Originally Posted by dar02081961

If you saw a 10.58 AFR on stock Z06 you where in COT. COT varies depending on the CAT temps so comparing AFR from one run to the next and drawing conclusions is nearly impossible. This why a good tuner will disable COT while tuning the car. Some turn it back on once they dial the tune in but others do not depending on the owners preference. Point is your differences in AFR are more likely to be from the difference in CAT temps.


You state Z06's run rich from the factory. What is your definition of rich? The Z06 factory target for AFR is 11.9ish for e10 or 12.3ish for pure gas neither of which is considered rich for a supercharged engine. No question you saw a change in the AFR after installing the CAI but the reason and repatibility of the change is in question if you are using 10.58 as you mention as an indicator of what a normal Z06's AFR is.

What AFR did you see after you installed your CAI?

Also the reason you didn't see the CEl is because the CAI only slightly altered the fuel trims. Probably by less than 3-5%. The CEL isnt triggered until way above that. And keep in mind regardless of what the MAF see's or says the car knows exactly how much air its getting. The map sensors constantly tell it so and the PCM is comparing the MAF and MAP a good bit of the time. Point is a small amount of unmetered air (not enough to trigger the CEL) isnt likely to through the AFR far off the commanded target. Again not saying you didn't see different AFR's. Just saying due to COT AFR varies even on a stock car from the factory. If you dont go into COT or you disable COT you will see the addition of a CAI makes only a small change of less than .2ish to the AFR. Which in itself is within the acceptable error margin of the factory MAF sensor.