmospheric dump in order to avoid recirculating exhaust gases back into the small and restrictive turbine housing. I posted about it in a hybrid thread I started in the 1.8t technical section, but I've just been lazy to post and update my threads here (the general lack of substance and disinterest in technical discussions have not been motivating). My approach is integrating the recirculating outlet, and flange, into the exhaust manifold to simplify things (since the factory turbo setup is bottom mounted my EW and dump will sit/exit at the top). 

As far as not been a regular practice, the involvement, fabrication for the minimal return is what IMO has stopped people from trying (especially on factory frame turbos that are considered a waste of effort by many). I personally don't think that going external offers much more control over a well put-together internal setup, but the flow advantages of not recirculating gases back into a restrictive turbine housing is undeniable.


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## RadRacer513 (Nov 1, 2010)

Well, I took my springs off thinking the car would be better since it wouldn't go into limp anymore. I don't hit full throttle much, so I figured I wouldn't miss the springs too much. With 2 springs I added 4lbs to the WG and was spiking over 25+ psi. With the springs removed, the car isn't fun anymore . I since have added one spring back (7# WG now) and am spiking 21ish. Here's my problem: part throttle boost (15ish psi) will throw me into limp. I'm assuming requested is lower than actual, so the ecu sticks it into limp mode. I don't know who tuned the car (tuned when I bought it), and I don't have vagcom :-/. Any suggestions for getting part throttle boost back down, but still hold it on the upper rpms? Maybe playing with the nut on the arm some?

Sent from my XT1034 using Tapatalk


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## Marcus_Aurelius (Mar 1, 2012)

RadRacer513 said:


> Well, I took my springs off thinking the car would be better since it wouldn't go into limp anymore. I don't hit full throttle much, so I figured I wouldn't miss the springs too much. With 2 springs I added 4lbs to the WG and was spiking over 25+ psi. With the springs removed, the car isn't fun anymore . I since have added one spring back (7# WG now) and am spiking 21ish. Here's my problem: part throttle boost (15ish psi) will throw me into limp. I'm assuming requested is lower than actual, so the ecu sticks it into limp mode. I don't know who tuned the car (tuned when I bought it), and I don't have vagcom :-/. Any suggestions for getting part throttle boost back down, but still hold it on the upper rpms? Maybe playing with the nut on the arm some?
> 
> Sent from my XT1034 using Tapatalk


Your suspicion is correct! If part-throttle (or WOT) is exceeding the request, or the the boost limits (preset in the tune) are exceeded, the ECU will take action by throwing you into limp. The ideal and proper way to take care of it is with a re-map that raises those limits. Fortunately, there are other ways around it. For example, clamping the pressure signal registered and reported to the ECU is a way to prevent the ECU's intervention when giving it more than it's expecting. This is known as the "diode mod" and is done by placing a Zener diode inline in the pressure sensor pigtail. The hack effectively clamps the voltage reported and the ECU never sees more voltage than what the diode allows (therefore not sending you into limp mode). 

If performing the diode pressure signal clamping mod, be careful and disconnect the battery when installing the diode. Failure to do so can potentially short the ECU. Also, pay attention to the polarity of the diode, if you mount it in reverse the car will run like crap or might not even start. Besides those warning, it's an effective way to solve your problem without a remap and I've used it for years in my car to avoid unwanted limps (to be noted that proper live mechanical monitoring of boost is important if running a clamped signal, that way things like overboost can be spotted).


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## RadRacer513 (Nov 1, 2010)

Ah yes, the diode mod. Was going to do it when I originally installed the springs, but didn't. Something about altering the seen signal doesn't sit well with me . But a remap isn't happening, so I may have to give it a try here soon. I work for an electronics manufacturer, so I'll snag one one day 

Sent from my XT1034 using Tapatalk


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## RadRacer513 (Nov 1, 2010)

Quick thought: if running the diode mod, do you need a MBC? I've been running the factory n75, and would like to stay that way. This is why I never did it before :-/.

I'm assuming I need the 4.3V since my problem is happening lower than 17psi. But since the signal is clamped at ~11psi, how will the ecu control the n75 at 15 psi?

Sent from my XT1034 using Tapatalk


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## racin2redline (Sep 25, 2008)

Ok I know this is kind of a pointless question but I think this is the best thread for it. but it's been floating around my head. And im pretty sure I know the answer already but here it goes...

What happens if you completely pull the vacuum line off the wastegate actuator and drove the car ? 
Would this cause an extreme over boost suituation? 

Or would the exhaust gas pressure in the turbine overcome the wastegate spring pressure and push the wastegate open at a certain pressure? 

Also senario is stock wastegate spring pressure and gradual throttle application. :flamesuiton:


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## vtraudt (Mar 1, 2010)

racin2redline said:


> Ok I know this is kind of a pointless question but I think this is the best thread for it. but it's been floating around my head. And im pretty sure I know the answer already but here it goes...
> 
> What happens if you completely pull the vacuum line off the wastegate actuator and drove the car ?
> Would this cause an extreme over boost suituation?
> ...



wastegate line off: extreme over boost, yes (limit to what your turbo can push (or engine can hold). Would be interested IF or at what pressure the stock spring would open. Does someone know. My case: pretty big turbo, MBC set to 25 psi, but boost drops to 19 psi at higher rpm (turbo can do more, as tested with MBC set to higher pressure, but again higher pressure (say 28 psi) holding at mid range rpm, then dropping again down to (say) 24 psi at higher rpm (shifting the curve up).

