Here in Michigan I run 93 non-ethanol fuel... Here is a run I made on the "good" gas:
Car went 13.78 here in Michigan...
Last weekend I headed to Atco, New Jersey to run the car there... The car should have been noticeably faster than here in Michigan.... instead the car was actually slower! Seems the gas in New Jersey is less than optimal... Check this run from Atco with "bad" gas:
As you can see in the first log, the timing slowly creeps up until it peaks at 36 degrees... there is a dip towards the beginning but that is due to the traction control. So here you can see the computer keeps adding timing...
In the second run you can see that the timing goes up, but not like the first run. It's hard to see but in the second run, instead of the timing going up the spark retard is going up! So here the computer is trying to add timing but my guess is the knock sensors are kicking in! Looks at where this run ends up.. 27 degrees of timing advance with 10 degrees of spark retard... hmmmm.... compare that with the 36 degrees of timing in the first log... that's the difference between 13.7 and 13.9... at least that's how it appears to me! Also appears that the car is going to try and run about 36 to 37 degrees of timing and I can tell you it won't be able to do that on 87 octane!