What Octane Fuel Should I Run?

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Junior Member
I own a B18C6 engine (Euro Spec Integra Type R 1998) and the head's chambers have been welded and then cloverleaf shaped. The compression has been increased from 11.1 to 11.5. This is a slight increase, but the knock sensor is retarding my ignition and I lost lot's of power.

The local gas varies between 89 and 92 octane. When I added some octane booster the car's power on the dyno increased by 22 bhp at the flywheel!!

What would be the best octane petrol to run in my car so as to maximise power. I don't want to add too much octane booster and end up with unburned fuel and backfires.

Tnx :eek:
I don't know if this is right, but if your engine is a Euro-spec type-R, I would run the hightest octane available at your local pump (92 octane most likely) because the car was probably running higher octane in Europe. When I was back in France the octane levels were 93, 95 and 98 if I remember correctly, the 89 octane-gas here in the states might be too low.
But then again I could be wrong...
Sounds to me like he's still in Europe somewhere. We don't call it petrol stateside. :lol:

Run the highest octane you can get- although 92 should be fine for that compression ratio.