Could boost at higher rpm overload the MBC (or even pushing the DV open? Forge 007 yellow spring)?


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## racin2redline (Sep 25, 2008)

Well max said a few pages back I believe he wanted to run a full mechanical wastegate to get the boost he wanted. And it's been stated that even with pressure acting against it the wastegate blows open on these cars around 25psi. 

What I'm trying to say that if driven semi normally (not mashing the throttle around) with no vacuum on the wastegate would the car even make much more [psi] than the spring pressure in the wastegate? I'm pretty sure there would be big boost spikes with quick throttle but idk..


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## Chickenman35 (Jul 28, 2006)

racin2redline said:


> Well max said a few pages back I believe he wanted to run a full mechanical wastegate to get the boost he wanted. And it's been stated that even with pressure acting against it the wastegate blows open on these cars around 25psi.
> 
> What I'm trying to say that if driven semi normally (not mashing the throttle around) with no vacuum on the wastegate would the car even make much more [psi] than the spring pressure in the wastegate? I'm pretty sure there would be big boost spikes with quick throttle but idk..



The answer to that question can be given by anyone who has run on a B&S MBC with the N75 Physically removed. Which I did for Autocrossing on my DD 1998 Audi A4 with an AEB DBC. You get very, very quick spooling even at light throttles to what ever PSI you set the MBC to. 

It actually makes the car very responsive in daily driving. Using less than 1/2 throttle ( 1/4 would easily do it ) and car lunges forward in traffic easily making full boost ( I ran 12-15 on the street and 18 in Competition ). In competition, particularly Autocross, the faster spooling is definitely an asset. Instant 18 lbs at around 2,600 rpm? What's not to like...other than holes in the block :laugh:

With no wast-gate control at all, you would have the same effect, but with essentially no upper limit. I've read reports of guys seeing over 25 psi with WG hose disconnected. WG Flapper crack pressure would have to be way way above spring load of WG actuator to make that kind of boost.

The crack setting due to exhaust back pressure is affected by the area of the WG port acting against the flapper wheel. The bigger the port and flapper wheel the more overall force exerted against the flapper valve. 

If you have a look at Big Rig Diesel engines they have combination electronic/hydraulic control. The electronics are essentially the same as our N75 valve but they have use hydraulic control in the WG because of the extreme pressures acting against the WG flapper valve. A Big Rig diesel can make 40 lbs of boost, even at part throttle. Relying on WG spring and air pressure is not accurate enough and subject to huge hysteresis. An electrical stepper motor by itself would like not last very long ( In an Industrial Diesel ) with the high gear forces involved, so they use hydraulic control with Moog valves and electronic regulation. Interestingly F1 cars also use hydraulic throttle control with electronic regulation for simplicity, reliability and fail safes ( 1 throttle blade per cylinder ). Not necessary on road cars using only 1 or 2 throttle blades.

So running a MBC by itself sounds pretty good right? Not necessarily. Gotta run right now but MBC alone does have it's pitfalls. Especially on DBW. ( My car was DBC remember )


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## racin2redline (Sep 25, 2008)

Thanks for the detailed response. That pretty much verifies my thoughts.


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## scristaldi89 (Jul 18, 2013)

Hi guys. Been reading through all the pages of this thread, really interesting stuff, and some smart guys in here. 

Background...
I have a 2000 TT with the FWD 180 HP motor. I have a Unitronic 1+ tune, and a forge diverter valve. The car is a blast to drive, and thought I might try this to see if any changes would occur. 

On to the install....
I went with the Home Depot springs, and used the (2) 5.28 lbs springs, effectively adding 10.56 lbs to the waste-gate actuator. During install I tugged on the actuator arm to physically move the flap inside the compressor housing and it felt pretty strong, more than 10 lbs of force to create movement, prior to any spring modification. Is this a cause for concern. Also I could hear the flapper physically touching/scrapping the inside of the housing during movement of the arm, this is with my hand of course during the install.
The install was very easy, 15 minutes top thanks to all the guys here documenting and giving pointers.

After install, testing...
I took the car for a spin, and I am no sure I see or feel much of a difference. The unitronic 1+ tune for my car is supposed to raise boost level to 20 PSI. Indeed at WOT in 3RD,4TH and 5TH I would see 20 psi prior to this mod. Since this mod, I am now getting 20 psi in 2nd gear, which for the most part was not occurring before. I have had the car inspected and repaired of all boost/vacuum leaks through my local VAG shop. During a WOT pull in higher gears, the boost is still failing, to roughly 15 PSI. I am just reporting my findings in hope yall might critique and decide if all went well. ROSS-TECH cable is in the mail, what block should I be monitoring post this install?


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## unknownissue (May 27, 2014)

*excuse the noob*

 Pardon my noobieness , this is my first vw , im trying to under stand this mod better. Im running all stock , so by adding this spring to my actuator will reduce my lag?


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## Boulderhead (Oct 21, 2012)

unknownissue said:


> Pardon my noobieness , this is my first vw , im trying to under stand this mod better. Im running all stock , so by adding this spring to my actuator will reduce my lag?


