Originally Posted by DarkZ
I just got my 08 Z06.
I previously had an 08 C6 w/LS3.
I installed my predator to do some custom tuning and notice that the Z06 @ WOT had a 12.6 Air fuel ratio.
Is this air fuel ratio set from the factory?
On my C6 LS3 it was 11.7 from the factory @ WOT.
I added fuel and got it down to around 12.3@WOT.
Wanting to know if 12.6 was the original tune from factory.
For one the predator is not the best tool to be getting facts.
That is a commanded AFR, not a true AFR.
Since GM is forced to warranty the CATs for 8 years by EPA law and depending on the run done, weather, and gas used the PCM could have been doing COT, which dumps in extra fuel to cool the CATs down to protect them
Other run can be done and happens at that time COT was not commanded on so AFR would look different
Also if E10 gas is used or not requires a richer/leaner AFR throughout RPM range.
AFR has to be tuned as to mods the car has, the elevation, type of gas used and if the CATs are installed or not.
Car at sealevel in 90 degree weather needs a totally different AFR then a car at 6,000 feet and 65 degree weather