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Old 03-16-2010, 06:16 PM   #6 (permalink)
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Originally Posted by thatguitarguy View Post
It doesn't make sense to spend more money on higher octame fuel if your engine is not knocking, and definitely not if the manufacturer calls for lower octane.
Um, generally fully functional OBDII cars cannot knock (at least not detectably to the driver)

If you have a timing guage and tap on an OBDII motor with a ballpean hammer lightly the timing retards rapidly.

So higher octane "May" improve some factor of performance, my Buick for example running hi test in the winter has its FE restored to summertime levels but the effect doesn't pass into the summer sadly. Also the additional cost exceeds the gain most of the time.

But I can't say hi octane is not beneficial in some circumstances, Ever try to run an older Smartcar on 87 octane ethanol? It is well rather craptaskic.

Also my Dodge gets BETTER FE running 100+ octane e85 mixed 50/50 with 89 octane e10 in the winter (again effect does not seem to translate into warmer weather)

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