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Old 07-28-2008, 06:16 PM   #15 (permalink)
Master EcoModder
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I have seen octane make a difference while towing. With higher octane I get a little better FE if the weather is over 85 degrees. I think my '88 Ford does a poor job of adjusting the timing for hot weather, it senses detonation and pull sout 10 degrees or something, and really runs bad. The ECU might be dumping in 10% more fuel as to cool things off, as well? So on that particular vehicle, it makes a difference.

Just know that higher octane gasoline has the same BTUs as lower octane gas. Higher octane than required will actually reduce engine power.
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