# DIY: Clamping the Map Sensor aka "Diode Mod"



## 1.8TWolfsberg (May 18, 2002)

Alright, such a nice mod and no write-ups anywhere...at least that I could find!
So with the help of John (Spooled_AWP) I went ahead and did a few diagrams and then finally did the mod myself!
Here is the link to my DIY page
And here are a few diagrams:
























Here is the page to my VW Links page which has a few other DIYs that I have done - http://www.anthonydanna.com/vw.html


_Modified by 1.8TWolfsberg at 1:43 PM 11-25-2008_


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## Spooled_AWP (May 29, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

http://****************.com/smile/emthup.gif


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## ::..BoraXTC..:: (Oct 16, 2003)

on your install page it says that a 4.7v diode = 17psi. if im not mistaken 17 psi will cause limp right. then how come when i dioded my car (unchipped) at 4.7 v i didnt limp? held a 19 all day long.


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## Spooled_AWP (May 29, 2004)

*Re: :..BoraXTC..:*

thats weird because on my car the 4.7 does nothing in stock mode...still only spike to 10 and hold 8 or so
maybe you are thinking of the 4.3?
when im in stock mode with the 4.3 i spike at 19-20!


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## ruba_dubdub (Dec 26, 2002)

Thanks 1.8TWolfsberg and Spooled_AWP. I'm sure there are A LOT of people who will appreciate the work you guys did to make this excellent write-up. And with all the talk of diodes, I'm sure people still had a lot of questions unanswered. This SHOULD (hopefully) clear things up now. Thanks again guys.


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## SHUMopper (Jan 2, 2002)

*Re: (ruba_dubdub)*

very nice....
definetly gonna do this, but with a smaller Voltage diode, like 4.27.
Props to u for an AWESOME DIY!!!


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## dknl (Jul 1, 2002)

nice writeup
never thought of using it as a on/off switch for chipped mode. 
Possible to emulate the valet mode using this method to prevent car from being driven hard?

















_Modified by dknl at 4:59 AM 7-9-2004_


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## Maggi (Feb 16, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

Is it safe to do this to a stock Gti?
I only have a K&N cone, And will i feel some huge difference?


_Modified by Maggi at 2:36 PM 7-9-2004_


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## Buttero J-Lo (Mar 5, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

http://****************.com/smile/emthup.gif


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## UmbroVR6 (May 23, 2000)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (ButteroJ)*

nice writeup, very detailed.
i know a few peeps who still don't know how to do the diode mod
i'll forward this info. to them. http://****************.com/smile/emthup.gif


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## hugemikeyd (Aug 28, 2001)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (UmbroVR6)*

you need to add those negative lines that are on the diodes since they are sensitive as to which way they must be installed


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## exS4 (Nov 8, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

Get some proper Software instead of using a Diode you bunch a cheapskates!


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## MRP2001GTi (Oct 6, 2000)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (exS4)*


_Quote, originally posted by *exS4* »_Get some proper Software instead of using a Diode you bunch a cheapskates!









While a good idea what’s the difference between software like Revo BT that removes overboost limp and using a diode to do the same thing?








End the end you accomplish the same thing. While Revo BT is great stuff (I would run it if I could) you guys need to admit the very thing that makes it better is the removal of most safety related triggers in the software. 
Revo is better because it allows you to exceed parameters that most tuners consider dangerous. Come on admit it!!!


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## hugemikeyd (Aug 28, 2001)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (MRP2001GTi)*


_Quote, originally posted by *MRP2001GTi* »_
While a good idea what’s the difference between software like Revo BT that removes overboost limp and using a diode to do the same thing?








End the end you accomplish the same thing. While Revo BT is great stuff (I would run it if I could) you guys need to admit the very thing that makes it better is the removal of most safety related triggers in the software. 
Revo is better because it allows you to exceed parameters that most tuners consider dangerous. Come on admit it!!!










the revo BT bothers me b/c of that, its just a boost program, when are ythey going to do up the timing?


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## Spooled_AWP (May 29, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (hugemikeyd)*


_Quote, originally posted by *hugemikeyd* »_you need to add those negative lines that are on the diodes since they are sensitive as to which way they must be installed

very good point...
although it does say, if the car cranks but does not start, you have the diode in the wrong way, take it out and turn it around.
anyone know which wire the negative end of the diode should be connected to? i guess i could go look on my car but im to lazy







http://****************.com/smile/emthup.gif


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## Fshowcars (Jun 23, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (MRP2001GTi)*


_Quote, originally posted by *MRP2001GTi* »_
Revo is better because it allows you to exceed parameters that most tuners consider dangerous. Come on admit it!!!










welll to my understanding, out of the box the revo BT is to be set at high boost 9... meaning you can't really excess any boost parameters (or load tables)... and the maf reading is goofed, so people run unplugged... once again, not metering air, and not raising parameters... so i'm wondering what the true benefit is? ... just a more solid idle on the 440s?


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## hugemikeyd (Aug 28, 2001)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (Fshowcars)*


_Quote, originally posted by *Fshowcars* »_
welll to my understanding, out of the box the revo BT is to be set at high boost 9... meaning you can't really excess any boost parameters (or load tables)... and the maf reading is goofed, so people run unplugged... once again, not metering air, and not raising parameters... so i'm wondering what the true benefit is? ... just a more solid idle on the 440s?

so how does a REVO BT car compare to a REVO car with a diode?


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## 1.8TWolfsberg (May 18, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (Spooled_AWP)*


_Quote, originally posted by *Spooled_AWP* »_
very good point...
although it does say, if the car cranks but does not start, you have the diode in the wrong way, take it out and turn it around.
anyone know which wire the negative end of the diode should be connected to? i guess i could go look on my car but im to lazy







http://****************.com/smile/emthup.gif










the striped side of the diode should be closest to the map sensor wire side...I have that mentioned in the DIY....almost last step...testing part!
Com on JOhn.....get with it


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## hugemikeyd (Aug 28, 2001)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*


_Quote, originally posted by *1.8TWolfsberg* »_

the striped side of the diode should be closest to the map sensor wire side...I have that mentioned in the DIY....almost last step...testing part!
Com on JOhn.....get with it









then i would just update your pic, i mean people don't read as often as they look at a pic...


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## Spooled_AWP (May 29, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*


_Quote, originally posted by *1.8TWolfsberg* »_

the striped side of the diode should be closest to the map sensor wire side...I have that mentioned in the DIY....almost last step...testing part!
Com on JOhn.....get with it









haha...that could also be a little confusing....maybe state which color wire the striped side should be connected to!


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## 1.8TWolfsberg (May 18, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (Spooled_AWP)*

whats confusing about it








striped side to map sensor side and non-striped side to switch side...easy as cake


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## A1.8T (Oct 1, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

Very Nice writte up!! http://****************.com/smile/emthup.gif


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## 1.8TWolfsberg (May 18, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (A1.8T)*

thanks man...glad it is helping people out http://****************.com/smile/emthup.gif


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## Maggi (Feb 16, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

Is this a good "mod" on a stock Golf Gti? Only thing i have is a K&N cone.
Has this mod been Dyno´d?


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## 1.8tizzle (May 22, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (Maggi)*

http://****************.com/smile/emthup.gif to you guys on a nice write up.


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## Maggi (Feb 16, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (Maggi)*


_Quote, originally posted by *Maggi* »_Is this a good "mod" on a stock Golf Gti? Only thing i have is a K&N cone.
Has this mod been Dyno´d?

Anyone know ?


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## spoolin turbo s (Mar 8, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (Maggi)*


_Quote, originally posted by *Maggi* »_
Anyone know ?

YES look at the post right above yours--------Tizzle made 203WHP stock ecu 4.3 diode


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## RABIDRABBIT1983 (May 13, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (spoolin turbo s)*


_Quote, originally posted by *Maggi* »_Is this a good "mod" on a stock Golf Gti? Only thing i have is a K&N cone.
Has this mod been Dyno´d?

it's not the best way to go about things, but it works. You have obd2 so the 1st o2 sensor/MAF bumps up the fuel out output. with a chip timing and fuel curves are going to be smoother. i'd get a MBC so you can manually tweek a lil bit more. Put in a heat ranger cooler plug run 93 octane and it will get you by until you get a chip. as stated you can get 200 wheel with a diode(ko3sport)


_Modified by RABIDRABBIT1983 at 11:59 PM 7-11-2004_


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## ::..BoraXTC..:: (Oct 16, 2003)

well before doideing a car you need to understand the difference in voltages verses boost levels verses voltage of limp. you want to clamp as high as you can boost wise before limp. this will make for better fueling.


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## Italian GTI 1.8T (Jun 20, 2003)

*Re: :..BoraXTC..:*

finally a writeup!


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## JettAffair (Jan 7, 2004)

new to the diode idea here. It looks like when you want to go with 1 diode/no switch, you simply put a diode between the purple/gray and the orange/blue. Is it that simple? and do I have to solder?


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## 1.8TWolfsberg (May 18, 2002)

*Re: (JettAffair)*

unless your 100% confident you can securley attach the diode to the wires, then I would solder them together


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## mach iv for more (Jun 29, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

I have an apr chip 93 now my question is do I need one 4.3 and one 4.7, or can I use one 4.7.


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## NYC GTI (Oct 9, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (mach iv for more)*

a








better make it















for the write up


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## QT_GTI (Mar 20, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

where is this map sensor??


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## 75Grabbit (Mar 16, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (QT_GTI)*

Beautiful write up guys. http://****************.com/smile/emthup.gif


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## biturbocurious (Jul 6, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (derschnellstemann)*

Awesome write-up ... one of the best diagrams I've seen.

bump for the switch box! http://****************.com/smile/emthup.gif


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## mJstk01 (Aug 15, 2003)

nice write up


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## SHUMopper (Jan 2, 2002)

*Re: (mJstk01)*

Links down just when i need it.
Figures.


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## bigmak (Jan 5, 2004)

*Re: (SHUMopper)*


_Quote, originally posted by *SHUMopper* »_Links down just when i need it.
Figures.


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## 1.8TWolfsberg (May 18, 2002)

*Re: (bigmak)*

I am sorry about that. I didn't realize until a few others mentioned it to me. I am currently working on the problem and will post here when the site is back up!
Thanks for your patience!


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## SHUMopper (Jan 2, 2002)

*Re: (1.8TWolfsberg)*

Thanks dude...need this writeup ASAP...i was looking foward to doing this today, definetly would like some guidence on it(thus the DIY post)....ill keep my eyes out for when its back up.


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## numb401 (Jan 22, 2004)

*Re: (SHUMopper)*

I'll host the writeup for you just shoot me an email numb401 (at) gmail.com or on AIM - numb401


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## gtihoot (Aug 21, 2001)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

Nice write up, I did this and boost all the way to 24 psi with a 4.7 zener diode on APR v2 software. defintely makes the car stronger! The 4.3 is MUCH stronger even, but boost come on too early and too much during part throttle, it would work perfect if you plan to do WOT at every gear. http://****************.com/smile/emthup.gif


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## JettAffair (Jan 7, 2004)

can anyone tell me where they are getting the zener 4.7 diodes. I've heard of places on the internet, but I hate to do that for such a small thing. If anyone has found one at a local store let me know, or if someone has an extra one they can mail me, I can send paypal.


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## shucky (Jun 2, 2003)

*Re: (JettAffair)*

no write up, links dont work, no pics, etc. Help !


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## 1.8TWolfsberg (May 18, 2002)

*Re: (shucky)*

The CSS styles for the page are in an external document. So everything will look like poop unless I either send you the files or edit the code. Either which is more hassle than its worth.
If you want the DIY, just email me at [email protected] and I will email you the writeup http://****************.com/smile/emthup.gif 
I purchased my diodes from:
4.3v - http://www.electronix.com/cata...e0b87
4.7v - http://www.electronix.com/cata...e0b87


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## JettAffair (Jan 7, 2004)

*Re: (1.8TWolfsberg)*

I've got a question before I go and do this today. Rather than routing the wire up to that loom where the map sensor wires are, could you just route them to the ecu wiring harness, where the map sensor wires connect there, and do the install right near the ecu? I'm guessing there is a reason this wouldn't work, or perhaps it's just harder to get to the ecu than the other spot, but I'd like to know if it would work.


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## viper_chan (Sep 16, 2001)

*Re: (JettAffair)*

Why complicate things by routing extra wires to the ecu and/or cabin? I installed my diode in between the map sensor and the oem map sensor connector. Just Plug & Play...can be returned to 100% stock in seconds.








http://forums.vwvortex.com/zerothread?id=1395136


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## JettAffair (Jan 7, 2004)

That looks like an excellent alternative. I'm not sure if I have the patience involved with getting the parts and making them fit. Did you use a 4.7v or 4.3v diode on this?


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## yuk (Feb 1, 2004)

*Re: (JettAffair)*

yo anthony or john, which diode should i be using on my car? im giac v.12 i finally got the boost better with the j valve with no surging, maybe some in 5th, but the boost is alot lower than it was before i had to use the overboost kit, i could hold 20 before, now i cant..... i want to do this mod, you guys busy on wed. this week??


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## Spooled_AWP (May 29, 2004)

*Re: (vw1point8turbo)*

Matt,
Try the 4.7v first and see how that works out for you.
the 4.3v is a little too much i have found out for daily driving since it gives me about 24 PSI. And i want my turbo to last me a little bit longer.








Let me know how it works out for ya. If you need a hand with anything let me know http://****************.com/smile/emthup.gif


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## ACEdubs (Apr 18, 2002)

*Re: (Spooled_AWP)*


_Quote, originally posted by *Spooled_AWP* »_Matt,
Try the 4.7v first and see how that works out for you.
the 4.3v is a little too much i have found out for daily driving since it gives me about 24 PSI. And i want my turbo to last me a little bit longer.








Let me know how it works out for ya. If you need a hand with anything let me know http://****************.com/smile/emthup.gif 

True, 
I would really try both. My car reacted better to the 4.3v. With the 4.7v I would still go into limp in higher gears.


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## Spooled_AWP (May 29, 2004)

*Re: (ACEdubs)*


_Quote, originally posted by *ACEdubs* »_ With the 4.7v I would still go into limp in higher gears. 

That might be partly because you have an '04


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## viper_chan (Sep 16, 2001)

*Re: (JettAffair)*


_Quote, originally posted by *JettAffair* »_That looks like an excellent alternative. I'm not sure if I have the patience involved with getting the parts and making them fit. Did you use a 4.7v or 4.3v diode on this?

I used a 4.3v diode for my stock ecu.


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## 1.8TWolfsberg (May 18, 2002)

*Re: (viper_chan)*


_Quote, originally posted by *JettAffair* »_I've got a question before I go and do this today. Rather than routing the wire up to that loom where the map sensor wires are, could you just route them to the ecu wiring harness, where the map sensor wires connect there, and do the install right near the ecu? I'm guessing there is a reason this wouldn't work, or perhaps it's just harder to get to the ecu than the other spot, but I'd like to know if it would work.


_Quote, originally posted by *viper_chan* »_Why complicate things by routing extra wires to the ecu and/or cabin? I installed my diode in between the map sensor and the oem map sensor connector. Just Plug & Play...can be returned to 100% stock in seconds.








http://forums.vwvortex.com/zerothread?id=1395136

Basically because I want the option to change between diode settings without having to get out of the car. There is no complication with doing this







Just run the wire into the car and hook them up to the switch...its very simple http://****************.com/smile/emthup.gif


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## 03slvrstoned (Mar 26, 2004)

*Re: (1.8TWolfsberg)*

so you need a three way switch for this right? or if you wanted to just use the 1 diode then you would only need a on/off switch? Also with the switch when you set the switch to off the car should go back to stock right?


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## 1.8TWolfsberg (May 18, 2002)

*Re: (03slvrstoned)*

correct when you set the switch to the middle position it puts the car back to stock mode.
Keep in mind, you dont NEED the switch. The switch is merely a convenience for going back to stock. I'd rather not run the diode all the time so the switch plays it safe for normal cruising.


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## 03slvrstoned (Mar 26, 2004)

*Re: (1.8TWolfsberg)*

http://****************.com/smile/emthup.gif thanks


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## shucky (Jun 2, 2003)

*Re: (03slvrstoned)*

I have a question ... people say "I installed the diode and boosted 24psi..." Do you not need to turn up the boost with a MBC ?? Just installing a diode doesn't increase boost on its own does it ? Hope this isn't a dumb question but nobody really confirms this in all of these posts. Tks, Mike


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## TurboZen (Oct 15, 2000)

*Re: (shucky)*


_Quote, originally posted by *shucky* »_I have a question ... people say "I installed the diode and boosted 24psi..." Do you not need to turn up the boost with a MBC ?? Just installing a diode doesn't increase boost on its own does it ? Hope this isn't a dumb question but nobody really confirms this in all of these posts. Tks, Mike

The diode prevents the cars computer from seeing any more boost than what the diode sets it for. you have to have a mbc set to your desired PSI. the diode eleminates the cars computer from regulating boost. so you need the mbc.


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## Spooled_AWP (May 29, 2004)

*Re: (shucky)*


_Quote, originally posted by *shucky* »_I have a question ... people say "I installed the diode and boosted 24psi..." Do you not need to turn up the boost with a MBC ?? Just installing a diode doesn't increase boost on its own does it ? Hope this isn't a dumb question but nobody really confirms this in all of these posts. Tks, Mike

Yes you boost and HOLD around 22 PSI til about 4500-5k with the 4.3 diode in...no MBC...with the 4.7v diode in you boost and HOLD at around 20PSI will the normal tappering point.
with my ECS n75 i hold boost at 24 til about 5k with the 4.3v in and with the 4.7v i hold boost at around 21.
so yes, with just the diode and no mbc you will see more boost and hold boost also even though you have not touched anything boost related or adjusted anything directly controller more or less boost. http://****************.com/smile/emthup.gif


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## shucky (Jun 2, 2003)

*Re: (Spooled_AWP)*

Okay thanks. Next question, on my 20th which some people say has a 3 bar MAP the 3 wires are not the same color as described elsewhere in all of these threads. They are orange/blue, solid violet, and violet with green stripe. I'm gathering I use the orange/blue stipe and the violet/green stripe wires but which way does the diode face ? As in, the stripe on the diode faces/towards which of these wires ? Anyone can help? Tks, Mike


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## 1.8tizzle (May 22, 2003)

*Re: (shucky)*


_Quote, originally posted by *shucky* »_I'm gathering I use the orange/blue stipe and the violet/green stripe wires 

incorrect. you use the orange/blue wire and the purple/grey wire, or just the purple one you were referring too. and the black band on the diode faces the pruple/grey wire, but good luck gettin it to work on your 20th.


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## shucky (Jun 2, 2003)

*Re: (1.8tizzle)*

Um, I dont have a grey / purple wire, thats what my post says. I have orange/blue, solid violet, and a violet/green. Nobody gets it to work on a 20th ?


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## Spooled_AWP (May 29, 2004)

*Re: (shucky)*

look harder...there are 3 wires there.
orange/light blue
purple/grey
purple/green
it MAY be different colors on the 20th though.
and no...nobody has been able to get it to work on the 20th's because the MAP sensor on the 20th's puts out completely different voltage acocording to boost then regular MAP sensors do.


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## numb401 (Jan 22, 2004)

*Re: (Spooled_AWP)*

So if your not planning on running a chip and you want nice smooth power, would the 4.3 or the 4.7 be better (paired with an MBC).


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## Spooled_AWP (May 29, 2004)

*Re: (numb401)*


_Quote, originally posted by *numb401* »_So if your not planning on running a chip and you want nice smooth power, would the 4.3 or the 4.7 be better (paired with an MBC).

you'd want to run the 4.3 then for sure http://****************.com/smile/emthup.gif


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## Nightrider (May 10, 2002)

*Re: (Spooled_AWP)*

Help... I know repidative stupid questions are annoying... but, I love to annoy people, soooo, I want more boost. I have an AWD with APR programming (ecms, not vtune), I need a MBC(?), and which diode do I use to run about 20-21psi? And keep my n75, or run a J, this isht is starting to confuse me, just when I thought I had it...







Sorry guys, but thanks in advance!


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## 1decimal8Tango (Jul 7, 2004)

*Re: (Nightrider)*

anyone have the DIY? thanks.


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## 1decimal8Tango (Jul 7, 2004)

*Re: (1decimal8Tango)*

oh yeah, pics would be nice too.


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## Spooled_AWP (May 29, 2004)

*Re: (1decimal8Tango)*

http://s90139951.onlinehome.us/vw/diodemod.htm 
there ya go! http://****************.com/smile/emthup.gif


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## 1decimal8Tango (Jul 7, 2004)

*Re: (Spooled_AWP)*

thanks, I found that 10 minutes after I posted


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## Spooled_AWP (May 29, 2004)

*Re: (1decimal8Tango)*

haha...so i wasted my time


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## BMFJETTA (Jan 21, 2004)

*Re: (Spooled_AWP)*

I just bought 50 of each 4.3 and 4.7 Zener Diodes. I am going to fab a switching box so it just doesnt look like some ghetto wireing job in the car. But I will be selling these shortly, soon as I get the diodes and figure out a box to mount them in.
any interest?


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## Spooled_AWP (May 29, 2004)

*Re: (BMFJETTA)*

i have been selling switches for a while now...better not steal my design















and i recommend not mentioning anything about selling them in any of your post or when a mod sees it you will get a warning...and if you do it again you will get banned...i learned the hard way


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## 1decimal8Tango (Jul 7, 2004)

*Re: (Spooled_AWP)*

then how would he go about selling them? telepathy?








I would buy one, but im more of a DIYer, plus im going to do it later today.


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## 03specv (Jan 18, 2004)

*Nice write up*

Nice write up http://****************.com/smile/emthup.gif I'm using the Split second boost controller to clamp the map sensor and then a MBC to crank up the boost. So far it has worked very well but I want to give the diode a try.


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## 1decimal8Tango (Jul 7, 2004)

*Re: Nice write up (03specv)*

one question, will this work with a EBC?


