Do GSXR's like Av Gas??

[inlinefour]

Have not found a motor that run really well for a shortish time on avgas. Killed t it though

[speedpro]

More energy can be liberated from fuel if it is compressed prior to ignition. More compression = more power. Unfortunately there is a limit, beyond which detonation destroys the engine. Some fuels resist detonation more than others. In order they would be 91 - 100 - methanol. 100 octane may burn slower than 91 but that isn't the factor that's important as it is a miniscule differance. The important point is that 100 octane, and more so methanol, resist detonation more than 91 octane and this allows higher compression.

The whole process is compression, ignition-flame front moving away from the plug across the chamber, pressure and temperature rising. If the temp and pressure rise enough before the flame front consumes all the fuel it is possible that the remaining fuel could spontaneously ignite. That is detonation and it causes a very 'sharp' increase in combustion chamber pressure and temp.

There's lots more to it, like the chemical changes that occur to the fuel as the pressure and temperature rise and the resultant changes in burn characteristics. One point that a lot of people missed with the change to unleaded is that although the old 96 octane fuel had benzene in it, that benzene didn't make it out the exhaust pipe. The new ULP doesn't have benzene in it but a by-product of burning it is benzene. Unless vehicles using it have a (working) catalytic converter that benzene goes out the exhaust. Benzene is highly carcinogenic.

Geez I hope that's right. Could someone please let me know if I got it wrong.

[DEATH_INC.]

You WILL get a reduction in power with higher octane fuel IF your engine doesn't need it.It may only be points of a hp but it will be there.The psychological benefits may outweigh this however,so just keep on putting it in if you must......
It does burn slower(do a search for info,it's out there),so think about it,the piston has travelled further down the bore before complete combustion,so you don't get maximun pressure.
If you want an easy power increase go with oxygenated race fuel....