I find it funny when people complain about the "high" cost of premium vs regular gas. Back when regular was 1.00, premium was 1.20(a 20% premium) now the price is 3.00 for regular and premium is 3.20(in Atlanta). Thus the difference(~6.5%) is much less and premium is a no brainer.

 

Luckily, virtually any motor made since otto started has variable timing...

Better still, most cars with computers have timing maps that use the knock sensor to set the upper timing limit. Basically anything since OBDII (1996). The only way to damage a motor like ours is to run low octane in the heat at high load. That can put the timing too high for the motor to retard enough.

 

If you can't afford to run premium you shouldn't buy an S2000. Knock sensors are great, but keep one thing in mind - they only work after knock has been detected. Running regular in an 11:1 compression engine is pennywise and a pound foolish.

 

Interesting.

It varies according to the octane I put in? Or does it stay with the same map until it detects knock. I thought people were adjusting timing on dynos when they changed things like octane. I didn't know the computer was adjusting as advanced as it can go to find the knock each time it was started.

Shy_guy mentioned the speed of fuel burn changing from octane to octane. If you load the motor with low octane you will knock and the OBDII will retard the timing. If the motor isn't loaded the OBDII computer will return to base timing on the low octane, detect no knock, and continue to have max cyclinder pressure sooner in the crank's rotation than the engineers designed. Giving you slightly more wear and tear and less efficiency. At least that is how I understand timing's ability to adjust to octane.