Originally Posted by fastgti69
The fuel allows for tons of advance, but different cars want to see timing at different degrees. Why I have no idea, but these seem to be particularly finicky motors. My E88 wants to see advance and 14 degrees on the dyno wasn't even close to MBT, on the other hand it wasn't happy with a lot of boost midrange. Obviously a single turbo changes the boost end of the equation, but the fundamentals are the same.
Get it on a dyno and see where you stop making power, back off a bit, and that's that. Don't think i've ever seen an N54 push more than 15-16 degrees of advance, regardless of octane. E85 is very, very tough to knock on, which is nice. "