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## BMFJETTA (Jan 21, 2004)

*Re: (Spooled_AWP)*


_Quote, originally posted by *Spooled_AWP* »_i have been selling switches for a while now...better not steal my design















and i recommend not mentioning anything about selling them in any of your post or when a mod sees it you will get a warning...and if you do it again you will get banned...i learned the hard way









oh thanks for the heads up, I just wanted to put a few together to try out on my buddies cars too. I may just do a few boxes for myself and my friends, and sell my diodes just as diodes. I am having a little trouble finding a good houseing for my boxes... do you have any recommendations? No i wont steal your design , I just want to make a few boxes. I and probably going to do something similar, but not to make a profit, just for us 1.8T guys.!


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## sushtsi (Sep 13, 2004)

*Re: (BMFJETTA)*

Hey guys I have a simple question about the diodes. I have an 01 GTI 1.8t 5spd AWW bone stock. Assuming I do the 1 diode no switch and nothing else (no mbc or changing of valves etc.) will my boost then increase? Or do I have to use the diode + mbc/ebc to raise the boost? Also, say I use the 4.7v diode and it causes my boost to go to 17psi, what happens with my fuel? Does the ecu only provide fuel for stock boost?
Thanks guys


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## Johnny Blaze (Oct 18, 1999)

*Re: (sushtsi)*

From my understanding the diode is there just to catch the signal going to the ECU by tricking it out to by making it think its at 16psi to prevent it from going into limp mode. Than you use the MBC/EBC to dial in the max boost you want the turbo to see. Is that correct there?
So if what I am guessing is true, does the ECU only provide fueling for 16psi? (if your chipped).. The logic makes sense there that it would, but do most chips have the ability to adjust fuel mappings slightly to protect the engine and maintain them? If not than how do you go about adjusting your fuel maps to handle even more boost? Secondary fuel controller?


----------



## wolfsburg2 (Jun 6, 2001)

*Re: (Johnny Blaze)*

the chip is providing the fuel that is set in its maps. those maps are specific to stock injectors. you would compensate for any adjustments with a fpr and lemmiwinks. but again 3bar seems to be pretty rich with 440s on a small turbo with mild boost.


----------



## {:sylph:} (Jun 27, 2003)

*Re: (wolfsburg2)*

it would seem only logical that without using software, or an adjustable FPR, the fuel would not be compensated for under higher boost than requested.
If the ECU requests 15Psi, and recieves 16+Psi then it goes into limp mode. 
If you clamp the MAP to "trick" the ecu into only seeing 15Psi then any extra boost that passes the turbo and into the cylinders would have to be under an abnormal mixture of the requested fuel for the "requested" boost level.
Wich would in turn cause you to run lean if you are boosting above request.
Using an adjustable FPR would probably fix that but it seems like it would take a lot of time and software to get the correct settings.
Also if you are running lean due to over boost / higher air mixture, the O2 sensors are going to pick that up. That can't be good for timing or fuel trims, since the ECU has a set rate at wich it will introduce fuel based on requested boost. If the 02 sensors detect a lean mixture, I really don't think the ECU would compensate with more fuel because it sees the fuel / air as being fine under the request parameters. It would most likely just retard the timing under the impression of failed components or emmisions. Just and idea .. and something for the guys with laptops to watch for if you clamp.
keep in mind for every 1Psi of boost there should be a 1psi raise in fuel as well.




_Modified by {:sylph:} at 2:42 AM 10-2-2004_


----------



## sushtsi (Sep 13, 2004)

So assuming I clamp the map to 16psi (everything else including ecu is stock) and I set the mbc to 15-16psi, I would only be getting fuel compensation for the stock 8psi, correct? What would be the max suggested boost using just an mbc and the clamp (no fpr's, ecu etc.) 11psi? 16?


----------



## 1decimal8Tango (Jul 7, 2004)

*Re: (sushtsi)*


_Quote, originally posted by *sushtsi* »_So assuming I clamp the map to 16psi (everything else including ecu is stock) and I set the mbc to 15-16psi, I would only be getting fuel compensation for the stock 8psi, correct? What would be the max suggested boost using just an mbc and the clamp (no fpr's, ecu etc.) 11psi? 16?

look at it like this. If you clamp it at 16 psi, you will get fuel for 16psi at full boost, reguardless of your actual boost pressure. so If your boosting 21psi, your only getting the fuel to support 16psi, because you ECU thinks its boosting 16psi....
*this is only assuming it works the way everyone is asking about now.*


----------



## {:sylph:} (Jun 27, 2003)

*Re: (1decimal8Tango)*

Someone needs to get a vag and check to see if the fuel is actually there. This is obviously just theory but it is stronger than the "it just works" theory that it seems most people doing this mod are basing their results from.
This ecu is very clever and I really would be very surprised to see it compensating fuel from this mod, it seems almost impossible that the ecu would bypass its own fail safes, and emmissions settings and raise the fuel.


----------



## tsuter (Dec 25, 2003)

The MAP sensor input is only one variable... mostly for boost and overboost identification vs requested boost and then the ECM makes a throttle plate close call. Or you go into limp. Hence you clamp its voltage signal to allow higher actual boost without limp or TP close calls.
The MAF ( Mass air flow sensor) is more directly related to how the ECM determines fuel... i.e., more measured air flow = more fuel.
So even though you clamp the MAP, the ECM will still try to adjust fuel based on MAF. Until you max out the table with high actual boost and high MAF. The you need to raise the FPR or injector flow.
Clear as Mad? I mean mud??


----------



## Johnny Blaze (Oct 18, 1999)

*Re: (tsuter)*

isnt this where a secondary fuel controller can step in and manage fuel maps/trims.. and just use lemmiwinks or something of that nature to handle your timing?
crank the FPR to the desired levels you need.. than let the clipped map sensor and the mbc/ebc setup manage your boost.. would bypassing the n75 have any affect here also? 
is this possible with this setup?


----------



## {:sylph:} (Jun 27, 2003)

*Re: (tsuter)*

I was thinking along simialr lines, but also remember that for every 1Psi of boost you raise you need to raise 1Psi of fuel. 
So lets say the ECU sets a fuel mixture for 18Psi based on MAF readings, however the MAP is returning a signal of 11-16Psi (depending on the diode). The ECU would then check the 02 for readings to determain the proper mixture. what you said would make sense that it would keep the proper mixture, but also keep in mind that the MAP is there to verify the MAF's performance.. or to compare the charge air with the incoming air. Since these 2 #'s would be off quite a bit I still think it is possible the ECU would pull timing to make for a more balanced reading.

I think some Vag logs would be the only real data needed to put speculations rest one way or the other. Any volunters?
I personaly wouldn't invest the $ into stand alone fuel setups or adjust any timing without some hard data to back up the changes.


_Modified by {:sylph:} at 5:00 PM 10-2-2004_


----------



## tsuter (Dec 25, 2003)

*Re: ({:sylph:})*

Vag...... sure. Here is an MB 54 and 115 log from last week on my 1.8T APH. Three thrid gear runs... one at WOT and two at partial throttle.
See in the far right where actual boost exceeds requested boost... highlited in red. The MAP reports this and the Giac program calls a TP close when the delta is 200mbar +-
See the MB 54 where I'm logging TP Position % as well as Throttle Plate %.
The Throttle Position is 100% as I'm on WOT in a 3rd gear run.
The Throttle plate gets closed to 67-33%... see red again. Thus Giac avoids Limp mode but performance suffers.
In a couple weeks I'll have a variable voltage clamp for the MAP sensor to stop the Throttle Plate closing.

Then I'll log the injector duty cycle with and without the clamp, the TP %s and the boost.
Lots of fun...


----------



## tsuter (Dec 25, 2003)

*Re: (Johnny Blaze)*


_Quote, originally posted by *Johnny Blaze* »_isnt this where a secondary fuel controller can step in and manage fuel maps/trims.. and just use lemmiwinks or something of that nature to handle your timing?


Exactly... the MAF is not so accurate as airflow goes way up... i.e., high boost plus the ECM fuel table may get maxed out so you need to adjust either FPR or Injector size(Flow) if you go well above the ECM programmed boost control level.

IMO that first you get the boost managed and the throttle plate manged via a clamp on the MAP and MBC or EBC.
Then log the fuel - injector pulse width and manage fuel second via FPR and or Injector size.
Changing to many things at once is difficult to see the effects even with a lot of VAG COM work.. And I do a lot of Vag Com.


----------



## mJstk01 (Aug 15, 2003)

im running the giac chip on the ko3s along with turbo back, pullies, n75H, and intake. Occasionally, I get hard limp and sometimes soft limp. Will the diode cure these?


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## wolfsburg2 (Jun 6, 2001)

*Re: ({:sylph:})*

"but also remember that for every 1Psi of boost you raise you need to raise 1Psi of fuel. "
i disagree with this statement completely.
also you guys are assuming that a big turbo(say a 50 trim for example) at 15psi of boost and 3 bar of fuel though 440s(standard fuel pressure, and the most common big injectors) is the correct fueling. it is not. at 3 bar most set-ups areruning dead rich at much higher boost. do some research. mrp2000gti runs 38psi of fuel and 19psi in his gt28rs. thats less than 3 bar.
do not underestimate how much fuel the 440s flow. while the ko3 maps will not be perfect, it is my opinion that even revo bt or apr's sw for the stg3 is not perfect either when you throw in variables. 
as of yet there is no affordable fully tunable tuning solution for our cars, just decent base maps. the apr sw is good for the specific apr kit, but what about when you add fmic, throw on a 3" exhaust versus 2.5"? or run a cai? or run more boost via mbc/ebc? etc. 
same goes for revo, they can't possibly have an off the shelf sw program for all the variables. hell people are using their generic bt sw with 50 different types of turbos. 
the sw available are good base maps, i think my giav ko3 v4 is a good enough base map for me. i just need to clamp the map to run more boost. that's it for me. maybe my car would run a little smoother on revo, maybe. maybe i might make 220 more hp on revo. but you know what for the 700 dollars, i am not in a place where i think i need it right now. my car runs strong and will run even better when i get it on the dyno and can play around with my settings a little.


----------



## omllenado (Jul 14, 2002)

*Re: (mJstk01)*

very informative guys keep it up
"im running the giac chip on the ko3s along with turbo back, pullies, n75H, and intake. Occasionally, I get hard limp and sometimes soft limp. Will the diode cure these?"
with the diode & the J or even H valve I hit boosts as high as 28psi then goes into hard limp.
with the stock C valve nothing happens cos it just spike to 19psi.
my diode switch


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## 1.8TWolfsberg (May 18, 2002)

*Re: (omllenado)*

updated the links on the first page so everything can been seen http://****************.com/smile/emthup.gif


----------



## mJstk01 (Aug 15, 2003)

*Re: (omllenado)*


_Quote, originally posted by *omllenado* »_very informative guys keep it up
"im running the giac chip on the ko3s along with turbo back, pullies, n75H, and intake. Occasionally, I get hard limp and sometimes soft limp. Will the diode cure these?"
with the diode & the J or even H valve I hit boosts as high as 28psi then goes into hard limp.
with the stock C valve nothing happens cos it just spike to 19psi.


Which diode are you using? 4.3 or 4.7


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## omllenado (Jul 14, 2002)

*Re: (mJstk01)*

right now no diode and I put back the J valve coz my mbc was leaking. fueling was ok at 20psi without the diode, with the diode it's kinda sketchy. I'm running 4bar fpr stock injectors.
here's the dyno
ko3s upsolute chip
1st run 20psi mbc w/ 4.7 diode
2nd & 3rd was 20psi without diode
look at the fueling and the dip on hp/torque on the 1st dyno



































_Modified by omllenado at 5:48 PM 10-3-2004_


----------



## BMFJETTA (Jan 21, 2004)

*Re: (omllenado)*


_Quote, originally posted by *omllenado* »_very informative guys keep it up
"im running the giac chip on the ko3s along with turbo back, pullies, n75H, and intake. Occasionally, I get hard limp and sometimes soft limp. Will the diode cure these?"
with the diode & the J or even H valve I hit boosts as high as 28psi then goes into hard limp.
with the stock C valve nothing happens cos it just spike to 19psi.



Man im running a J vavle and I cant spike 20 to save my ass







, i will try that diode again. I have Version 11 Giac maybe thats why... i dunno. I just bought a MBC , so I will be in the 20 psi range soon. How the hell are you slapping 28psi? I have yet to go into limp with the j valve.


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## omllenado (Jul 14, 2002)

*Re: (BMFJETTA)*

with 28psi nothing is happening, most power is on 20psi on my ko4, overthat it just feels like it's pushing air.


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## 99txturbo (Oct 1, 2004)

I run a APH 1.8 in a NB that does not use a MAP sensor per say. The only sensor that could remotely be considered to meassure manifold pressure is the boost sensor on top of intercooler. Is the MAP on the Jettas, ect located on the manifold itself or are you calling the boost sensor a MAP? The ECU's in our version of Motronic software will and can richen up the fuel mixture if a potentially lean burn condition could cause damage to engine. It has its limits and finaly just goes into limp mode. Funny how much difference there is between applications of this mighty 1.8 20 valve. Where would or could I alter that pressure signal to allow more boost? 99txturbo


----------



## Nessal (Nov 24, 2002)

*Re: (1decimal8Tango)*

Nm haahaha


_Modified by Nessal at 12:17 AM 10-4-2004_


----------



## tsuter (Dec 25, 2003)

*Re: (99txturbo)*


_Quote, originally posted by *99txturbo* »_I run a APH 1.8 in a NB that does not use a MAP sensor per say. The only sensor that could remotely be considered to meassure manifold pressure is the boost sensor on top of intercooler. Is the MAP on the Jettas, ect located on the manifold itself or are you calling the boost sensor a MAP? The ECU's in our version of Motronic software will and can richen up the fuel mixture if a potentially lean burn condition could cause damage to engine. It has its limits and finaly just goes into limp mode. Funny how much difference there is between applications of this mighty 1.8 20 valve. Where would or could I alter that pressure signal to allow more boost? 99txturbo


The NewBeetle APH MAP Sensor is called the Charge Air Pressure Sensor G31. It is locacted on top the intercooler below the passenger headlight.
It has a violet/grey wire only that provides the rising voltage signal to the ECM pin101. It is this wire's voltage signal that you clamp if you want to mask the Actual Boost reading to the ECM. There is no orange/blue wire on this sensor only a violet/green to the Camshaft Position sensor and a brown/blue for ground. 
See Vag Com MB 115 for Actual and Requested boost.


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## tsuter (Dec 25, 2003)

*Re: (tsuter)*

Here is a shot of the MAP Sensor (Charge Air Pressure Sensor G31) for the NB APH o top the intercooler


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## RedGTI18t (Feb 15, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

where do i find the orange/blue wire, i cant find it


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## 1.8TWolfsberg (May 18, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (RedGTI18t)*

There is a small piece of loom with 3 wires in it right next to the washer fluid tank. You will find the orange/blue wire inside that piece of loom








Check the pics in my DIY for more help!


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## shucky (Jun 2, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (RedGTI18t)*

can someone outline the different colors on the MAP sensor wires? I see some different year cars have different colored wires on the MAP. For example, my 20th has different colors. Can someone point to the correct wires to install the diode for each version? It would probably cut down on posts like this. Thanks, Mike


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## OEMplus.com (May 27, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (shucky)*

Very informative!
I would like to try this out but I have some concerns. Particularly with which diode to use. I want to run no more than 20 psi since I have a completely stock AWP. I am also concerned as to whether the ecu will adjust to the appropriate fuel levels for the upped boost. 
If the a/f mixture runs lean due to this mod, and the ecu pulls back timing to compensate, what detrimental effects would this have over a period of time on the engine?
For the moment I will be running this without a MBC.


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## tsuter (Dec 25, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (shucky)*


_Quote, originally posted by *shucky* »_can someone outline the different colors on the MAP sensor wires? 

Here is the wiring diagram for VW 1.8T NB 1998-2002. The G31 is the Charge Air Pressure Sensor.








If anyone has the GTI 1.8T wiring diagrams these are the best reference possible.


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## Johnny Blaze (Oct 18, 1999)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (tsuter)*

I see a 1 watt diode is recommended.. I have also heard and read about diodes burning out... wouldnt it be better to run a diode with a higher wattage.. say 5watts? or I am on the wrong track here..


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## RedGTI18t (Feb 15, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (Johnny Blaze)*

I've checked every peice of loom an there is no blue/orange wire, i found the purple/grey, purple/green, and a dark blue/brown wire


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## tsuter (Dec 25, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (RedGTI18t)*


_Quote, originally posted by *RedGTI18t* »_I've checked every peice of loom an there is no blue/orange wire, i found the purple/grey, purple/green, and a dark blue/brown wire









Just like the VW NB 1.8T electrical wiring diagram I posted above...
Maybe someone will post a GTI diagram and clear this up.....for GTI owners that is....


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## viper_chan (Sep 16, 2001)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (RedGTI18t)*


_Quote, originally posted by *RedGTI18t* »_I've checked every peice of loom an there is no blue/orange wire, i found the purple/grey, purple/green, and a dark blue/brown wire









I'd suggest locating your MAP Sensor, and unplugging the connector and look at the pin-outs instead of only the wire colors. Wire colors can vary by year, make/model....but I think the pin-outs of the MAP Sensor connector should be the same. If you plan to try this mod, take a look at my stealth Plug & Play setup using oem connectors & wires.










_Modified by viper_chan at 10:44 PM 10-6-2004_


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## tsuter (Dec 25, 2003)

He has the pins labeled correct. See the electrical drawing. The 2 is open and the 4 is the rising voltage signal to the ECM pin 101.


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## RedGTI18t (Feb 15, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (QT_GTI)*

ok 3 least questions, I kno i'm a pain in the ass, sorry guys. 1, wat wires am i hookin the diode up to, like + to -, or + to output, or output to - an which way does the stripe on the diode have to face? 2, I went to so many electrical stores an they told me a 4.3 or a 4.7v diode doesnt exist, wat should i ask them for? an 3, will this throw a check engine light?


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## 1.8TWolfsberg (May 18, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (RedGTI18t)*

visit the website that is linked on my DIY page. They are cheap and hassle-free. Don't waste your time in a store because they prolly won't know what your looking for or udnerstand its application








The striped side of the diode should be closer to the map sensor wire. I will update my DIY asap to show this. That is the one thing, for some reason, I did not add


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## tsuter (Dec 25, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (RedGTI18t)*

OK.. before you screw this up....
Using a diode is an electrical way of fooling the ECM from seeing over a 14 psi of boost. The ECM "sees" boost by providing the MAP sensor with a 5 volt signal and based on the amount of pressure (or vacuum) the sensor is reading returns a voltage between 1. to 5. volts. 2.5v is the center point more or less, any voltage below that is vacuum and any voltage above that is boost
If you have a stock chip, you should use the 4.3v diode. If you use the 4.7v, the boost reading the ECM still sees is higher than the requested boost "target" and you will still get overboost limp or throttle close. You should have a aftermarket chip to use the 4.7v diode, they have a higher "requested" boost voltage and won't shut down at the 4.7v map sensor reading.
So now depending on your chip you will need either a 4.3v or a 4.7v zener diode in the 1/2 watt to 1 watt range. Zener diodes work by "dumping" any extra voltage over their rating to ground; thus preventing the computer from seeing over the diodes rated voltage! 
The diode goes as shown between the ground and the signal wire.









Install the diode as shown in the above diagram, be careful take your time and make sure you don't use to much heat as this will damage the diode and it will not function properly. (A small electronics soldering heatsink isn't a bad idea) its important to note which way the stripe on the diode goes! If you get it backwards, your car will not run correctly.
Warning! You should have a non-ECM controlled wastegate to take advantage of this modification. I.e., a MBC. Any boost over stock or chip set levels will also not be seen by the computer and extra fuel may have to be added.

That is pin 1 and 4 in the electrical drawing and the picture above.




_Modified by tsuter at 9:29 PM 10-6-2004_


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## tsuter (Dec 25, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (tsuter)*

Those of you who can get around a VOM here is the spec on the Charge Pressure sensor... MAP.
ECM pin 98 - 101 Supply Voltage to Signal Voltage should be 4.5V minimum - ignition on.
ECM pin 101-108 Voltage Signal to ground should be 0.40-0.50 V at idle.
ECM pin 101-108 Voltage Signal to ground should be 2.5-3.0V at 3000RPM car in neutral.
ECM pin 101-108 Voltage Signal to ground should be 4.3-5.0 under boost.


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## 1.8TWolfsberg (May 18, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (tsuter)*


_Quote, originally posted by *tsuter* »_...its important to note which way the stripe on the diode goes! If you get it backwards, your car will not run correctly.

Correction, your car won't start if they are installed backwards


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## tsuter (Dec 25, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*


_Quote, originally posted by *1.8TWolfsberg* »_
Correction, your car won't start if they are installed backwards









Yeah... you would be essentially grounding out the MAP sensor.
Re: the Orange Blue, I wonder if its what VW lables Blue Brown in the drawings.
I wish I had a GTI Electrical laying around but I don't.
In anycase its the ground for sure.
Very nice drawings on p1. by the way!


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## mJstk01 (Aug 15, 2003)

What would happen if you installed a 4.7v diode with a chip using n75h w/o mbc? I'm running giac + n75h (no mbc) and peak 19psi - occasional soft limp, but would like to hit about 21psi w/o any limp.


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## tsuter (Dec 25, 2003)

*Re: (mJstk01)*


_Quote, originally posted by *mJstk01* »_What would happen if you installed a 4.7v diode with a chip using n75h w/o mbc? I'm running giac + n75h (no mbc) and peak 19psi - occasional soft limp, but would like to hit about 21psi w/o any limp.

You just have to watch your fuel because the 4.7 is more agressive and the higher boost may result in a lean condition that doesn't get compensated. Your setup is very similar to mine.
Very important to use the Vag if you got it and watch for timing pull back... knock retard. I would consider the 4.0Bar FPR in your setup.


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## 1.8TWolfsberg (May 18, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (tsuter)*


_Quote, originally posted by *tsuter* »_
Very nice drawings on p1. by the way!









