# Strange zip/whistle-ish noise from around throttle pedal during throttle blips (rev match) and sputtering noise at WOT only - Seemingly NO boost loss



## Thy_Harrowing (Dec 7, 2014)

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*Solution has been reached for both the noises mentioned in the title and for another completely separate issue that comes up later in the thread... Post #39 and #40 detail the whole chain of events, investigations, testing, fixes, etc. so if you don't want to read the entire thread then skip ahead to those (and if you are here from my other thread then just skip to #40). They're basically the TL;DR version, although they are still quite long. The super-TL;DR version is this: noises were caused by an exhaust manifold leak caused by the bizarre occurrence of 1 loose manifold stud and 1 completely missing manifold stud. It shocks me that the leak wasn't bad enough to have more noticeable symptoms but it's fixed... 

If you are here from my other thread then this part right below is the TL;DR for you, then skip to #40 and #47 for details on the issue, the diagnosis, and the fix...
The second issue that came up at some point in the thread was a boost related issue that was NOT a boost leak and was NOT any other mechanical reason for lack of boost, it was simply that my tune was too aggressive in the boost it was requesting of the little K03 that the wastegate was unable to hold closed against the exhaust pressure against it and was flapping open, thus thwarting the turbos ability to make target boost at all and also forcing the N75 and turbo to work over-time to correct this (unsuccessfully). Moral of the story: if you have K03 turbo and tuning software that requests, say, ~20 PSI or definitely 21+ PSI, you definitely want to take a look at my post #40 and #47 as you may have the same situation and not even know it. I data-logged a friends Stage 2 Eurodyne GTI right after I fixed my issue and sure enough he is having similar looking symptoms...*
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Original post:


There is this strange zip/whistle-ish noise that occurs at times when I press the throttle. It almost sounds as if it were coming from the throttle pedal itself or at least pretty low in the engine bay behind the firewall. It does not occur all the time. It seems to only occur after cruising on the highway for long enough (5+ minutes) and if I sit at a light for a bit or turn the car off, etc. it takes a few minutes of being on the throttle a lot to come back. It is loudest during throttle blips (like when rev matching) at which time it is more of a quick whine/zip noise but it does create a bit of a sputtering noise when I'm on the throttle steadily. It happens during partial throttle or WOT, either way. Acceleration is completely unaffected. NO performance loss whatsoever. Seemingly no boost loss (numbers on my gauge look good but I'm gonna keep a closer eye on them from here out), and no symptoms of vac leak.

A throttle switch was my first thought the very first time I heard it due to location of the sound and the absence of any performance issues/DTCs but it quickly became clear that wasn't it based on the way it sounds... doesn't sound like any pedal switch issue I've ever heard; again it is almost a whine/whistle/zip sound when blipping the throttle to revmatch and it makes this sort of light sputtering noise when I get on the throttle and stay on it instead of blipping it. It only happens after I've been driving for a bit (mainly on highway with constant throttle). Never there after cold start and never there in stop-and-go. 

I believe we can rule drivetrain out. It occurs in any gear and out of gear and whether clutch is engaged or disengaged.

My only theory at the moment is the N75 starting to tire a little bit. It fits in some respects, but in others it doesn't (e.g. you'd generally expect boost and power loss with an N75 issue, right?). Is there anyway one could be tiring out but not actually causing boost loss?

I have no other theories at the moment so I am open to any and all suggestions and pointers. If I can clarify or go into more depth about anything else that is lacking let me know.

Thanks for you time!


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## Thy_Harrowing (Dec 7, 2014)

Any ideas?


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## Fogcat (Apr 29, 2015)

Any scan info? N75 problems should give faults. I do not have vcds but can get fault info with another scan tool (not obd2, more detailed). Check it out and there are many who can help you.


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## Thy_Harrowing (Dec 7, 2014)

Fogcat said:


> Any scan info? N75 problems should give faults. I do not have vcds but can get fault info with another scan tool (not obd2, more detailed). Check it out and there are many who can help you.


Nah, I scanned with VCDS. There's nothing. I plan to log some data and compare what I see to logged data I've saved previously (I keep tabs on my car religiously). I haven't gotten around to it yet because honestly I don't expect to find a anything out of the ordinary. There's literally nothing different about how the car behaves besides the noise, at least for now. That's why this is tricky.


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## Thy_Harrowing (Dec 7, 2014)

> I haven't gotten around to it yet because honestly I don't expect to find a anything out of the ordinary.


I spoke too soon. It seems I am down on boost by a bit. Usually hit 21-22PSI, today maxed at 18PSI (AC off). Oddly I haven't noticed any performance loss, car drives totally normal. What gives.


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## ROH ECHT (Dec 9, 2010)

Regarding the N75 fading and shouldn't that give a code?...it can fade and you get no codes. Mine was replaced last year. I had no codes. My boost would only go to 18 psi max, then drop to about 10 psi but would then climb again to about 14 or 15 psi. This would happen in one gear's rev range. When the N75 is on its way out, it seems the boost behavior varies for each of us. But, if you know all is well with the boost plumbing, DV and vac lines...you can assume to try a new N75 when boost is not right.

Now, with regards to the pulsating noise...perhaps that is also associated with the N75 behavior. It has a signal that controls and allows boost force onto the wastegate actuator to control opening of the WG. So, if the N75 has, or has recently, begun to fade...the sound may be related to the first stage of it failing in your particular case...weird behavior in other words. Where now you may be seeing another symptom of further fading seeing abnormal boost. 

Hope to see data soon.


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## Thy_Harrowing (Dec 7, 2014)

Got it, thanks. Data will be forthcoming soonish. As for the vac lines, the only lines I am at all skeptical about would be the brake booster lines as I had to replace them recently. I replaced the lines from the vac pump to check valve and then from check valve to brake booster because the one going into the brake booster developed a small crack so I figured I'd do the rest (Spulen silicone brake booster hose kit). Well while I was removing the one that goes from brake booster into a part of that 4-way plastic valve pass-through flange thing (part of it passes coolant and the bottom part is just for the vacuum hoses to meet up) I cracked off the end to the flange (so fragile) so I wound up just direct connecting the hoses from brake booster to below check valve which required some hose connectors and a short piece of plain old cheap heater hose (which I figured was sufficient for this application). See the pics below

https://drive.google.com/open?id=0Bzeazv76x9MXTndva2U1aGsxemM

Every connection point has clamps and there were NO issues for a good few months but I suppose something could be up someone along the line. Do you think there is any chance that this has something to do with it. Wasn't my first guess as I find it hard to imagine given how secure the install was on every joining part... I guess one pretty simple answer is take them out and re-install and see what happens but wanted to see what you think of symptoms fitting; would a teansy leak have anything to do with this throttle noise? Again, no performance loss and no brake power loss.


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## Fogcat (Apr 29, 2015)

Just a wild swing.....intermittent relay issues? Easy to check and costs nothing. I did break my booster line just as you described but the cars reaction to it was dramatic and obvious, I did not have to guess lol. Misfires and limp mode results, not like yours but again, somethings not right. I was told the N75 when the relay acted up (one of the 100s in the engine bay) and tracing wiring it definitely impacts the N75 performace. Easy check and easy check off that problem if not.


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## ROH ECHT (Dec 9, 2010)

I don't think so...but could be opposed to my thinking. I think when the boost is trying to crack the WG...something is off with either the N75 operating incorrectly or the WG preload calibration. Sound, in my opinion, is waste exhaust pushing and pulsating through the WG by amount of exhaust/spring load ratio or the N75 is opening prematurely.


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## Thy_Harrowing (Dec 7, 2014)

So were thinking a teansy vac leak in the new lines I put it is out of the question for this issue? Still thinking N75/WG even though the noise is happening at ANY level of throttle, not just WOT?


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## ROH ECHT (Dec 9, 2010)

Thy_Harrowing said:


> So were thinking a teansy vac leak in the new lines I put it is out of the question for this issue? Still thinking N75/WG even though the noise is happening at ANY level of throttle, not just WOT?


Thinking more it's the N75 based on behavior alone...but there is always a chance it is the WG spring and preload may be light to zero. There's always a chance it is something altogether...but you gotta start somewhere. Data for wgdc, boost, and then fuel trims that will show vacuum leak presence.


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## Thy_Harrowing (Dec 7, 2014)

Ten-four. I'll get the data as soon as I can.


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## ROH ECHT (Dec 9, 2010)

I may have already shared this link, but it will help anyone determine if they do have vacuum leaks: https://www.youtube.com/watch?v=yM3iarhSP68


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## Thy_Harrowing (Dec 7, 2014)

I haven't gotten around to logging yet but I did stumble upon some stuff while researching that is making me wonder about whether my GFB DV+ might have something to do with what is going on. The GFB DV+ is a simple yet elegant design and I do believe that it does all the things they say it does but there are some concerns I've uncovered during some research. These range from simple little things like the brass piston becoming dry over time (even if you lubed it well on install) and thus causing issues, to the more serious functional concern that APR has brought to light which is essentially that the heavier spring actuation method that is integral to the DV+ doing what it is intended to do can actually be its downfall in one area... that is, when the ECU decides based on whatever environmental conditions/factors that is needs to pulse the DV the heavier spring makes this this difficult and the ECU can't anticipate or account for that. The ECU is expecting a certain functionality at times that just isn't there.

That's as much as I care to explain about it, a simple summary, there's more I read about too but, at the end of the day, APR and other tuners are only running Rev D stock DV on their super built big turbo cars so there's got to be something to that, I'd assume. And they recommend just sticking with that DV in all applications with all of their tunes. You could say that they are just saying that so they don't have to be responsible for anything when people use non-OEM parts but, when it comes down to it, would they really use the rev D stock DV on some seriously built cars if it wasn't ideal??

Anyway I'm on a little bit of a tangent there. As far as it relates to my situations... well I'm not entirely sure if the GFB does have anything to do with it. If it does then it's kinda sudden considering I had no issues with it for months. That could be dry piston, could be warmer temps making ECU calculated differently, who knows? Or maybe it has nothing to do with it. To be fair, the stuff I relayed above is all second-hand info and it could also be dated. I am aware the GFB has made some revision to their product but I'm not sure if that was before or after the stuff that has been said about ECU actuation difficulties.

I have no real reason to suspect the GFB is responsible other than conjecture. The conjecture is pretty simple... I'm pretty sure that I don' t have a vac leak because I'm pretty sure I'd be noticing other issues and because the symptoms do seem pretty like a minor N75 or DV issue (as you've pointed out ROH) then I figure I should target the GFB before I target the N75. 

