are there any fuel regulations in BMW CR? I looked through my semi complete rule book and i didnt see anything about Fuel, in modified im sure your allowed but how about prepared.

The only requirement is that you use the same fuel for which the engine was ORIGINALLY designed by BMW. In other words you can't run nitro-methanol in a gas engine, for example. There are no existing limits on additives or octane rating or a requirement concerning commercial availability.

Andrew what are you looking to do, a higher octane, or another substance?

Please do not use toluene... I knew a guy that died from exposure to it in karting. He was following another kart quite closely for a sprint race, and later that day his throat closed up due to exposure to toluene combustion products... and he died.

Don't do that.

Octane is free ... substance ain't !!! :nono