ok so my mods are listed below and the chip runs at 15 pounds. they have been in teh car for just about a month and the car has 60,000 KM on it. please help me out.

i hit boost adn everything is cool until i hit 4500-5000 rpm. once i hit between 45 and 5 rpm's my boost drops from 15 pounds to 10 pounds. during the 5 psi drop it is very smoth and is not a sudden drop its drops alomost as if its being a controld drop. this just happened all of a sudden. there are no weard noises comming from my turbo and it sounds exactly the same as when i first chipped the car. also the car still pics up great until 45-5rpm's then the boost drops and my cars power obviously drops. please i need help beucase i dont know what this could be. even if im shifing at lets say 4,000 rpm the next geer it boost's up to 15 and then once i hit 4500-5000 it drops off. can you guys help me out.

Iv checked for codes... there's none
mechanic looked over the hoses and couldent see a hole. (doing pressure test asap)
blocked the dv and wastage one at a time and the pressure drop still ocured.

please guys i need help diganoicing this problem. and please tell me its not my turbo diying(pretty shure its not) again no weard noises or anything from before also this problem jsut all of a sudden happend and wasent something voer time or anything.

 

Maybe bad N75 valve... Havent we already discussed this 14 times already?

 

ya ok and for the 14th time i dont have that valvei have a balieys dv

 

The N75 and your bailey DV valve are 2 different components. Let me explain:

N75 valve is an ECU controlled solenoid that controls the turbo wastegate

The bailey DV valve is your aftermarket diverter valve that "diverts" boost pressure away when the throttle closes and recirculates it back into the low pressure side of the intake ( i.e., before the turbo ).

OK, now that's established....the boost dropping off is most likely normal. From what I hear, the stock turbo cannot hold that 15 PSI all the way to the redline. Therefore, it should drop off. Now, I'm not sure if it should drop down to 10 PSI..but it does not sound out of reach.

 

The N75 is different than the DV. it's located on the turbo inlet hose right above and to the side of the turbo (quick fix: buy a N75 J race valve from ecs). check all the clamps on the hoses from airbox, turbo, IC, and intake mani. there may be a loose connection that is only allowing air to escape at high boost. possibly replace all one time clamps with re-usable screw clamps and tighten them hard.

question: can you hold 15 psi at lower rpm's?

 

yes i hold the 15 pounds fine under lower rpm also GIAC said that the thrubo should hold around 15 pounds all the way threw and the 5 psi drop is not normal and should not happen. pluss i have noticed as well as a firend of mine that the car is slower now then before so the 5 pound drop is not normal. is the N75 liek a little box with a little vac line in it? located under the headers o n the right side of the engine. ? if that isit then i had changed it with one from a 225 tt engine and there was no diffrence

 

No the N75 is not on the right side of the engine bay. It's on the passenger side. It's on the intake tube that goes out of the airbox to the turbo. It's has a cylindrical body, with a three way tube end. You can see two vacuum line running to it. The third end is inserted in the intake pipe. To locate, follow the intake pipe toward the turbo. It should be locate just about in front of the turbo on top of the intake pipe. Here's a picture on a N75 valve and and N75 valve still connected in the engine bay .


[IMG]local://upfiles/1213/AA3DC66113394369BA6C4967D464DD31.gif[/IMG]

[IMG]local://upfiles/1213/128EBC472E37446C8B72D17C729FF2EA.jpg[/IMG]

 

You're right, the stock turbo should peak at 17 PSI then come down and hold about 1 BAR all the way through -- with the GIAC ECU flash. So, you may have a leak somewhere.

The N75 valve should have 2 vacuum lines coming from it with a 2-pin electrical connector. If you've changed that and there is no difference, then it really sounds like you have a leak, or even a worn wastegate. Start troubleshooting.

 

ok imtaking it tomorrow and will let you know. thanks for the help

 

Where are you taking it?? Havent you already had it someplace 2 times already with no luck?? Or was that just going to retrieve fault codes at autozone or something?? Make sure that someone who is familiar with Audi/VW is looking at it, preferably a tuner. Those NAPA/Firestone/Midas guys probably woulndnt even be able to locate the turbo under the hood.