The main reason for doing this is to increase the hotside efficiency of the turbo, for cars running higher boost pressure than stock. The reason we do this is because it helps the turbo achieve the requested pressure by not bleeding exhaust gas off prematurely due to 10+ year old actuator that was rated for less than 10 psi. Hope that helps


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## Marcus_Aurelius (Mar 1, 2012)

Boulderhead said:


> The main reason for doing this is to increase the hotside efficiency of the turbo, for cars running higher boost pressure than stock. The reason we do this is because it helps the turbo achieve the requested pressure by not bleeding exhaust gas off prematurely due to 10+ year old actuator that was rated for less than 10 psi. Hope that helps


Well formulated answer, thanks Tony! :beer:


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## [email protected] (Jul 1, 2009)

Have any of you folks running these spring contraptions on your K03 turbos checked your exhaust gas temperatures? Called "EGTs", this value has a direct impact on the longevity of not just your turbo, but the cylinder head as well. And from our testing, an un-modified K03 turbo is at the safe maximum on just a standard chip tune.











The suggestion of doing a "spring modification" to these turbos is, in my opinion, a bad idea. It leads to dangerous exhaust temperatures and opens the door to costly repairs. Leave the turbos alone, and enjoy the added performance a chip tune provides.


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## RadRacer513 (Nov 1, 2010)

I haven't checked EGTs, and don't have any means to. But, by allowing the wastegate to remain closed longer while trying to build boost, if anything it should be lowering EGTs as the turbo has to work less to achieve the same boost. If you're like me, you don't have a MBC and this mod will cause spiking, which can and will damage the turbo like you're describing. But if used in conjunction with a boost controller, and not exceeding normal chipped boost levels, this mod should be beneficial in the higher RPMs where the turbo is struggling to hold boost
I'm no engineer though

Sent from my LG-LS980 using Tapatalk


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## Boulderhead (Oct 21, 2012)

[email protected] said:


> The suggestion of doing a "spring modification" to these turbos is, in my opinion, a bad idea. It leads to dangerous exhaust temperatures and opens the door to costly repairs. Leave the turbos alone, and enjoy the added performance a chip tune provides.


Hi Doug, just curious if you have some data you can share of the EGTs and the difference you measured with a added mechanical resistance to the WG arm on the same vehicle / actuator?


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## Boulderhead (Oct 21, 2012)

RadRacer513 said:


> I haven't checked EGTs, and don't have any means to. But, by allowing the wastegate to remain closed longer while trying to build boost, if anything it should be lowering EGTs as the turbo has to work less to achieve the same boost.
> 
> Sent from my LG-LS980 using Tapatalk


That is what makes sense to me too...If I have a balloon with a perfect airtight seal I have to exert less energy / heat to fill the balloon to a certain pressure, than if you poked a hole in my cheek (waste gate opening early) which requires me to work even harder to create the same pressure in the balloon. 

Doug, would love to see some data if you have it to visualize your explanation of why this is harmful.


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## Marcus_Aurelius (Mar 1, 2012)

opcorn:


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## Kacz07 (Mar 4, 2012)

opcorn:


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## 20v master (May 7, 2009)

RadRacer513 said:


> I haven't checked EGTs, and don't have any means to. But, by allowing the wastegate to remain closed longer while trying to build boost, if anything it should be lowering EGTs as the turbo has to work less to achieve the same boost.


No. If the WG is closed and the throttle is open, then EGT's are going to climb. This is caused by forcing exhaust through the turbine, which is very restrictive, which creates pressure in the manifold, the source of EGT's. Opening the WG lowers the pressure in the manifold, dropping EGT's.


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## Boulderhead (Oct 21, 2012)

Hey Adam, thanks for chiming in. Any idea how this plays out in real life with the change in temps with spring vs no spring? The way I understand it is that the WG is still opening when the ECU asks for it... just not sooner than requested. What you explained makes sense.. but is this there really enough change in temp to reduce component lifecycle?


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## RadRacer513 (Nov 1, 2010)

20v master said:


> No. If the WG is closed and the throttle is open, then EGT's are going to climb. This is caused by forcing exhaust through the turbine, which is very restrictive, which creates pressure in the manifold, the source of EGT's. Opening the WG lowers the pressure in the manifold, dropping EGT's.


True, but that's also how you build boost. If you're running stock boost levels, this mod isn't for you. When you start pushing boost to the point that the wastegate is blowing open, adding a spring helps hold boost in the upper RPMs. Can it cause higher EGTs, yes, and I can see you're argument. My counter argument is this: a turbo that is trying to achieve a boost level that it never will, due to the wastegate being blown open, will cause more stress than some potentially higher EGTs. Truth is, until someone tests it, there's no telling which of us is correct  

Sent from my LG-LS980 using Tapatalk


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## Chickenman35 (Jul 28, 2006)

^^ Agreed. 

Anytime you take any mechanical part beyond it's design specification you are going to stress parts. It is part of the game we play called " going faster ". 

Data should be constantly monitored and adjustments made whenI would be less worried about things like EGT's get too high. 

A K03 pushing 25psi is far more likely to expire from constant over speeding, rather than EGT's that are pushing the high limit. Note that I did not say EGT's OVER the high limit. 

There are ways to reduce EGT's when running high boost pressures and Max has pretty much covered them all :thumbup: But sometimes you are stuck with the cards you are dealt, and have to make the best of it. Or as Herb Adams once famously said:

* You can't make a pig fly. But you can make a damned FAST pig!!! * :laugh:


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## Chickenman35 (Jul 28, 2006)

^^ I think Max's TT should have a Nick Name.... How about " Pork Chop " :laugh: :beer:


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## unknownissue (May 27, 2014)

*just Attempted this*

Yeah i just tried this , on my B5 Passat , there is no way in hell you can get your hand in behind the turbo to get this spring on , without removing the turbo , and thats not gonna happen.


