Quote:
Originally posted by Mudog715
Not necessarily. My Ford 7.5L EFI motor will tolerate 4 degrees of timing advance on 87 octane with no pinging. And the 4 degrees IS noticable. The same for the 1st Gen Lightnings ('93-95), which can tolerate 2 degrees on 87 oct. and 4 deg on midgrade 89. Two degrees doesn't sound like much, but it can add 5-10 hp.
Generally vehicles operated in cooler and/or more humid areas can tolerate more advance before needing premium.
|
True. My race car runs 4 additional degrees of advance in all conditions (110 degree days at Thunderhill Raceway aren't uncommon) and has no problems. But I have tested the car in various conditions to see what I could get away with.
The thing to remember about modern motronics is that it is far more costly on performance to advance timing until you hit a ping then it is to just run a little more conservative. On BMW's I see the ECU pull out 6-8 degress of advance as soon as it senses a knock. So if you advanced the default timing by an extra 4 degrees at a given RPM point and get a ping you will wind up netting negative 2-3 degrees of timing. If you had just played it conservative at 3 degrees of extra advance you would always be ahead of the game.
Doug