Quote Originally Posted by PMK View Post
If a true comparison of octane were to happen, it can not be on a tank to tank fill up. Rather it would require say 100 miles on one fuel, then after completely purging the system with the next fuel, again, allow the engine computer say 100 miles to optimize the parameters. The entire tuning process can be very complicated.
All the best and hopefully the applicable items will carry over to your daily driver, or the Aston Martin.
Refer to my post #143 above. My experience over two summers is probably as close to an objective comparison as you'll be able to find in the SL world. It shows that as far as MPG is concerned there is no practical difference between regular and premium. This makes sense when you consider that both octanes have virtually identical energy content. My original discussion is here: https://www.spyderlovers.com/forums/...remium+mileage.

I have not seen anyone post photos of two engine tear downs, one that ran only 87 octane and one that ran only 91 octane. Until we see what the engine internal condition is like for the two octanes we cannot definitely state that 87 octane harms the engine. I don't recall anyone on here reporting engine damage from using 87 octane. I argue that ROTAX engineers have done a damn good job of designing the Spyder 1330 to be able to tolerate the combustion differences between the two octanes.