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## unknownissue (May 27, 2014)

*I got it. There's something that wasnt explained or i over looked.*

I got it. There's something that wasnt explained or i over looked. So i took the intake off my turbo....i was able to get my big hand in there and guide the spring from the front of the turbo , between the turbo and the engine. very very tight spot , i then grabbed the spring with one finger and pushed it over onto the actuator rod, then pulled the spring and held it with one hand , then hooked the other end onto the front of the actuator where the hose connects to the male end , and ta da! i have a very noticeable get up and go now. She used to take a bit to get up to speed from low rpm's , she rolls now , no lag. Very nice Mod


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## vtraudt (Mar 1, 2010)

*Wastegate crack open pressure*

Couldn't find it in the pages of this thread:
Has anybody bothered to actually MEASURE the cracking pressure of the modified setup?
Most stock actuators (installed, preloaded) crack around 4 psi.

If no hand pump with pressure gauge on hand, a simple test (those who have done the mod: please post your result (and short description of mod):
Unplug the N75 and log the boost pressure (effectively sending engine into limp mode) (from low rpm on).

I may get a HomeDepot spring set (don't plan on doing the mod, just trying to figure out what the net spring force is, and maybe measure the spring rate of the HomeDepot spring) and modify a turbo to compare stock 'crack pressure' vs. 'modified crack pressure'.

With turbo off the car, maybe there is a more elegant but still simple/cheap way of increasing the spring rate (crack pressure); on several occasions, I have struggled to find a suitable actuator (10 psi, 14 psi) that fits the turbo (difficult to find, took long to get, still had to do a lot of cutting, bending, drilling, dremeling to make it fit).

So at least as a quick fix: let see what net crack pressure the various HomeDepot spring combinations can produce.

Also: for more sophisticated 'loggers' out there: how does the boost curve and wastegate duty cycle curve look like before/after spring mod?


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## RadRacer513 (Nov 1, 2010)

vtraudt said:


> Couldn't find it in the pages of this thread:
> Has anybody bothered to actually MEASURE the cracking pressure of the modified setup?
> Most stock actuators (installed, preloaded) crack around 4 psi.
> 
> ...


I unhooked the n72 valve and my car was running 5psi, so that's where the wastegate was opening. With the single spring I have on there (different than the home depot setup, BTW) it moved to 8psi. 2 springs was around 11 . I felt 2 springs threw me into limp too much (still no MBC!) So I stayed with the 1. Much nicer drivability, IMO. If I ever throw a MBC on it, I'll give 2 springs a try again


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## vtraudt (Mar 1, 2010)

RadRacer513 said:


> I unhooked the n72 valve and my car was running 5psi, so that's where the wastegate was opening. With the single spring I have on there (different than the home depot setup, BTW) it moved to 8psi. 2 springs was around 11 . I felt 2 springs threw me into limp too much (still no MBC!) So I stayed with the 1. Much nicer drivability, IMO. If I ever throw a MBC on it, I'll give 2 springs a try again


Nice. To replicate your setup: what spring(s) DID you use? If not spring rate (N/m, lbs/inch) is available, maybe hang a weight on the spring and measure the resulting extension?

I am shooting for 10-11 psi for 'medium' boost (22 psi) setups and 1 bar (14 psi) for 26 psi setups. 
But would be nice to have a list of 'spring rate for desired crack pressure increase'. 

At least in one case, we struggled for weeks to get decent boost control (humps, boost swings, etc.) until we finally yanked the turbo out and put another actuator (11 psi) on, and redo the whole boost control loop in the tune.


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## Boulderhead (Oct 21, 2012)

I was seeing 16lbs cracking pressure with two of the larger diameter springs on from HD. Never measured without the springs on... But can do it when I get home from my trip to TX.


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## RadRacer513 (Nov 1, 2010)

vtraudt said:


> Nice. To replicate your setup: what spring(s) DID you use? If not spring rate (N/m, lbs/inch) is available, maybe hang a weight on the spring and measure the resulting extension?
> 
> I am shooting for 10-11 psi for 'medium' boost (22 psi) setups and 1 bar (14 psi) for 26 psi setups.
> But would be nice to have a list of 'spring rate for desired crack pressure increase'.
> ...


I'll see if I can find the specs. I got them from McMaster Carr and just searched for 5lb spring


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## vtraudt (Mar 1, 2010)

RadRacer513 said:


> I got them from McMaster Carr and just searched for 5lb spring


What is meant by a 5 lb spring? Spring rate of 5 lb/inch?


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## RadRacer513 (Nov 1, 2010)

vtraudt said:


> What is meant by a 5 lb spring? Spring rate of 5 lb/inch?


http://www.mcmaster.com/#9654k383/=squ2ay
That's what I bought. 4.06lb/inch


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## ExtremeVR6 (Sep 6, 2001)

amazing amount of information here! I'll be giving it a try on my 98 Audi A4 AEB (yeah I'll probably have troubles like the fella with the passat a few comments back. 

I really wish Doug from frankenturbo would reply back with some data....

