I plan on running 11-13 psi on my 87 turbo w/ intercooler, 180 thermo and rebuilt heads and had a few questions. first, is there any way to run 89 octane with this setup? Second, does advancing the timing past 20 degrees BTDC to say maybe 25 degrees BTDC make the upper RPM power decrease. I seem to recall hearing that advancing the timing boosts low end at the sacrifice of top end. I was wondering if this is true.

At that high of boost, if you advance your timing you will probably experience pinging, same goes for running 89 octane.

 

depending on how things turn out, you may even end up having to retard your timing a little to avoid detonation. probably not, but it is possible