2006 300c advanceing the timing

[brandy16]

I think I read some where that with a 91 cai tune and running 100 octain gas I could advance the timing by 4 degrees. any one know what the rule of thumb is on advancing the timing with higher octain fule. I can get the 100 oct fule at the drag strip when I go out to run.

[Cruisin1966]

Best bet is to do some logging an ensure you don't have any ST/LT knk even with the 91 tune and 100 oct fuel. If no knock, then add 2º across the board and log again. If there isn't any LT and very little (or no) ST knock, then add another 2º.

[DGatzby1]

If you mean four degrees over the 91 octane tune remember, there will some point of diminishing return. The highest timing I have logged with high octane fuel (E-85 100-110 octane - CMR Tune) is about 27 degrees under WOT and that was on a dyno pull. On the road I have seen 25-26 degrees or so, upper RPM range with everything perfect. I believe anything much higher begins to drop performance. Good luck, let us know how it works for you.

[brandy16]

Thanks guys I will try logging first and then if everything is ok I will add 2degrees ect.