I've read through C. Bell's Maximum Boost (which I recommend for anyone wanting to do anything on their turbocharged car!) and with regards to EGT's ... my feeling is that you're going to create more heat and more "trouble" by pushing the turbo into lower efficiency islands than by the heat created from pushing more air through the turbine. IIRC, the K03 higest efficiency island happens from around 7psi to 16psi. So if you've got a stage 1/1+ running 15-18psi, you're still going to be operating near that highest efficiency island. The K04's highest efficiency range covers from approx 9 to 18psi. So locking in 18psi to redline in my book is going to be better that having to overspin the turbo as described earlier. However, empirical evidence is an amazing thing when available. 

It's a cheap mod to do, if you have the tools to measure EGT's, I don't know why you wouldn't take a couple few hours to do the mod and run some tests. 

One thing that has gone through my head while reading this is that adding springs to the outside is ultimately a workaround solution, albeit an amazingly effective one. Ideally, the strength of the internal spring would be strong enough to keep the WG closed until the targeted amount of compression was achieved. Two things are obvious... 
1: VW/Audi engineers were designing a safe reliable system with good emissions and suitable performance, and their probably pretty smart too. The stock amount of compression is well suited for the stock WG pressure, at least for a properly functioning, unworn OE turbocharger. 
2: Doing this "mod" is far cheaper, quicker, and more easily scaled than finding a aftermarket WG designed for the amount of compression intended. 

That being said, when I consider a company (like Gonzo Tuning, or FrankenTurbo) who are trying to make a name for themselves based on their hybrid turbos and tuning, I would imagine information like this could be invaluable. I myself would test the mod. Depending on the amount of perceivable benefit, would then being selling turbos that automatically came with internal wastegates with springs designed to provide a crack pressure relative to the stage of tune accompanying the turbo (presumably in a kit). Or, would utilize a modular approach when building turbo's for distribution. Ie, ordering a stage 2 kit? When building that particular turbo, put on internal wastegate #20. Customer orders a custom tune for their build intending on running 30psi... when building the turbo, install wastegate #25. Now you have a kit that performs smoothly and reliably. Beyond that, you've got a system that is far less prone to a condition that probably 85% of the enthusiast market takes as a given, boost spike due to these itty bitty turbos. 

but hey, what do I know? 

I'll try to remember to update once I get around to adding some springs.


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## Brake Weight (Jul 27, 2006)

I run an f23 with a three outlet MBC and it does nicely. Some don't wanna run a MBC and complain that they should, but I don't care. It works. I've got a EGT gauge and I'll try to get a spring on there in the next few days to see what'll happen. 

I will agree with the theory about working the turbos will do for heat. The most heat I've seen generated was during a long 5-6th gear pull at 23psi. Even then it's around 1400* F. But on low boost long HWY cruises, it creeps up around 11-1200*. I think this area here is the most detrimental because it's maybe -5 to 5psi...and hot. This is now blowing into my intake as well as heat soaking the FMIC. At these boost levels the w/m isn't spraying either and the IM is hot as fvck. I've already turned the onset setting for w/m low as possible so I can feather the boost to get some cooling periodically. But I've got a plan...maybe.


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## [email protected] Performance (Jul 20, 2011)

You shouldn't have boost while cruising 

Fix that and you don't need to rig anything


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## Brake Weight (Jul 27, 2006)

It's hill country where I live. On the flats it's just like sitting still at an idle. 

It's just that little bit over a 15-20 in/hg vacuum that raises the EGT more than I would have expected. 

I would've done some experimenting yesterday, but I couldn't find that pack of springs.


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## Chickenman35 (Jul 28, 2006)

[email protected] Performance said:


> You shouldn't have boost while cruising
> 
> Fix that and you don't need to rig anything


Actually I prefer driving my AEB powered A4 with a stand alone B&S MBC. Boost is instantaneous, much quicker than the N75. Totally transforms the car making it more like a " Pocket " Rocket " than a 3,300 lb slug. 

DBC is the trick of course. Doesn't work so well on DBW. Only draw back is that the MBC makes the Cruise control " hunt " as it builds boost too quickly under any type of small load. I can live with that though. 

A hidden benefit is that it makes starting on hills so much easier. Boost is building right away and you have so much torque that you don't have to slip the clutch as much. ( I have a 9.5 lb aluminium flywheel ). Even driving the car up driveway service ramps is easier with the MBC.


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## [email protected] Performance (Jul 20, 2011)

Yeah, that's on an AEB... Not DBW like the above poster 

And I don't like AEB. It has identity issues. 058 block from old generation with 20v tech from 06A. Old engine management in a newer chassis. I think its confused :laugh:


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## GrapeBandit (Dec 13, 2010)

Chickenman35 said:


> Actually I prefer driving my AEB powered A4 with a stand alone B&S MBC. Boost is instantaneous, much quicker than the N75. Totally transforms the car making it more like a " Pocket " Rocket " than a 3,300 lb slug.
> 
> DBC is the trick of course. Doesn't work so well on DBW. Only draw back is that the MBC makes the Cruise control " hunt " as it builds boost too quickly under any type of small load. I can live with that though.
> 
> A hidden benefit is that it makes starting on hills so much easier. Boost is building right away and you have so much torque that you don't have to slip the clutch as much. ( I have a 9.5 lb aluminium flywheel ). Even driving the car up driveway service ramps is easier with the MBC.


anyone have a diagram on how one would delete the n75 and run just a B&S MBC?


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## ExtremeVR6 (Sep 6, 2001)

Simply take the vac tube from the compressor and clamp it to the ball side of the MBC, and the vac tube from the wastegate and clamp it to the outlet on the MBC? As for the n75, I left it plugged it, but zip tied it up with the evap hose on the backside of the airbox. Lastly, plug the n75 port on the TIP. Incidentally a m8x16 (same bolt as the upper turbo brace bolt) works perfectly! 