The real question will be if putting the DV back to stock doesn't change anything then what lol. I'd be 50/50 since there are decent reasons on both sides of the fence for keep it on or keeping it off lol.

EDIT: Annnnnnd of course I didn't keep the flange piece that you take off the rev D to install the GFB piece so now I can't return it to stock without buying a new Rev D. I usually keep these sort of things just in case but figures the one time I didn't is the time I wish I had..... I guess I could actually just remove the spring for the GFB which makes it go back to a stock open or shut function instead of progression with spring, which in theory would be like having the stock DV but if the issue is with something else about it then that wouldn't make a difference


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## Thy_Harrowing (Dec 7, 2014)

Addendum to previous post:

The plot thickens. I decided to do what I said at the end of the previous post and remove the main piston spring included in the GFB DV+ solution. Doing so is an intentional optional feature of the DV+ design and allows the piston to go back to the stock DV open or shut function. Why anyone would normally do this, I don't know. I did it because I wanted to go back to stock to test my throttle zip issue but I don't have the stock parts anymore. So anyway, I did remove the spring and re-installed the rest.

Well not 10 seconds after I started my car (totally cold start) to my horror it sounded like there was a very loud hair dryer in my engine bay, a constant noise not a flutter, which I hope means it wasn't some kind of compressor surge. I almost shut the car off right away but I knew I installed everything properly (I mean it's kinda impossible to screw up) and I decided to trust GFB wouldn't lie about telling you that you can safely use their product this way, so I let it go a bit longer as there were also no other signs of any problem. No smoking anywhere, no engine surge, no misfire, no CEL, steady idle, steady and normal vacuum reported by P3. Well by the time my car warmed a bit and idle rested down at 800rpms, etc. it was gone. I gave the car a few revs and notice an additional tone pretty much right on the end of the noise my intake makes. So I heard my typical intake noise and then immediately as that ends I hear a tone not too unlike intake noise except higher pitch but quieter. Sounds kinda like a hawk or eagle or screech owl too be honest. I'm bad with bird noises but it's one of those. I decided instead of putting the spring back in the DV+ that I would drive around the block as the car was not acting up in any way other than these new noises. The original hair dryer noise was gone at this point and was also gone while driving but the noise coming on the end of the intake noise when lifting off the throttle was still there. I drove cautiously for a few minutes and built up confidence that I could go for a normal drive, did that, and gained more confidence that I could go for a hard drive. So I did that too. 

All told I drove the car for about 20 mins with plenty of hard pulls and I was astounded when I came to realize that this new noise that was happening when lifting off the throttle at low to mid RPMs was precisely what GFB says to expect to happen when you install the DV+ *WITH the spring* but I also noticed that my car held more boost between shifts which is the *WHOLE* purpose of the GFB DV+ if you install it*WITH the spring* in the first place. During this whole drive my butt dyno told me my car probably wasn't down on power and my P3 gauge data indicated nothing was amiss either so clearly the install was fine and things were functioning as intended. I'm confident the new noise while driving is what GFB tells you to expect. I am however NOT at all sure about that hair dryer noise when I first started that car. That is nowhere in their description of the product nor have I come across it in any readings about the product online. So that is of some concern... 

Now as far as the original problem this thread is about, I did not notice the throttle pedal whistle/zip or sputter symptoms at all during this drive. That is NOT yet conclusive though b/c this drive may not have been consistent enough to produce it but I will be taking a drive tomorrow that will definitely produce it if it is not fixed. If I don't hear it tomorrow then somehow doing this change to the DV+ (either deleting the spring or lubing the piston, since I did both) somehow fixed the original problem noises that this thread was about in the first place. However, I'm not holding my breath on that because my boost still hasn't gone back to normal. Even though my butt dyno has been telling me ever since the original noise issue came up a month or so ago that my car hasn't lost any power compared to what it should be at, P3 cars reports that I'm still only maxing 18PSI whereas I should be maxing 22PSI and was before this throttle pedal whistle/zip/sputter thing started a month or so ago.

Hopefully this isn't too confusing since we now have 2 separate issues that are both noises that occur with throttle input haha. I will update tomorrow if the original noises are gone. If they are then I just need to figure out *WHY ON EARTH* my GFB DV+ *WITHOUT *spring is behaving like it should* WITH *the spring, as well as find out why it sounds like a hair dryer on cold start and why I'm down 4PSI boost in the first place.

I had contacted GFB via e-mail but with this new finding a phone call is definitely in order... nevertheless I am interested in what any feedback/input that you guys have on this matter. Let's hear it...


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## Thy_Harrowing (Dec 7, 2014)

*Update*:

Good bit of driving today. The original whistle/zip noise thing that I made this thread about hasn't changed at all so now I'm still trying to figure that out as well as why the GFB DV+ is behaving the opposite of how it should be in regard to whether it is installed with the spring or not. 

On the good side, that crazy "hair dryer" noise I mentioned in the previous post on cold start after taking out the spring to the DV+ did NOT happen today at cold start. I don't know whay that was all about but it's gone now completely.


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## ROH ECHT (Dec 9, 2010)

I don't think the DV has anything to do with the noise. I also don't know anything about the GFB DV...I briefly looked at or into it when it first came out but decided that if my AWE DV ever does wear out, I would go back to oem as well.

"Noise still the same"...I still think the N75 is a good place to start. You don't have a situation where it has been this way all along. Something has changed in your boost behavior. That would point me to the N75 beginning to have problems, as long as there is nothing obviously wrong with the WG actuator or rod, and we aren't completely thrown off as to where the noise originates from. We sort of came to the conclusion it is from near the turbo but it may be something else we haven't thought of. You may want to do more investigation of the location of the noise and I would do a visual to make sure, with the WG rod, all is connected and normal there. Then, after you confirm boost specified and actual data, I'd replace the N75. Then see if fixed or not. If not, hold on to the old N75 as an extra. I would still look at short and long term fuel trim @ idle...trim under load isn't relevant to see if there is a leak. If the N75 fixes the boost and not the noise, then?????, is the noise turbo related? If it is and the N75 is good, I would think to adjust WG preload. But it could need more or less spring preload. Depends on when the noise is happening. Try, when doing the data run, noticing what rpm it is when you first hear the noise. Have your data in front of you. Did the noise start when boost is trying to climb and reach max boost or do you hear it when boost has already reached max boost and has begun to taper down? If you heard the noise begin as boost is trying to reach max boost...likely the WG is pulsing open unable to hold closed. If you hear it when boost tapers...perhaps the preload is too much and is opposing the opening of the WG by boost to allow waste to pass. This is just my thinking with my understanding of how the internal wastegate operates...welcome to any input or criticism.

This stuff we could at least cross off to being the source of the noise...there is the issue of changed boost behavior to correct regardless. You get through this and if still there...you just need to locate the exact source. I'm not sure as I haven't heard it. From your description before, it reminds me of boost pulse I get every time I build boost from a low rpm as boost builds initially to reach max pressure. Mine quits when it has reached mid range rpms to redline. If your noise happens other than what I get...perhaps the noise is elsewhere.


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## Thy_Harrowing (Dec 7, 2014)

All sounds like solid advice and makes sense according to what I know about the WG, etc. too. I'll do as you say looking specifically for those patterns in the data logging. I can tell you right now without logging though that the sputtering noise (which is how it sounds when steady on throttle instead of the whistle/zip noise when blipping throttle) definitely begins the second I put the pedal down, even a little bit, and as the turbo is building up to approach max. It's on the entire time. So yeah assuming this isn't something else entirely then it does sound like the WG is unable to hold closed. But in this scenario boost wouldn't climb consistently right? Although max boost is 4PSI lower it still gets up there consistently, no fluctuation on its way up, at least as far as my gauge indicates, but the data logging will be the final word on that...

Anyway, the reason I went into great detail about the DV+ and what was going on after I removed the spring from it is because it makes absolutely NO sense that it is giving me the benefits it is supposed to when it is NOT supposed to (spring not installed) and NOT giving me the benefits when it is supposed to (spring installed). It's literally behaving the opposite of how it should. It's not the source of the original issue, clearly, BUT I can't help but wonder if that give opposite behavior gives some insight into what IS going on with the turbo/N75/WG situation since they all work closely together. I wonder what the DV+ behaving this way can tell us about the actual/original problem.

The way the DV+ works is quite simple. I don't mean to impose but if you do have a few moments just watch this very well done video from GFB's Brett and everything I said will make sense about how it is behaving opposite of how it should.

https://www.youtube.com/watch?v=3EgXspDfI08


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## Thy_Harrowing (Dec 7, 2014)

Made a new thread about the GFB situation so things don't get to muddled and confusing on this thread... I'll update when I get a chance to data log.


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## ROH ECHT (Dec 9, 2010)

I thought you may try getting answers to the GFB DV+ behavior at this UK site. http://www.mk5golfgti.co.uk/forum/index.php/board,3.0.html

I hear/read more installs of the GFB DV over there than I do here.


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## ROH ECHT (Dec 9, 2010)

Thy_Harrowing said:


> I can tell you right now without logging though that the sputtering noise (which is how it sounds when steady on throttle instead of the whistle/zip noise when blipping throttle) definitely begins the second I put the pedal down, even a little bit, and as the turbo is building up to approach max. It's on the entire time. So yeah assuming this isn't something else entirely then it does sound like the WG is unable to hold closed. But in this scenario boost wouldn't climb consistently right? Although max boost is 4PSI lower it still gets up there consistently, no fluctuation on its way up, at least as far as my gauge indicates, but the data logging will be the final word on that...
> 
> https://www.youtube.com/watch?v=3EgXspDfI08


Boost data would not show WG pulsing if that is what it is doing, no. Because boost is still building even if the WG is pushed open due to either incorrect preload calibration or spring rate...it is not likely that the opening is excessive enough to affect compressor spin rate. What you will look for is how quickly boost is achieved in relation to the request in a 2k, to redline, rpm pull.

