VicG

I hooked my stock A4 to vag com to gather some data readings. My wastegate duty cycle from group (115 or 118) was over 90%, and a another reader suggested I might have a boost leak. My requested boost was something like 1850, but actual boost always in the 1500's. Well, I installed the replacement GIAC/ECU and it seemed to perk up a little (no 40hp by any means - I've been a drag racer for 10 years a while back, and I know what HP is :-) but nothing like I expected. Driving around with Vag-com running, I see boost is now 1850's. But something is still not right...

I did also buy a Bailey BPV and got to installing this yesterday. Well, I can't say what this actually cured, but what a difference! Vag reports requested AND actual boost over 2000mbar now, and it's like driving a new car! I attempted to put back in the stock BPV, but the hose clamp wouldn't secure the hose adequetley since the stock BVP hose nipple is a little too short. So my test to determine if the stock BPV had a problem can't be known. I did try the "lung pressure test", and it does not seem that my stock BPV was leaking, as far as I can determine.
Can the change of BPV make this much difference? My wastegate duty cycle reading is still in the 95 percent range, but car seems to run so well maybe I don't need to pursue that (I was told >90 I probably have a leak someplace...)

Comments? Can a BPV have this drastic an effect?
Vic

CMH

tq curve. Now it is more of a peak.

LCP

Yes, bad BPV can cause that big of a problem. It is, after all, a BOOST LEAK after one fails.