[BiturboS4] mod feedback

Chris Newbold chris at newbold.org
Thu Nov 20 11:59:36 EST 2003

On Wed, 2002-10-23 at 16:45, California Fields wrote:

> in the gas pedal (like a turbo lag or something).  It's kind of hard to
> explain but does this sound normal?  Here's an example of the delayed
> response:  I'm cruising along in 3rd gear at about 3k rpm...I abruptly press
> the throttle down from about 10% (cruising) to half way and hold it....the car
> lurches forward with strong force but then the power backs off a bit...kind of
> like there was an initial spike of pressure but then it equilibrates to a
> plateau of power (still accelerating strong but just not AS strong)...kind of
> like I pulled back on the throttle when I really hadn't.  Is this a normal

I'd take a long, hard look at your bypass valves.

I was having the same symptoms on my stock S4 Avant; dealer said, "Oh,
they all do that after 15k miles or so..." Uh huh, sure. So I bought
myself two new bypass valves, installed them, and voila! The lumpy,
irregular power delivery is gone...

I'd imagine that the symptoms would be even more noticeable with a
chipped car and higher boost levels.


2001 S4 Avant 6spd

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