Thank you


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## 4cefed (Sep 1, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

installed diodes tonight and correction, i installed them either way and the car still ran and didnt die, but im running 19psi with MY N75 unplugged and a HKS EVC


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## 1decimal8Tango (Jul 7, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (4cefed)*


_Quote, originally posted by *4cefed* »_installed diodes tonight and correction, i installed them either way and the car still ran and didnt die, but im running 19psi with MY N75 unplugged and a HKS EVC
they must not be working then because when I installed mine backwards it would not start


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## mJstk01 (Aug 15, 2003)

*Re: (tsuter)*


_Quote, originally posted by *tsuter* »_
You just have to watch your fuel because the 4.7 is more agressive and the higher boost may result in a lean condition that doesn't get compensated. Your setup is very similar to mine.
Very important to use the Vag if you got it and watch for timing pull back... knock retard. I would consider the 4.0Bar FPR in your setup.

I dont have a vag yet


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## The Cheat (Aug 30, 2003)

This all sounds extremely interesting but I have a question that hasn't been answered:
What will the engine computer report for max sustained boost if/when the dealer scans the ECU for fault codes? 
Also - what is the approximate boost gain with the 4.3v diode on a non chipped car w/ no MBC? 
What can be expected with a MBC installed? 
Are there any problems with running too lean with this setup?
It looks like this has only been known for about 3 months - any long-term damage possible?
I know that some of these questions have been partially answered but I need hard numbers... if someone tells me they run 18 lbs of boost reliably with a diode, MBC and DV then I'm all over this. As it is, I'm still hesitant because it seems like there should be a horrible downside to it and that it's too good to be true.


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## 4cefed (Sep 1, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1decimal8Tango)*


_Quote, originally posted by *1decimal8Tango* »_they must not be working then because when I installed mine backwards it would not start

HOw am i able to run this amount of boost then? i installed them both ways and it didnt die?


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## 27psiBoom (Jun 13, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*


_Quote, originally posted by *1.8TWolfsberg* »_


























I tried to do the mod yesterday with a 4.7v 1W zenner diode but the wires where of completely different colors







this is an APU engine I'm talking about.
So I had to guess and came up with this, is it wired properly?


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## DarkBlueGolf (Jul 16, 2003)

what if i already have a revo 4bar chip? should i still do this?


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## harry_the_cake (Sep 30, 2001)

*Re: (DarkBlueGolf)*

Am I correct in assuming that this mod only applies to drive-by-wire engines.
I have a cable throttle AGU engine, which as far as I know does not have a MAP sensor or any way of reading actual boost.
So my question is, how does this type of engine know if you are overboosting and is there a "diode mod" for my car.
Thanks.


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## 27psiBoom (Jun 13, 2003)

*Re: (harry_the_cake)*

You are correct, there's no diode mod for drive by cable engines.
Our ECUs can't read actual boost because we don't have map sensor.


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## JazzB3709 (Apr 14, 2004)

*Re: (DarkBlueGolf)*

Will this mod benifit me if i have a chip already? I know i would need a mbc for this mod but im wondering if this will give me more power even if i have a chip. How much more boost can you get outa your stock turbo? without seeing it go kaboom... http://****************.com/smile/emthup.gif


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## Motek (Oct 30, 2000)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (RedGTI18t)*


_Quote, originally posted by *RedGTI18t* »_I've checked every peice of loom an there is no blue/orange wire, i found the purple/grey, purple/green, and a dark blue/brown wire









I'm beginning to wonder about this myself. 
Yesterday I installed the VC2 adjustible clamp and may have got the wires wrong. I assumed the "blue/orange" must be the same as the "blue/brown" but now I've got problems. (Other than this Tsuter's instructions were great.)
No matter how much I turn down the adjustment screw for voltage I keep getting a 
16622 - Manifold Pressure / Boost Sensor (G31): Signal too High code.
This morning I boosted to 21 psi and then went into soft limp. I tried to boost again and the car shut off. Luckily it restarted.
From reading other posts it sounds like you can get this code even if the MAP is unplugged, i.e., it really means "problem with MAP"
Anyone have any ideas? Thanks. 
2/2/05 Update - Sorry, false alarm, it was just a bad connection. By the way this proves that 16622 does not mean "signal too high" it really means "bad signal, i.e., signal too high or too low".


_Modified by Motek at 12:07 PM 2-2-2005_


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## KrGs_MrN-Kusinagi0 (Dec 9, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (QT_GTI)*

think saddam had it in his spider hole


----------



## JazzB3709 (Apr 14, 2004)

bumb how can this benifit if you are chiped already? I mean i hear a lot of people doing this when there car has a stock ecu?? thanks to all opinions....


----------



## EuroHoMIE1.8T (Apr 24, 2003)

*Re: (JazzB3709)*


_Quote, originally posted by *JazzB3709* »_bumb how can this benifit if you are chiped already? I mean i hear a lot of people doing this when there car has a stock ecu?? thanks to all opinions....


It can benefit you in a way also, even if you are chipped. Slap on a 4.7v diode and an mbc and run a little bit more boost. You MIGHT bea able to get a few more ponies, I doubt it though, its not good to push the stock turbo that far....


----------



## JazzB3709 (Apr 14, 2004)

*Re: (EuroHoMIE1.8T)*

thanks.. true on the extra boost on stock turbo! To much and kaboom


----------



## arapcemal (Aug 18, 2004)

*Re: (27psiBoom)*


_Quote, originally posted by *27psiBoom* »_You are correct, there's no diode mod for drive by cable engines.
Our ECUs can't read actual boost because we don't have map sensor.

I have a cable engine(AGU). If there is no way for ecu to read actual boost, then then there will be no problem about the ecu or not?
I want to increase boost so only using a mbc is enough? Anyone have experience on cable engnes? Please help


----------



## arapcemal (Aug 18, 2004)

*Re: (arapcemal)*

Help please


----------



## JazzB3709 (Apr 14, 2004)

*Re: (EuroHoMIE1.8T)*

Can i just throw a mbc and crank it up alil? or without the 4.7v diode if i crank it up it might throw me into limp?????? see i spike at like 17 18psi settles down to 16psi. Once i hit like 4500 5000 rpm it drops way under 15lbs??? whats happening? Do i need a J valve?


----------



## arapcemal (Aug 18, 2004)

*Re: (JazzB3709)*

Help for diode on cable engines please...


----------



## EuroHoMIE1.8T (Apr 24, 2003)

*Re: (JazzB3709)*


_Quote, originally posted by *JazzB3709* »_Can i just throw a mbc and crank it up alil? or without the 4.7v diode if i crank it up it might throw me into limp?????? see i spike at like 17 18psi settles down to 16psi. Once i hit like 4500 5000 rpm it drops way under 15lbs??? whats happening? Do i need a J valve?









You will hit limp if actual boost goes over requested boost. A diode will prevent this.
I think the reason for the drop is because the turbo cant simply handle that much boost at that rpm?







Im not sure


----------



## JazzB3709 (Apr 14, 2004)

O so once you do the 4.7 diode and set the mbc to what boost you want, boost will never go under what is set at.? Even with a aftermarket chip...?


----------



## 27psiBoom (Jun 13, 2003)

*Re: (arapcemal)*


_Quote, originally posted by *arapcemal* »_Help for diode on cable engines please...


?????????
drive by cable don't come with MAP sensors








what would you need run a diode for? are you getting limp mode on your AGU (that's what I suppose you have)


----------



## arapcemal (Aug 18, 2004)

*Re: (27psiBoom)*


_Quote, originally posted by *27psiBoom* »_

?????????
drive by cable don't come with MAP sensors








what would you need run a diode for? are you getting limp mode on your AGU (that's what I suppose you have)

I have not increased the boost yet so no limp mode but if there is no map how the engine preventº the damage in high boost??


----------



## Pablo1.8t (May 24, 2004)

*Re: (JazzB3709)*


_Quote, originally posted by *JazzB3709* »_Can i just throw a mbc and crank it up alil? or without the 4.7v diode if i crank it up it might throw me into limp?????? see i spike at like 17 18psi settles down to 16psi. Once i hit like 4500 5000 rpm it drops way under 15lbs??? whats happening? Do i need a J valve?









No, the lowest i have brought my mbc was 13-14psi and that is more than the ecu will allow. Diode cost .25 cents and real easy to do, took me about 10mins, just make sure it is all covered well. The reason it is dropping is b/c it is hitting limp. Don't buy a J valve the mbc should replace your current n75.


----------



## EuroHoMIE1.8T (Apr 24, 2003)

*Re: (JazzB3709)*


_Quote, originally posted by *JazzB3709* »_O so once you do the 4.7 diode and set the mbc to what boost you want, boost will never go under what is set at.? Even with a aftermarket chip...? 

With an mbc, boost will only drop if:
1. Your throttle body closes, which it should NOT with a diode.
2. If you go too much and your turbo simply cannot handle it.


----------



## 27psiBoom (Jun 13, 2003)

*Re: (arapcemal)*


_Quote, originally posted by *arapcemal* »_
I have not increased the boost yet so no limp mode but if there is no map how the engine preventº the damage in high boost??

N75 duty cycle or maxing out the injectors will cause limp mode on DBC


----------



## Ramseytex (Jan 19, 2005)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (QT_GTI)*

what would be the advantage of clamping the map with an ECU tune wouldnt this defeat the purpose?


----------



## EuroHoMIE1.8T (Apr 24, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (Ramseytex)*


_Quote, originally posted by *Ramseytex* »_what would be the advantage of clamping the map with an ECU tune wouldnt this defeat the purpose?

THe point is to go over requested boost via bigger turbo or simply by trying to push more boost out of the stock turbo.


----------



## Mimi03GTI (Oct 21, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (EuroHoMIE1.8T)*

Currently have the 4.7 diode and mbc running parallel with the stock N75, which helped remove the high spikes (25/26) and holds 20 and the normal decline from there with my KO4. Tried the MBC & diode without the N75 also. The problem is in the upper gears (3rd-4th) at 6000 rpms, it goes into limp (5 psi) everytime and sometimes during partial throttle. According to the vagcom, it is overboosting. So I'm guessing a 4.3 diode may prevent this after reading through all of this? At one point had the MBC to hold only 17 psi and still overboosted at the same point. It even overboosted at 6000 rpms before I installed the MBC and diode and that was the reasoning behind go to MBC and diode to correct that in the first place. I'm hoping the 4.3 does the trick.


----------



## Slapahoe (Sep 22, 2004)

Here's my question...
It has been said that when you do this by tricking the ECU the car doesnt put out enough fuel to keep up with the boost because it still thinks it's running normal.
If thats the case, i was just thinking why dont i just chip it and not have to worry about plug and play senarios, wiring up stuff, and what not.
Does installing a chip just flat out do all this mentioned and raise boost and remove limp mode and so fourth????
Thanks for any help....


----------



## NEP (Sep 12, 2003)

*Re: (Slapahoe)*

just wondering if anyone has got this to work on a 20th?


----------



## 27psiBoom (Jun 13, 2003)

AFAIK the fueling isn't controlled by the map sensor just the maf and o2 sensors


----------



## kellygti (Sep 5, 2003)

*Re: (NEP)*


_Quote, originally posted by *NEP* »_just wondering if anyone has got this to work on a 20th? 

My question as well. I have an Apr chip too and run 93 octane mode. Just put an MBC on the car bypassing the N75 because I was getting limp mode. Yet I am *still* going into limp








What do I need to do!?


_Modified by kellygti at 8:07 PM 2-27-2005_


----------



## Scarab_Beetle (Dec 11, 2004)

^^ how much boost? its been said that leaving the stock n75 and dialing the wastegate arm as tight as possible will increase the boost and will suffer MUCH less from part throttle limp. just something to try... or perhaps you need the overboost kit from boostvalve.com? if you're running high boost with an mbc you'll get part throttle limp in some cases because the actual boost is higher than the requested boost at a given rpm/speed... this is because the mbc only opens at maximum boost, so you need some kind of a bleed or to dial the wastegate so the boost comes on more gradually. At least thats what i've gathered from researching this subject... someone smack me if i got it wrong


----------



## Brandon24 (Jan 12, 2005)

*Re: (Scarab_Beetle)*

ok, I have four questions
*1.* I was told if you have a aftermarket chip use a 4.7v and if its all stock use a 4.3v.......(true/false)?
*2.* Will i need a mbc to get this higher boost, or can i adjust the wastegate?
*3* Does the 4.3 or the 4.7 directly affect the peak boost level that can be achieved by diodeing?
*4* How does unpluging the n75 affect anything?


_Modified by Brandon24 at 8:35 PM 2-27-2005_


----------



## Brandon24 (Jan 12, 2005)

anyone.....


----------



## EuroHoMIE1.8T (Apr 24, 2003)

*Re: (Brandon24)*


_Quote, originally posted by *Brandon24* »_anyone.....

Didnt you find your answers in the last thread that was made bout a diode?








But I dont want to be a ***** so i'll give u what your looking for.
1. Stock chip then clamp at 4.3v, aftermarket chip then clamp at 4.3volts or preferably 4.7v.
2. You can control boost via an mbc, ebc, or wastegate adjustement.
3. Peak boost will be determined by your way of controlling boost.
4. Unplugging the n75 will not let the ecu control boost....


_Modified by EuroHoMIE1.8T at 10:04 PM 2-28-2005_


----------



## Brandon24 (Jan 12, 2005)

*Re: (EuroHoMIE1.8T)*


_Quote, originally posted by *EuroHoMIE1.8T* »_
1. Stock chip then clamp at 4.3v, aftermarket chip then clamp at 4.3volts or preferably 4.7v.


see, i thought i did, but than i read this and people are saying that the 4.3 wont boost as high or hold bosst, what if i want 17psi with the stock chip....i would need the 4.7v.....or is it just not good to do that with out the chip...cause a/f ratios are very far off?


----------



## EuroHoMIE1.8T (Apr 24, 2003)

*Re: (Brandon24)*


_Quote, originally posted by *Brandon24* »_
see, i thought i did, but than i read this and people are saying that the 4.3 wont boost as high or hold bosst, what if i want 17psi with the stock chip....i would need the 4.7v.....or is it just not good to do that with out the chip...cause a/f ratios are very far off?


no no no. your boost controller decides your boost, thast the point of having a boost controller.
a clamp is a clamp, for stock clamp the map sensor to 4.3 volts, thats all.


----------



## Brandon24 (Jan 12, 2005)

thanks....


----------



## GeosAvant (Apr 17, 2004)

Just an FYI for those looking at this. VW doesn't use orange in their wiring colors. They use brown. A brown that looks just like orange.
Three wires for the map sensor. Hook the diode between the Brown/Blue and Violet/Gray wires. Stripe goes toward Violet/Gray.
And also, I have a BT setup and a 4.7V diode with APR 93 programming and I am getting part throttle limp FWIW...


----------



## Scarab_Beetle (Dec 11, 2004)

sure as hell looks orange to me!







oh well, i figured it out well enough. Now to tweaking the wastegate arm just right......


----------



## vengeance18t (May 20, 2004)

Alright I just read this entire post and I still have a few questions. 
First of all, I have revo 3bar with sps3 currently set at hb4 tm4 and I hold about 18psi until it starts to taper off. If I understand correctly, I should use the 4.7V diode since Im chipped. If I get a mbc to control the boost, what effect will changing the boost setting on the sps3 have? 
Secondly, do I want to buy the overboost mbc or set it up in the regular configuration? With the n75h i have no surging and have never gone into limp, if that even matters. Thanks a lot.


----------



## MaxedOutCredit (Jan 24, 2004)

*Re: (necromanx13x)*

If you have sps3 a MBC is pretty much pointless.


----------



## vengeance18t (May 20, 2004)

So would it make sense to just use a diode without the mbc? And what about using a MBC to bypass the n75, doesnt it serve more purposes than just setting the boost.


_Modified by necromanx13x at 1:24 AM 3-19-2005_


----------



## sq4myvw (Sep 2, 2003)

*2004 GTI*

I clamped my MAP with a 4.3 ZD and all was good the first day. Peaking at about 16 and holding strong all the way to redline at 12. But day 2 couldn't get above 5. Any ideas? I'm all stock except the ZD.


----------



## 1.8tizzle (May 22, 2003)

*Re: 2004 GTI (sq4myvw)*

its cuz you have a 20th.


----------



## vudbbin1.8t (Mar 16, 2005)

sorry if i'm new but i'm planning on trying this on my 2000 awd jetta with only a n75j valve and stock ecu. has anbody had problems with limp mode or no partial throttle reponse or any other suggestions. oh yeah i m going to use the 4.3zender any advice, should i tighten down the wastegate controller ect?


----------



## simonm (Apr 19, 2005)

*Re: (27psiBoom)*


_Quote, originally posted by *27psiBoom* »_You are correct, there's no diode mod for drive by cable engines.
Our ECUs can't read actual boost because we don't have map sensor.

Damn. i have a drive-by-cable car and i always assumed a diode would fix my problem too!
i hit an overboost cut (big limp mode?) at about 15psi under heavy load in cool weather. i then have to reset my ECU to fix it. i have to run my MBC at as low as 12psi to prevent it from overboosting under all conditions! i have unknown brand chip, unknown cam mod, a MBC bypassing N75 and hybrid BOV.
where is it reading this boost to hit this limp mode? (where do i fool it?







)
i want more boost - nothing special - about 18psi peak with NO chance of overboost cut would be nice. i have dual stage MBC so i wont run it high all the time. what are my options?
(i know it's not perfectly on topic, but you guys seem knowledgable in this area) cheers!


_Modified by simonm at 10:13 PM 4/18/2005_


----------



## sq4myvw (Sep 2, 2003)

*Re: 2004 GTI (1.8tizzle)*

Actually, no. I traded it in for a 2004 GTI. 'NK' computer. Here's my setup:
2004 GTI 1.8T w/ K&N Panel filter, GFB Blowoff, 4.3V ZD, Custom Manual boost controller, And I tightened the wastegate a few turns.
What it's doing is peeking at 16 and sustaining 12, which is great. But it goes into limp on the highway and gets worse as time goes on. If I cycle the key while driving to reset the ECM it works fine again for a couple minutes. Any ideas?


----------



## GTIAWW (Jan 18, 2004)

*Re: 2004 GTI (sq4myvw)*

I run a 4.7 Diode +93oct Vtune along with the other mods on my signature below.(N75 race valve, 3'GHL turbo back+Samco Inlet pipe+Carbonio CAI+Split SecondBoost Controller+Bailey'sDV) I have a couple of questions that were not clearly answered in the topic for all the diode gurus out on the forum.
1- Will addin a 4bar FPR do anything for my set up?
2- Should I use a MBC instead of my Split Second Boost Controller or get a better EBC?
3- Are their any particular settings/parameters out there for the V-tune guys better than the ones that APR sets for you when you get chipped?
4- What would a grounding kit do for the DIODE if anything? 
5-Should I adjust my wastegate actuator rod a bit?
I already had the diode before the chip so they should have adjusted accordingly to what was on VAG. Any help would be greatly appreciated. Car does 17PSI in 3rd, 21PSI in 4rth and 23 PSI in 5th. 
THANKS AGAIN and see you all in WATERFEST!


----------



## attackeagle (Aug 16, 2005)

*Re: (Scarab_Beetle)*

I take it you guys are running ball and spring MBCs not bleeder type?
Would a bleeder type work better at avoiding part throttle limp in connection with a diode on a k04?


----------



## viper_chan (Sep 16, 2001)

I fixed the pics to my plug & play install finally...hopefully someone will find them useful if they're considering the diode mod.


----------



## double0vr6 (Mar 16, 2004)

*Re: (viper_chan)*

havent gotten the diode to work on my gli as yet do they not work on the gli's or somthing. Rite now i have the wastegate turn up 2 time and it will hit 16-17 real fast and i feel the power and then rite down to 10 real fast and then somtimes it does even go past 8 psi. no diode on car 
so what my problem


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## ryanvw (Feb 27, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

nice diy!!!


----------



## ANT THE KNEE (Aug 25, 2000)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (ryanvw)*

since someone else posted today about this,and it's really old
I'm just finding out about this mod, and it sounds pretty good for a temporary solution. I agree about the MBC too. I'm just wondering about the timing though. I'm just starting to read though so I'll be patient for now


----------



## AllofurVWRbelong2me (Jul 12, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (ANT THE KNEE)*

If your asking if it gets advanced...no It doesnt, thats one of the problems with it and why the people with chips say it suck and what not...lol.
If you really want you can DL lemmiwinks and advance it a bit...I think I did 1.75 on mine but I wouldent go very far over that unless ya have a FMIC or a bigger SMIC IE: Tyrol Sport's (I know theres others...just an example)


----------



## gergel1 (Mar 16, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (RABIDRABBIT1983)*

and how much will it cost if ecu goes in limp mode
how to fix it
oh ! the pain.
gergel1


----------



## beachball6 (Apr 22, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (gergel1)*


_Quote, originally posted by *gergel1* »_and how much will it cost if ecu goes in limp mode
how to fix it
oh ! the pain.
gergel1

turn key off, then turn key to on position and fixed.


----------



## [email protected] (Dec 5, 2005)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (gergel1)*


_Quote, originally posted by *gergel1* »_and how much will it cost if ecu goes in limp mode
how to fix it
oh ! the pain.
gergel1

how much will it cost????????
it doesnt cost anything to go into limp mode...lol
as beachball said, just turn the car off and turn it back on.
if that doesnt work, disconnect the battery and just let it sit for 30 mins.
and then plug it back in, align your TB and your good to go.
The whole purpose of the diode mod is so that your ECU does NOT go into limp mode though...so with the diode installed, it will not go into limp.


----------



## performula (Apr 10, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

This is the best diode thread. 
For my stock car I need a 4.3 diode and an MBC, then follow the DIY?


_Modified by performula at 11:34 PM 3-16-2006_


----------



## gergel1 (Mar 16, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" ([email protected])*

hey folks, thanks for all the info....i clamped the ( on mine ) charge air sensor at the cooler , used 4.3 diode - switch- posi locks for wire hook up & diode hook up ( makes it easy to change diode if needed ) also quick wire clamps @ the 2 wires.
seems to work well, feeling of a lot more power 1st 2nd 4th 5th however 3rd seems flat oh - also i had n75 j valve on for a while also.
when i switch out of diode mode all gears pull great
much less then diode mode. gergel1 
works well for fwy- on ramps here in nor cal.


