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Re: Ethanol-laced 91 octane is highest in IA, yes? (archive)

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Posted by SL on November 13, 2000 at 09:19:07:

In Reply to: Ethanol-laced 91 octane is highest in IA, yes? posted by bmv on November 12, 2000 at 13:17:45:

I believe gasohol does slightly aggravate hard-starting problems in low temps but this should only be noticeable in bitter cold weather. Very old cars can have some serious problems with the stuff, but all newer ones are designed so that nothing in your fuel system is going to develop cirrhosis.

Personally, I'd rather run gasohol than something that's below recommended octane. The engine's knock detectors are obviously intended to control pinging well enough that the engine won't suffer major damage in short order from sub-spec fuel (which you can easily buy unwittingly from shady cut-rate stations catering to travelers). The valves will be saved to survive the warranty no matter what. But in the absence of a better explanation, I have to assume knock sensors work by allowing at least *some* potentially harmful pinging to occur especially when the octane is substantially below rec. Else how would it know to give the green flag to the timing computer when you switch back to the "good" stuff?

Neurotic that I am, this octane thing bothers me even more than the ingredients in my wheel cleaner ;-)

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