Watching the video on GFB DV operation...I could only see it being the DV if in need of cleaning before you removed the spring...or still happens because now the spring is removed, it will not close until you are building boost again. Seems to me you do not want to use it with the spring removed because one is not always out of vacuum when daily driving. He says their DV+ is designed to close regardless of the ecu keeping it open...and does so with the spring installed. Not sure the benefits of running it without the spring would be other than it will operate as the oem did, right? Think you've said that so,


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## Thy_Harrowing (Dec 7, 2014)

> I thought you may try getting answers to the GFB DV+ behavior at this UK site. http://www.mk5golfgti.co.uk/forum/in...board,3.0.html


Ah, good call. I'll do that.



> Boost data would not show WG pulsing if that is what it is doing, no. Because boost is still building even if the WG is pushed open due to either incorrect preload calibration or spring rate...it is not likely that the opening is excessive enough to affect compressor spin rate. What you will look for is how quickly boost is achieved in relation to the request in a 2k, to redline, rpm pull.


 Ah, gotcha I understand now. That fills in the missing bit I had about the waste gate theory. Thanks



> Watching the video on GFB DV operation...I could only see it being the DV if in need of cleaning before you removed the spring...or still happens because now the spring is removed, it will not close until you are building boost again. Seems to me you do not want to use it with the spring removed because one is not always out of vacuum when daily driving. He says their DV+ is designed to close regardless of the ecu keeping it open...and does so with the spring installed. Not sure the benefits of running it without the spring would be other than it will operate as the oem did, right? Think you've said that so,


Yes correct, the DV+ should be run WITH the spring for the reason you stated. Also correct that WITHOUT the spring it *should* literally behaves no differently then stock. What boggles my mind is that mine is behaving in the reverse. I had it installed for months WITH the spring and there were none of the benefits or noise cues one expects according to GFB after installing. Then the other day I uninstalled the spring to return the DV to stock functionality and for some reason I can't fathom the boost holding between shifts is better and the noise you're supposed to hear WITH the spring was there now too. So how the GFB should behave WITH the spring is happening WITHOUT it and vice versa. It's behavior WITH/WITHOUT spring installed is reverse of how it should be. And I should also point out that this isn't an issue of misperception on my part either, I'm 100% positive it's behaving reverse of how it should, it's clear. So I'm wondering how that could be and, more importantly, if it indicates something about how the turbo is operating that could help figure out the other issue (the one I originally made this thread on). Idk, it's all really weird behavior.


Anyway, Brett from GFB got in touch with me so I'm waiting to hear back on my latest e-mail to him, hopefully he can make sense of the DV+ oddity. We'll see how this unfolds. Log data should help clear up the original issue too, hopefully. On the bright side, at least the car drives like a charm and seems like there is no actually problem so far. I just hope my turbo isn't starting on a slow dragged out death of some kind lol... unless it's slow enough that I have time to save up for that K04


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## ROH ECHT (Dec 9, 2010)

Good, perhaps some real world feedback at the UK site if available will help....or GFB's Brett. opcorn:


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## Thy_Harrowing (Dec 7, 2014)

I wanna circle back to something I brought up earlier. I mentioned that I accidentally broke the little brake booster pass through portion of this (https://www.ecstuning.com/b-genuine-volkswagen-audi-parts/cylinder-head-cooling-flange/06f121132h/), it's the smaller pass-through in the middle. I broke it while replacing brake booster hoses all the way from vac pump to brake booster, due to a small crack. So I just routed the brake booster lines directly instead of using that pass-through spot. 

I dismissed this as a cause for any of the issues I'm having (the noise and the boost loss) because it really does just seem like a pass-through pipe and nothing else, and by the looks of it, once it is not being used it's basically like it doesn't exist. Well I kept telling myself that but I *think* this throttle zip noise started afterward so that though is nagging me. I emphasize "think" because I honestly can't remember exactly when it started so I'm not 100% certain it was after that.

Does anyone know beyond a shadow of a doubt that this thing is just a little plastic pass-through and doesn't have any kind of tiny valve or something in it that is now operating with no brake booster lines connected on either end of the plastic inlet/outlet?


Also, I tried to keep the size of the connectors and hose I used to make my own pass-through to the same size as the original pass-through on that flange (see here: https://drive.google.com/open?id=0Bzeazv76x9MXTndva2U1aGsxemM) but could the pass-through I made if it were slightly wider or slightly narrower be responsible for boost loss? 

Also on a separate note: I have mentioned that I am missing 4 PSI of boost but that I have not once noticed any decrease in performance of the car... how does that work? I know that boost isn't the only measure of cars power/performance but I would have thought that losing 4PSI boost would still be noticeable...


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## Thy_Harrowing (Dec 7, 2014)

Welp, here's the data. I'd like to start off by saying the the logs are not ideal for a number of reasons, however I made comments within them to make it more clear what is going on. First of all, there was more traffic on the road than I was expecting so that was a factor. Secondly, my VCDS was randomly throwing an error for losing connection to the controller during logging so multiple times it cut me off in the middle of logging. And, thirdly, my laptop battery is **** so I only had a pretty brief window to get this done in before I was SOL. All these things combined made me have to rush at the end (after the controller quit 2 previous good logs in the middle) and so the log I'm uploading for the pulls was a long, continuous log which several pulls but also several lulls with just cruising (waiting to get enough space between me and other motorists, etc.). 

That being said, I apologize that they aren't the most ideal HOWEVER I took time to run through them and put comments to clarify everything that is going on and of course I also logged engine speed and accel pedal position so you can tell when a pull is happening vs. when I was just cruising (although comments I left help to clarify even more). For readability I color-coded the most important values. Engine speed = blue, accel pedal position = red, N75 duty = brown, boost specified = darkish green, and boost actual = light green. This is to make it easier to tell what you are looking at after you've scrolled down the page a bunch. There are some other values logged but didn't color-code them as they weren't so important. 

I hope that between the color-coding and comments everything is clear and easy to follow and that hopefully what would have been a pretty ****ty log is now pretty clear and helpful. 

The link below is a shareable link to a google drive folder with all logs inside. There are 4 logs. The log with the pertinent data mentioned above is "Multiple Pulls 3rd Gear (and Some 4th Gear) Pulls For Boost + N75 Duty Data". There is another log called "APR Support Logging - Round 1 (1 pull, marker 1 = 4th to 5th, marker 2 = throttle cut issue at top of 5th)" that I took way back in January when I was having APR help diagnose a completely different issue (one that I have not noticed in awhile) which was a throttle cut issue sometimes at top of 4th and almost always at top of 5th. I DID NOT include that log because as a tangent issue to get into (again it seems to have disappeared, I think)... I DID include it because I wanted to give a frame of reference to compare against the current log you requested. I wanted you to be able to see what the data looked like back in January long before this weird whistle/zip/sputter noise started and also before I became aware of any loss of boost, so that you could compare that to the data from now. The only thing that isn't totally comparable from a boost perspective is that the log from January was a 4th and 5th gear pull, whereas the log from today has mostly 3rd gear pulls and some 3rd to 4th gear pulls. Interestingly enough, the data from VCDS is not showing much boost loss in boost actual now compared to before. As I said, I was under the impression that I was peaking at 22PSI not too long ago and am now peaking at 18PSI so for a little while now I've been saying I am missing 4PSI boost. BUt peak boost actual values from the log in January were only slightly higher than peak boost actual values from the log today. This presents a few different possible scenarios:

1) The VCDS values are RIGHT and I have not lost boost between January and now. And my P3Cars gauge which has shown readings of 22PSI peak boost before but has recently been showing 18PSI peak boost is WRONG.
2) The VCDS values are somehow WRONG and my P3Cars gauge is right, in which case I am missing 4PSI boost but VCDS is somehow not showing it
3) I saw 22PSI max on my P3Cars gauge over the span of a month shortly after install of the gauge (December, 2016) and then by the time I got around to logging for the throttle cut issue a month later in January, 2017 something happened and I lost 4PSI boost and somehow didn't notice it was only maxing at 18PSI until just a few weeks ago. (***Note: This is an enormous stretch and I consider it highly unlikely as I'm virtually positive I saw 22PSI on that P3 gauge in the spring not too long ago which of course was quite some time after the January log which was showing similar boost values via VCDS as I am seeing in the log I just took today.)

Some other things of note... atmospheric pressure here is 990-995 mbar. So it looks like peak boost (actual) for both the January log and the log from today is in the 20 - 20.5PSI range for VCDS. This is curious considering that I was seeing 22PSI on the P3 gauge at one point and am now seeing 18PSI from that gauge, but VCDS is reporting values right in the middle. I don't really have an explanation for this as it was my impression that the P3 gauge (being an electronic gauge plugged into the OBDII just like VCDS) is supposed to read data from the ECU just like VCDS so I was under the impression that they read data from the same sensors... Also, it's curious that peak boost actual from VCDS is very similar values from today as it was in January considering that it is much, much warmer now than it was then... I should be seeing more boost pressure (NOT power, I'm talking just pressure) now in the warm weather than back in January.

Lastly, there are 2 more logs that are purely for fuel trims at idle (since we discussed fuel trims in some PMs ROH). One of the fuel trim logs is after I did clear codes to clear fuel trim data and you'll see that the data looks off. I guess I didn't wait long enough for long-term trim to correct itself and, in turn, to correct short-term trim. The other fuel trim log was taken AFTER I had driven (for the other log) so the long-term fuel trim had readjusted and short-term looks more regular too. I think that is the good log and probably indicative of what my fuel trims actually look like day to day, not after doing clear codes like for the first log.


https://drive.google.com/open?id=0Bzeazv76x9MXZnpsbHVCc1VVMTQ


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## ROH ECHT (Dec 9, 2010)

Thy_Harrowing said:


> I wanna circle back to something I brought up earlier. I mentioned that I accidentally broke the little brake booster pass through portion of this (https://www.ecstuning.com/b-genuine-volkswagen-audi-parts/cylinder-head-cooling-flange/06f121132h/), it's the smaller pass-through in the middle. I broke it while replacing brake booster hoses all the way from vac pump to brake booster, due to a small crack. So I just routed the brake booster lines directly instead of using that pass-through spot.
> 
> I dismissed this as a cause for any of the issues I'm having (the noise and the boost loss) because it really does just seem like a pass-through pipe and nothing else, and by the looks of it, once it is not being used it's basically like it doesn't exist. Well I kept telling myself that but I *think* this throttle zip noise started afterward so that though is nagging me. I emphasize "think" because I honestly can't remember exactly when it started so I'm not 100% certain it was after that.
> 
> ...


Not aware of that part having any sort of valve inside it. I think it would be specific if it were also a check valve or non-return valve.

