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Nice work on collecting data to show the difference in ignition timing when using 87 octane vice 93 octane. Definitely turn traction control off to eliminate the potential for the engine to cut back on power when tire slip is detected. With the cold weather, breaking traction will likely be the norm and not the exception.
You are able to pull data from the knock sensors (Knock Correction Learn Value [KCLV] and Knock Feedback Value [KFV]) but AFAIK it can only be done from one of two methods:
1) Techstream
2) The OBD Fusion app with the Toyota/Lexus Enhanced Diagnostics add-ons.
Tracking these values will give you additional information on how the ECU is responding to the lower octane fuel (For KCLV, a value of 20+ means ignition timing advance is functioning at its peak).
Thanks.
yeah, sadly that data is unavailable to my puny blue driver obd2 reader. But I figured, that the timing is gonna be where those KCLV and KFV corrections will “end up” anyway.
With enough boost pressure you will only get exactly one knock.... before the engine eats itself.
Aka terminal boost pressure )
Had a couple knocks on a super charged fox body and one big fireball out of the turbo on an evo 8 do to pre-det before the valve closed. Had a 289 that was backfiring out of carb due to the timing being off about 30 degrees. That was a fun moment, buddy lost some hair haha
Had another run while still being on 93 e10, but this time with TC off.
high rpm TC ON avg timing was - 24
high rpm TC OFF avg timing was - 27
low rpm TC ON avg timing was - 15
low rpm TC OFF avg timing was - 16
Basically, there wasn't much difference and the ECU was again cutting the timing, although not that severely and not that many times.. Overall, readings were a bit more consistent with TC OFF, I think. I might do another test with e0 91, instead of e10 93 (TC OFF, of course)
12-10-18, 01:00 PM
