I know you can use E85 in a regular engine for the most part that works with regular gas as well but the problem is it isn't optimized for E85 so you get a lot less performance than you could. Since E85 has a much higher octane level, it is capable of being used in engines with much higher compression ratios. As of now, it seems 10.5:1 is the limit for 87 octane gas with Premium showing gains in the same engine. Now anything more than that and 87 should detonate which is very bad. So if you increase compression ratio to like 13:1 and use exclusively E85, you're fine, but soon as you go to regular gasoline you'll probably detonate pretty badly...

Now here comes the question, would an engine with a Compression ratio of 13:1 detonate if running on regular gasoline BUT you have the car in a limp like mode where it retards the timing significantly, and I think squirts a LOT of fuel or very little fuel into the combustion chamber so in the event you can't get E85, you can at least limp the vehicle along? In its default configuration at 13:1, would the engine detonate at idle? Or like 1500rpm 100% load or something? This is opposed to high load high rpm operation.