"4 psi loss being noticeable"....if I didn't have a boost gauge, I wouldn't have noticed when my N75 started failing. Seemed to have normal power, but the gauge showed only 18 psi peak, then drop to about 10 to 12 psi, and would build again up to 15 or 16 psi. The new N75 got boost back to 25 psi and a taper to 21 psi.


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## ROH ECHT (Dec 9, 2010)

The fuel trims before clearing look fine. 

One thing I see is in the early logs from January show wgdc able to drop into the 60% range...but the current wgdc looks to always be in the 80's% to 90's%...and only briefly dropping into the upper 70's%. My wgdc usually drops from 90's% into the 40's% or 50's% before climbing back into the 60's%. 

Your actual boost was only getting to a bit over 19 psi(2330 mbar)...I can tell your WG actuator spring preload is weak and could use a couple of mm's more. Your actual never met your highest request and then stayed below specified from then on. 

"I" would give the WG preload two full turns more. If that doesn't change the boost so that it reaches highest request before specified begins dropping and then actual is equal to or a tiny bit above specified throughout the run....I would give it a new N75. I say "I", because the adjustment is easy to do and will tell me if it was just out of calibration or that the N75 is the cause for having to work into the high 70's% and above to achieve requests for boost.

Could you just do one pull from 2k rpm to redline in 3rd or 4th gear and trim/delete unnecessary cells before full throttle and after redline? There would be much :heart: :laugh:


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## Thy_Harrowing (Dec 7, 2014)

> The fuel trims before clearing look fine.


Thought so. So then considering the fuel trims look on the money and I have no idle or performance issues we can basically say that there are no vac/boost leaks right?



> Your actual boost was only getting to a bit over 19 psi(2330 mbar)...I can tell your WG actuator spring preload is weak and could use a couple of mm's more. Your actual never met your highest request and then stayed below specified from then on.


I think it is fair to compare a 4th gear run from the log yesterday to a 4th gear run from the logs in January and during one of the 4th gear runs yesterday it peaked at like 2390. 2390 - 995 * .0145 = 20.2 something. My peak boost in January was 20.4 (if memory serves) so they are quite similar. It seems according to VCDS I haven't really lost any boost. Although, I should be seeing higher peak boost pressure in the summer right? Less air density = less efficiency = more pressure required to meet same ECUs target, and all that, right? So if that's true then in a sense I *have* lost boost pressure since I should be seeing more (probably why I was seeing 22PSI on the P3 cars gauge at one point). The only odd thing is that instead of seeing 20PSI on the P3cars gauge like VCDS says, I am only seeing 18-18.5PSI now. 

So what is your take on that? On the fact that peak boost is very close now to how it was in January despite weather? And on the P3Cars readings vs VCDS readings conundrum? I just mean, first of all, which do you think is more accurate... P3 or VCDS, and how might you explain the disagreements they are having on peak boost? Seemingly accurate peak numbers from the P3 gauge before but they are now not accurate according to VCDS.



> "I" would give the WG preload two full turns more. If that doesn't change the boost so that it reaches highest request before specified begins dropping and then actual is equal to or a tiny bit above specified throughout the run....I would give it a new N75. I say "I", because the adjustment is easy to do and will tell me if it was just out of calibration or that the N75 is the cause for having to work into the high 70's% and above to achieve requests for boost.


Got it. Yep you're right, everything seems to point to WG preload or N75 issue now just as you suspected all along. I'm gonna have to put my hand up for a second though because I have some concerns. I've been reading around a bit, threads like the couple I linked below. Granted those ding dongs in that one thread surely over-adjusted the preload but still, it seems that adjusting preload *can* lead to physical problems with the turbo behavior but, more realistically, it may at least throw off the ECU and it's calculations/assumptions on how things should be behaving. 

So I'm at a bit of a cross-roads here: on one hand my turbo isn't hitting peak boost anymore and is having trouble achieving specified BUT nonetheless I have 0 noticeable performance loss from it (so far) and the only noticeable manifestation of the issue is possibly this weird noise we've been discussing. When I think about it that way it almost makes me wonder if I shouldn't just let it go and enjoy the car/try to tolerate the noise since there have been no other issues. Plus if I really haven't lost performance as my butt dyno is telling me then it's like an "equal power for less wear on the turbo" scenario since peak boost is lower. I need this turbo to last until I can afford a K04 and related hardware I plan to buy, and that won't be for probably a good year, maybe more. On the other hand, maybe I don't have too long before this weakening actuator (or possibly N75) does turn into a real performance issue and maybe this noise isn't harmless, so maybe it is in my best interest to adjust the actuator and hopefully get everything back into proper spec and behavior. Maybe adjusting the actuator isn't as mysterious and scary as it seems from the reading I did and, in fact, since it is weakening I am just adjusting it back to the way it should be essentially.

What are your thoughts on this? If you were in my shoes where you can't take any chances on the turbos health and you have not yet had any noticeable performance issues what would you do? Would you still adjust the actuator because there's virtually no risk to minor adjustments? You know a lot more about this stuff and have experience so I differ to what you would do.

http://forums.vwvortex.com/showthread.php?1620228
http://forums.fourtitude.com/showthread.php?5011511-How-s-the-wastegate-work-on-these-things


Closing thought/question: Is the weakening of the actuator (possibly N75) an isolated case of weakening or can it have a relationship with a tiring turbo itself? Should I treat this as it's own issue or should I expect that it may mean the turbo itself may not be too far behind on approaching a tired state? Also, do you think the DV+ (which was installed with spring for about 6 months) could have had to do with this WG actuator (or possibly N75) weakening? The idea in my head being that since the DV+ w/ spring is designed to hold more boost when letting off the throttle momentarily for shifts - and to "only vent enough boost needed to avoid compressor surge" - that that extra boost could be tiring to the turbo and its components like the WG and N75? Or are they subject to more abuse and tiring forces just doing there jobs over the life of the turbo regardless of the DV+?



> Could you just do one pull from 2k rpm to redline in 3rd or 4th gear and trim/delete unnecessary cells before full throttle and after redline? There would be much :heart: :laugh:


Yes, I really should have done that, sorry! Would you like me to do that now or did you get everything you need to from the data?


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## ROH ECHT (Dec 9, 2010)

Thy_Harrowing said:


> Thought so. So then considering the fuel trims look on the money and I have no idle or performance issues we can basically say that there are no vac/boost leaks right?


No vac leak...not sure on boost yet. If the wgdc eventually shows signs of not having to work like it did in that log...and boost cannot be corrected by wg preload adjustment, then it may be a tiny leak but I doubt a wg preload increase and/or a new N75 doesn't correct it. 





Thy_Harrowing said:


> I think it is fair to compare a 4th gear run from the log yesterday to a 4th gear run from the logs in January and during one of the 4th gear runs yesterday it peaked at like 2390. 2390 - 995 * .0145 = 20.2 something. My peak boost in January was 20.4 (if memory serves) so they are quite similar. It seems according to VCDS I haven't really lost any boost. Although, I should be seeing higher peak boost pressure in the summer right? Less air density = less efficiency = more pressure required to meet same ECUs target, and all that, right? So if that's true then in a sense I *have* lost boost pressure since I should be seeing more (probably why I was seeing 22PSI on the P3 cars gauge at one point). The only odd thing is that instead of seeing 20PSI on the P3cars gauge like VCDS says, I am only seeing 18-18.5PSI now.
> 
> So what is your take on that? On the fact that peak boost is very close now to how it was in January despite weather? And on the P3Cars readings vs VCDS readings conundrum? I just mean, first of all, which do you think is more accurate... P3 or VCDS, and how might you explain the disagreements they are having on peak boost? Seemingly accurate peak numbers from the P3 gauge before but they are now not accurate according to VCDS.


Boost pressure is controlled and pressure shouldn't increase or decrease by temps. You get more or less oxygen but not pressure. 




Thy_Harrowing said:


> Got it. Yep you're right, everything seems to point to WG preload or N75 issue now just as you suspected all along. I'm gonna have to put my hand up for a second though because I have some concerns. I've been reading around a bit, threads like the couple I linked below. Granted those ding dongs in that one thread surely over-adjusted the preload but still, it seems that adjusting preload *can* lead to physical problems with the turbo behavior but, more realistically, it may at least throw off the ECU and it's calculations/assumptions on how things should be behaving.


Haven't read those threads yet, but a *minor* adjustment of less than 3mm(3 full turns) should show a difference. I can't remember reading the Jan. for APR data, but look at it and see if actual max boost reached specified before specified began declining. The cold/dense air should allow boost to max sooner than warm air. If not, a 2mm adjustment only keeps the wg shut a tiny bit longer to achieve max boost sooner and raise boost just a bit throughout.



Thy_Harrowing said:


> So I'm at a bit of a cross-roads here: on one hand my turbo isn't hitting peak boost anymore and is having trouble achieving specified BUT nonetheless I have 0 noticeable performance loss from it (so far) and the only noticeable manifestation of the issue is possibly this weird noise we've been discussing. When I think about it that way it almost makes me wonder if I shouldn't just let it go and enjoy the car/try to tolerate the noise since there have been no other issues. Plus if I really haven't lost performance as my butt dyno is telling me then it's like an "equal power for less wear on the turbo" scenario since peak boost is lower. I need this turbo to last until I can afford a K04 and related hardware I plan to buy, and that won't be for probably a good year, maybe more. On the other hand, maybe I don't have too long before this weakening actuator (or possibly N75) does turn into a real performance issue and maybe this noise isn't harmless, so maybe it is in my best interest to adjust the actuator and hopefully get everything back into proper spec and behavior. Maybe adjusting the actuator isn't as mysterious and scary as it seems from the reading I did and, in fact, since it is weakening I am just adjusting it back to the way it should be essentially.
> 
> What are your thoughts on this? If you were in my shoes where you can't take any chances on the turbos health and you have not yet had any noticeable performance issues what would you do? Would you still adjust the actuator because there's virtually no risk to minor adjustments? You know a lot more about this stuff and have experience so I differ to what you would do.


I would adjust the WG 1 to 2 full turns towards the actuator diaphragm. If WGDC doesn't decrease its %...I would do a new N75. 

