SUPPOSED TO BE A TIRE BURNER

[Ghoste]

Not being a chemist I have to ask, how so?

[maxwellwedge]

True - The gas will only hurt his wallet.

[Ghoste]

The price part is a for sure, but how does it affect performance negatively in a low compression engine?  Would it not just be a case of of the engine not being able to take advantage of what the high octane can offer?

[Troy]

Not being a chemist I have to ask, how so?

Octane is a detonation inhibitor - ie it makes gas harder to burn.

Troy

[idahogrumpy]

Advance the the cam shaft 4 degrees. Set the timing at 38 degrees total, all in by 3200 rpm. Readjust carb. Do a power run and check plug color, sounds rich to me.  
Grumpy

[Ghoste]

Not being a chemist I have to ask, how so?

Octane is a detonation inhibitor - ie it makes gas harder to burn.

Troy

That makes sense I suppose,  But at what compression ratio does it become detrimental.  I don't have what I consider to be a high squeeze in my car (10.5 to 1) and when I dump a tank of 104 or 110 in the car it makes a difference.  The car even becomes easier to start and idles much smoother.  In fact, you can hear the engine note change when you are driving and the good stuff finally reaches it.

[oldschool]

Not being a chemist I have to ask, how so?

The higher the octane of the fuel the slower it burns.  Anymore octane than required to prevent detination, will slow the combustion process.  As an example, my 580 CI motor has 14.16 cr.  When I put in on the dyno I first tried 116 race gas, the EGT's were very low but air fuel and everything else was good.  I then tried 110, the EGT's went up to where they should be and the motor picked up about 20 hp.