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## Gr8Scott95 (Nov 24, 2001)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (gergel1)*


_Quote, originally posted by *gergel1* »_hey folks, thanks for all the info....i clamped the ( on mine ) charge air sensor at the cooler , used 4.3 diode - switch- posi locks for wire hook up & diode hook up ( makes it easy to change diode if needed ) also quick wire clamps @ the 2 wires.
seems to work well, feeling of a lot more power 1st 2nd 4th 5th however 3rd seems flat oh - also i had n75 j valve on for a while also.
when i switch out of diode mode all gears pull great
much less then diode mode. gergel1 
works well for fwy- on ramps here in nor cal.

You put the diode on and what did you do to increase the boost? MBC? The diode only keeps the ecu from seeing too much boost. You still have to do something like a MBC to raise the boost.


----------



## GLI64 (May 3, 2005)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" ([email protected])*


_Quote, originally posted by *[email protected]* »_
how much will it cost????????
it doesnt cost anything to go into limp mode...lol
as beachball said, just turn the car off and turn it back on.
if that doesnt work, disconnect the battery and just let it sit for 30 mins.
and then plug it back in, *align your TB* and your good to go.
The whole purpose of the diode mod is so that your ECU does NOT go into limp mode though...so with the diode installed, it will not go into limp.

what exactly do you mean by align your throttle body?


----------



## gergel1 (Mar 16, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (Gr8Scott95)*

the n75j takes boost up to 13.5 then seems to level out @ 10 good enough for this 64 year old.


----------



## JettaRed (Aug 14, 2000)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (gergel1)*

don't know if this has been covered, but the wires to use for Audi are the *grey/blue *to the *black*.


----------



## TickTack (Feb 27, 2004)

*Re: (arapcemal)*

Nice writeup, IM sent.


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## mikeygti18t (May 2, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

im curious how this "clamping" trick works... i understand the theory of tricking the computer into allowing a greater boost level, but i dont see how this diode does it by the wiring diagram can anyone tell me. a zener diode is generally installed in reverse bias, and will not conduct current until a set voltage is reached. and in forward bias is just conducts in a normal fashion as a typical diode does. so how does this apply to the situation. i see the diode installed across two wires in schematic, im just curious as to how is operates....


----------



## mikeygti18t (May 2, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

just found another site that went into greater detail oops


----------



## surfo (Jan 6, 2006)

Ok... here is a quick cuestion... first of all the car in cuestion is a IBIZA FR with UNITRONIC chip, wich is hitting limp mode even at 18psi... Chip is suposed to work at 22-23 peak psi...
Map sensor has 4 wires 1 2 3 4... colors are different from image, so can anyone please tell us between wich and wich number it goes... 3 and 4 2 and 3, 2 and 4... ???...
thanks...


----------



## Mimi03GTI (Oct 21, 2002)

*Re: (surfo)*

Has anyone been experiencing partial throttle limp mode (5 psi) with this mod lately? I'm currently running the 4.7 1w diode with the boostvalve MBC. It is just one big pain to shut the car off and back on every now and then. If there is a fix for this, please let me know. I'm thinking of playing around with the wastegate but several folks have said not to touch it. Other than that, the car is running great. Thanks.


----------



## Rac_337 (Sep 24, 2004)

*Re: (Mimi03GTI)*

Sorry to bring this back from the dead
but you should put a line on the diode indicating the correct direction its supposed to go


----------



## SLEEPER_DUB (Sep 2, 2006)

when you say automotive wire, whats the amprage or size of wire???


----------



## no_limit_larry (Sep 30, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

if i ordered it off the net..how long would it take to get here!?!?!?!? i have a race this weekend and i could use this...any alternative options to get this like at a local store?!?!?!?


_Modified by no_limit_larry at 3:57 AM 11-10-2006_


----------



## pickles and mayo (Mar 6, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (no_limit_larry)*


_Quote, originally posted by *no_limit_larry* »_if i ordered it off the net..how long would it take to get here!?!?!?!? i have a race this weekend and i could use this...any alternative options to get this like at a local store?!?!?!?

_Modified by no_limit_larry at 3:57 AM 11-10-2006_

The only place that would even remotely have a chance of having the diode would be Radio Shack... but they don't really have stuff like that anymore. Bastards... http://****************.com/smile/emthdown.gif


----------



## no_limit_larry (Sep 30, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

is there any possible way that i could use a different size diode.....like what does the volts and watts mean on the description?!?!?!


----------



## no_limit_larry (Sep 30, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (no_limit_larry)*

radio shack has a 5.1 V and 1 W







...how would this work? need to know asap please!!! thanks


----------



## Rac_337 (Sep 24, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (no_limit_larry)*


_Quote, originally posted by *no_limit_larry* »_radio shack has a 5.1 V and 1 W







...how would this work? need to know asap please!!! thanks









it wouldnt
the signal is a 5 volt circut.


----------



## pickles and mayo (Mar 6, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (Rac_337)*


_Quote, originally posted by *Rac_337* »_it wouldnt
the signal is a 5 volt circut.

Yeah the diode basically "caps" the voltage to whatever it is set to, and the more boost the sensors see the more voltage goes through the line. 4.7 is about 17 psi (from what i have gathered on here) which is when limp mode kicks in. the 4.3 will only show 13 psi, well below limp mode. the 5v won't do anything (please, someone correct me if i am wrong) http://****************.com/smile/emthup.gif















EDIT: I think 13 psi is a soft limp and 17 is hard limp http://****************.com/smile/emthup.gif


----------



## NJ1.8T (Nov 4, 2005)

Well, I did the diode mod to my 2003 Jetta 1.8T which is chipped. Both the 4.3 and the 4.7 diode bring my boost way to high, up around 25psi. So I thought since I have a Vag Com and Laptop that I could try something without using an MBC. I have the Lemmiwinks program installed and can use Channel 12 which is the SEL Scaling. I was thinking of dropping the % from 100% down to about 90% and see where I peak at while WOT.
Has anyone else used Lemmiwinks to work out there boost spikes with the Diode?


----------



## budgetko4a4 (May 9, 2006)

*Re: (NJ1.8T)*

Does this work on a AEB motor? Thanks ('99 a4 FWD)


_Modified by budgetko4a4 at 11:55 AM 12-27-2006_


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## Still-Boostn' (Aug 13, 2006)

*sweet!*

great write up, i finally did this mod. works great, but i still go into limp every now and then.
so one should make a map sensor package and sell it with this mod already done. just plug in the new map and play.
http://****************.com/smile/emthup.gif


----------



## JettaRed (Aug 14, 2000)

*Re: sweet! (Still-Boostn')*


_Quote, originally posted by *Still-Boostn’* »_great write up, i finally did this mod. works great, but i still go into limp every now and then.


Limp may also be caused by too much air flow regitered by the MAF. So, to limit boost with the diode mod, you need to add, not replace the N75, a manual boost controller. 
I have found the best place is between the intake manifold and the wastegate actuator by inserting a "T" fitting after the N75 and before the wastegate. Then, when you hit the set pressure, say 21-22 lbs, the boost controller opens and pressurizes the actuator to open the wastegate.
This setup keeps the smooth driveability that the N75 provides while limiting the boost manually.


----------



## TonyZGTI (Dec 29, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

Nice diagram, thanks!!!


----------



## 3ur0Tra$h (Mar 27, 2005)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (TonyZGTI)*

Thanks for all of the info on the "diode mod". I did this to my 337 last night with the addition of a MBC.
Durring the install I was a bit unsatisfied with the answer: "If it doesn't stat flip the diode around and try again". I searched and searched, but no luck. So I told myself I would post MY OWN findings so there might be some sort of info as to which way the diode is supposed to go.
I used a 4.3v 1w Zener Diode, one end was black (cathode) and the other a beige brown color. I soldered the diode in with the *BLACK END towards the ORANGE/Blue Stipe WIRE*
The car starts, idles, and drives fine with NO DTC's. I cannot guarntee that this will work on EVERY CAR, but it worked for me. Also I did not reverse it to verify outcome (car cranks but won't start). Hope this info helps other lost souls like myself. Now that I think about it, there was some humor in sitting in front of the computer, all excited to "crank up the boost" and not being able to remember d*** from 7th grade tech-ed, when I made my little Circuit Board Robot with flashing LED's and *DIODES*.
Thanks again, hope this is informational.


----------



## sexwagon (Jan 12, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (3ur0Tra$h)*

ummm so ya..
great idea and all but I might sound like a cheapo.
On the online site there is a min. of a $10.00 order. I mean thats not that bad, but I dont feel like wasting that much money when all I need is a .10 part....its kind of ridiculous in my opinion.
Soooo would anyone know where else to get them or have an extra one they want to mail me? I mean im sure i can send you like a $1 through paypal haha.
-Ricky


----------



## Rev. Longride (Jul 6, 2005)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (sexwagon)*


_Quote, originally posted by *sexwagon* »_ummm so ya..
great idea and all but I might sound like a cheapo.
On the online site there is a min. of a $10.00 order. I mean thats not that bad, but I dont feel like wasting that much money when all I need is a .10 part....its kind of ridiculous in my opinion.
Soooo would anyone know where else to get them or have an extra one they want to mail me? I mean im sure i can send you like a $1 through paypal haha.
-Ricky

IM sent
and for everyone else I found this place with no min. order. 4.3v 1w zener diodes are $.08 but shipping was like $6. http://****************.com/smile/emthup.gif 
http://www.mouser.com/search/P...4731A


_Modified by severed at 3:58 PM 1-12-2007_


----------



## mystery chip 1.8t (May 7, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (severed)*

maybe with this DIY you could put in which way the diode gets conected to the wires. it only works one way.


----------



## 3ur0Tra$h (Mar 27, 2005)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (mystery chip 1.8t)*

Look about 4 posts above yours (last page)


----------



## .skully. (May 18, 2005)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (3ur0Tra$h)*

doesnt this need a resistor wired in also?
the way the zener works, is that it forces its terminals to be at 4.7V which means something is dissipating the power somewhere usually a resistor is thrown in to do the job so nothing else burns up.
or would it not need one since their isnt a lot of current running through there?


_Modified by .skully. at 1:42 PM 3-22-2007_


----------



## FictionWeLive (Feb 19, 2007)

hope im not asking something already asked, i searched and didn't see it. I have a 2003 GTi. I installed a 4.7 diode today and used my MBC to about 19 psi, unfortunately, it spikes at 19 and drops down, then goes to limp at 5. anyone know why? i tried switching it around and it seemed to run poorly. Should I try the 4.3 diode? or am I doing something wrong? Thanks for any help!


----------



## XB4AX (Aug 24, 2004)

*Re: (FictionWeLive)*

Some one please correct me on this if im wrong, but this is how i understand (or maybe don't actually) what's happening
Is your car chipped? If not then i believe you would need a lower volt diode.. The 4.7 sends the ecu a reading of 17 psi which, if your car is unchipped, is much greater than the ~7 that is runs on stock, causing it to go limp. A chip changes the amount of boost it is suppose to be running at. I would think that an unchipped car would need a diode that would send the ecu a stock boost reading.
Like i said, i could be completely wrong on this, but that is what i think.
Hope this helps you, or leads someone else to http://****************.com/smile/emthup.gif


----------



## theswoleguy (Jan 25, 2006)

*Re: (XB4AX)*


_Quote, originally posted by *FictionWeLive* »_hope im not asking something already asked, i searched and didn't see it. I have a 2003 GTi. I installed a 4.7 diode today and used my MBC to about 19 psi, unfortunately, it spikes at 19 and drops down, then goes to limp at 5. anyone know why? i tried switching it around and it seemed to run poorly. Should I try the 4.3 diode? or am I doing something wrong? Thanks for any help!


_Quote, originally posted by *XB4AX* »_Some one please correct me on this if im wrong, but this is how i understand (or maybe don't actually) what's happening
Is your car chipped? If not then i believe you would need a lower volt diode.. The 4.7 sends the ecu a reading of 17 psi which, if your car is unchipped, is much greater than the ~7 that is runs on stock, causing it to go limp. A chip changes the amount of boost it is suppose to be running at. I would think that an unchipped car would need a diode that would send the ecu a stock boost reading.
Like i said, i could be completely wrong on this, but that is what i think.
Hope this helps you, or leads someone else to http://****************.com/smile/emthup.gif 

pretty much you said it, the top poster needs to swap in a 4.3v diode which is like 14lbs, then log some with vag just to make sure you not leaning but you shouldnt be. Worst case add a 4bar and tweak it via LW.
Switching the diode? as in you reverse it 180*? hell if you did that im surprised you even got it started lol, when i hooked mine up backwards it wont start. Thats bc your now not getting a voltage reading bc its being block as a diode is like a check valve, it only flows one way.










_Modified by theswoleguy at 2:31 PM 3-26-2007_


----------



## JettaRed (Aug 14, 2000)

*Re: (FictionWeLive)*


_Quote, originally posted by *FictionWeLive* »_hope im not asking something already asked, i searched and didn't see it. I have a 2003 GTi. I installed a 4.7 diode today and used my MBC to about 19 psi, unfortunately, it spikes at 19 and drops down, then goes to limp at 5. anyone know why? i tried switching it around and it seemed to run poorly. Should I try the 4.3 diode? or am I doing something wrong? Thanks for any help!

Here's the problem you're having. The diode mod only addresses the overboost problem; it does not address the airflow problem. Your ecu will still detect excessive airflow and throw you into limp, especially if it also detects a lean condition. You should not do this mod unless you have also adjusted fueling and reprogramming the ecu for greater air flow. In other words, use it with a chip.


----------



## thelettert (Sep 23, 2005)

*Re: (JettaRed)*

so im bumping this thread back up. i read up allot about this and im still afraid to do it but i have no choice. i dont want too much more boost, i just want to stop hitting soft limp mode and the occasional engine light flashing. i hit about 18-20 psi with any of the n75's and i usually surg right before it limps.
1. could my MAF sensor be broken/dirty, since if i read corectly that limp mode is from air problems?
2. i dont have a vag-com, so this makes things difficult.
3. how diferent is "limp mode" and "overboost". either way the cpu limits boost to 5psi till you remove your foot, or sometimes restart the car.
please help...








i also made another thread here...
http://forums.vwvortex.com/zerothread?id=3263537


----------



## Xx03GTIxX (Apr 9, 2007)

*Re: (thelettert)*


----------



## thenick (Jun 19, 2004)

I'm gonna be doing this mod within the next week, so expect a simplified " Dummies Guide to The Diode Mod " thread to pop up soon.


----------



## MDA0303 (Apr 16, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

hey do i need to do the diode?
i have apr's 93 oct software
just installed gt2871r (whole kit w 440inj and mbc)
Im tuning w vag at the dyno.

Is the diode needed? because my software let me boost to 20psi on the ko3.


----------



## JettaRed (Aug 14, 2000)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (MDA0303)*


_Quote, originally posted by *MDA0303* »_hey do i need to do the diode?
i have apr's 93 oct software
just installed gt2871r (whole kit w 440inj and mbc)
Im tuning w vag at the dyno.

Is the diode needed? because my software let me boost to 20psi on the ko3.

Not if you are not having limp mode problems.


----------



## A4x4T (Jul 11, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (JettaRed)*

Does anybody have an extra 4.3V they can send a poor soul??


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## Guyver96 (Jan 17, 2007)

Wow Alot fo people do this i see lol ... I've been running on the diode for about 7 months now ive had to change it everynow and then cause for some reason they stop working... Ive gone through 3 of them already thank god i dont soder them in but im boosting 14 psi with the wastegate cranked a bit. At first itll run up to 10 psi fast and then slowly creep up to the 14. Ive tried with a mbc but i dont like the way it jumps boost ... My mods are... 
Front mount
4 bar reg.
Diode
cranked wastegate 
at 14 psi 
runs great no problems I Just got the 4 bar reg. today and havent had a chance to install the BC yet but im gonna try it tomorrow and take it up to about 18 psi.. I believe with the 3 bar you only get good fuel to about 15 psi anything over that your looking for problems... 
I've done this because im going to be doing Revo stage 2 soon and just been doing what i need to do little by little. Now all i need is the Down Pipe and Im SET!!! WOOHOO anyway not sure if this will help any of you but just my expireance with the Diode.


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## A4x4T (Jul 11, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

OK. I was going to do the 4.3V diode but I am boosting to around 11.5 psi max dead stock. So what I need to know is should I go to the 4.7V or what. What is the factory stock boost limit in the computer? I have the MBC ready to take the N75s place but I don't know which diode to use. I am only going to wire in one no switch.


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## Guyver96 (Jan 17, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (A4x4T)*

do the 4.3 diode... If you do the 4.7 you run into limp mode.


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## A4x4T (Jul 11, 2007)

So whats the boost limit on the stock computer before throttle cut?? If I run the 4.3V whats the max boost I can run without over running the injectors duty cycle and going lean???


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## Guyver96 (Jan 17, 2007)

*Re: (A4x4T)*

I believe its 16 psi. Its always good to try a search tho just incase. Search for Stock Fuel cut or max stock boost....


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## wakesslide12 (Jul 25, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

so when you do the diode mod do you just strip the wires or cut them? then the diode goes from purple/gray directly to the orange/light blue for use without a switch?


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## theHAGGIS (Mar 4, 2002)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (wakesslide12)*

You gotta point...aren't you basically short-circuiting the loop by crossing the wires? I have absolutely NO background in electronics, other than don't touch the black and white wires together. Feel free to tell me to shut up and just follow the pretty pictures on the first page.

Wouldn't you run the diode like one of the below?










_Modified by theHAGGIS at 4:33 PM 3-6-2008_


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## diymirage (Mar 16, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

well, i took a lok at it today and im confused 
this is the right sensor is it not ?
(its on the charge pipe coming of the cold side of the intercooler and going into the throthle body. 








i checked all 3 wires and none of them gave me read out on a regular 12 volt meter. 
i tried it with the engine running and at different boost/vacuum levels but nothing. 
i double checked the couloring of the wires and this is how they are: 
1 black wire 
2 not used 
3 white wire with a black stripe 
4 striped blue/grey wire 
am i on the wrong sensor here ?


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## MightyDSM (Apr 16, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (diymirage)*

^^^
There's only one MAP sensor and it's on your intercooler.
Nice sig. It's true if you are racing a non-turbo eclipse


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## zeusenergy (Feb 25, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (theHAGGIS)*

Well, it's not "shorting" the circuit at all. A diode will allow one way flow from the striped side to the other. So your output line on the MAP sensor has an output level that stock ECU reads should only hit 4.3 V or so... anything more, and you will limp-out








Imagine water flow from a pipe. The signal wire to the ECU is the pipe. The water flows in from the MAP sensor (faucet!) Above a certain pressure, a valve opens up in the middle of the pipe, and dumps the extra pressure on the ground (GROUND as in the ground, or electrical ground! Take your pick.), and continues to output the preset amount of pressure to the end of the pipe where you are using the water (ECU). 
When you install the diode on the car properly, the ECU will see anything UP TO BUT NOT ABOVE the voltage level of the diode you install. *So the ECU is requesting boost from the turbo, and sending the signal to open up the waste gate will be PREVENTED because the ecu thinks it's not time yet. So your turbo continues to build boost, and without an MBC it will top out around 20-22 PSI.... Big power, poor reliability!
It's common knowledge that 15-16 PSI continuous is fine for stock fueling. The MBC doesn't RAISE the boost, it keeps it in check!*
EDIT: found out I was wrong about this and I'm man enough to admit it. http://****************.com/smile/emthup.gif 
_Modified by zeusenergy at 7:34 PM 3-25-2008_


_Modified by zeusenergy at 9:01 AM 4-5-2008_


----------



## diymirage (Mar 16, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (zeusenergy)*

so your saying i can run 14 PSI of holding boost while spiking at maybe 18 without any supporting mods (diode obviously) whatsoever without burning holes in my pistons because im running to lean ?


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## Vdubwolf1.8t (Mar 20, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (diymirage)*









I have my diode line facing the orange/light blue
so here it is...
Purple/green
--------------------------
Purple/grey
--------------------------
l
l
[_] <---diode ( line facing orange/light blue )
l
l
Orange/light blue
--------------------------

I have tried both ways
Nothing happens. Car still turns over, i took it for a spin, and the boost gauge only reads 5-8 psi


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## diymirage (Mar 16, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (Vdubwolf1.8t)*


_Quote, originally posted by *Vdubwolf1.8t* »_








I have my diode line facing the orange/light blue
so here it is...
Purple/green
--------------------------
Purple/grey
--------------------------
l
l
[_] <---diode ( line facing orange/light blue )
l
l
Orange/light blue
--------------------------

I have tried both ways
Nothing happens. Car still turns over, i took it for a spin, and the boost gauge only reads 5-8 psi


















not sure about your xolours but here are the locations on the connecter
pin 1 == GND
pin 2 == Not used
pin 3 == +5v
pin 4 == signal 0-5v

you want to install the diode between pin 1 and pin 4 
(just roll hacn the rubber sleeve on the connecter and you will see the wires going into it and they will be numbered) 
now, once you have done and your car still starts the map sensor is capped .
(if it doesnt start the diode is in backwards) 
this does not mean your turbo is making any more boost then before, beacuse you did not change the N75 valve 
this only means that if you were to replace the N75 with a mabual boost controller your ECU will not go into limp mode because of overboost since it will never register more then (i think the number is) 14 pounds of boost


----------



## 02boosted^gti (Feb 28, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (QT_GTI)*

whats wrong with my carif this mod doesnt work?


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## zeusenergy (Feb 25, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (02boosted^gti)*

If you have a 20th AE then it won't work at all. So I've heard....


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## zeusenergy (Feb 25, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (diymirage)*

You'll need a MBC but they are super easy and cheap to build. Here's mine, keep in mind you have to drill a tiny hole 3/32 in the coupler. You can add some small plastic washers inside the spring end to increase boost easily:








Just disconnect the N75 charge side and wastegate line and add them to this.
I pushed 14 PSI with no limp, and no diode. I'm at 15 PSI now with the diode.








