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beepbeep beepbeep is offline
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Join Date: Jun 2001
Location: Sweden
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Originally Posted by patkeefe View Post
I have the curves in another thread, which I will try to find in this forum. That thread is: BAE Install Dyno Data

I have since changed the old wastegate to a new Tial Sport with 5.8 PSI spring.
The pop off valve is actually a return valve back to the inlet side of the turbo, vacuum controlled. I believe it is an OEM Audi valve. I believe you have a good idea about that, maybe I am bleeding of boost, so I will plug it this weekend and see if I get any improvement with it plugged.

No, I'm talking about pop-off, not BOV. I'm talking about rectangular spring-loaded thing on the top of your air-box:

I assumed that your home-made sping-loaded pop-off valve was downstream from turbo. Your picture makes it somewhat hard to understand the path of air. What I was trying to say is following:

1. Boost momentarily spikes above normal due to unknown condition.
2. Spring-loaded thing opens due to excessive boost, dumping measured air.
3. CIS still believes that dumpad air is in the loop and injects extra fuel and rich condition occurs.

I understand that there is BOV in the loop as well, but as BOV (hopefully) re-circulates air back into turbo intake it will not affect AFR condition as it keeps air in the loop and is only open during the shifts.

With other words, keep an eye on everyting that might vent air during the boost onset. Especially the spring-loaded thingie (if it's in pressurized part of air) and eventual cracks.

Also, your boost treshold is waaay high up in revs. You either have a monster turbo or a gigantic leak somewhere.
Thank you for your time,
Old 01-04-2008, 03:18 PM
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