If you wanted completely delete the n75, it's spec'd as a 25-35 ohm resistance, I'm guess you could resistor the line with a 30ohm resistor ... but don't quote me on that!


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## GrapeBandit (Dec 13, 2010)

ExtremeVR6 said:


> Simply take the vac tube from the compressor and clamp it to the ball side of the MBC, and the vac tube from the wastegate and clamp it to the outlet on the MBC? As for the n75, I left it plugged it, but zip tied it up with the evap hose on the backside of the airbox. Lastly, plug the n75 port on the TIP. Incidentally a m8x16 (same bolt as the upper turbo brace bolt) works perfectly!
> 
> If you wanted completely delete the n75, it's spec'd as a 25-35 ohm resistance, I'm guess you could resistor the line with a 30ohm resistor ... but don't quote me on that!


tnx:thumbup:
ill try that after I order my MBC. now I can crank up my k03 to 30+psi


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## UCFQuattroguy (Jul 5, 2005)

This thread has caught my attention, as I autocross a DSP class A4(B5) Quattro 1.8T. I'm pretty limited for power and torque with my off the shelf APR tune, however if this mod will bring a little more efficiency to the table through the mid-range and up-top, I'm sure that's plenty to make it worth while. Ideally the tune would let me go MBC only and have set or 18-20psi and not trigger a limp condition. Does anybody have any first-hand experience with testing just how tolerable APRs tunes are to such "schenanagans"? I've only ever used my MBC in parallel to combat spikes that weren't severe enough to cause Limp, but enough for the N75 to constantly be playing catch-up.

With having a tune where you can see that the boost taper is ECU controlled (looking at N75 DCs), I'm guessing the efficiency gain here is that it's *ONLY* the N75 boost signals cracking the WG..and not a combo of both boost signals as well and internal backpressure. Yes? No?

Those who've done this on a longitudinal setup: Small hands and patience for pulling this off?


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## Chickenman35 (Jul 28, 2006)

UCFQuattroguy said:


> This thread has caught my attention, as I autocross a DSP class A4(B5) Quattro 1.8T. I'm pretty limited for power and torque with my off the shelf APR tune, however if this mod will bring a little more efficiency to the table through the mid-range and up-top, I'm sure that's plenty to make it worth while. Ideally the tune would let me go MBC only and have set or 18-20psi and not trigger a limp condition. Does anybody have any first-hand experience with testing just how tolerable APRs tunes are to such "schenanagans"? I've only ever used my MBC in parallel to combat spikes that weren't severe enough to cause Limp, but enough for the N75 to constantly be playing catch-up.
> 
> With having a tune where you can see that the boost taper is ECU controlled (looking at N75 DCs), I'm guessing the efficiency gain here is that it's *ONLY* the N75 boost signals cracking the WG..and not a combo of both boost signals as well and internal backpressure. Yes? No?
> 
> Those who've done this on a longitudinal setup: Small hands and patience for pulling this off?


I autocross my 1998 A4 and track day it. Important to note that I have an AEB with Drive By Cable. It's my DD ( when the damned thing decides to run!! :banghead: ) I run an APR Stage 1 tune and have run it with a stand alone MBC. I could run 18 psi no problem in Autocross. I have tweaked it to 20 psi with no fuel cut..but I was getting mighty worried with stock injectors and fuel pump. 18 psi is what I consider a " safe " limit with my components.... and then only for a short time like Autocross. I ran 15-16 psi Max on Track days This was on Chevron 94 Octane with a bottle of 104 NOS Racing Octane Booster.

Throttle response and low end boost was immediate. Car was MUCH quicker in Autocrosses with the MBC. Could compete with E30's which was batting above it's " considerable " weight. 

Apr Stage 1 tune is very conservative as you mentioned, particularly on AEB models. The injectors are just so tiny ( 215cc prated at 3 Bar )...even driven at 4 Bar ( stock ). Boost taper is necessary at high revs to keep IDC under 100%. I limited shift RPM to 6,000 RPM in 3rd and 4th because of IDC concerns ( and there was no more power to be had ).

Now DBW may change everything. You may have surge problems with DBW. DBC was relatively unaffected by using a stand alone MBC. At higher boost levels you would get a big " buck " from the engine if you let off the throttle suddenly at full boost. You learned how to deal with that through through driving style.


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## Chickenman35 (Jul 28, 2006)

On an AEB... 20psi on an APR Stage 1 is a waste of time IMHO. Makes no more power than 18 psi. Not enough injector to support more boost. Similar story on later 150 HP models. 

The waste-gates are very weak on these models. 7 psi. And the WG spring gets weaker with age. Adding a couple of turns to the waste-gate nut helps a lot. Check for exhaust manifold leaks at the head and Turbo flange. The nuts like to work loose. Re-Torque them on a regular schedule. Once they are loose the gasket will be damaged in short order, especially the Turbo Flange gasket. Be prepared to replace gaskets if you find any loose exhaust flange nuts.

Exhaust leaks may not be noticeable at idle by feel or sound, but at full boost the K03 has soooooooo much back pressure that a small leak effectively becomes an auxiliary waste-gate. Sea-Foam the intake and watch for any smoke coming from exhaust gaskets. 

Use Copper High Temp Permatex RTV on the Turbo flange gaskets and cat/downpipe gaskets. It helps the gaskets survive longer.


