Help Gurus- Waste gate Pressure to fully open

[MaxRS6]

Hello all:

As I've been posting, my car has been on a long repair journey.

Currently, the techs replaced both of my turbos. However; the car would run normally and normal boost one moment. Then, it would over boost and go into limp mode.

They have done some testing of the lines from the N75 down to the waste gates by manually shooting some pressure down the line. They say the hoses do not have any leaks. They have determined that the driver side waste gate is fully opening, yet the passenger side waste gate does not fully open under the same pressure. They say the hose is a T that goes to the separate waste gates, and thus each side should be getting the same amount of pressure. They don't think anything is clogging the hose after the T split.

Now for the question- Does anyone know the psi amount that should fully open both waste gates?

TIA Brain Trust!

[QuattroRS]

Bypass N75 and isolate each side. Apply pressure to each line in 1psi steps. Watch the wg actuator at each 1psi step. Log results for both sides.

If the same or very close. Then bypass the N75 and isolate both sides yet again with a manual boost controller.

http://compare.ebay.com/like/120671224736?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar

Bench test both controllers to the exact same psi and isolate one for each turbo.

Drive it and report because I cant hold my breath much longer waiting for the Billy Bonkers group buy to expire.

http://i1039.photobucket.com/albums/a476/drh11/holding_breath.jpg

[MaxRS6]

^LOL- Thanks for the advice

They don't call you blue balls for nothin...;0

[yokust]

Well I know both the 2.7t and the 4.2t the wastegates are set to TWO different pressures. To compensate for different lengths and piping and what not.

That is why you are not supposed to mess with the threaded nut on the wastegate to gain more boost.

They should have come preset to an exact ammount

[QuattroRS]

We only have one throttle body. Why would there need to be two different w/g settings on the turbos? Boost dumps into one Y pipe before hitting the throttle body. There is only one N75 valve and it releases into both w/g's. How can they be set to different pressures?


Well I know both the 2.7t and the 4.2t the wastegates are set to TWO different pressures. To compensate for different lengths and piping and what not.

That is why you are not supposed to mess with the threaded nut on the wastegate to gain more boost.

They should have come preset to an exact ammount

[yokust]

From what Audi and KKK have said, its because there is different back pressures in each manifold, and small amounts of different length in intercooler plumbing, and different lengths in the hose coming from the N75 valve.

[QuattroRS]

I hear ya but we're not talking about a huge difference. One may open say at 9.6 and the other at 9.9psi. Would you concur?


From what Audi and KKK have said, its because there is different back pressures in each manifold, and small amounts of different length in intercooler plumbing, and different lengths in the hose coming from the N75 valve.

[MaxRS6]

Thanks guys and I certainly appreciate all your input and will share with the tech tomorrow. After 5 months out of 7 with the horse in the shop, I'm ready to get him back on the trail.

[4everRS]

Sorry to hear of all of your tribulations with Crazy this year. It's almost as though the wastegates weren't set right from the beginning. Or they were adjusted for some reason before or during install. I really don't have any experience in this field and wish I could help more. Pat would likely add to this but he is having technical difficulties with his computing hardware.

[MaxRS6]

Update- Boost issue resolved!!!!:applause::applause::applause::applaus e::applause::applause:

The tech determined the waste gate was misaligned slightly. He got it lined up and says the car is running great with steady boost! He says I'm good to go and can pick it up. The tech is almost as giddy as I am to have it resolved. I look forward to taking it for a spin. Watch out Arkies!!!!

I sincerely appreciate everyone's input/comments. A special shout out to Dhall & Pat who looked through my data logs, and offered input/comments throughout the process!

[4everRS]

This is great news Randy. Get that thing back on the road! Congrats

[ben916]

couldn't resist...



http://www.youtube.com/watch?v=VLpa8-hsuV0

[MaxRS6]

LOL- Good one Ben. I may need that prescription soon. ;0

However; I spoke toooooooo sooooooon. The tech called as I was on my way to pick it up. The car has lost all boost again on the passenger side as they were on their final test drive :(

Back to square one to try to find out the source of the metal that clogged the turbo. It is a setback. I headed over there to pick it up on the wings of euphoria and came back on the heels of agony. However; my better half always has a great way of keeping me in line. She says- "it is what it is- and it is only a piece of metal". She is right as our family is in good health and I have a great daughter that is growing up to make her daddy very proud of her accomplishments. :) I'll get through this one- and I do have a R32 to tool around in.:incar: