Originally Posted by BISHILVR
The higher the duty cycle the richer the car will be until the injectors cant keep up anymore due to being maxed out, you need to make sure your wideband is accurate and is recently calibrated first of all, and 10:1 is likely what the stock programming is calling for at your load point! the factory runs the cars rich to protect them from detonation damage, there are ratios in the 9:1 area on the fuel map and sometimes even richer depending on the ecu, so you need to datalog and look at the map before deciding that there is actually a problem AFTER you make sure your wideband is working right.
Wideband is functioning properly, I am sure.
14.4 to 14.7 at idle, cruse AFR is in normal ranges, and WOT AFR goes straight to 10.0, and would not budge, even at higher boost on a T28.
BUT, I installed a Megan Test Pipe and bam, problem solved! WOT at 15ish psi, AFR goes straight to 10.0 and slowly climbed to 10.3, I did 3 pulls with the same result, I never went into higher RPM's because I didn't want to go past 10.4 AFR, I know this could do damage as I am still on 450's. However, with the addition of a Test Pipe, and the freeing of the exhaust, I am now confident that the car is ready for the 560's and blackbox set up. I was very surprised how well the car took to a Test Pipe! I haven't had any really "noticeable" gains from cat deletes in the past, but this car loved it. It was the last of my BPU upgrades, and the car did pull harder after it was on.