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## GrapeBandit (Dec 13, 2010)

can anyone recommend a good inexpensive B&S MBC that works well?


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## All_Euro (Jul 20, 2008)

GrapeBandit said:


> can anyone recommend a good inexpensive B&S MBC that works well?



Forge UNOS :beer:


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## UCFQuattroguy (Jul 5, 2005)

Chickenman35 said:


> I autocross my 1998 A4 and track day it. Important to note that I have an AEB with Drive By Cable. It's my DD ( when the damned thing decides to run!! :banghead: ) I run an APR Stage 1 tune and have run it with a stand alone MBC. I could run 18 psi no problem in Autocross. I have tweaked it to 20 psi with no fuel cut..but I was getting mighty worried with stock injectors and fuel pump. 18 psi is what I consider a " safe " limit with my components.... and then only for a short time like Autocross. I ran 15-16 psi Max on Track days This was on Chevron 94 Octane with a bottle of 104 NOS Racing Octane Booster.
> 
> Throttle response and low end boost was immediate. Car was MUCH quicker in Autocrosses with the MBC. Could compete with E30's which was batting above it's " considerable " weight.
> 
> ...


I've got an AWM engine code, so I know I've got *some* more injector than you do...and also additional "nannies". I'll have to do a full round of data logging to see what I've got to work with. Recently replaced a very "diva-like" N75 and have gotten a bit more of a consistent low-end spool back.

As far as the part throttle driving of having an MBC-only setup: this is no longer a daily driven car...so it's not really an issue if/when I give it a shot.


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## Chickenman35 (Jul 28, 2006)

Inexpensive MBC? You don't need anything fancy IMHO. Last B&S MBC controller that I bought cost me $10. ( Used ) Generic B&S and it works just fine. 

VooDoo-V B&S models work just dandy. Don't bother with the Ceramic ball nonsense. $19.95 everyday. 

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2051067.m570.l1313.TR0.TRC0.H0.XVooDoo+Boost+controller&_nkw=VooDoo+Boost+controller&_sacat=0

A BS MBC is just about the simplest thing ever made. I don't need to pay extra for " Billet Bling " nonsense that adds zero performance value.

Edit: Bought a Joe Pro Billet MBC some time ago. Nice polished " Billet " piece. Lasted three years then Internal threads stripped out of housing. Replaced it with a $10 generic used model I bought from a friend. Hed' had it on his DSM for 10 years. The $10 MBC will likely out live the car judging by it's simplicity, and if it does break... who the Frak cares for $10. :laugh:

And I can take it apart, play with different springs, blast it with WD40 every once in a while if I remember. Or toss it in the garbage if I want. Simple & Cheap. :thumbup:


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## ExtremeVR6 (Sep 6, 2001)

I built one from ace hardware. The main trouble I had was originally the bearing would get jammed in the barbed nipple it was in. Heavy vacuum was sucking pretty hard on it at -25psi. I used a bit close to the size of the inner diameter and created a bit of a landing for the bearing to rest on, instead of the decreasing diameter that was allowing the bearing to get jammed. 

The biggest benefit I could see from purchasing a more expensive b&s MBC, is not having to figure out the spring rate so that you actually have some variability/adjustment of the valve.


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## Chickenman35 (Jul 28, 2006)

The $19.95 VooDoo B&S MBC has options for choosing springs to control opening points. You can buy the springs separate from them as well. I think they're a whole $1.50 each :laugh: 

Unit easily disassembles for spring changes or cleaning. Oil from Intake system can gum up the works after a while. Being able to take a MBC apart and service it is a big plus in my books.


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## GrapeBandit (Dec 13, 2010)

Chickenman35 said:


> The $19.95 VooDoo B&S MBC has options for choosing springs to control opening points. You can buy the springs separate from them as well. I think they're a whole $1.50 each :laugh:
> 
> Unit easily disassembles for spring changes or cleaning. Oil from Intake system can gum up the works after a while. Being able to take a MBC apart and service it is a big plus in my books.


I actually saw that voodoo one on ebay yesterday lol...I didnt know they sell different springs for it either. also, I didnt know I would need different springs, I never messed with a MBC before.

edit: the voodoo one says adjustable to 30psi, I would be doing maybe 22psi, so I assume I wouldnt need a different spring


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## ExtremeVR6 (Sep 6, 2001)

Agreed


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## blackmajikk (Jul 3, 2013)

I know I'm digging at an old thread...but I had a friend tell me I should do this mod.

How many springs would I put if I'm roughly running 15-16 lbs of boost?


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## Boulderhead (Oct 21, 2012)

blackmajikk said:


> I know I'm digging at an old thread...but I had a friend tell me I should do this mod.
> 
> How many springs would I put if I'm roughly running 15-16 lbs of boost?


Do you have any trouble meeting the requested pressure? What is the cracking pressure of your WG? Without knowing that info, its hard to make any recommendation.

The only reason to do this is to keep the WG from opening pre-maturely on cars running boost beyond the tired hardwares ability to keep it contained.


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## Marcus_Aurelius (Mar 1, 2012)

Boulderhead said:


> Do you have any trouble meeting the requested pressure? What is the cracking pressure of your WG? Without knowing that info, its hard to make any recommendation.
> 
> The only reason to do this is to keep the WG from opening pre-maturely on cars running boost beyond the tired hardwares ability to keep it contained.


+1 :thumbup:
Well said!