Spring rate changes over time. Your Actuator spring is not exempt from this. The N75 may be fine and everything with boost and wgdc, including the noise, may be corrected by the adjustment. If boost gets corrected, but not the noise, I would let it go until the sound worsens and becomes much easier to locate...whatever it is. 

http://forums.vwvortex.com/showthread.php?1620228
http://forums.fourtitude.com/showthread.php?5011511-How-s-the-wastegate-work-on-these-things




Thy_Harrowing said:


> Closing thought/question: Is the weakening of the actuator (possibly N75) an isolated case of weakening or can it have a relationship with a tiring turbo itself? Should I treat this as it's own issue or should I expect that it may mean the turbo itself may not be too far behind on approaching a tired state? Also, do you think the DV+ (which was installed with spring for about 6 months) could have had to do with this WG actuator (or possibly N75) weakening? The idea in my head being that since the DV+ w/ spring is designed to hold more boost when letting off the throttle momentarily for shifts - and to "only vent enough boost needed to avoid compressor surge" - that that extra boost could be tiring to the turbo and its components like the WG and N75? Or are they subject to more abuse and tiring forces just doing there jobs over the life of the turbo regardless of the DV+?


So hard to determine what is having an effect on what. Tiring turbo? Everything wears per each use. Your turbo is likely fine and will be for some time...when you see dramatic changes is when you know its time is up.





Thy_Harrowing said:


> Yes, I really should have done that, sorry! Would you like me to do that now or did you get everything you need to from the data?


No, LOL, I was kidding after just having finished looking at it.


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## ROH ECHT (Dec 9, 2010)

Wow, the 1st link... I mostly :laugh:'d

I can do a vid of doing the adjustment. It's tough but I have done it many times and manage to do one in ten minutes or less. Probably different on the K03 because of knurled outer nut...where mine has a coupling nut, cut in half, for the outer nut so I can use a socket and ratchet on it.


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## Thy_Harrowing (Dec 7, 2014)

> Boost pressure is controlled and pressure shouldn't increase or decrease by temps. You get more or less oxygen but not pressure.



I thought it was pretty much an accepted fact that due to greater density/volumetric efficiency of air in winter turbos can make more power, or at least the same power, with less boost pressure in the cold... and that I *should* be seeing about 22PSI now in the summer (up from ~20-20.5 in winter) just like the P3Cars gauge was reporting 22PSI up until recently... but are you saying that boost pressure readings should be the same in winter and summer? If that is the case then that changes things. That would mean I have really not lost any boost between January and now and that the only thing that has changed is that the turbo doesn't actually achieve peak boost until after specified has already started dropping.

If that is the case then I no longer have a partial explanation for why my P3Cars gauge was reading 22PSI (which I thought was right) and is now reading lower.



> Haven't read those threads yet, but a minor adjustment of less than 3mm(3 full turns) should show a difference. I can't remember reading the Jan. for APR data, but look at it and see if actual max boost reached specified before specified began declining. The cold/dense air should allow boost to max sooner than warm air. If not, a 2mm adjustment only keeps the wg shut a tiny bit longer to achieve max boost sooner and raise boost just a bit throughout.


I had several logs I did for the APR ticket back in January. I only linked one to you but I just went over all of them. For most of the pulls in January peak boost actual did meet or exceed boost specified before boost specified started to drop off. In some pulls it did not quite meet it before boost specified started dropping off BUT it was still damn close. Much closer than any pull in the log from yesterday. It is also worth noting that even on the couple pulls from the January logs where boost actual did NOT meet boost specified before boost specified began dropping, it still ALWAYS does meet boost specified at some point by or before 3/4 into the pull, whereas a majority of, if not ALL, of the pulls on the log from yesterday show that boost actual NEVER reaches boost specified at all. 



> I would adjust the WG 1 to 2 full turns towards the actuator diaphragm. If WGDC doesn't decrease its %...I would do a new N75.
> 
> Spring rate changes over time. Your Actuator spring is not exempt from this. The N75 may be fine and everything with boost and wgdc, including the noise, may be corrected by the adjustment. If boost gets corrected, but not the noise, I would let it go until the sound worsens and becomes much easier to locate...whatever it is.


Got it. If you're sure that making a minor 2mm adjustment won't harm anything or jeopardize the turbo's future then that's what I'll do when I get around to it. 

I also plan to either return the DV+ to using the spring or just return to a stock Rev D DV because the extra noise that the DV+ is making without the spring is not sitting well with me. I also compared the boost data from logs in January (when the spring was installed) to pulls from the log yesterday (without the spring) and I don't see any compelling difference in boost held between shifts so, unless the current situation with the WG/N75 thing is effecting that data and making it an unfair comparison, then I would say the DV+ isn't really making much difference and I'll return the spring to it since things sounded less eerie withe the spring in, or I'll just return to stock DV and sell the DV+ lol.



> No, LOL, I was kidding after just having finished looking at it.


Well I know you said you were kidding but I did actually shave out all the cruising data between pulls anyway this morning because I was pouring over the logs and it was annoying me too so if you do have any reason to review it in the future as we continue with this diagnosis then know that it will be less painful to go through 



> I can do a vid of doing the adjustment. It's tough but I have done it many times and manage to do one in ten minutes or less. Probably different on the K03 because of knurled outer nut...where mine has a coupling nut, cut in half, for the outer nut so I can use a socket and ratchet on it.


I definitely won't turn down and offer for a vid if you're up for that. That would help a lot. I'm sure things will make more sense once I get under there but at the moment I haven't really the foggiest idea what the adjustment looks like since I've never paid attention to much else other than the DV as far as the turbo is concerned, never had a reason to until now.



*EDIT*:



> Have you noticed, in your boost data, if actual boost reaches maximum that is specified before specified numbers begin to drop? Then, later in the revs, near redline, does actual drop below, stay above, or equal to specified boost?


You asked me that in a message awhile back before I logged. Just remembered and wanted to address the second part in particular, about the boost actual near redline...

In ALL January pulls I did (which is like 10) the boost actual and boost specified are very close in the upper RPM range. In some cases boost actual is slightly higher (like 10mbar) and in some cases it is slightly lower, in others it is exactly he the same. But point is, even when it isn't exactly the same as boost specified in that upper RPM range it is still damn close. As you probably expected, that is not the case for the logs from yesterday. In the pulls from yesterday, not only does boost actual rarely, if ever, even meet boost specified but it isn't really that close even in the upper RPM range. I imagine this was what we should have expected to see.


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## ROH ECHT (Dec 9, 2010)

Colder air can help make more power, but not when controlled as much as ours are by our ecu and tune. If you could tune it yourself when air temps change...you could make adjustments to make use of condensed oxygen in cooler air. Ours will just do what it can based on intake air temp readings. You may get back to boost as you are used to seeing it, but your wgdc shouldn't be as high as it is and still struggling to match boost with specified. Colder air with our ecu may build quicker, hold longer, but shouldn't be allowed to stray far from specified just solely due to temps.

The GFB DV+ benefits they say about closing when there's no boost for improved throttle response...that will only happen when you go light onto the throttle after boost release by the DV. Why I need throttle response under no boost and in vacuum is beyond me...usually in vacuum driving I try staying greater than 12 Hg for 30+ mpg. LOL

All the boost and wgdc I saw in yesterdays data made me think a small increase in wg preload will sort the boost out with a slight chance the N75 is just beginning to fail and why I would adjust the preload a tiny bit...look for improvement...and if not, get a new N75.

Sure, I can get a wg preload vid done soon. Not for nearly a week though. Not a problem as long as I can prop the gopro somewhere up in there.

Lastly, there are always changes in data. Like I said, IAT, ignition, lambda, and everything with a sensor and reporting to the ecu will make data look different.


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## Thy_Harrowing (Dec 7, 2014)

ROH ECHT said:


> The GFB DV+ benefits they say about closing when there's no boost for improved throttle response...that will only happen when you go light onto the throttle after boost release by the DV. Why I need throttle response under no boost and in vacuum is beyond me...


It's more about that fact that it doesn't dump all boost in a split second of no throttle (during a shift) like the stock DV does. It has the ability to only dump enough to avoid surge, so when you get back on the throttle you have more boost already and can build up to max quicker. But as to whether it really does or whether that makes a difference I can't really confirm. My own comparisons of data from logs with the spring in the DV+ and without the spring later are showing no noticeable difference between shifts. That could be taken at face value, or it could be that my WG issue is making the DV+ look bad between shifts. Either way I have come to the conclusion that whatever small difference it makes is not worth the unease that started when I removed the spring and have all these extra noises from the DV (well manifesting in the intake), so I'm either returning the spring to it or just putting a stock DV back in to be safe.




> Sure, I can get a wg preload vid done soon. Not for nearly a week though. Not a problem as long as I can prop the gopro somewhere up in there.


That would be great, I appreciate it! Hopefully this knurled nut you mentioned on the K03 isn't a good pain compared to yours...


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## ROH ECHT (Dec 9, 2010)

Well....I find, or have found, bits that meant nothing and could've remained stock. Once that discovery is made a time or two, you begin thinking more whether or not you do need something just because available. 

I had a stage 1 BSH PCV block-off...but I never had an OEM PCV fail, so I went back to stock. I have an oem sized crank pulley by AgencyPower and wish I hadn't thrown out the OEM harmonic balancer because noticed nothing, I'd reinstall it if I still had it and sell the lightweight pulley. I have a bullet proof AWE DV, good for up to 30 psi boost...if it ever should fail, I'd go back to stock DV. 

When I upgrade my turbo from K04 to TTE 420 or BW EFR 6758...I wouldn't transfer my FORGE K04 WG, I'd use it's oem WG. The FORGE WG slams boost at shifts...meaning I see my boost go from the point it tapered to to over max boost. I see it shoot from 18 psi to over 25 psi at up-shifts...boost needle bouncing about and all. It is not smooth like the OEM WG is...because the FORGE shuts the WG more dramatically. Not that it is bad with the K04 because the lunges forward feel rather cool. But with one of those other turbos mentioned, and at 370+ whp and 400 lb*ft, it could be problematic on the internals. APR already recommends a valve spring upgrade for their TTE 420 due to valve float...but I already added 0.030" exhaust spring shims when I rebuilt my head.


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## Thy_Harrowing (Dec 7, 2014)

Yeah, I hear ya. A lot of mods are just pure marketing. Unlike many mods out there I actually thought the GFB DV+ was very well, and soundly, explained from a technical stand-point on their website though and between that and the reasonable price I was sold. Now after using it I don't think the product is bad, just not fond of the out-of-place noises without the spring installed and also seeing nothing reflected.