EDIT: 16 PSI strong now.
_Modified by zeusenergy at 8:46 AM 4-5-2008_

_Modified by zeusenergy at 8:46 AM 4-5-2008_


_Modified by zeusenergy at 5:08 AM 4-14-2008_


----------



## zeusenergy (Feb 25, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (wakesslide12)*


_Quote, originally posted by *wakesslide12* »_so when you do the diode mod do you just strip the wires or cut them? then the diode goes from purple/gray directly to the orange/light blue for use without a switch?











Here's my NB, so your wiring will be different. The 3m gel scotchlocks (SL) can be purchased at electric supply places for electricians or radio shack. You cut the CPS wire that normally goes towards the stripe side of the diode, now you have two ends. Take a scrap piece of wire and put its end into the middle hole of the SL. Take the two cut wires and put the in the other two holes of the SL. Make sure the wires all go to the end of the hole, past the metal bar inside. Squeeze with pliers. The seal is water-resistant and will outlast the wires themselves. Cut the new scrap wire so it can be accessed under the hood. Crimp on a round connector and get a bolt and nut for it. You can wrap the diode's stripe side leg around the bolt and gently tighten.
Do the same with the other side of the diode and create another wire with round connectors at both ends. Attach the other round end to the battery negative terminal. Wrap the whole diode and bolts deal with tape. Now if the diode goes south, or you want to remove it, it will be easy and accessable!







You are done.









_Modified by zeusenergy at 8:59 AM 4-5-2008_


_Modified by zeusenergy at 9:04 AM 4-5-2008_


----------



## Seth-VDub.GLI (Feb 15, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (zeusenergy)*

*If anyone is interested, I have some 4.7's for sale.* http://****************.com/smile/emthup.gif 
http://forums.vwvortex.com/zerothread?id=3778457


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## Dur7yFix (Sep 30, 2007)

*Re: :..BoraXTC..:*

oh well what boost controller are you running?
thanks im running a stock passat


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## BIG MACK 310 (Sep 24, 2007)

*Re: (Dur7yFix)*

what would happend if i use the diode mod but not use a MBC??? will it work that way???


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## diymirage (Mar 16, 2008)

*Re: (BIG MACK 310)*


_Quote, originally posted by *BIG MACK 310* »_what would happend if i use the diode mod but not use a MBC??? will it work that way???









you will not see any gains because you will now be able to run more boost (because the ECU will no longer cut out after a certain PSI) but you have no way of doing it because you are not changing anything that would affect the wastegate. 
i guess you could try adjusting the wastegate actuator arm ?


----------



## zeusenergy (Feb 25, 2008)

*Re: (diymirage)*


_Quote, originally posted by *diymirage* »_
you will not see any gains because you will now be able to run more boost (because the ECU will no longer cut out after a certain PSI) but you have no way of doing it because you are not changing anything that would affect the wastegate. 
i guess you could try adjusting the wastegate actuator arm ?

Yeah, that will work. Or build a cheap MBC like I show^^^^^^ a few posts up. Super cheap, super easy, and you can use plastic washers inside to increase boost about 1 PSI per washer.....
It's really not hockus-pokus







even though you may think it is. http://****************.com/smile/emthup.gif


----------



## gti1.8tpolo (Nov 10, 2007)

Hi from england love this site you lot know so much bout the 1.8t! Anyway got a 1.8t vvt model running k03s in a polo which you dont get! Recently had a custom remap and it holds boost bout 15psi! Is their any point in doing this diode mod will i get more boost on stock n75 valve? If so is it safe!?


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## zeusenergy (Feb 25, 2008)

*Re: (gti1.8tpolo)*


_Quote, originally posted by *gti1.8tpolo* »_Hi from england love this site you lot know so much bout the 1.8t! Anyway got a 1.8t vvt model running k03s in a polo which you dont get! Recently had a custom remap and it holds boost bout 15psi! Is their any point in doing this diode mod will i get more boost on stock n75 valve? If so is it safe!?

Nope. Well, no, it won't give any boost. And hello back at ya from across the pond...


----------



## gti1.8tpolo (Nov 10, 2007)

*Re: (zeusenergy)*

Thanks well wats all the fuss bout it then suppose its only good wen you run manual boost control, but i not into that scared of lean mixtures!!! Been looking at the J valve though many polo owners over ere say it smooths out the boost? cos it does kick in quite hard bout 3000rpm tyres really spin LOL


----------



## Space9888 (Mar 18, 2002)

*Re: (gti1.8tpolo)*


_Quote, originally posted by *gti1.8tpolo* »_Thanks well wats all the fuss bout it then suppose its only good wen you run manual boost control, but i not into that scared of lean mixtures!!! Been looking at the J valve though many polo owners over ere say it smooths out the boost? cos it does kick in quite hard bout 3000rpm tyres really spin LOL









put a mbc in there, as long as your 02 sensors are not throwing failure faults the fuelling will be adjusted for.


----------



## zeusenergy (Feb 25, 2008)

*Re: (Space9888)*


_Quote, originally posted by *Space9888* »_
put a mbc in there, as long as your 02 sensors are not throwing failure faults the fuelling will be adjusted for. 

I began to go lean at 16+ PSI. From what I hear 17 is the limit on stock fueling and software.








Hopefully I am wrong here.


----------



## gti1.8tpolo (Nov 10, 2007)

*Re: (zeusenergy)*

a guy over ere tried a mbc on his polo but found the ecu kept retarding the timing and using the n249 to drop boost will the map clap method work on my engine code bjx?


----------



## zeusenergy (Feb 25, 2008)

*Re: (gti1.8tpolo)*

No clue, but it's cheap enough to try it out. Buy two 4.3V zener diodes with 5 watt rating. Figure out which wire is going to the ECM on your intercooler map sensor (CPS) and push the stripe side of diode into that part of the connector. The other side of the diode goes to the brown wire. Make sure the pins get good contact to the wires inside, and turn the boost up. if it works, you won't get shut down anymore. Then you can install it better if the test passes.


----------



## gti1.8tpolo (Nov 10, 2007)

*Re: (zeusenergy)*

ill try it out, but how high can i boost it on a k03s its already remapped to 1.1bar ish!


----------



## zeusenergy (Feb 25, 2008)

*Re: (gti1.8tpolo)*

Ahhh I didn't realize you had software done already.








You should be good up to whatever the remap allows without any diode at all. some people get to 20-21 PSI or so then you get shut down. If you are at 15 PSI, and pushing that much HP, then trust me you will get alot more power out of the motor with 17-19 PSI. Diminishing returns begin around there anyway. Run a better intercooler and colder plug range.
Oh, and running an MBC will CERTAINLY help you get more power. I suggest doing two with switching and a solenoid to prevent the part-throttle problem others have with MBC's. 


_Modified by zeusenergy at 8:34 PM 5-3-2008_


----------



## vwjetta02 (Nov 27, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

ok, i need a answer!! i have a stock 1.8t and i just found this and iam going to buy the revo software! but now i dont know if i need too? do i or can i do this and will it make the same effect? it will be the stage 2 that i will be getting. can any answer the question? do i need the software? or will this work just as will? please help !!!!!


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## thetwodubheads (Dec 6, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (vwjetta02)*

If you have the budget for the tuning, get chipped. I did the Diode for over 2years. It was only recently with a baby in the back seat did the surging at part throttle get to be too much, so I'm stock for a couple weeks. But I can afford the $500 now so REVO here I come.


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## zeusenergy (Feb 25, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (thetwodubheads)*


_Quote, originally posted by *thetwodubheads* »_If you have the budget for the tuning, get chipped. I did the Diode for over 2years. It was only recently with a baby in the back seat did the surging at part throttle get to be too much, so I'm stock for a couple weeks. But I can afford the $500 now so REVO here I come.









X2! http://****************.com/smile/emthup.gif


----------



## gti1.8tpolo (Nov 10, 2007)

*Re: (zeusenergy)*

intercooler hard for this model custom the best, good one made to fit eg forge is in excess of £600 pounds!!! wat cool plugs you recommend?? got ngk platinums at the mo! Ill look into mbc just to test as they cheap anyhow give it a try! thanks for advise


----------



## thetwodubheads (Dec 6, 2004)

*Re: (gti1.8tpolo)*

I am sorry, please remove weiner from mouth then speak. Clear consice phrases please.
I am also thinking a search could be very useful to you.


----------



## gti1.8tpolo (Nov 10, 2007)

*Re: (thetwodubheads)*

nonse!


----------



## Jetta4Life (Sep 5, 2001)

*Re: (gti1.8tpolo)*

I have the K04-001 with kinetic exhaust mani and as others who have this knows that limp mode is a problem. I'm looking to do this mod to eliminate this and fortunately, my MAP sensor is right near the throttle body with my FMIC. I read all the pages and from what I understand all I have to do is splice the ground wire and lead wire then connect the 4.7V diode to it and thats it? Is that correct? maybe a 10 min job? I dont need or want a switch like the diagram shows. Thanks


----------



## thetwodubheads (Dec 6, 2004)

*Re: (Jetta4Life)*

Just make it look like a ladder. Don't just connect the two with the diode like some have done.


----------



## Jetta4Life (Sep 5, 2001)

*Re: (thetwodubheads)*


_Quote, originally posted by *thetwodubheads* »_Just make it look like a ladder. Don't just connect the two with the diode like some have done.
 do you mean like an "H"? (colored diagram) OR do you splice the purple/grey wire and stick the diode in between where you cut the wire like in the diagram below? (solid line is wire to MAP, dotted is diode) I need a picture of how to connect just the 4.7V diode in the wiring near the MAP, there really is no good pic in the DIY. Thanks


_Quote, originally posted by *JettaRed* »_








Did you hook it up like in the picture?

__________________/-----------[]-----------/_________________


_Modified by Jetta4Life at 6:44 PM 5-13-2008_


_Modified by Jetta4Life at 6:45 PM 5-13-2008_


----------



## thetwodubheads (Dec 6, 2004)

*Re: (Jetta4Life)*

Just like the picture shows.... Like one step on a ladder. I don't mean to bust your balls, but if you didn't understand that by the diagram and write-up. You may not want to be doing it yourself. Either buy someone near you some beer and have them help, or save up for a chip from one of the many tuners.


----------



## Jetta4Life (Sep 5, 2001)

*Re: (thetwodubheads)*


_Quote, originally posted by *thetwodubheads* »_Just like the picture shows.... Like one step on a ladder. I don't mean to bust your balls, but if you didn't understand that by the diagram and write-up. You may not want to be doing it yourself. Either buy someone near you some beer and have them help, or save up for a chip from one of the many tuners.
 dont worry about it man, I actually did post a request for help in my area in the regional section but no replies yet. I'm good with the diagram about the ladder. Just wanted to be certain before I start cutting and spicing wires. I'm not a noob with electronics, can install a stereo system with no problems http://****************.com/smile/emthup.gif Thanks


----------



## vwjetta02 (Nov 27, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

i put on a diode and i think i need a mbc also can you clear this up for me and also were do i put it and will i still need the n75


----------



## vwjetta02 (Nov 27, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

i put a 4.7v diode on and i am still staying at stock boost and one could tell me what i could have done wrong. i tryed three different ones and i even put on backwards if to make share that they were working and they are!?! i dont have a mbc or software its just stock.


----------



## diymirage (Mar 16, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (vwjetta02)*

all that the diode will do is limit the amount of boost the computer will read 
in order to take advantage fo this you WILL need to install a boost controller (manual or electronic)


----------



## thetwodubheads (Dec 6, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (vwjetta02)*


_Quote, originally posted by *vwjetta02* »_i put a 4.7v diode on and i am still staying at stock boost and one could tell me what i could have done wrong. i tryed three different ones and i even put on backwards if to make share that they were working and they are!?! i dont have a mbc or software its just stock.









You sir need to leave things alone! If you cannot even read the instructions properly you should not be messing with your car, especially when it is something that can easily blow your motor. I could understand if maybe you had read the instructions and asked a silly question like what direction do I put the MBC, but not even reading thouroughly enough to know you need one is just








Go back, read the instructions, then use the forum's search function to search "archived" threads about "diode mod."


----------



## gti1.8tpolo (Nov 10, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (thetwodubheads)*

hey hey , i fit the N75j valve , and when it works it is very good , but keeps puttin my car into mini limp with no EML ?? If i do the map clamp will this stop this annoying problem? or will i have to go back to my original N75?? Thanks for the help guys


----------



## -Khaos- (Dec 22, 2003)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (gti1.8tpolo)*


_Quote, originally posted by *gti1.8tpolo* »_hey hey , i fit the N75j valve , and when it works it is very good , but keeps puttin my car into mini limp with no EML ?? If i do the map clamp will this stop this annoying problem? or will i have to go back to my original N75?? Thanks for the help guys









The diode will prevent you from falling into limp mode from overboost, so yes, it'll fix the problem.


----------



## gti1.8tpolo (Nov 10, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (-Khaos-)*

cheers nice one ill try source one asap!!! will this one do me http://uk.farnell.com/9557946/...337bg
my wires are completely different colours, one is black next to that is purple/red trace than an empty terminal then brown/black trace, i think i should be connecting purple/red to black as i assume black is earth??


_Modified by gti1.8tpolo at 4:55 AM 6-6-2008_


----------



## diymirage (Mar 16, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (gti1.8tpolo)*


_Quote, originally posted by *gti1.8tpolo* »_cheers nice one ill try source one asap!!! will this one do me http://uk.farnell.com/9557946/...337bg
my wires are completely different colours, one is black next to that is purple/red trace than an empty terminal then brown/black trace, i think i should be connecting purple/red to black as i assume black is earth??

_Modified by gti1.8tpolo at 4:55 AM 6-6-2008_

unless you are chipped that is the wrong diode. 
4.7 only works on chipped cars because the chip raises the maximum allowed boost. 
if you are not chipped get a 4.3. 
as for you wires not sure about your colours but here are the locations on the connecter
pin 1 == GND
pin 2 == Not used
pin 3 == +5v
pin 4 == signal 0-5v

you want to install the diode between pin 1 and pin 4 
(just roll back the rubber sleeve on the connecter and you will see the wires going into it and they will be numbered) 
now, once you have done and your car still starts the map sensor is capped .
(if it doesnt start the diode is in backwards)


----------



## janjan (Jul 26, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (diymirage)*

so everyone knows... *YOU NEED A MBC OR EBC FOR THIS TO WORK!* jsut the diode itself without a mbc of any kind will not work properly. ok now,
i made a thread about my problem:
http://forums.vwvortex.com/zerothread?id=3875879


----------



## gti1.8tpolo (Nov 10, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (diymirage)*

cheers buddy that really helps yes im running chipped but get limp with n75j valve ya see! I have a mbc but need a boost gauge before i let rip with that!!!


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## thetwodubheads (Dec 6, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (gti1.8tpolo)*

Just the N75J valve shouldn't put you into limp, you need to make sure you fix any problems you are having before tinkering and trying to make your car fast. Otherwise it will just explode and become another parts car that sits in someones driveway for 3 years before enough parts are sold to pay it off, or make it worth it... then it'll go to be crushed.


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## gti1.8tpolo (Nov 10, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (thetwodubheads)*

well it does cos it causes it to overboost slightly on this chip, so clamping it will stop this it only over boosts slightly so , no it will not blow up, i do know wat the crack is mate, wind ya neck in!


----------



## karis112 (Jun 18, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (gti1.8tpolo)*

hey guys if you find your car stumbling have you checked your map wires? i found my map wires spliced and somehow the wires would contact causing the car to stumble as boost built up, i think during acceleration the wires move with the front fmic or engine vibration movement. so wraped some electrical tape on the wires, no more stumbles http://****************.com/smile/emthup.gif 


_Modified by karis112 at 3:39 PM 6-7-2008_


----------



## thetwodubheads (Dec 6, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (karis112)*

You left them bare to begin with!?!?!


----------



## MMcGon (Jun 14, 2008)

Going to try this in about 2 weeks when i return to the states. 
Is there any update on whether this will or will not work on 04.5 GLI? I read in another archived thread that 20AE's and GLI's 04-05 cannot be modded ??? Is that true?


----------



## Levi20AE (Feb 16, 2005)

*Re: (MMcGon)*


_Quote, originally posted by *MMcGon* »_ read in another archived thread that *20AE's* and GLI's 04-05 cannot be modded ??? Is that true?

Did this to my 20th two weeks ago and am now boosting 25psi smoothly http://****************.com/smile/emthup.gif 
I read the same stuff but I have not hit limp mode after several days of driving.


----------



## turbovdubber (Oct 8, 2006)

awesome...i assume w/ 25psi ur already chipped?


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## skisoccer13 (Jun 1, 2007)

*Re: (turbovdubber)*

i read that the diode doesn't react well to heat so i put it close to the switch instead of in the engine bay. at stock setting i see 2 psi less than what i did before the diode (which was around 7 psi).
i also read that wolfy's (i have a 2001) might not like the diode, could that be the reason for the loss in psi?
i am running a 4.3v 1w diode.


_Modified by skisoccer13 at 8:14 PM 7-19-2008_


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## nickersonaaron (Sep 18, 2007)

I just installed the diode with the single diode with switch. I did the 4.7v diode and ran all the connections correctly, at least I think. I ran the off position wire to the orange/light blue and another wire from the on position to the purple/grey with the diode connected in between close to the map sensor. It seems like I am still stock because it is the same in both positions, I seem to spike at around 12 or 13 and hold 9. Did I do something wrong or is it possible the diode is blown? Do I need a different kind of switch? Someone please help!!!


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## FergyGTI (Aug 23, 2008)

*quick question*

ok so which one should i go diode should i go with. i am running a 3in tubo back exhaust, larger diverter valve, larger turbo inlet piping and all larger hose piping and small engine tweaks here and there but no chip. and do u have a pic of the wiring for just one diode no switch thanks for any help


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## jokerny77 (Jul 1, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

I may be beating a dead horse, read all the posts confused me a bit. did the mod 02 Jetta, double checked everything still getting a reading of 10 psi spike on my boost gauge. Do I need a MBC to see results? Or should I check something else. thanks


----------



## stjacket (Apr 26, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (jokerny77)*

a new patented idea


----------



## mario.ibarra (Sep 30, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (stjacket)*

Hey i'm new at this but i'm thinking of a new version of the diode mod 
so it is basically the same with our cars, the idea here is to make an adjustable diode that intercept the signal sent to the ECU so we can boost the hell up out turbo system =D
With this system I hope to adjust the voltage anywhere around from 4 to 5 volts that we know it works with our cars
The MAP sensor has 3 cables: one (+), one (-) and one that sends a signal maybe between 0 and 6 volts which is the pressure amount transformed into electricity so that the ECU will read it.
I will use:
(1) 15 turn 1k ohm potentiometer, 1.5 watt max
(2) 1n914 (1n4148) diodes connected in series.
some cable and a box to hold this so that it would not get broken
then connect the positive terminal from the potentiometer to the positive MAP cable (which I have to figure out which one it is) same with the negative and the middle cable (that has soldered the 2 diodes) will go to the signal cable (orange/light blue cable I think)
Anyways tomorrow I will set up this mod and see how it goes.. I'll keep you guys updated
P.S sorry for my not to good english::: I'm from mexico =P




_Modified by mario.ibarra at 7:21 PM 1-16-2009_


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## MechEngg (Jan 13, 2009)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (mario.ibarra)*

I have a completely stock 1.8t and i was wondering how much boost the turbo can take...maybe 17 or 18 psi????


----------



## cincyTT (May 11, 2006)

and then some


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## Boostin20v (Mar 22, 2000)

*FV-QR*

A standard chip spikes ~20-22psi before falling off to ~12-14psi at redline. Pushing more than that is going to just create more hot air not power.


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## Boostin20v (Mar 22, 2000)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (mario.ibarra)*


_Quote, originally posted by *mario.ibarra* »_Hey i'm new at this but i'm thinking of a new version of the diode mod 
so it is basically the same with our cars, the idea here is to make an adjustable diode that intercept the signal sent to the ECU so we can boost the hell up out turbo system =D


The diode mod isn't about controlling the amount of boost made by the engine, its about controlling how much the ECU thinks the engine is making. I'd suggest rereading why you'd want to diode the car.


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## Abriscoe1986 (Feb 15, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

ok witch way dose the diode go.
on one side of the diode it clear on the other side it black and in the middle the diode red.



_Modified by Abriscoe1986 at 7:19 AM 1-23-2009_


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## max13b2 (Jul 24, 2007)

there are many variations of the diodes, however, your diode seems to look like mine, in which case the black strip side goes to purple wire. However this is just speculation. Try it, my car would not start if installed backwards, just flip it and enjoy!


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## Abriscoe1986 (Feb 15, 2008)

*Re:*

ok i install the diode mod. it seem to be working fine. 
I have A APR 91 Chip, and a Bleed type MBC.
i have the MBC running off the n75. not sure if that the way your supposed to hook it up, LOL
before i install to diode mod. i was hitting 18.5 psi and sitting at 10psi by red-line
after i installed the diode mod. it was 19.5psi and sitting at 16 by red-line.
anyway now I'm trying to Delete the N75 all together and it going in limp with the diode mode turn on.
how do i do this.


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## Buschwick (Feb 12, 2007)

*FV-QR*

Just unhook the N75 from the vac/boost hoses and replace with the MBC. Also if you're not using the Forge MBC the hole in the TIP will need to be plugged. I used a clevis pin. Leave your N75 plugged into the wiring harness and ziptie it out of the way.


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## Abriscoe1986 (Feb 15, 2008)

*Re: FV-QR (Buschwick)*

ok i have a Bleed type Forge MBC


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## Buschwick (Feb 12, 2007)

*FV-QR*

alright...same thing goes...so install the MBC with the bottom nipple in the TIP, and the side nipples in the two hoses (from the charge side and to the wastegate).
Leave your N75 plugged into the wire connecion and move it out of the way.


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## frostythesnowguy (Nov 28, 2008)

so does it acctually up the boost? or just allow you to up the boost without going limp?... cause going limp in the middle of something fun sucks for everyone involved


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## Buschwick (Feb 12, 2007)

*FV-QR*

does what? the zener?


