87 vs 93 octane tune
11-22-2006, 08:01 PM
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87 vs 93 octane tune
can anyone post a finely tuned fuel and spark graph for an 87 vs 93 octane tune for me to compare or give a good generalized adjustment for both to make a performance tune "10% spark 2% fuel" something along those lines
Last edited by Paul94Z; 11-22-2006 at 08:06 PM.
11-23-2006, 02:27 AM
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Car: 91 GTA, 91 Formula, 89 TTA
Engine: all 225+ RWHP
Transmission: all OD
Axle/Gears: Always the good ones
No general guidelines that I have found.
Some I have found its not worth the waste of time. Backing off to run the 87 would cause the mileage to come down 1-2mpg which would pay for the extra 20 cents a gallon to run premium in the first place.
Seems to me that the overall combustion chamber design is the biggest factor. If its modern quick burning type it dramtically impacts detonation tolerances. In that aspect your 94 LT1 would be good as would vortec heads, but not so much the L98 head and its older design.
WOT timing I have only tended to end up pulling 1-2 degrees from premium but found that at the part throttle/tip in point I had to roll a lot more timing out quicky to keep it out of detonation.
Anything to do with getting colder air into the engine and running decent T-stat and fan temps: ie 180 t stat, and along those lines will help as well.
Just what I have found in my musings.
later
Jeremy
Some I have found its not worth the waste of time. Backing off to run the 87 would cause the mileage to come down 1-2mpg which would pay for the extra 20 cents a gallon to run premium in the first place.
Seems to me that the overall combustion chamber design is the biggest factor. If its modern quick burning type it dramtically impacts detonation tolerances. In that aspect your 94 LT1 would be good as would vortec heads, but not so much the L98 head and its older design.
WOT timing I have only tended to end up pulling 1-2 degrees from premium but found that at the part throttle/tip in point I had to roll a lot more timing out quicky to keep it out of detonation.
Anything to do with getting colder air into the engine and running decent T-stat and fan temps: ie 180 t stat, and along those lines will help as well.
Just what I have found in my musings.
later
Jeremy
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