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## Thy_Harrowing (Dec 7, 2014)

So I was reading up some more and found a thread where a guy seemed to be having similar findings as me for requested vs actual and somebody said this:



> I would not play around with the actuator settings .. it's a biatch to get it back to oem again . Its a 3 page procedure and the turbo needs to come out if you want to do it right.


. 

http://vwclub.co.za/forum/viewtopic.php?f=94&t=138627

If I adjust it and somehow it is a bad adjustment and things go wrong is it not as simple as jusy adjusting it back to the way it was? They make it sound like once you play with it you cant get it back to how it was just as easily... Any comment?

There are a lot of other people on that thread with more reasons to not touch the actuator. It seems like a straightforward and logical adjustment to make given my cars circumstances and everything you've explained but I'm hesitant simply because of the fact that aside from the weird noise I have no other ill affects that I've even noticed (yet). Are all these naysayers being irrational or would I perhaps be better letting it go until/if I actual have an issue more than just noise?


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## Thy_Harrowing (Dec 7, 2014)

Still haven't gotten around to messing with the WG actuator but I did put the piston spring back in the GFB DV+ and the logged some more to see if anything changed. Data doesn't look all that much different, but there are some that I'll get into below, and at least the extra weird noises the DV+ was making without the piston spring are now gone again. Anyway...

Here is a new round of pulls. I took these when it was maybe a little bit cooler than the last round of data I did in early August, but not by much. It was ~75F outside when I took these pulls last night. Looks similar to the last round; peak boost isn’t too much lower than the logs I had done in January but it never catches up to specified boost. N75 is working really hard, harder than it was even in the logs from a few weeks ago, it’s at 94% duty cycle virtually all the time. I am currently waiting to hear from Brett at GFB if the reason the N75 could suddenly be working even harder is because of the difference DV behavior with that piston spring back in. Otherwise the fact that it is working even harder is concerning. I did notice that my highest peak boost value in this round of logging (2390mbar ~ 20.2PSI) was in a moment where the N75 duty cycle dropped a bit to 82% which was rare in this round of logs, again it was almost always working at 94% for entire pulls. Could that higher boost spike when the N75 wasn’t working as hard be coincidence, is there anything to that? My only other question is this: if I start out at 2k RPM and do 3rd gear to redline then 4th gear to redline in one pull VS. starting at 2k RPM and doing a 4th gear only pull to redline, would I expect to see different peak boost numbers in 4th gear depending on whether I shifted up to 4th after 3rd or whether I started out in 4th? The reason I ask is this... I noticed that in this log I took last night (AND the one in earlier August) when I do 3rd gear to 4th gear pulls the 4th gear part of the pull to redline has surprisingly low peak boost compared to the 3rd gear peak boost and ALSO compared to the 4th gear pulls I was doing for my January log. The only difference between these logs from August and the January log is that for the August logs I was doing 3rd to 4th gear pulls and in January I was starting out in 4th gear for the pull. Could that alone explain why the peak boost for 4th gear in the August logs (only ~2100mbar – 16PSI) is so low compared to the peak boost in for 4th gear in the January logs (2380mbar – 20PSI)??? I intend to run some more logs soon and test 4th gear only pulls for peak boost to see if it is much higher without the 3rd gear pull first but thought I’d bring this up for now.


Other than that and the fact that N75 working super hard there isn’t much that looks all that different in these logs. Peak boost values for a majority of the 3rd gear pulls in this log from last night was on average are 2360mbar – 19.7PSI, with one peak of 20.2PSI. The January logs (which again were 4th gear starting pulls not 3rd to 4th) didn’t have peak boost any higher than that, the difference was just that the N75 wasn’t working so far and that actual boost eventually caught up to specified boost in January, unlike now where it never catches up. 

Does this new data bring anything to light or change anything? I've got a guy from APR telling me that it means either I have a leak or my turbo is failing, although I don't really see how it could be failing and still performing relatively well. As for the leak, is it possible to have a tiny enough boost leak that the turbo could still reach the same peak boost as before the boost leak (but by working harder) or would a leak always mean lower peak boost?


Google drive link to all logs (the most recent one with new data is the "Late August...." log) - https://drive.google.com/drive/folders/0Bzeazv76x9MXZnpsbHVCc1VVMTQ?usp=sharing


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## Thy_Harrowing (Dec 7, 2014)

> ? My only other question is this: if I start out at 2k RPM and do 3rd gear to redline then 4th gear to redline in one pull VS. starting at 2k RPM and doing a 4th gear only pull to redline, would I expect to see different peak boost numbers in 4th gear depending on whether I shifted up to 4th after 3rd or whether I started out in 4th? The reason I ask is this... I noticed that in this log I took last night (AND the one in earlier August) when I do 3rd gear to 4th gear pulls the 4th gear part of the pull to redline has surprisingly low peak boost compared to the 3rd gear peak boost and ALSO compared to the 4th gear pulls I was doing for my January log. The only difference between these logs from August and the January log is that for the August logs I was doing 3rd to 4th gear pulls and in January I was starting out in 4th gear for the pull. Could that alone explain why the peak boost for 4th gear in the August logs (only ~2100mbar – 16PSI) is so low compared to the peak boost in for 4th gear in the January logs (2380mbar – 20PSI)??? I intend to run some more logs soon and test 4th gear only pulls for peak boost to see if it is much higher without the 3rd gear pull first but thought I’d bring this up for now.


Quoting myself above, this was one of my questions in the last post. I haven't gotten answers regarding the other few questions but I got an answer to this question myself today when I went data logging. The answer, as I suspected, is that doing a 4th gear only pull instead of going from 3rd to 4th absolutely changes the boost curve for 4th gear. 

The data made that clear and it also showed a HUUUUUGE discovery. The data from 4th gear only pulls shows boost behavior VERY similar to that of the January logs. I really have no f****** idea why I didn't just do 4th gear only pulls for these most recent logs just like the January logs but for some reason I just didn't (I guess to avoid potentially getting hit with a ticket for doing 110mph). Anyway... yeah the data for a 4th gear only pull, that is a pull starting at 2k in 4th gear and going to redline instead of starting in 3rd gear and pulling through 4th gear, this data looks very much like the January data, as in NO PROBLEM. The peak boost is just like in January which was on average anywhere between 2400-2450mbar (20.3 - 21PSI) *AND BOOST ACTUAL MET AND EXCEEDED BOOST SPECIFIED LATER IN THE PULL JUST LIKE IT SHOULD*. So fourth gear pulls actually show data that looks pretty much exactly like it should. There is literally only one thing that still looks different and that is the N75 data which still shows it working at 94% load virtually all the time.

I am gonna take more/better logs tomorrow. I forgot to put on turbo mode for faster sample rate so I can get even better logs to post of to show what I'm talking about but for now suffice to say the data actually looks right from what I can tell aside from the N75. The only exception to that is if it is still irregular that 3rd gear pulls boost actual never meets specified, BUT I have to figure that might actually be normal... after all the higher gears/speed you go the more you tend to boost so those high boost specified values of 2450mbar may just not be attainable in 3rd gear? Just thinking out loud, not 100% sure on that...


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## Thy_Harrowing (Dec 7, 2014)

****Figured I'd update this thread for future readers to benefit since at least I'm about 75% of the way to a solution right now****

I've ticked a whole lot of things off my list over the last few weeks, as I will go into detail about below. To pick up at the place of my last post though, I should point out that my hopeful/wishful theory regarding the 3rd gear data actually being acceptable was, indeed, wishful. The fact one with the setup I have should expect more boost in 3rd and should especially expect it faster than I was receiving it. It should peak somewhere in the 3K RPM range, mine was much delayed. And as always the N75 duty was still maxed all the time which suggests a problem. That being said, I wanted to see a glimmer of hope but quickly came to the reality that was just not the case. I then proceeded to address some potential causes of the problems. More on that below...

Despite previous thorough inspection of all boost plumbing and deciding a leak was unlikely I decided to remove and replace all boost pipes from turbo all the way to throttle body. I noticed some oil residue on outside of the silicone hose from throttle body to my BSH throttle pipe and one of the clamps was not exactly loose but not exactly tight either. I thought, AHAH, small boost leak. So I cleaned it up, thoroughly checked, cleaned, re-installed all boost hoses thoroughly, and used strong v-band clamps for the throttle body pipe hose. Well turns out the oil was just some oil sweat that had built up over time (normal for silicone, although perhaps a bit abnormal for a hose at throttle body but would be normal for a silicone turbo outlet hose).

Next thing I noticed after further inspection later was that I had a loose stud on the exhaust manifold, noticed purely by feel which was kinda lucky. So I took off my intake and removed the heatshield/integrated coolant hard-line thing that connects the coolant hoses from the expansion tank a line on the other side of the engine bay. With that off I was able to see that not only was one loose but one was COMPLETELY GONE! On top of that there was significant evidence of an exhaust leak there. I'm surprised with how close of attention I pay to my car, both audibly and with frequent data logging, that I never noticed anything to suggest an exhaust leak. I think turbo must have been replaced prior to my ownership and who ever did the job rushed (odd b/c it only had 55k on it when I bought it and was not owned by a modder or someone likely to abuse it). Either that or they were just not torqued well from factory. Anyway got new studs and nuts, fixed that. Thought for sure this was the fix to both my noises and my boost issue. Come to find out, after data logging with VCDS, the boost situation did not change one bit!! However, both noises described above were gone for good. I surmise that when the engine and exhaust mani got HOT enough under certain driving conditions to expand, as things do when hot, and open up a large enough exhaust leak to start hearing.

Next step was going to be the N75 itself but I figured if was really failing I'd have erratic boost issues, which I wasn't having. So, as ROH ECHT himself suggested to me quite early in this thread, I finally decided to take the plunge and try giving the turbo wastegate actuator rod 2 turns toward the diaphram to strengthen the wastegate's preload; the theory being that perhaps the wastegate was opening slightly prematurely (despite the maxed N75 duty cycle demanding it stay closed) and thus allowing some boost to escape, making the turbo work extra hard to achieve even the subpar boost I was seeing. It's not very common at all that this needs to be done, as far as my research suggests, but it was one of the only options I had left to consider that were reasonable.

Turns out that making the adjustment to the wastegate has mostly fixed the boost issue only but not the N75 duty which still suggests some issue. The turbo spools noticeably quicker now although maybe not quite as fast as it should, meaning boost is climbing to specified levels roughly when it should, and VCDS reported proper boost levels as well. 