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## frostythesnowguy (Nov 28, 2008)

does the diode mod acctually up the boost or just allow you to up it with out hitting limp mode


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## Buschwick (Feb 12, 2007)

*FV-QR*

the zener installed on the MAP sensor wires to the ECU will effectively "clamp" the voltage correlating to certain PSI. For instance, a 4.3v zener will clamp a AWP at 11psi, which means that no matter how high you turn the boost up the ECU will only read 11psi.
But...the upside is that under 4.3v the zener does nothing. So your car will still read anything under 11psi correctly.
So you can turn your boost up to 17psi for example, and once the ECU reads 11psi the rest of the voltage is dumped to ground by the zener so the reading will stay pinned at 11psi...until the voltage falls back under 4.3v and the ecu will read under 4.3v correctly.


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## l88m22vette (Mar 2, 2006)

*Re: FV-QR (Buschwick)*

So if you clamp the MAP will you have to be able to tune the a/f settings or will the ECU adjust automatically? (sorry if this is a stupid question)


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## frostythesnowguy (Nov 28, 2008)

so does it lean you out a ****ton because its not adjusting the fuel accordingly?


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## Buschwick (Feb 12, 2007)

*FV-QR*

No...but maybe. Fueling is 90% controlled by the MAF and 02 sensors. Some people (like myself) may run a little lean. I think I may have a 02 sensor on its way out though. Ignition angle is what the MAP is there for...that's it's purpose. The car will adapt though. I actually was able to add .75* to my timing angle today and pull only 3-4* up high on #4....after I beat on my car already.
You will most likely be fine as far as fueling goes. But definitely watch it with vag com. 
I used unisettings to bump increasing load fuel to 104% (that shows how minute of an adjustment was needed) and my a/fs are good through redline.


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## pugi03 (Mar 14, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

http://****************.com/smile/emthup.gif


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## s40986a (Dec 1, 2007)

so is it a bad idea to do this to my bone stock 98 passat? cus Ive been holding off on doing this because I was told it only runs 8.63 pounds of boost usually and I'm kinda partial to this motor and turbo thats still in my car... but if I'm wrong about the usual boost levels I was wondering where to look for the diode?


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## jackkel (Dec 16, 2006)

*Re: (s40986a)*

why is the diode mod frequently used on the 1.8T but almost unheard of on the 2.0T FSI engines?


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## pat293 (Feb 9, 2009)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

Is it a 5W or 1W because the diagram says 1W but everyone is saying 5W for the diodes??










_Modified by pat293 at 12:25 AM 4-6-2009_


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## Buschwick (Feb 12, 2007)

*FV-QR*


_Quote, originally posted by *pat293* »_Is it a 5W or 1W because the diagram says 1W but everyone is saying 5W for the diodes??










Doesn't really matter. .5w, 1w, and 5w will do the exact same thing. The only thing is the 5w will last longer than the .5w and 1w. I've had a 1w installed in my homemade adjustable voltage clamp for about 4-5 months now I think with no problems. I ordered 10 of them and I'm still on #1. Don't sweat the wattage too much, just buy like 10 of them and you'll probably never run out.


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## Axelbora (Mar 7, 2009)

*Re: FV-QR (Buschwick)*

Ok...I have read all the post and still having some questions????......I got a 2000 with GIAC...I already buy the diodes...OK...I have the OEM stock 3 bar fuel regulator and the stock N75 valve....now....if I put the diode I will run tooo lean? or im OK with this fuel regulator....I can buy the 4 bar its just to know..... I buy the 4.7v-1w...please let me know...!!!


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## crsmp5 (May 26, 2005)

so i go ta question fo ra 02 1.8t jetta... what wire goes to which terminal in the plug? plug has # 1-4 on it.. which wire goes in which spot.. been working on a basket case for a while.. someone changed the plu gon the map sensor so its 3 yellow wires.. its got a vag error of low pressure at throttle body which would be the map.. once i reset it via vagcom it runs great.. till turned off then gotta reset it again on next start up else it pops and bangs this is th eonly error and does not turn on the check engine light.. but runs like crap.. till codes reset then life good..


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## Axelbora (Mar 7, 2009)

*Re: (crsmp5)*

Up-date...:
Ok...well...I just put the N75j valve...and I dont feel the big diference I just see the boost presure a little bit stable...but..its stills going down from 21 psi to 10 psi...and after 2 or 3 pulls it goes to a hard limp mode...4 or 5 psi...turn off and on again the car and its goes good again...ok like I said before I got the 4.7 Diodes But still having the 3 bar fuel regulator...I take the car to a dyno run and it trows a lot of fuel after 4000rpm...if i put the diodes I will run lean??? or I







can put the diode with out any problem...by the way I have GIAC...thanks..


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## dirtydumpd18t (Jan 27, 2009)

*Re: (Axelbora)*

bringing this back! i was reading through this and i was trying to determine if using the switch set-up the OP used with a lower rated diode on one side would create the "valet" mode so to speak by causing the ECU to go into limp mode sooner? or am i completely wrong on this one?


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## Budsdubbin (Jul 14, 2008)

*Re: (dirtydumpd18t)*

Would a 5.1v zener diode work? I'm asking because I put one in the other day and its all setup right I just didn't know if I should be hitting a higher psi then I used too because I'm still spiking at about 19-20.


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## howani18t (May 12, 2009)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

You'll all hate me for asking, but: am I correct in understanding that this mod and an mbc will allow me to run my stock 03 GTI at ~20 psi (when the diode circuit's on)?
It seems too easy. Should I consider a 3-bar and/or bigger injectors? This beats the **** out of chipping pricewise. Barring my engine exploding.


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## dane. (Nov 16, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (howani18t)*

from what i understand anything over 14 psi, the ecu will not accommodate the extra fueling needed. just put a 4.3v 5w diode in with a MBC inline to the n75 set to 14 psi


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## cincyTT (May 11, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (wylde)*

I have been running a diode for over 3 years now and 1 of those with a 2L. All the time running between 17-20psi daily. All on stock injectors and 3 bar fpr


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## coreyj (Aug 18, 2006)

*Re: (Budsdubbin)*


_Quote, originally posted by *Budsdubbin* »_Would a 5.1v zener diode work? I'm asking because I put one in the other day and its all setup right I just didn't know if I should be hitting a higher psi then I used too because I'm still spiking at about 19-20. 

umm that is pointless... since the map sensor doesnt go above 5.0v anyway.


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## nbkkb7x (Jan 12, 2009)

*Re: (coreyj)*

Alright, I've been trying to do a little research for this project, but I don’t think anyone has tried this (if so, could you point me in the right direction). If I get a EBC, can I safely delete my N75 (keep it in the wiring harness) and just run off the EBC? Has anyone tried this? I’m only going to push 15-17PSI tops, so I can pump up my fuel in unisettings to avoid running a little lean, correct? Thanks guys.
-MP


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## max13b2 (Jul 24, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (cincyTT)*

x2 on 17-20 psi, stock injectors, 3bar, and logging the whole way from 15-20psi. Runs like Butter.








However I have a 180hp hardware motor, so I think the injectors are a weeee bit larger than 150hp motors, however you should be able to increase fuel vis Unisettings (correct me if I'm wrong http://****************.com/smile/emthup.gif )


_Modified by max13b2 at 3:45 PM 5-21-2009_


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## coreyj (Aug 18, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (max13b2)*


_Quote, originally posted by *max13b2* »_x2 on 17-20 psi, stock injectors, 3bar, and logging the whole way from 15-20psi. Runs like Butter.








However I have a 180hp hardware motor, so I think the injectors are a weeee bit larger than 150hp motors, however you should be able to increase fuel vis Unisettings (correct me if I'm wrong http://****************.com/smile/emthup.gif )

_Modified by max13b2 at 3:37 PM 5-21-2009_

correct the 180hp motors have larger 317cc injectors from the factory. put in a 4 bar and they turn to 380cc's.


----------



## coreyj (Aug 18, 2006)

*Re: (nbkkb7x)*


_Quote, originally posted by *nbkkb7x* »_Alright, I've been trying to do a little research for this project, but I don’t think anyone has tried this (if so, could you point me in the right direction). If I get a EBC, can I safely delete my N75 (keep it in the wiring harness) and just run off the EBC? Has anyone tried this? I’m only going to push 15-17PSI tops, so I can pump up my fuel in unisettings to avoid running a little lean, correct? Thanks guys.
-MP


there has been guys that run ebc's its just so expensive for a good one most people tend to over look them. but if your going to spend $450 on a good ebc then you might as well just buy a chipped ecu since they are the same price


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## max13b2 (Jul 24, 2007)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (howani18t)*

No need to turn the diode "circuits" off....... Just solder in the diode and be done w/ it, no switch necessary! If you need to turn down the boost, just pop the bonnet (thats about as German as I get!), adjust the MBC and Bingo!
And it IS EASY, just up your boost in small incriments, allow the ECU to adapt, and if your able to, log it w/ VAG-COM


----------



## nbkkb7x (Jan 12, 2009)

*Re: (coreyj)*


_Quote, originally posted by *coreyj* »_there has been guys that run ebc's its just so expensive for a good one most people tend to over look them. but if your going to spend $450 on a good ebc then you might as well just buy a chipped ecu since they are the same price

My end goal is a BT (50 Trim/550 CC) setup. If I can get out of chipping the K03s until I get there, that would be great. I don't want a MBC due to the surge issue at partial throttle. With an EBC I can bring it over to my BT setup. You can find a used EBC from 150-250 easily.
What about deleting the N75? Can I just run the EBC in it's place? (Keep the N7e in the harness) Does the N75 trim fuel, or just boost?
-MP


_Modified by nbkkb7x at 5:34 AM 5-22-2009_


----------



## zeusenergy (Feb 25, 2008)

*Re: (nbkkb7x)*

That's the other problem. I still haven't seen what the diode does to A/F readings beyond the intended diode voltage- 4.3V in your case. The pressure it sends to the ECU gets capped at 11 PSI so it's possible that the ECU could send less fuel.... Even if the MAF reads right, and the O2 reads right, it's still not compensating for the added boost and if your MAF goes and you unplug it... the ECU is forced to use the MAP or open loop as it's source.


----------



## nbkkb7x (Jan 12, 2009)

*Re: (zeusenergy)*


_Quote, originally posted by *zeusenergy* »_Even if the MAF reads right, and the O2 reads right, it's still not compensating for the added boost and if your MAF goes and you unplug it... 

Couldn’t you compensate the fuel for this thru unisettings? As long as you bump the fuel under load you should be good (as long as you log of course). Really if I’m only boosting 5 PSI more then stock I should be able to adjust within efficiency. I’d just hate to have the N75 AND an EBC (which does the N75’s job way better) I’ll have to look thru my Bentley to see if Motronic pulls any data from the N75 to trim fuel. 
-MP


----------



## nbkkb7x (Jan 12, 2009)

*Re: (nbkkb7x)*

PS: this was an interesting read about the N75: http://www.ozaudi.com/forums/I...3.pdf 
-MP


----------



## zeusenergy (Feb 25, 2008)

*Re: (nbkkb7x)*

Hmmm.....


----------



## nbkkb7x (Jan 12, 2009)

*Re: (zeusenergy)*

I've seen that before in the FAQ, just offering another bit of information.








-MP


----------



## zeusenergy (Feb 25, 2008)

*Re: (nbkkb7x)*

I will have diodes available in the week for anyone who wants one cheap. Send me an IM or post in the resistor link below.


----------



## DJmart (May 8, 2009)

*Re: (zeusenergy)*

My 2000 Audi TT 180HP quattro has an intake, a 710n DV , and a hallman pro boost controller.
I have no other modifications.
If I do the diode mod, do I have to change any tubing, hoses, or anything like that to handle the 17psi?
Thank you!
P.S. i searched everywhere for this question.


----------



## Absolu1e (Sep 12, 2006)

*Re: (DJmart)*

I read through this thread but I'm still unclear. I have a few boltons and I'm chipped. Car is running fine; not hitting limp. Would this mod help me in any way?


----------



## Absolu1e (Sep 12, 2006)

*Re: (DJmart)*

I read through this thread but I'm still unclear. I have a few boltons and I'm chipped. Car is running fine; not hitting limp. Would this mod help me in any way?


----------



## audi_techy (Oct 26, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

hey, i just wanted to find out how safe this mod is?
has anyone checked the mixtures before and after this mod?
How much difference does it make?
Tks
Patty


----------



## interceptorvfr (Jun 25, 2009)

Ok so this might sound dumb but if i dont run a switch then i basically just lay the diode across the two wires....dont actually cut them just strip the plastic enough to solder and thats it the wires still run to the map sensor you dont actually cut anything ?????


----------



## interceptorvfr (Jun 25, 2009)

and if thats the case then what wire goes to the negative side of the diode ???


----------



## dirtydumpd18t (Jan 27, 2009)

*Re: (interceptorvfr)*

anyone find a good source for the diodes that doesnt charge a ridiculous amount for shipping


----------



## elRey (May 15, 2001)

*Re: (dirtydumpd18t)*


_Quote, originally posted by *dirtydumpd18t* »_anyone find a good source for the diodes that doesnt charge a ridiculous amount for shipping

zeusenergy


----------



## max13b2 (Jul 24, 2007)

*Re: (dirtydumpd18t)*

Ummm yeah.... ME!
$1 to cover shipping via paypal and I'll send you 2 of them (4.3v). The diodes are FREE, just postage is necessary http://****************.com/smile/emthup.gif


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## lebedevster (Aug 6, 2009)

*Re: (max13b2)*

So I did this mod with the switch the other day and it ran fine all day yesterday and this morning. In the afternoon it started misfiring then after shutting the car off and turning it back on with the switch in 'standard' mode it started throwing a CEL. It still drives but it DRINKS gas, sucked away an 1/8 of a tank in 28 miles! It misfires very noticeably and there is NO acceleration anymore, I'm hitting limp from the moment I turn the ignition.. The diodes are in the right way and soldered well with a good connection which I measured earlier. What's the deal here?
I haven't read the code yet but has anyone else had this or a similar issue? Is there an easy way to resolve this without ripping everything back out?


----------



## lebedevster (Aug 6, 2009)

*Re: (lebedevster)*

So as an update, I ordered new Hitachi 'E' bolt-down ignition coils because it's about their time to go (I still have the original ones in there). Now I've got a whole new deal going on. I'm throwing code p1296 air/fuel metering. I've cleaned the MAF several times and borrowed a buddies which does not fix the problem. I've replaced the coolant temperature sensor and did a coolant flush and refill with new stuff. I've checked the thermostat and that seems to operate perfectly fine. What's going on here? It's still throwing p1296 despite clearing the code using the disconnect battery method as well as through ODBII. Has anyone else gotten this with the diode mod? The code comes up regardless of which position I have the switch in, diode 4.3, diode 4.7 or standard mode which is what I have been driving on ever since I put it in due to the issues that have come up.


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## dynedta (Oct 13, 2007)

fwiw ive been running a adjustable clamp for 2 years now on my 225tt (4bar fpr) 22psi the 4.3 diode worked ok but deff was running lean (logged), now with the adjustable clamp im spot on. pm for details on source of clamp (non vendor)


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## TooLFan46n2 (Oct 18, 1999)

*Re: (dynedta)*


_Quote, originally posted by *dynedta* »_fwiw ive been running a adjustable clamp for 2 years now on my 225tt (4bar fpr) 22psi the 4.3 diode worked ok but deff was running lean (logged), now with the adjustable clamp im spot on. pm for details on source of clamp (non vendor)

Thank you someone has the right idea. Split-Second makes a nice adjustable voltage clamp for around $50. Less than a chip, more reliable and refined then just a diode. http://****************.com/smile/emthup.gif


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## esilviu (Nov 1, 2006)

*Re: (TooLFan46n2)*

At Split Second the voltage clamp v2-5 costs 90 usd not 50 and yes it is adjustable from 2v to 5v.
Where did you find split sec voltage clamp with 50 usd?
Thanks


_Modified by esilviu at 11:27 PM 8-7-2009_


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## dynedta (Oct 13, 2007)

ahhh guys should look alil harder *cough* kingclamp.com *cough* 21 bux shipped!


_Modified by dynedta at 7:24 AM 8-8-2009_


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## twin2626 (May 11, 2006)

I just did the mod today with a 4.3volt diode. Running good so far. It def pulls a lot harder off the line and through the gears. I hope it stays that way. So the 4.3v diode will give more power on a stock 1.8t than a 4.7v? 

_Modified by twin2626 at 10:57 AM 8-11-2009_


_Modified by twin2626 at 2:26 PM 8-11-2009_


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## maxiice (Apr 18, 2009)

how about combining the diode metod with an wather/methanol injection. to cool things down an add ecstra fuel ?(ethanol/methanol)
My injection kit can inject baded on boost or MAF input or a mix with both..
I hav another idea, If the car gets in limpmode for maxing the MAF sensor, maybe a diode mod is possible here to?


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## Rantu (Feb 24, 2009)

Can you get these 4.3v 1w zener diodes at radioshack?


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## bmonroe1 (Oct 24, 2006)

*Re: (maxiice)*


_Quote, originally posted by *maxiice* »_I hav another idea, If the car gets in limpmode for maxing the MAF sensor, maybe a diode mod is possible here to?

Split second, which has been mentioned for their voltage clamp, also makes a dual channel "signal conditioner". You can use this to adjust the gain on your MAP _and_ MAF signals so that they stay in the control range, but they still track actual trends happening in your engine, so the ECU can still do its job controlling boost and air/fuel. It basically makes your giant, big-boosting turbo look to the computer like the stock unit.


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## New2theGame (Aug 14, 2008)

*Re: (Rantu)*


_Quote, originally posted by *Rantu* »_Can you get these 4.3v 1w zener diodes at radioshack?

I just bought 10 of the 4.7v 1w Zener Diodes from a website for $4 shipped. If you need one send me your address and ill hook it up.


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## bmonroe1 (Oct 24, 2006)

*Re: (bmonroe1)*

To be more clear about my last post, you still need to artificially add fuel. The proportion should be the same amount that your MAF is reading over what you adjust it to read, i.e.: if your MAF is reading (in reality) 120% more air than your (adjusted) signal to the ECU reads, you need 20% more fuel as well. However, since your ECU can still track trends (instead of just seeing a trend up to the "clamped" level, then seeing a flat line), it will be able to control your boost and timing up and down the RPM range. The way I accomplished the extra fueling was by installing my 415's. They flow proportionally more fuel than my stock injectors as my new turbo flows air vs stock. You can also use Lemmiwinks. Normally, using LW for fueling is like using a hammer to do surgery, but in conjunction with the signal conditioner, you can dial everything in real nice. All of the above is just a very polished, slightly more expensive version of the "diode mod" that will run smoother and not blow up your engine.


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## bmonroe1 (Oct 24, 2006)

*Re: (bmonroe1)*

Sorry, meant boost and *fueling* up and down the range.


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## max13b2 (Jul 24, 2007)

*Re: (Rantu)*

Still have several 4.3v 1w diodes left. I will mail out 2 for $1 paypaled to [email protected] to cover postage. Hell, give one to your buddy! IM me if interested


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## Rantu (Feb 24, 2009)

*Re: (Rantu)*

So i installed the 4.3v diode in with a switch and i was spiking around 15-16...the next day i was only getting around 9-11psi...is my car in soft limp mode? if it is what can i do to fix this...because i have no idea..any help would be appreciated


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## spoileda4 (Dec 28, 2008)

*Re: (1decimal8Tango)*

Nobody has seemed to mention this as far as I can see... Try running a cooler thermostat to keep the car from reaching the 91C. When the car is under 91C its map allows the car to have more fuel to "warm up " the car even though it is as warm as it will get. Added with an increase in the FPR it seems to even out my 1.8T and stopped running lean completely. Downside- 2MPG less 
Power or Mileage?


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## Nicos (Jan 4, 2010)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

Hi to everyone here - I'm a newbie, but I've tried to read this topic up properly.
Sorry to drag this up from the past but I tried to perform this mod on my car and ran into a couple of problems and I have a couple of questions about this to get my head round it. 
The problem I had is that the wires don't match up at all on my car. Looking at what seems to be my map sensor (pretty much just after throttle body), I only have two wires, the bundle tapped into in the pictures looks more like the fuel rail/throttle body wiring to me - is there a map sensor built into the throttle body? My car has no purple/grey, closest was purple/white. 
I took readings from this wire to ground and I was hoping it may be the correct wire as it as reading 2.something volts and slowly rising with revs until I got around the boost range when it jumps from about 2.9v to 12v! Can't see any sign of any orange coloured wire in the area. Could it be because my car is UK/rhd the wiring loom is coloured different?
Also I'm trying to get my head round this, and I can't seem to put the info I'm reading from various sources together. Apparantly this mod is meant to let the ecu read boost until we reach the clamping value at which point the reading is artifically locked from rising to prevent ecu going into limp home due to overboost.
This doesn't quite make sense to me - if we put a zener diode in the forwards direction - it will let everything through i.e. we could use a straight wire instead of a zener diode. If we put one in reverse, it will let nothing through until the diode's breakdown voltage is reached, then it will conduct that voltage, but even if the voltage rises, it will not let more through. 
Thinking about it this way, this would mean we are preventing the ecu seeing any boost being generated until we reach our clamping value (as well as not allowing ecu to read any higher). Therefore I'm guessing when ecu tries to boost, it won't see anything so will keep trying to wind the turbo up until it eventually sees some at our clamping value, then an unchipped ecu probably thinks it's overdoing it a bit so tries to turn it down a bit, sees nothing, cranks it up again......
Also just wondering if anyone knows what the actual wires are for - my gut reaction is that if we want to trick the ecu re the value of this sensor, we tap into that wire and play with that reading only. My curiousity would be incredibly greatful if anyone can explain why we appear to be leaving the reading down the original wire but are also now sending a modified version down another wire. 
I would check UK vs US wiring diagrams before signing up and posting but unfortunately my laptop with autodata won't be back with me until the weekend, and I'm dying to crack this!
Edit:
Also check your diodes with a small powerpack, I had to buy them in packs of 5. Checked them and found manufacturing tolerances which makes some more suitable/preferable for use than others. 
Edit2: Are we pulling the reading to ground?

