what is the most I should run for a timing advance if I don't wanna change from 87 octane? I mean I was thinking of 14 degrees but I am just a little worried that might be a bit much with 87 octane..
It all depends on the car, my friend. However, I highly doubt you will get away with regular in an SN95 5.0. We are notorious for our poor cooling abilities and detonation problems.
If you run 14* of base timing, then you will need to run 91 octane, without a doubt. Otherwise you will detonate. Here is the real test. Fill up w/ 91, set it to 14*, and take it out for a spin. Run the car in 2nd & 3rd gear all the way to 5000 rpm's @ WOT. If it doesn't detonate, bump it to 15*. Repeat the test drive. 16* is about the highest you will get w/o detonation.
If it's warm out, you might not get away w/ 15-16. I would try 14* and leave it there if it doens't ping. That seems to be the best timing to run with the most gains. If you advance it too much, you will lose power.
Scott
You do get to a point of diminishing returns on the timing. I think our max torque is somewhere around 4° advanced globally, but it depends on the load and rpm, some rpm will take more timing than others. Usually at the peak torque, it won't take as much as in the lower rpms and high rpms.
Im haveing alot of the same problem.
I think I went down to 12 and still detonate.. Im going to check in to it next week and see whats up I cant remember what I set it to last time. Im still getting detonation at 92octain...