So the exhaust mani repair fixed my noises that noises that this thread was titled for and the wastegate adjustment at least sorted out my boost issue, mostly, but it seems it was more of a band-aid as far as I can tell. The N75 duty cycle is still maxed all the time in WOT pulls which means the ECU is determined to keep that wastegate shut the entire time whether the turbo is in it's efficiency power band or not. This suggests some issue lurking but that has yet to be discovered, or perhaps there is some little detail that is being missed. Either way, we are currently stumped a bit but working towards a solution. I will update the post if I find one...


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## Thy_Harrowing (Dec 7, 2014)

****Final Update: Solution Reached*

First of all, shout out to ROH ECHT for working very closely with me, initially on the thread and more recently over PM, to come to this conclusion. This guy knows his **** and is very generous with his time! We bounced tons of ideas off of each other (mostly his ideas) and finally came up with a conclusion to this puzzle.

This is an update on top of the previous post I made. In the previous post I made I detailed some of my first investigations and the fix that did help fix the noises I started out discussing in the beginning of this thread (exhaust manifold leak) but it wasn't until adjusting wastegate preload that the boost issues showed signs of improvement. The N75 duty cycle, however, did not. The solution builds off of that point and is actually rather simple, in retrospect of course. We realized that although the boost data looked healthy with a wastegate preload adjustment of 2 turns toward the diaphram (more preload on the WG), the boost data was not yet completely ideal. We realized this the more we studied that data and that is when we decided that if we could get the actual boost to exceed specified boost just a bit more and also a bit more quickly that we would hopefully see the N75 duty cycle relax some. At this time ROH also dug up a thread that I failed to find in which a slew of APR Stg. 2+ users just like me were having very similar boost/N75 data anomalies just like me and while there was never a resolution in that thread a majority of those involved came to the conclusion that they either had a very, very small boost leak that was nearly impossible to find OR that the APR software was to blame. Not that the APR software was directly responsible for the N75 duty cycle, after all the ECU is what commands that, but that the APR software was just too aggressive, pushing the K03 to its absolute limit to achieve specified boost that the turbo just couldn't make. He and I discussed this and realize that this made sense given all the data I've been logging over the last couple months; it totally fit. Basically, we concluded that the APR software was specifying so much boost (in this case the max boost that the stock MAP can even see: 2550mbar = ~22.5PSI) and that not only was the K03 struggling to make this boost in the first place, but it was struggling even more because the wastegate itself could not hold itself closed against the exhaust pressure against it. It's basically what ROH suspected from the beginning, just with the added twist of it being a result of the tuning demands as opposed to the actuator arms preload weakening. In the end, it appears that the wastegate was flapping open and thus disallowing boost to build as quickly or as high as it should, hence why the N75 duty was literally constantly maxed in all of the latest pulls I did (which I don't think I actually posted on here, sorry). Because the wastegate was letting some boost go the ECU was trying desperately to get the N75 to get it under control by designating a max duty cycle at all times. 

With this in mind, I figured that all I'd have to do to prove that theory once and for all is to do something I had though about doing over a month ago but (stupidly) did not... and that is to simply put the car in stock mode and go for a data run. Sure enough, the car made stock boost laughably easily in this case, as expected, AND that meant the N75 was able to relax significantly. With that behavior confirms, I added 1 more turn of preload to the WG actuator rod and now the turbo is able to meet AND exceed specified boost anywhere between 600-900RPMs from the start of the 2K-redline data pull AND the boost stays above specified for the remainder of the pull (with only a slight dip at 3/4 of the way into the pull B/C the N75 duty relaxes) but then continues to exceed specified as specified boost tapers off in the later rev range. This is the behavior that should be seen.

So in summation, the solution seems to have been pretty straightforward. It was not a boost leak, it was not an exhaust leak, it was not low crankcase pressure supplying subpar exhaust pressure to turbo, nor turbo weaking/dying slowly, nor any other reason that the turbo would not be able to perform at peak. It was simply that the tune was demanding so much of the K03 that its wastegate could not hold up to the job and was opening, thus counteracting the boost build. This may not be an issue unique to APR either. Any tune for a K03 that is requesting boost above probably ~20 or definitely 21+ PSI range may very well have this same issue; the worst part is you damn well might not even know it because it's a a very subtle issue; let me be clear, I wouldn't have realized it if I hadn't had that weird noise going on (which wound up being totally unrelated) which prompted me to log some data and see a subpar boost curve through the pulls and the alarming N75 duty cycles. Make no mistake, this issue very well may have been going on ever since I got Stg. 2+ flashed (up from Stg. 1) so that entire time (over a year) I was not making full power and I didn't even realize it because it still felt a bit quicker than Stage 1. My recommendation to anyone running K03 with an aggressive tune with above mentioned boost levels who has access to VCDS... run some logs and check your boost curve. Who knows, maybe my WG preload was weaker than most and that was why but I tend to think not; I tend to think the tune was just demanding too much from the start. I data-logged a friends Stage 2 Eurodyne GTI right after I fixed my issue and sure enough he is having similar looking situation... In any case, I'm glad I logged and I'm glad that, with ROH's help, I was able to get to the bottom of this because my car is noticeably quicker than it ever was before and I'm loving it all over again!


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## gtimakesmebroke (Sep 30, 2006)

Would the upgraded forge unit help?


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## Thy_Harrowing (Dec 7, 2014)

gtimakesmebroke said:


> Would the upgraded forge unit help?
> 
> 
> Sent from my iPhone using Tapatalk



It should but considering the amount of logging you would have to do to calibrate its preload correctly as well as the installation of the unit VS. relatively little logging and ease of adjustment of the preload on the OEM wastegate actuator... I wouldn't bother with the Forge (unless it turns out that the OEM wastegate/actuator cannot keep the extra preload for a long time and starts to slack off after awhile again... I have no cause to believe that would happen though time will tell).


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## Crzyrio (Aug 14, 2013)

Can you post a log of what things look like now?

So If I read correctly you simply adjusted the pre-load on the N75?
I feel like I have a similar issue but haven't taken the time to try solving it.


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## sloppy_robby (Jul 28, 2016)

I wonder if this rings true to K04. I've never hit target boost on my stage 2+ tune. I've always related it to altitude, but I think looking into this is worth a try. Let's see what my Watergate duty cycle winds up being. 

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## Thy_Harrowing (Dec 7, 2014)

> Can you post a log of what things look like now?
> 
> So If I read correctly you simply adjusted the pre-load on the N75?
> I feel like I have a similar issue but haven't taken the time to try solving it.


Yes, later today when I get some time I will post logs of what the data looked like before and after. I may also put up a little DIY video because I will be making an adjustment to a friends K03 wastegate preload as I'm seeing very similar boost curve issues on his Eurodyne Stage 2 base map.

You're on the right track but it's not an adjustment to the N75, it's an adjustment to the preload on the wastegate's external actuator arm. The N75 is just a valve that allows for dynamic control of boost via the wastegate. I could explain how it all works but it'd be easier on both of us if you look up the vids that Brett from Go Fast Bits has on turbo/wastegate/n75 functionality. They are the best I've seen at succinctly explaining functionality. Brett's an awesome dude. Anyway, the problem occurs when the factory set preload on the wastegate actuator is not strong enough to prevent the wastegate from blowing open while the turbo is trying to make target boost during pulls, which of course makes the turbo have to work much harder to make said boost. This seems to be likely to occur past roughly the 20PSI mark based on my experience here. There are signs in the boost curve as well as a maxed N75 duty cycle which indicate what is going on. I will explain what precisely too look for later when I post the data comparisons I have from before/after. 

*Bear in mind that the signs in the data that I am referring to and will explain later are similar to what you will see if you have a very small boost leak SO to those reading this: if you have a similar situation based on data you want to be sure you don't have a small boost leak before assuming that the preload is the issue. But again, based on my findings, anyone running over 20PSI may very well have the same issue. *




> I wonder if this rings true to K04. I've never hit target boost on my stage 2+ tune. I've always related it to altitude, but I think looking into this is worth a try. Let's see what my Watergate duty cycle winds up being.


It very well might but I can't attest to that personally. ROH would probably have some input on that though since he is K04'ed and knows all about this whole subject; although the preload set on his K04, and indeed aftermarket K04 kits in general, may be set higher than the factory K04 on your Golf R so I'd say it is definitely worth looking into. Check back later for data comparisons and what to look for aside from maxed N75 duty.


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## sloppy_robby (Jul 28, 2016)

That would be awesome to see if he's noticed anythin.

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## Thy_Harrowing (Dec 7, 2014)

Thy_Harrowing said:


> Yes, later today when I get some time I will post logs of what the data looked like before and after. I may also put up a little DIY video because I will be making an adjustment to a friends K03 wastegate preload as I'm seeing very similar boost curve issues on his Eurodyne Stage 2 base map.


Apologies folks but I was not able to do that DIY video because the stock turbo on my friends Mk6 GTI is a bit different then the one on my B6 Passat (FSI) in that it appears that the wastegate preload is NOT externally adjustable on his. His actuator rod does not have the same (well any) external components to adjust the preload. I have a feeling this is probably the case on all the turbos fitted to EA888 Gen 2 (which his is) and probably Gen 3, but GEN1 TSI should be an exception. I cannot confirm right now but it's easy enough for anyone interested in finding out to confirm by putting the car up and looking at the bottom of the turbo above the axle and looking for the rod going from near the turbo-to-downpipe manifold all the way over to the wastegate diaphram body.

I might actually wind up putting half a turn more preload on my wastegate actuator for my car so if I do I will make the DIY video then but I haven't fully made up my mind on whether I want to do that. I have been working on the car way too much lately and need a break and I'm pretty content with where it's at right now. Although there's room for minor improvement in the data I am seeing now and a small little bit more preload would likely fix it; I am still cautious of going too far though as going overboard with preload is a recipe for overboosting. That being said, don't just think this is some free power mod without consequences people. You should do as I did and make small adjustments and data log in between to see the results. I started with 2 turns which is pretty minor and probably a safe starting point for just about anyone. I would probably never do more than 4 though no matter what though. My hunch is that if 3-4 turns doesn't solve things for you then you have other problems, like a boost leak.

