IA3+ issues

[Phil Rose]

At 1:48 PM -0800 11/18/08, robert weinberg wrote:
>hi all,
>
>i'm borrowing the IA3+ from ian. he's experienced the same thing with his car.
>
>sometime you stomp on it and you get thrown through the back window 
>(i.e. fast!). other times you jump on the gas and it doesn't give 
>you that kick in the ass. still fast but no "pay-off" when you hit 
>4,000 rpm which is typical of the IA3+.
>
>on both our cars - engine pulls smoothly to redline. no studdering, 
>smooth idle. no check engine light.
>
>my car - samco boost hoses, 034 billet bypass, new 02 sensors. i do 
>have a torn breather hose (just got an 034 silicone one to replace 
>it - would that make any difference?). ALSO, we noticed that one of 
>the 02 sensor's was not plugged in (the passenger side one). the 
>connector was just dangling. who knows - maybe the car was running 
>super lean before and that's why it felt faster?
>
>we'd like to check the boost, but booth out gauges are 
>non-operational. i did buy another IC - but haven't gotten around to 
>the swap yet.

Hi Robby,
Those "seat of ass" gauges can be misleading.  The rate of boost 
delivery tends to be very dependent on the gear, the load, and the 
rpm at the time of throttle application--so I wouldn't obsess too 
much about this being an "issue" until you have a working boost 
gauge. You mentioned swapping in a replacement IC, but I'd hope you 
also are intending to install a real gauge, too.

There might be some sort of intermittent problem with the MFTS or 
wastegate freq. valve? You could try briefly pulling the appropriate 
engine management (ECU) fuses to reset whatever ECU "adaptation" 
might be reducing power because of various  kinds of sensor issues 
detected recently (knock sensors, ... etc).

BTW, do you know about Audi/Bentley's official procedure for 
testing/defining the vehicle's maximum boost? IIRC, the maximum boost 
value (for stock-- specified to be 1.8 bar ) is to be achieved as 
follows : while driving in 4th gear on level road (a slight uphill 
grade is useful, though) start the test at 1800 RPM (i.e., cruise to 
whatever moderate speed it takes to hold steady at 1800 RPM)--  than 
rapidly apply full throttle and watch to see the boost value that's 
reached when the RPMs hit 3000. Helps to have an assistant. With my 
Lehmann-chipped '91, I see 17-18 psi under those conditions.

Phil

-- 

Phil Rose
Rochester, NY
mailto:pjrose at frontiernet.net