roadtalontsi

e85 is closer to 110 octane with better cooling properties. The reason you dont notice a difference is it's not tuned for it. With e85 you can add more timing without detonation past the point of max. brake torque. - meaning the engine is no longer producing any extra power. e85 is not bad for high performance engines just requires more constant oil changes and better care when storing. I've ran some 100 octane unleaded in my car and it made a noticeable difference - i have a blower though. The detonation threshold on a 11.3:1 engine doesnt leave much room for errors in the timing department. You can actually make more torque on e85 than on race gas. race gas 8$-30$/gal vs 3$/gal e85. true e98 is only about 7$/gal much higher quality but no other advantage octane wise. E85 is a great thing - but only in the right context. Which means it has no business in a car not designed to use it... like the c63. however e10 isnt going to hurt anything. Dont get me started on afr's. They are a generalization. rich would be considered anything more than 14.7:1 which any engine runs "rich" when used performance wise. Stoich is only for fuel economy and emissions. sure turbo cars run richer but what does that really have to do with anything. As for the other question some asked about how is ethanol content determined. You have 2 ways, a flex fuel sensor like gm uses, or by lambda which is benz uses in certain cars. E85 requires about 30% more fuel from the less btu's as mentioned above. Now the trick question if your car isn't setup for e85/flex fuel with a flex fuel sensor or lambda tuning how does it know? It doesnt and thats why you dont put it in a car that was designed for it without the proper tuning.

aussie e55

thanks guys for all your replies i think i will play it safe & stick to non ethanol fuel.