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## 20v master (May 7, 2009)

Marcus_Aurelius said:


> +1 :thumbup:
> Well said!



I took off my springs this past week actually. They helped when using the N75 but boost is more stable without them since I switched to an EBC.


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## Marcus_Aurelius (Mar 1, 2012)

20v master said:


> I took off my springs this past week actually. They helped when using the N75 but boost is more stable without them since I switched to an EBC.


Stable as in tamed? Are you going soft on us Adam? :laugh:


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## 20v master (May 7, 2009)

Marcus_Aurelius said:


> Stable as in tamed? Are you going soft on us Adam? :laugh:


:laugh: I can run 30+ with the EBC with no springs, and it doesn't spike and surge as much without them. I did find E85 about 12 miles from my current house, so I'm going to do rods on stock pistons and a clutch in my daily the next chance I get. Is that going soft?


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## jsmith2015 (Mar 7, 2015)

20v master said:


> I can run 30+ with the EBC with no springs, and it doesn't spike and surge as much without them. I did find E85 about 12 miles from my current house, so I'm going to do rods on stock pistons and a clutch in my daily the next chance I get. Is that going soft?


What EBC are you running


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## Marcus_Aurelius (Mar 1, 2012)

20v master said:


> :laugh: I can run 30+ with the EBC with no springs, and it doesn't spike and surge as much without them. I did find E85 about 12 miles from my current house, so I'm going to do rods on stock pistons and a clutch in my daily the next chance I get. Is that going soft?


E85  Hell yeah! I'll pay some kids on the block to stick a pink FlexFuel badge on the back of the car and snap some pics. :laugh:


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## focswagen (Jan 26, 2013)

Great thread, read most of it.

Trying to get a handle on if this is really helping folks hold more boost through the upper revs, that's all i'd like to add. I don't need more down low/midrange, but holding more up towards the top, making each gear a little more usable, is what i'm after. I know that adding this will be adding more down low(inherent with the mod itself), but just want to get see if anyone has some hard facts on what it did for them above 6000rpm. Held 2-3-4 more psi than prior? That'd be great.



Almost done fixing boost leaks, then i'll get this a shot.

- Drew


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## vtraudt (Mar 1, 2010)

20v master said:


> I took off my springs this past week actually. They helped when using the N75 but boost is more stable without them since I switched to an EBC.


What EBC (make/model/source)?


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## JohnFXT05 (Feb 6, 2017)

*My Wastegate Actuator Mod (Pics)sailin cadyville*


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## kobekakluote (Dec 3, 2017)

plan to mod my k04-064 (2.0tfsi)

anyone can advise the spec of spring i need ?

(the length,tension.etc.)


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## kobekakluote (Dec 3, 2017)

*spending spree*

plan to mod my k04-064 (2.0tfsi)

anyone can advise the spec of spring i need ?

(the length,tension.etc.)


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## TheDeckMan (Sep 26, 2004)

That should do the trick.


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## Converted2VW (Apr 8, 2009)

Reviving old thread for the sake of keeping records.

Car: 01 TT 225
Tune: Uni Stg2 (Normally Boosts up to 22.2psi - Boost readings via LiquidTT Gauge)

WG Actuation Pressure (Stock): 3.5-4 psi 
Springs Used: 2x Small Springs from Home Depot
WG Actuation Pressure After WASM: 7-8 psi (Approx, was hard to read)

Result, much more solid acceleration at WOT. Holds boost higher into power band. 
Butt Dyno approves! even passengers stating the car feels faster. Me = Happy 
Part-throttle needed much more finesse.

Installed Forge Unos MBC to ensure boost is capped properly. Currently experimenting on MBC setting:
- MBC setting turned all the way down (min): Max Boost 16.5psi
- MBC setting Min+4 clicks: Max Boost 18.2psi

First impression: Part-throttle issues went away fully!! much more drivable now.
Will keep playing and hopefully will remember to update.
:thumbup:


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## Converted2VW (Apr 8, 2009)

Update:
Continued driving without change to get a better grasp of the evolution of the mod.

Car is now boosting up to 20psi without issues (up from 18 psi).
Perhaps the ECU adjusting to the new conditions?


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## ExtremeVR6 (Sep 6, 2001)

I’m little confused, in your previous post you said that it goes to 22.? Psi... but now it’s up from 18? Not trying to bust your balls, just wanting to figure out what I missed... 

Edit: Eh, never mind, I finished reading your post... 18 is with the MBC you’re testing. Got it... 

So, it crept up 2 psi and there was no change with the MBC? Any chance the knob is loose and vibrates a bit? 


Sent from my iPhone using Tapatalk


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## Converted2VW (Apr 8, 2009)

I hear ya. The knob feels solid though. I can only assume ECU adjusting to new dynamics?


Sent from my iPhone using Tapatalk


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## Dave Brabant (Sep 4, 2017)

i know this is an old thread but i have unitronics stage 1+ i love the way the car accelerates right now boost rips me into my seat ... but at 5500 rpm it falls on its face so would this help my high end revs and not mess with my lower rpm feeling ?


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## Brake Weight (Jul 27, 2006)

No. Your turbo is reaching it limit and can’t keep up. It may get an extra PSI or two, but I doubt it.


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## Dave Brabant (Sep 4, 2017)

Wow I used a spring from brake drums out of a pack I had left over and it started boosting to 28psi so I took it out.. I don't want to lean the engine out.. I just want it to hold the 22psi till redline and not spike at 22 and drop down to 15..


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