In the absence of a video, at least for the time being, the best I can do right now is provide the below linked picture which shows what you'll be looking at with labels, plus an explanation. This should be sufficient because it is really not hard:

https://drive.google.com/open?id=0Bzeazv76x9MXU0FRY0Q1bFhBa28

1) After putting car up on jack stands and making sure it is safe to get under, position yourself under the axle/turbo and remove the U-shaped plastic guard that surrounds the axle. It is bolted on with 2 16mm bolts. Now you have an access point for your hand/arm to get at the actuator rod adjusting components
2) You'll need a mini-vice grip (or alternately one of those very long-handled, needle nose types so you can avoid having to reach up there all together), and you'll also need a flat blade screw driver and a 10mm crescent wrench. You'll also want a sharpy to mark the current positions of the components
3) Using the sharpy, put a mark on the actuator rod to the right of the 10mm nut (this is to make sure that when you are adjusting the preload you are turning the 10mm and knurled nuts, NOT spinning the actuator rod itself inside the wastegate diaphram. I did not have this issue at all but I suppose if the 10mm nut is tight enough it could happen. If it does you'll need to have an additional vice grips clamping the rod and braced in order to keep it from spinning. ALSO mark the 10mm nut and the the knurled nut. Mark all these aligned with each other.
4) Using the flatblade screwdriver, remove the retaining clip that connects to a slot on the knurled nut and the actuator rod on the other side of the 10mm nut.
5) Using the 10mm wrench, loosen the 10mm nut. Only need the wrench for initial loosening, you can use your fingers after. To loosen you push the wrench towards the front of the car (assuming you're looking up at the rod and nut and your have the wrench latched on the bottom of the nut).
6) Using your mark as a reference point, continue loosening the 10mm nut until it is a little bit further than the desired preload amount you wish to add (e.g. if you want to start with 2 turns of preload then loosen the nut closer to 2.5 turns). The nut should now be traveling towards the WG diaphram and turbo itself on the right.
7) Now using your vice grips get a good grip on the knurled ring and start turning it the same direction. It does not take much force, but the angle you get with your vice grips is key. It takes a lot of these to get one full turn out of it. I probably needed to grip it and turn it about 10 times to get a full turn out of it.
8) After adjusting the knurled nut to your desired position, now bring the 10mm nut the opposite direction so that it snugs up against the knurled nut again. Once it is finger snug, give it one light additional snug with the wrench.
9) Re-install the retaining clip. There aren't really any specific directions for this, but it cam be a PITA. Make sure you didn't bend the tabs on the clip at all when removing it or it will not slot onto the knurled nuts position correctly.

*__*

Also, as promised, I have provided links to before/after data logs below on my google drive and will explain what to look for when you log. First, some tips on proper data-logging with VCDS just to be clear:

1) Use "Advanced Measuring Values" so that you can log more than 3 values at once.
2) Make sure that at a minimum you are logging: Engine speed, Accelerator Pedal Position, Boost Pressure - Control (N75), Boost Pressure (specified), and Boost Pressure (actual). These are the values we will focus on. I am not going to get into any other data here
3) Make ABSOLUTELY sure you have turbo mode on before you start a log. It increased the sample rate of VCDS by about 10x which allows you do get data roughly every 40RPMs instead of every 400RPMs. This is absolutely crucial to accurate analysis. A lot happens in the space of 400RPMs. If you log without turbo mode engaged it is basically trash. I logged like 10 times over the last couple months as I was figuring this all out. A few of those times I forgot turbo... if you do the same thing, just delete it and re-log.
4) Generally speaking you're going to want to log data in 3rd gear, however, 4th gear can be useful to gain some insights (more on that later). All logging should be done doing immediate WOT pulls from 2K RPMs to redline (or at least 6K RPMs) and the air con MUST be off! This should go without saying but you will need to have a relatively open space to do these (especially for those 4th gear pulls) and minimal or zero traffic. Be safe and be smart. Don't get yourself or someone else hurt and don't get pulled over because the cop isn't gonna let you off when you explain you're an enthusiast who is doing high speed pulls to data-log/diagnose an issue LOL.
5) Be mindful of when/where you do your first data logging because all subsequent data logging must be done in very similar atmospheric conditions (e.g. altitude and ambient temp outside, since both factor into boost).
6) To calculate PSI from mbar use the following equation: Actual boost (mbar) - atmospheric pressure (mbar) * 0.0145 = PSI; where atmospheric pressure = 1000mbar at sea level (you're altitude, and thus, atmospheric pressure value may vary)

When you have your data, aside from a maxed, or nearly maxed, N75 duty cycle (generally 94% not 100%) you are also looking for actual boost that does not meet and then exceed specified boost within ~800RPMs (which a healthy, properly functioning K03 should) and, furthermore, actual boost that does not continue to exceed specified boost through the rev range afterward. Once actual boost meets and exceeds specified boost within ~800RPMs it should continue to exceed it by ~20 - 40mbar. This is how the N75 is allowed to relax the duty cycle and thus the wastegate is able to release an equivalent amount of boost as the specified boost value tapers so that the actual boost curve is smooth. If the actual boost curve were to never exceed specified and hold itself above specified then the N75/wastegate could never relax and the above would not be able to occur. Additional wastegate preload is what allows all of this to come together because the wastegate will no longer flap open intermittently before it is supposed to from being unable to hold against the exhaust pressure and you get a poor boost curve that may never even meet specified, much less exceed it. Sometimes the boost may dip very briefly below specified boost at around 3/4 of the way through a pull. This may because the tune is still specifying a lot and not tapering off much yet even though the K03 is coming out of it's powerband, or it may be that slightly additional preload is needed to hold the boost above specified all the way, further relaxing the duty cycle.

You will notice that the condition I just mentioned (regarding a brief dip below specified boost around 3/4 of the way into the pull) is still occurring even in the most recent log I took after 3 total turns of preload. This is why I may add another half turn to the preload. I think it would probably counteract that but I'm not sure at this point it would be worth it. While the N75 duty cycle didn't relax all that much, the boost curve and peak values are healthy and the more preload adjustment the more diminished returns you will see so it may not even improve by much; this dip at around 3/4 is probably fine. As for the still high duty cycle: my understanding of how N75 works is that it may not really be able to get much better given the demands of the tune combined with the K03 being asked so much and especially combined also with the ambient temp where I live now (it's pretty hot out). That is because the N75 function is not linear; once you’re above ~80% duty cycle the ECU has very little control left. That means tiny changes have a much bigger affect on the boost since the ECU no longer has much, if any, power to correct for tiny changes like atmospheric conditions. So maybe it won't really get much better at this time of year but probably will get exponentially better (due to that non-linear function) as the weather gets cooler.

The last pull is in 4th gear. I did this as a control/comparison pull as I had a hunch that 4th gear pull would show a more relaxed N75 duty cycle than 3rd gear and it proved correct. This 4th gear pull is particularly important in coming to the conclusion I have come to. As you will see, 3rd gear pulls did reach peak boost exceeding specified at 600-900rpms max which is just what we were looking for and did remain exceeding for a bit, dips slightly below about 3/4 into the pull, and then back up as specified tapered off. As far as I can see these 3rd gear pulls are pretty damn near ideal and even so the N75 duty cycle only relaxes down to like 89% at the lowest. However, compare this to the 4th gear pull which stays above specified much more easily and much longer and the N75 duty cycle relaxes even more as I suspected it would BUT it still only relaxes to low 80s at it's lowest point despite how effortlessly the boost data exceeded specified and held. This tells me that it's not really going to get much better than this, maybe a little but barely, for reasons stated above about the non-linear nature of N75 behavior as well as because if 4th gear boost data can be THAT good and still only reduce the N75 duty to low 80s then I think that's basically the end of that. I don't see the situation getting much better. At least not without possibly dangerous levels of preload adjustment and a potential for overboosting the little K03 because at this point the preload adjustments are having diminished returns (the original 2 turns had a huge impact and this 1 turn had much much less of an impact comparably speaking, so another turn would probably have even less still, and so on). I think at this point it's just the reality of how much boost the tune is asking this little guy to make, so to conclude I don't think that any N75 duty is going to get below 80% on a K03 with aggressive tuning in these atmospheric conditions (read: hot ambient temp). While N75 duty didn't get too much better I am no longer concerned as I understand how it all works and I am pleased that I got my boost curve looking nice and my car performs better than it ever did!

I hope this helps many people to arrive at the same place... unleashing some hidden power in their tune that they didn't realize they had because of stock WG limitations! Good luck and feel free to post or PM with questions!


Before WG adjustment:
https://drive.google.com/file/d/0Bzeazv76x9MXMWlsTnNvUlpZblE/view?usp=sharing
After first WG adjusment:
https://drive.google.com/file/d/0Bzeazv76x9MXLWx5bW1JcDBMdDg/view?usp=sharing
After 2nd WG adjusment:
https://drive.google.com/file/d/0Bzeazv76x9MXYURjS2tqalQtTG8/view?usp=sharing


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## Thy_Harrowing (Dec 7, 2014)

Follow-up to previous post:

I didn't wind up adding any more pre-load (still on a total of 3 turns of additional pre-load) because I suspected that once it gets even a little bit cooler than it was at the time I did the last logs (when it was very hot) that the N75 duty cycle would relax a lot and the extra pre-load would be unnecessary. I was correct. I did some data logging at about 65 degrees F out tonight and data looked excellent.

https://drive.google.com/open?id=0Bzeazv76x9MXTGc1MlFUU256aTA


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## ROH ECHT (Dec 9, 2010)

I finally got a vid made for adjusting WG preload. The adjustment design changes from K03 to K04 and other WG's, but adjusting is identical for adding or subtracting preload.

https://www.youtube.com/watch?v=EyzS-vvuFmA&t=158s


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## Thy_Harrowing (Dec 7, 2014)

ROH ECHT said:


> I finally got a vid made for adjusting WG preload. The adjustment design changes from K03 to K04 and other WG's, but adjusting is identical for adding or subtracting preload.
> 
> https://www.youtube.com/watch?v=EyzS-vvuFmA&t=158s



Nice vid!! I'm sure that'll be super helpful for anyone who stumbles on this thread - although with the convoluted title of my thread I'm not sure that will be many 

I found marking a corner of the nut and just counting full rotations was more reliable than counting separate turns, at least for me anyway.


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## chumeta (Apr 26, 2009)

To gain more space to manipulate the wastegate, I recommended undoing the rectangular sheet metal support secured with 2 size 13 nuts, the turbo remains in place and we can easily work in the adjustment rod. Then we put this metal support back in place. Sorry for my English


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