i ran my car at the track the other day, granted the track wasnt the greatest, but i ran a 14.7 with a 2.2 60ft and trapped at 94mph....i have a 06 cobalt ss/sc with zzp intake and full exhaust. aeroforce reads 0 degrees of knock. my car runs rich i think because when i clean my exhaust tip and drive it hard, the next day its all black, the car has a factory tune too. what do u guys think?

 

That really isn't all that bad. Do you have anything to read fuel trim?

 

He has a Interceptor it says in his post

Set it to O2 mv and tell us what that says when WOT. Im sure its way rich tho.

 

What target mv do you hope to see on a narrowband, Nick?

 

intercooler pump....

 

over 900, Im sure it will be richer then that but its always good to make sure it is going rich. Ive seen a couple cars that came and were lean on factory tunes. Not sure if it was a certain intake or what.

 

I found a table, that's why I was wondering. It shows .875 for NA and .900 mv for blown. Sorry for the threadjack.

 

IIRC:

(O2 mv/1000)+10=AFR

 

what should the fuel trims be reading?

 

Zero ideally. 0- -2 are good numbers.

 

This needs to be clarified a little....

At WOT you want your long term fuel trims to be as close to zero as possible. While you are crusing you will see some fluctuation in the long term trims (more with short term trims). Many things can affect your fuel trims on a day to day basis so don't get too crazy over small changes.

 

Your long trims and short trims are going to 0 out when in WOT since it goes into open loop... So they could be 0'd out and you still could be running rich/lean... WB gauge is the only way to see how your car is fueling.

 

Long terms do not zero out at WOT (unless tuned that precisely). Your short term trims will/should always though. The short term are the trims affected by open loop.

My long term fuel trims are usually +/- 1.5 at WOT.

 

Yea, they don't 0 but they stay pretty minimal.

You're just looking to see they aren't 15-20% mainly, obviously it won't be dead on like it should without a tune.

 

This.

If they peg 15-20% +/- they will set a rich/lean code (usually).

 

Hmmm.. No matter if I just started a tune or finished the LTFT's near 0 part throttle or WOT. I dont think I have even seen it over 1%...