_Modified by Nicos at 12:31 PM 1-4-2010_


_Modified by Nicos at 1:25 PM 1-4-2010_


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## mj23wizards (Nov 29, 2006)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (Nicos)*

I bought a 4.3v diode that has a tolerance of 3.7v for example...
don't know if MAP could go till 12v ...


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## 04glsjetta1-8 (May 1, 2009)

ok so im still confused just putting a diode in automatically raises ur boost? i dont see how it dose it without a MBC


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## Anthony1.8 (May 20, 2008)

*Re: (04glsjetta1-8)*


_Quote, originally posted by *04glsjetta1-8* »_ok so im still confused just putting a diode in automatically raises ur boost? i dont see how it dose it without a MBC 

If your running stock boost, nothing will happen. You are right. You need an MBC along with this mod. All it does is not let the ecu know if you are over boosting. It only lets the ecu see what it wants to see regardless of the boost your making.


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## mj23wizards (Nov 29, 2006)

*Re: (Anthony1.8)*

Yes but if you have your ECU reflashed you hold for more the peak boost and you could have a higher spike like +0.15 bar


_Modified by mj23wizards at 2:00 AM 1-8-2010_


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## 04glsjetta1-8 (May 1, 2009)

*Re: (mj23wizards)*

ok thats what made sense but somone said they instantly saw 19 psi or something would u hook up the MBC in place of n75 or inline with it?


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## mj23wizards (Nov 29, 2006)

*Re: (04glsjetta1-8)*

Well I don't know because i don't use that kind of configuration...
With only the diode mod at 3.7v (more or less) the overboost and boost depends by the wastegate configuration because the ECU cannot see the real boost after 0.7 bar (more or less) and the boost is managed by wastegate. As I said before the only problem is the ignition timings!


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## importrepairguy (Feb 27, 2008)

*Re: (mj23wizards)*

Anyone have any Diodes for sale still? I'm in need of*1* . PM me with the detail's. http://****************.com/smile/emthup.gif


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## denimboy (Jul 7, 2009)

I have not read through the whole thread but I did read the DIY and many posts. 
There's something I'd like to know. 
First: does that mod work on stock or it needs something else. People wrote about MBC, what is it?
Second: If the diode tells the ECU a constant voltage (4.3) while turbo keeps increasing its pressure, why do you put two different diodes? Both shoud let the turbo increasing freely.


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## Anthony1.8 (May 20, 2008)

*Re: (denimboy)*


_Quote, originally posted by *denimboy* »_I have not read through the whole thread but I did read the DIY and many posts. 
There's something I'd like to know. 
First: does that mod work on stock or it needs something else. People wrote about MBC, what is it?
Second: If the diode tells the ECU a constant voltage (4.3) while turbo keeps increasing its pressure, why do you put two different diodes? Both shoud let the turbo increasing freely.

I'm not too tech savvy, but this is how I understand it..
The mod won't do anything at stock boost. an MBC, is a Manual Boost Controller. You can install an MBC, and turn your boost up. However, when your boosting more than what the ecu is set to, you go into limp mode.. Where the ecu shuts you down. Because with all this extra boost, the manifold air pressure (MAP) sensor sends high voltage to the ecu. (this is how the map sensor communicates with the ecu) By doing this mod, you clamp the map sensor. You insert a diode in the map sensor wires, so no matter how much boost you're making, no matter how much voltage the map sensor is trying to send to the ecu, the diode only allows a certain amount through.
This is when you ask yourself well which diode do I put in? You can put pretty much any voltage diode you want. Each voltage is read as a different boost level. For example, if you put the 4.3v zener diode in the map sensor wires, NO more than 4.3 volts will be seen by the ecu. 4.3 volts happens to be interpreted by the ecu as 13 psi of boost. So, by inserting the 4.3v diode, your ecu thinks your boosting at 13psi. Now you can set your MBC to whatever you want. Essentially higher than 13 psi, therefore tricking the ecu. You will actually be making more boost than the ecu thinks. This can also be a problem, because if the ecu is only seeing 13 psi, it will only fuel you for that much! If you're actually boosting more than that, you run the risk of running a lean air/fuel mixture. Which is extremely dangerous for your motor.
This is where that second diode comes in that you are confused about. The 4.7v zener diode that people use. As you can imagine, installing this diode will only let the ecu see 4.7 volts, which happens to correspond with 17psi of boost, i believe, that could be wrong. This allows you to run a much higher boost level, and be fueled for that boost level.
I am not sure if running the 4.7v diode is recommended for a non chipped car, as I believe the ecu will send you into limp mode after seeing anything more than 4.3 volts from the map sensor.

Again, don't know how correct this is, but that's how I understand it from what i've read.


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## denimboy (Jul 7, 2009)

*Re: (Anthony1.8)*


_Quote, originally posted by *Anthony1.8* »_
I'm not too tech savvy, but this is how I understand it..
The mod won't do anything at stock boost. an MBC, is a Manual Boost Controller. You can install an MBC, and turn your boost up. However, when your boosting more than what the ecu is set to, you go into limp mode.. Where the ecu shuts you down. Because with all this extra boost, the manifold air pressure (MAP) sensor sends high voltage to the ecu. (this is how the map sensor communicates with the ecu) By doing this mod, you clamp the map sensor. You insert a diode in the map sensor wires, so no matter how much boost you're making, no matter how much voltage the map sensor is trying to send to the ecu, the diode only allows a certain amount through.
This is when you ask yourself well which diode do I put in? You can put pretty much any voltage diode you want. Each voltage is read as a different boost level. For example, if you put the 4.3v zener diode in the map sensor wires, NO more than 4.3 volts will be seen by the ecu. 4.3 volts happens to be interpreted by the ecu as 13 psi of boost. So, by inserting the 4.3v diode, your ecu thinks your boosting at 13psi. Now you can set your MBC to whatever you want. Essentially higher than 13 psi, therefore tricking the ecu. You will actually be making more boost than the ecu thinks. This can also be a problem, because if the ecu is only seeing 13 psi, it will only fuel you for that much! If you're actually boosting more than that, you run the risk of running a lean air/fuel mixture. Which is extremely dangerous for your motor.
This is where that second diode comes in that you are confused about. The 4.7v zener diode that people use. As you can imagine, installing this diode will only let the ecu see 4.7 volts, which happens to correspond with 17psi of boost, i believe, that could be wrong. This allows you to run a much higher boost level, and be fueled for that boost level.
I am not sure if running the 4.7v diode is recommended for a non chipped car, as I believe the ecu will send you into limp mode after seeing anything more than 4.3 volts from the map sensor.

Again, don't know how correct this is, but that's how I understand it from what i've read.









I agree with you. However, why would people use the 4.3V diode if (as you stated) the ECU doesn't fuel you enough ? 
Using a 4.7V diode makes more sense. So why switch between both ?
*Correction*
A diode mod without MBC, the wastegate will keep boost pressure at, lets say, no more than 13psi. Therefore I need this to allow more than the diode's peak pressure. Thus still causing running lean??
(I'm newbie to most pneumatic/intake and turbos so I might not make any sense but this is how I understand it from what I read)


_Modified by denimboy at 5:16 PM 1-14-2010_


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## Anthony1.8 (May 20, 2008)

*Re: (denimboy)*


_Quote, originally posted by *denimboy* »_
I agree with you. However, why would people use the 4.3V diode if (as you stated) the ECU doesn't fuel you enough ? 
Using a 4.7V diode makes more sense. So why switch between both ?

_Modified by denimboy at 5:16 PM 1-14-2010_

the ecu wouldn't fuel you enough normally, but you can make adjustments to fuel trim levels via lemmiwinks or unisettings
You wouldn't use a 4.7v diode if you want to run a lower boost. 13-16psi. If you did, the ecu would fuel you for 17psi all the time.You'll be running rich.
Plus, this is not a very reliable/safe mod.. I don't suppose it's highly recommended.

_Quote, originally posted by *denimboy* »_
*Correction*
A diode mod without MBC, the wastegate will keep boost pressure at, lets say, no more than 13psi. Therefore I need this to allow more than the diode's peak pressure. Thus still causing running lean??
(I'm newbie to most pneumatic/intake and turbos so I might not make any sense but this is how I understand it from what I read)

_Modified by denimboy at 5:16 PM 1-14-2010_

I can't make sense of what you're trying to say there ^
If you run this mod with no mbc, you're wastegate probably won't let you boost to 13psi, unless the wastegate is adjusted or something. I think, stock, you're looking at around 8-10psi. So If you we're to run this mod, you could turn your mbc up to 13psi and run the 4.3v diode and safely boosting at 13-14psi, a little more than stock. For a little bit of fun. You could even adjust some fuel trims with lemmiwinks/unisettings to get things right on the money.

I'm not sure, i'm still trying to figure all this out, it's a little confusing. These are some good questions, i currently have both diodes hooked up to a switch in my car, but I can't test em out until I get my new fuel pump wired up. I'll let you know my findings, meanwhile hopefully someone will chime in and clear some things up.


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## denimboy (Jul 7, 2009)

*Re: (Anthony1.8)*

well thanks for your help, I was just asking to see if I can do a quit mod on my current 1.8t. I will not tune this car for performance because it's in bad shape and the engine as a lot of milage. But it will certainly be interesting to try on my future GLI. 
Meanwhile, I keep reading so let me know your results.


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## carsluTT (Dec 31, 2004)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

nice info


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## importrepairguy (Feb 27, 2008)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (carsluTT)*

Paging *"max13b2"*, Please check your PM's.


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## mj23wizards (Nov 29, 2006)

*Re: (Axelbora)*

no it won't run lean but check ignition timings


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## mj23wizards (Nov 29, 2006)

Anyone knows how much is 2010mbar? 
I clamped my MAP with a zener that allows 2010mbar...


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## PernellGTI (Jan 1, 2010)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

Hey nice job, I feel like doing this to my car but I have some questions before I start, do I need a manual boost controller for this? or simply by clamping the map I get the boost? Also, if I use both Diodes (4.7v and 4.3v) and the switch, both diodes need to be clamped to both wires? I dont know if in the diagrams the diodes actually clamp on both wires and then to the switch, Thanks for any help!


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## abbey1 (Apr 11, 2010)

*Re: DIY: Clamping the Map Sensor aka "Diode Mod" (1.8TWolfsberg)*

I have tried this mod on my TT but am only boosting 14 PSI, without it I go up to 18 PSI and spike to 21 PSI. Any ideas why ?


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## RStras898 (Apr 11, 2010)

*Diode question*

I found some diodes on eBay. They say 4.3v 1w. What should be the wattage on the diode that I want for my 04 1.8T Jetta?


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## DGOMDK (Jul 30, 2007)

*Just did the diode a couple days ago....my experience*

Basically 4.3v or 4.7v zener diode clamps the map sensor @ specified psi - 4.3=11psi & 4.7=17psi. I'm stock (no chip) with all bolt ons and have not yet installed MBC (will tonight to make boost adjustments). 
The reason I have not install MBC is because (of threads like this) I wanted to see if indeed with just a diode, would there be any differnce with boost. Every car adapts differently to whatever mod is installed (thats why theres so many different opinion/experience that pop up on threads like this one). 
After installing the 4.3v 1w diode & 4bar fpr (A 4bar is not needed - the only reason its installed is I plan on doing adjustments via lemmiwinks) it started up fine with slight (10-20rpm less) idle issue (most likely because of the diode & 4bar/ecu adapting to more FP) that I adjusted to stock idle via lemmiwinks. I took it out to perform a couple WOT pulls and (for the record) it boosted to *15psi (*the car was able to this before diode) with no problem and on the second WOT in 4th & 5th (load) gear I seen 16.5psi. 
Anyway, thanks to mjmi11er Diode DIY; http://forums.vwvortex.com/zerothread?id=4824103 
it helped a ton with installation i.e. clean & easy!! http://****************.com/smile/emthup.gif


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## Buschwick (Feb 12, 2007)

*FV-QR*


_Quote, originally posted by *Anthony1.8* »_
the ecu wouldn't fuel you enough normally, but you can make adjustments to fuel trim levels via lemmiwinks or unisettings 
You wouldn't use a 4.7v diode if you want to run a lower boost. 13-16psi. If you did, the ecu would fuel you for 17psi all the time.You'll be running rich. *No. In fact the zener won't affect the MAP signal at all in this scenario.*
Plus, this is not a very reliable/safe mod.. I don't suppose it's highly recommended. *Sure it is if you know what you're doing*
I can't make sense of what you're trying to say there ^
If you run this mod with no mbc, you're wastegate probably won't let you boost to 13psi, unless the wastegate is adjusted or something. I think, stock, you're looking at around 8-10psi. So If you we're to run this mod, you could turn your mbc up to 13psi and run the 4.3v diode and safely boosting at 13-14psi, a little more than stock. For a little bit of fun. You could even adjust some fuel trims with lemmiwinks/unisettings to get things right on the money. *You do not need to adjust fueling at 13psi dude. The ECU will figure it out quicker than anyone can. I'm at 19psi daily and zenered for over a year nad a half and I currently have no fueling adjustment. On 2002+ cars you don't even need a diode for those boost levels you mentioned*

I'm not sure, i'm still trying to figure all this out, it's a little confusing. These are some good questions, i currently have both diodes hooked up to a switch in my car, but I can't test em out until I get my new fuel pump wired up. I'll let you know my findings, meanwhile hopefully someone will chime in and clear some things up.










just trying to edumicate you cause you're kinda spreading wrong info.
You don't need much fueling at all if any. But it's always a good idea to have vagcom to log some things to make sure it's running well. And you don't need a 4bar FPR, it's hard to max out the injectors on the stock turbo with a 3bar. Just stick one diode in there whether it be 4.3v for stock or 4.7v for chipped and turn the boost up.


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## codergfx (Jan 11, 2009)

Say i diode my car at 4.3v = 11psi can i boost it to 19-20? will it have enough fuel? Does map control fueling?


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## @lex20th (Jul 28, 2009)

*Help*

HELP!! 

i dont want to do this mod.... but I'm on limp mode because of this: 










 


i'm not an electrical kind of guy...so how can i fix it??? anyone knows if i can find a new sensor clip???


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## dubinsincuwereindiapers (Jan 16, 2008)

:sly:OK.... so... FIX IT


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## codergfx (Jan 11, 2009)

Just take the pin out and hook up a new wire? not that hard =/


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## dubinsincuwereindiapers (Jan 16, 2008)

My sig says it all


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## halchka99 (Apr 18, 2002)

thats why you should go to the "other one" LOL


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## codergfx (Jan 11, 2009)

lol if you are relating to my post its a possible solution don't hate...


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## wagner17 (Oct 20, 2009)

2000 jetta awd. i used a 4.7volt 5watt diode im still boosting 9?? should i switch put to a 4.3 but im completly stock no boost controller nothing. just a diode and a dv can someone help me


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## sounrealx (Apr 4, 2007)

diode is not a boost controller. It only keeps you from hitting limp mode.


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## wagner17 (Oct 20, 2009)

oh sorry iforgot to add i still hit limp tho when i spike at like 10 or 11lbs so. idk should i throw in the 4.3 and forge unos valve?


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## dubinsincuwereindiapers (Jan 16, 2008)

wagner17 said:


> 2000 jetta awd. i used a 4.7volt 5watt diode im still boosting 9?? should i switch put to a 4.3 but im completly stock no boost controller nothing. just a diode and a dv can someone help me


 First off the diode only keeps the ecu from hitting limp mode, it doesnt raise boost. Second the 2000 AWD engine doesnt even have a map sensor to clamp, so you couldnt do the diode mod even if you wanted to... *You just got caught in the stupidist lie ive ever seen on the vortex* congratulations.... YOU are the 1.8t forum *TOOL OF THE YEAR* :thumb:


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## wagner17 (Oct 20, 2009)

huh.. to bad it does. purple gray wire was conected to the orange blue . oh btw i did so thanks for being a d$%k chows how cool you can be. but in all honisty its done still hit limp with the 4.7 installed. 

oh if you think your so cool that you know everything 

http://www.urotuning.com/shop/boost-pressure-sensor-aka-map-sensor-ealry-18t-p-1505.html 

buy one....


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## codergfx (Jan 11, 2009)

try the 4.3 instead of the 4.7


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## twin2626 (May 11, 2006)

In sync diapers, You got Pwned!!!!!


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## wagner17 (Oct 20, 2009)

going to install a 4.3 today and see if i still hit limp


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## Buschwick (Feb 12, 2007)

This thread needs to be in the MKIV forum. Too much fail and not enough reading.


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## @lex20th (Jul 28, 2009)

codergfx said:


> Just take the pin out and hook up a new wire? not that hard =/


Just did that yesterday, didnt work, anyone know if i can buy the 3-pin conector(MAP is good), if yes where?


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## hxcisthaway2be (Mar 26, 2010)

OK I've been doing a lot of reading on this diode mod, but there are still some conflicting ideas and opinions out there. And plus I'm more of a mechanical than electrical guy. I currently have 2005 mk4 gli (the 180hp awp that runs about 11-12psi stock). The car is basically stock, I would like to run a little more... say around 15-17psi. I would also like to have a toggle switch so i can run stock for daily driving. Correct me if I am wrong in what I have to do...

-run the two switch between a 4.3v diode and stock.

1)Do I have to do anything else to get the fuel ratio up to normal?
2)Or to actually get the k03s up to around 16psi such as adjust the wastegate or mbc? I'd prefer to not run MBC if I don't have to. 

Thanks


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## dubinsincuwereindiapers (Jan 16, 2008)

the map sensor is located on the top of your oem intercooler on the pass side of the vehicle. Peer down into your bay to the left of the throttle body. See where the t/b hose goes? Right next to that is your map sensor.. It has the wires going to it


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## JohnsonMOD (May 14, 2010)

hxcisthaway2be said:


> OK I've been doing a lot of reading on this diode mod, but there are still some conflicting ideas and opinions out there. And plus I'm more of a mechanical than electrical guy. I currently have 2005 mk4 gli (the 180hp awp that runs about 11-12psi stock). The car is basically stock, I would like to run a little more... say around 15-17psi. I would also like to have a toggle switch so i can run stock for daily driving. Correct me if I am wrong in what I have to do...
> 
> -run the two switch between a 4.3v diode and stock.
> 
> ...


"-run the two switch between a 4.3v diode and stock." All this switch will do is engage/disengage your overboost cut-out,a.k.a. "Limp mode".


1. Your factory fuel set-up,if in perfect working order will be good to about 17 max psi safely.You should get an air/fuel guage to make sure it's good. The diode will be tricking your factory system.

2. The diode is safe to install now and won't change anything. All it does is stop the MAP signal from going so high it puts your car in "limp"(safe)mode.When you install the diode you need to understand that you just took away your cars overboost protection. You will need to install something to get the car to boost higher.It sounds like you should look into "dawes devices" or just buy a cheap EBC. If you get a cheap EBC you can set your boost from 5-16psi from inside the car. Some people hit 17psi safely on fact fuel.

Hope this clears it up a bit.


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## JohnsonMOD (May 14, 2010)

wagner17 said:


> huh.. to bad it does. purple gray wire was conected to the orange blue . oh btw i did so thanks for being a d$%k chows how cool you can be. but in all honisty its done still hit limp with the 4.7 installed.
> 
> oh if you think your so cool that you know everything
> 
> ...



Words spelled wrong in this add don't inspire confidence.
"Boost Pressure Sensor aka MAP sensor, _ealry _1.8T"


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## hxcisthaway2be (Mar 26, 2010)

that helps a ton. thanks


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## hxcisthaway2be (Mar 26, 2010)

getting a cheap ebc (about 300 bones) and installing the diode, seems like i should just go with a full reflash...not much more expensive... safer, more ecu setting changed other than just boost. 

why can't I just adjust my wastegate actuator for a couple more psi to about 15psi and install the 4.3v diode/stock switch to prevent limp mode? seems like the most cost-effective approach to me...


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## ColoradoSoul03 (Sep 14, 2006)

I am getting ready to do a 4.3v diode mod on my friend's 03 AWP Wolfsburg. We are planning on using Unisettings to tweak his fueling and timing. What are some good basic settings to start from?


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## giles712 (Aug 4, 2009)

So I did the diode mod to my 02 Jetta AWP code. its stock other than an ecs CAI. I used the 4.3v 1W zener diode. I wasnt impressed at all. Yes, I could hit 20psi easily, but my power was choppy, unpredictable, and i went into limp mode everytime I hit 20psi. My opinion?: Don't do this mod. its ghetto, and just feels wrong to do to a german automobile. Unitronic here i come


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## AmIdYfReAk (Nov 8, 2006)

giles712 said:


> So I did the diode mod to my 02 Jetta AWP code. its stock other than an ecs CAI. I used the 4.3v 1W zener diode. I wasnt impressed at all. Yes, I could hit 20psi easily, but my power was choppy, unpredictable, and i went into limp mode everytime I hit 20psi. My opinion?: Don't do this mod. its ghetto, and just feels wrong to do to a german automobile. Unitronic here i come


 hitting 20 will cause you to hit soft limp. 

you should have aimed for 17-18PSI, and had the according gaped spark plugs.


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## lamarvannoy (Jan 29, 2010)

Thanks guys, I can't believe it took me this long to find this. Sweet deal.


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## 4ePikanini (Aug 29, 2007)

correct me if I'm wrong.

If you put a diode in you are fooling the ecu into receiving an altered signal from the map. This means you are actually boosting high but ecu sees low so you are underfuelling - lean - melting piston ?????


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## player2 (Feb 20, 2010)

yep i do look like an idiot, i hope you guys dont mind. i certainly don't.


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## JTAudet (Aug 12, 2010)

same on the a4 b6?


