What is a good number to shoot for when tuning for performance? I am seeing about 14.7 to 15.4 at wide open throttle. I know this is lean but what should I be shooting for. This car will be on the bottle with a 150 shot. Thanks, BranZ

cease and desist. that is way too lean. 14.7 i believe to be the magic number where all the gas and air makes for a clean burn. call stoich. with 10% ethanol i believe it is closer to 14.3. E85 a much small number due to the ethanol providing more 02 during combustion. so for cruising or closed loop i am set up for 14.3 and do not use lean cruise mode. i will guess the stock WOT or PE in older GM bins was at 12.5/1 as that is what my startup bin was set too assuming it was a virgin .bin. i run at 12.7/1 commanded in .bin for PE. if i added N02 i would probably start PE in .bin at 12.0/1 and run a fat mixture as far as the N02 jet. Not sure what A/F should be on a hit of nitrous? possibly newer LS GM tunes are leaner for PE. not sure.

i assume your WB02 is calibrated to free air and accurrate.

Also, I believe the richer PE mixture provides cooling in combustion chamber to disallow detonation.

yeah. too lean. mine's at 13.0 for PE