Fuel octane is as mentioned resistance to the fuel burning. Higher octane fuel burns slower.
I run 9.5:1 CR with 10.5psi of boost on 93 octane everyday. I boost on hot, cold, ect days with no problems. Basically, when you encounter detonation on a certian grade of fuel, you can do these things:
1) Lower the compression ratio
2) Run higher octane fuel
3) Retard timing
4) Cool the intake charge better(AKA alky/water injection)
Water/alky injection is a very good solution to running expensive racing gas while still having the power of it.
And as jekylandhyde was touching on:
Quote:
|
Seriously though, cars run best on the lowest octane they can get away with without seeing detonation. Octane is a fuels resistance to blowing up ... you want it to explode! That's what makes power. If it is too ready to explode it will ignite when it shouldn't (knock/detonation) so you need a higher oct.
|
IMO you should run a known safe octane fuel/AF ratio and play with timing to get maximum power. BTW, if you end up having to retard timing lower than 20* Total timing BTDC, you should seriously consider #1, #2, or #4 that I listed above. WI/AI is what I would recommend.
We over on the KA-T boards tend to stay away from anything past 18:1 dynamic CR on pump gas. We end up running insanely low total timing and it is just not in any way better to run more boost with less timing.
And on every grade of fuel, there is a knock limit. Or "the maximum and mean cylinder pressures that can be achieved,"
SDSEFI Tech: Pushing it too far.
Very good read on everything engine destruction related.