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## player2 (Feb 20, 2010)

*misread*

_"2000 jetta awd. i used a 4.7volt 5watt diode im still boosting 9?? should i switch put to a 4.3 but im completly stock no boost controller nothing. just a diode and a dv can someone help me" 


"First off the diode only keeps the ecu from hitting limp mode, it doesnt raise boost. Second the 2000 AWD engine doesnt even have a map sensor to clamp, so you couldnt do the diode mod even if you wanted to... You just got caught in the stupidist lie ive ever seen on the vortex congratulations.... YOU are the 1.8t forum TOOL OF THE YEAR :thumb:"_ 


that guy could've had a jetta, all wheel drive (AWD) made in 2000 and has a MAP sensor. and 9 is sometimes zero. and 9 lbs isnt any more than stock. i think the late 2000 cars had 11 lbs or something (AWP) my "01" gti made in 2000 has 57 lbs. of boost with just a doide mod and wastegate done up. well maybe not 57 lbs., but close.


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## martin13 (Apr 20, 2010)

4ePikanini said:


> correct me if I'm wrong.
> 
> If you put a diode in you are fooling the ecu into receiving an altered signal from the map. This means you are actually boosting high but ecu sees low so you are underfuelling - lean - melting piston ?????


 no this is wrong. the maf sensor and o2 sensors will aid in adjust fueling accordingly up to about 17 psi. at this point if you want to boost higher you would need a new fpr, injectors, etc. the stock ko3/ko3s is only good to about 20 psi before it goes out of efficiency range though. 

:beer: 

edit: 


player2 said:


> _"2000 jetta awd. i used a 4.7volt 5watt diode im still boosting 9?? should i switch put to a 4.3 but im completly stock no boost controller nothing. just a diode and a dv can someone help me"
> 
> 
> "First off the diode only keeps the ecu from hitting limp mode, it doesnt raise boost. Second the 2000 AWD engine doesnt even have a map sensor to clamp, so you couldnt do the diode mod even if you wanted to... You just got caught in the stupidist lie ive ever seen on the vortex congratulations.... YOU are the 1.8t forum TOOL OF THE YEAR :thumb:"_
> ...


 you are a ****ing idiot


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## Buschwick (Feb 12, 2007)

player2 said:


> that guy could've had a jetta, all wheel drive (AWD) made in 2000...


 Ya only 8psi that year but good thing they had all wheel drive! 

Are you fuggin' serious?


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## player2 (Feb 20, 2010)

*no john stewart*

yeah, those all wheel drive cars. thats where its at. all i was sayin was if that guy has the wrong info and no MAP sensor, where exactly did he put the diode? he propably just needs some pound injectors. yeah that'll fix it. some pound injectors. also someone mentioned hitting soft limp mode with 20 p.s.i. they could be right, but in my experience they will hit limp the first couple of times they drive it and then it'll go away. mine did exactly that.


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## smarks77 (Feb 10, 2010)

Has anyone done this mod on a 1999 passat with the AEB motor and is it even possible???? and can u do this with out running a chip the only mods i have on my car are ko4, intercooler and short ram intake


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## BoostAdict (Dec 5, 2010)

giles712 said:


> So I did the diode mod to my 02 Jetta AWP code. its stock other than an ecs CAI. I used the 4.3v 1W zener diode. I wasnt impressed at all. Yes, I could hit 20psi easily, but my power was choppy, unpredictable, and i went into limp mode everytime I hit 20psi. My opinion?: Don't do this mod. its ghetto, and just feels wrong to do to a german automobile. Unitronic here i come


Wow. You really ran 20 psi on only a diode mod? stock fuel system is only safe for up to 17psi. Lol... its a great mod, and with any $50.00 mbc you can. Run up to 17 psi safely. So in reality the mod is about $50.00 total. Well worth it. Btw. I saw someone said they were using a 5 volt diode. Only the 1 volt diodes work.


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## cincyTT (May 11, 2006)

smarks77 said:


> Has anyone done this mod on a 1999 passat with the AEB motor and is it even possible???? and can u do this with out running a chip the only mods i have on my car are ko4, intercooler and short ram intake


AEB's dont have a map, thus no diode mod.



BoostAdict said:


> Wow. You really ran 20 psi on only a diode mod? stock fuel system is only safe for up to 17psi. Lol... its a great mod, and with any $50.00 mbc you can. Run up to 17 psi safely. So in reality the mod is about $50.00 total. Well worth it. Btw. I saw someone said they were using a 5 volt diode. Only the 1 volt diodes work.


I ran 20psi on stock fueling with a 2L and had 12:1 afr while chip tunes only run 13:1 (leaner). BTW, made over 300wtq with just a dp and 2L. Please learn things for yourself instead of spreading more misinfo


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## codergfx (Jan 11, 2009)

Idk about fueling system but I'm running 22 psi on eurodyne tune on stock fueling system. No problems yet. 

I ran a diode mod @ 16 psi and logged the timing pulls and I was getting 13 degree timing pull! But with eurodyne no problems.

Soon after I tried diode I just went and bought tune. IMO diode performance doesn't compare to a tune.


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## smarks77 (Feb 10, 2010)

Is their anything we can do to get this "extra" boost?


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## Spooled Rotten (Dec 13, 2010)

:banghead:


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## hodfolly (Jun 15, 2010)

at your own risk.

instead of a diode, use a blown" glow when it blows" fues from advanced auto. the red led light on the fues clamps the map to 1420 mbar. im callinmg it the 420 mod. :snowcool:same wiring as the diode, except you can use a inline fues holder. "KISS"

if you want a cheap homebrew way to rase the boost, T off ther DV line from the manifold to the pressure port on the n75, and put a bolt in the old pressure line.

btw, if you log mb 204,. you will see that tyhe ecu still regeisters boost in feild 2 with the map clamped. its a calculated value, but pretty spot on.

enjoy


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## ilay975 (Apr 29, 2009)

1.8TWolfsberg said:


> Alright, such a nice mod and no write-ups anywhere...at least that I could find!
> So with the help of John (Spooled_AWP) I went ahead and did a few diagrams and then finally did the mod myself!
> Here is the link to my DIY page
> And here are a few diagrams:
> ...




i dioded my mk4 1.8t AWD and didnt work in any sence plz help!!!!! thank you


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## codergfx (Jan 11, 2009)

Explain didn't work? Still limping?


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## rains (May 30, 2008)

thanks for DIY!

Quick question:

Does this mod play nice with chipped ECUs? I have Revo Stage 1 and still occasionally hit soft limp ... with a 4.7 (17PSI) diode I should solve this problem?


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## Buschwick (Feb 12, 2007)

rains said:


> thanks for DIY!
> 
> Quick question:
> 
> Does this mod play nice with chipped ECUs? I have Revo Stage 1 and still occasionally hit soft limp ... with a 4.7 (17PSI) diode I should solve this problem?


This on a AWD? That 4.7v zener won't "clamp" at 17psi on an AWD. My 01 AWW voltages are higher than AWPs. A 4.3v zener clamped my AWW at 8psi. I now have it clamped at 10psi with about 4.5v going to the ECU.


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## rains (May 30, 2008)

AWD, you bet.

If a 4.7v diode won't clamp @ 17 ... it'd just need a higher voltage diode?


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## tdogg74 (Mar 1, 2002)

Bringing back from the dead...

So what voltage diode are the 150hp 8.9psi guys using? a 4.3v diode will not work because the expected boost programed into the stock ECU mapping will never go past 9, so clamping it for 11psi is pointless.

Whats the voltage correspond to then for 9psi? 4v, 4.1v, 4.3v?


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## codergfx (Jan 11, 2009)

I had success with a 3.9v diode


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## Killathrilla (Sep 21, 2011)

Quick question, does this mod need to be used in conjunction with a manual boost controller or some other boost mods? Or will it take a Bone stock AWP from stock boost to 17psi with just this mod?


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## dubinsincuwereindiapers (Jan 16, 2008)

This mod doesn't raise the boost. It allows YOU to raise the boost without hitting limp mode. So yes; you need a boost controller of some type


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## Killathrilla (Sep 21, 2011)

Ahh i see thanks! :beer:


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## dubinsincuwereindiapers (Jan 16, 2008)

:beer:


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## Tate393 (Jun 21, 2011)

i cant wait to do this


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## Tate393 (Jun 21, 2011)

W/o the diode i am at 13psi. what diode's would i use if i wanted to switch from 8psi to Stock(my 13) to this 17psi?


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## dubinsincuwereindiapers (Jan 16, 2008)

dubinsincuwereindiapers said:


> This mod doesn't raise the boost. It allows YOU to raise the boost without hitting limp mode. So yes; you need a boost controller of some type


Cough


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## jayzus (Feb 2, 2009)

*Question*

so if im going to place a diode in the option to place a single diode with no switch , which way should the Stripe be facing? Should the stripe face the Purple/gray or the Orange/light blue cable??

Thank you mate!


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## nuff said (Nov 22, 2011)

*Diode Mod*

Wow ,this is confusing for a diode mod.The pics show 3 colored wires,orange /blue,next to that(middle wire)purple gray,and on the opposite side is the purple /green wire.The map sensor on my new beetle shows the wires on one side orange /blue,in the middle purple green,and on oposite side is the purple gray wires .So my sensor wiring is not the same position as shown .Is there a difference.Well ,I tried hooking this up using a 4.3 zener the way shown and it threw a cel and did not work.I flipped the zener ,same wires ,did not work ,threw cel again.When you talk about the position of the zener ,it is not a question of what side the cathode is towards ,but what end it is towards,in other words towards the map sensor ,which is at the end of a plug ,not at the 
side of a plug.Anyway ,I am running 9 psi and cannot get it higher .I have a boost control .,gauge,dv valve ,n75 j valve ,I cleaned the iat,maf,map,throttle body,tightened all hoses I could find,adjuted wastegate(made no difference)adjust mbc ,no difference,tried diode mod ,threw a cel.I want more boost and shoul be able to get it according to all these posts .I cant afford a chip otherwise I would buy one.I just wish something would work!!!!! If I were leaking boost ,which I may be,then why would car run at stock boost ,unless it is going limp at 9 or 10 lbs,which might make sense due to fact that some guys say using a 4.3 or 4.7 does nothing ,but a 3.9 works which is identicle to stock boost on a new beetle 1.8t .Any ideas?


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## codergfx (Jan 11, 2009)

U hooked em up to wrong wires then...


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## nuff said (Nov 22, 2011)

*Diode Mod color code*

Hey all you guys that have a new beetle 1.8t 2001 awv ,like I do ;I tried the diode mod ,but noticed that my 3 wire positions were not the same as shown in this diagram.Starting from the bottom ,the diagram shows an orange /gray wire,in the middle a purple gray wire,and on top position a purple green wire .I followed the color code,making sure to put diode in correct position .I tried it ,engine ran like crap,flipped the diode ,same thing.I then borrowed my friends 
volt meter .The orange gray showed no voltage.This is my ground.The purple /gray wire showed 5.64 volts which is sensor input.The purple/ green wire showed 4.99 volts,this is sensor output.The correct connection is run diode from ground(orange /gray),to purple /green(output),
making sure the cathode (stripe)is closer to and facing toward the purple green wire(output).Lesson learned ;Do not do this mod without having a volt meter to check the wiring yourself.The wire with less than 5 volts will always be the sensor output.The wire with more than 5 volts will always be sensor input.Do not trust only using the color codes,as it could cause you to give up or wreck your ecu.I read about a guy who did it and this was result.I wonder if he hooked up according to color codes and just kept running it wrong.....Heads up.....


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## vwmoneypit2 (Mar 23, 2008)

*clamping ect..*

So I get the clamping it like a controlled short to the 2 wire Ie a switch..did that..I have a stock 2000 gti 1.8t car with a ace made mbc...the diode and still running the n75 paralell to all this and guess what ..best it will do is 9 lbs..will bearly spike 9 lbs.....Am I missing something..I know if i turn up the mbc(so more leakage) ie slower gate reaction...It comes on quicker but none more than 8-9 lbs.....someone help..how do u boos tmore with a stock ecu golf......safely no half tricks


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## vwmoneypit2 (Mar 23, 2008)

nff said im right there with u...i dont get it and i even have the wicked custome 3 inch down pipe and exhaust all the way back.. i did a parelell mbc and did make it come on quicker but no diff 9 lbs all day long and i have a 2000 awd..what gives no leaks either:banghead:


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## dubinsincuwereindiapers (Jan 16, 2008)

Guys.. You have to disable the n75 and turn the boost up with a boost controller. The diode mod doesn't increase boost; it allows YOU to increase boost without hitting limp. 

Running a boost controller parallel to the n75 is done to eliminate a boost spike from an aggressive tune which (which if you had; the diode mod wouldn't be necessary)


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## Big_Tom (Aug 19, 2007)

i dont know why you guys still bother with diodes lol, so primitive:screwy:


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## Buschwick (Feb 12, 2007)

Big_Tom said:


> i dont know why you guys still bother with diodes lol, so primitive:screwy:


 
cause it works if you know what you're doing for about $450 cheaper than a toon

doesn't get as much power as a real tune but alot of people don't have that kind of cash lying around for burning under the hood

I'll gladly accept any contributions to make my car more state of the art for you, if you want.


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## codergfx (Jan 11, 2009)

Buschwick said:


> cause it works if you know what you're doing for about $450 cheaper than a toon
> 
> doesn't get as much power as a real tune but alot of people don't have that kind of cash lying around for burning under the hood
> 
> I'll gladly accept any contributions to make my car more state of the art for you, if you want.


I've used both diode mod and now running actual tune but you're right performance isn't even close to bein the same. 

Problem with running a diode is ecu stock requests 13.4-14.0 afr @ boost which doesn't help even at 10 psi
And now you are turning the boost to say 16 psi without making the mixture richer to cool down the cylinders with pump gas, there for creating even more knock. At one point my knock sensors were maxed out with a diode mod running an mbc on stock ecu. I did 2 dyno pulls 12psi and 16psi with mbc and power difference was about 3-5whp and 10-15wtq not worth blowing up the motor if your knock sensors fail IMO. Just my 02.


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## ~Enigma~ (Jul 8, 2009)

codergfx said:


> I've used both diode mod and now running actual tune but you're right performance isn't even close to bein the same.
> 
> Problem with running a diode is ecu stock requests 13.4-14.0 afr @ boost which doesn't help even at 10 psi
> And now you are turning the boost to say 16 psi without making the mixture richer to cool down the cylinders with pump gas, there for creating even more knock. At one point my knock sensors were maxed out with a diode mod running an mbc on stock ecu. I did 2 dyno pulls 12psi and 16psi with mbc and power difference was about 3-5whp and 10-15wtq not worth blowing up the motor if your knock sensors fail IMO. Just my 02.


i ran the diode mod a few times, actualy I put on the diode and went back and forth using a MBC and back to stock n75... the A/F ratios on my awp work great all the way to the 18psi i was giving it. I did mess with my static fuel trims with unisettings, but i was running just as good with stock settings... I did play with my timing a bit, but because it was a static setting I was getting big pull in higher rpms, but i had a big gain in lower end power... BEST to get a chip... BUT the diod mod is great for occasional 15 to 18 psi boosts...

YOU WILL GET LIMP MODE STILL... it wont be for over boosting, it will be for requested boost wont match actual boost... you can stop this by learning to drive less agressive...and flooring it when you want power... but why drive less agressive if you up the boost???? AGIAN.... a chip will make your timing more agressive, up boost, and let you have max driving pleasure... diode mod only makes u want more... Enjoy the diode mod.. just turn up boost little by litte cause all our cars are diff... 18 psi was fine on mine.. but urs may not be.

**ISSUES WITH DIODE MOD** If your MAP fails with the diode in, you will only get codes for pressure drop between turbo and throttle valve... I cut my diode off, and then realized i had g71 and g31 failure (implasable signal g71 (f96), and signal too low (g31))... feels like a faild maf, but no cel and back firing through intake manni....


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## Big_Tom (Aug 19, 2007)

Buschwick said:


> cause it works if you know what you're doing for about $450 cheaper than a toon
> 
> doesn't get as much power as a real tune but alot of people don't have that kind of cash lying around for burning under the hood
> 
> I'll gladly accept any contributions to make my car more state of the art for you, if you want.


nah, run it brah :thumbup: lol this is the equivalent of those ebay resistor tricks to get you "x" amount of HP guaranteed :laugh:


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## Buschwick (Feb 12, 2007)

Big_Tom said:


> nah, run it brah :thumbup: lol this is the equivalent of those ebay resistor tricks to get you "x" amount of HP guaranteed :laugh:


Yeah...exactly the same.

ur the awesomest guy here :thumbup:


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## Big_Tom (Aug 19, 2007)

Buschwick said:


> Yeah...exactly the same.
> 
> ur the awesomest guy here :thumbup:


thanks . in all fairness i will say i did buy a 4.3 and a 4.7 zener diode, but once i saw what they were and how this works i went a bought Uni stg 1+ reflash same day. i still have the diodes somewhere in my garage :beer:


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## nuff said (Nov 22, 2011)

*How To know The Correct Diode Wiring*

Good Writeup on the diode mod.I think it is very important for people attempting this mod ,to know how to check for correct set up and take the guesswork or wire color code out of the picture ,just in case the color codes on the wiring is different like mine was.The 3 wires coming off your map sensor are ground,sensor input,and sensor output.You can confirm which is which by using a voltmeter.With the wires stripped off a little,battery connected ,key in accessory mode,using a voltmeter.There will be a sensor that reads more than 5 volts,one that reads less than 5 volts and one that reads no volts.The wire with less than 5 volts is sensor output,the wire with more than 5 volts is sensor input.The wire with no voltage is ground.The correct wiring for a basic set up,no switch,is ground wire,solder diode from ground,cathode line ,towards the sensor output wire,and diode from ground (north or up position) diode (cathode )pointing towards the south or down position.
(closer to the map )My 2001 new beetle 1.8t ,the ground wire was orange /light blue and my sensor 
output was purple green ,this being the opposite wiring color code as shown on the forums;Lesson learned ,check with a voltmeter .My sensor output wire read 4.99
volts,my sensor input read 5.64 volts.Remember correct wiring is diode from ground to output wire,cathode toward or closer to,the output wire.


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## nuff said (Nov 22, 2011)

*diode*

So,Awp.your getting more boost with a 4.3 zener then a 4.7?


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## ddeleon4 (Sep 26, 2010)

hey guys,

I have been reading up on this for a while now and was wondering if anyone knew if the map sensor wire ran into the cabin without going into any other systems? 
basically, supposing the wires don't change color randomly in the engine bay, could i just install the diode inside the cabin? 
if no one know i'll probably just take my multimeter and check for my self, i just rather not b/c i rather save myself the diss-assembly that would be required to check this if someone already knows the asnwer 

i just figured that it looks cleaner and there is less actual wire required.


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## clutchpack (Jan 31, 2012)

Wondering if this thread has been updated. I have a 02 passat and want to attempt this mod.


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## fresh_paint (Sep 17, 2011)

How/ where did you find out at what voltage the ECU clamps the MAP sensor at? I just picked up a mkvi gli and am interested in doing this with the 2.0t.


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## Dave926 (Mar 30, 2005)

fresh_paint said:


> How/ where did you find out at what voltage the ECU clamps the MAP sensor at? I just picked up a mkvi gli and am interested in doing this with the 2.0t.



You've got a brand new car and want to use a $2 diode to make more power.....smh


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## fresh_paint (Sep 17, 2011)

Dave926 said:


> You've got a brand new car and want to use a $2 diode to make more power.....smh


So tell me dave, what is the difference of me doing it now or a year from now? Or 4 years from now? Either way I am going to get the most power I can. Not to mention it's not something that is common and is just another thing I can do to my VW myself.


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## Volkswagencrazy (Dec 10, 2012)

Hey guys, I have been doing alot of reading on the diode mod, and I ended up finding a Zener diode, I don't have a chip so I was told to use a 4.3volt 1 watt, put it in my car and holy what a diff. The only thing I don't know about is will it be to lean for having the mod in the winter? I am from Canada ont. so gets cold some times lol, and another thing, I have had the mod for like 3 days now and today when I get past 10psi it misses, and sputters, u think it might be a bad MAF? Please let me know thanks, opcorn:


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## mk4gti2step (Dec 21, 2012)

Which wire(tell me the color) does the striped side of the diod e go to?


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## Halfstack (Jul 15, 2008)

*DIY: Clamping the Map Sensor aka "Diode Mod"*

The question nobody seems to be getting an answer to is what wire color the striped side of the diode goes to???


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## vdublove11 (Feb 24, 2013)

Halfstack said:


> The question nobody seems to be getting an answer to is what wire color the striped side of the diode goes to???


it HAS been answered PLENTY of times. The STRIPED side FACES the MAP SENSOR!


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## Kid p (Nov 28, 2014)

Interesting. Had my car flashed with stage 2 apr setup. 2002. Awm code passat fwd tip. Didn't install a boost gauge or nsx mbc I bought, since we are getting rid of the car. But just for ****s & gigs would this benefit my car if I did the 4.7 diode & installed the mbc as a standalone..meaning unhooking/deleting the n75 while still leaving it plugged into the harness?


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## ChuckA4TDI (Dec 26, 2014)

1.8TWolfsberg said:


> Alright, such a nice mod and no write-ups anywhere...at least that I could find!<p>So with the help of John (Spooled_AWP) I went ahead and did a few diagrams and then finally did the mod myself!<p><A HREF="http://www.anthonydanna.com/vw/diodemod.htm" TARGET="_blank">Here is the link to my DIY page</A><p>And here are a few diagrams:<p><IMG SRC="http://www.anthonydanna.com/vw/diodemod/2diodediy.gif" BORDER="0"><p><IMG SRC="http://www.anthonydanna.com/vw/diodemod/1diodediy.gif" BORDER="0"><p><IMG SRC="http://www.anthonydanna.com/vw/diodemod/noswitchdiodediy.gif" BORDER="0"><p>Here is the page to my VW Links page which has a few other DIYs that I have done - <A HREF="http://www.anthonydanna.com/vw.html" TARGET="_blank">http://www.anthonydanna.com/vw.html</A><BR><BR>
> <i>Modified by 1.8TWolfsberg at 1:43 PM 11-25-2008</i>


Does this mod works with 1.9tdi engine?


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