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Old 10-08-2008, 01:11 PM   #20 (permalink)
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Join Date: Jun 2008
Location: Northwest Lower Michigan
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Red Car - '89 Chevrolet Celebrity CL 4 door
Team Chevy
90 day: 36.47 mpg (US)

Winter Wagon - '89 Pontiac 6000 LE Wagon
90 day: 28.26 mpg (US)
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Originally Posted by metromizer View Post
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.
When I used to tow with the 6000 wagon, I would make it a point to put in 93 octane because it gave more power as well as reduced pinging. It made a difference without towing too, on the large hills that are on my way to and from work, but I would just use 87 usually because I didnt really need the power that bad. But the engine also had well over 200k on it. I figured that the added octane wont really give you more power than stock, but it will help compensate for the loss of power in a well worn high mileage engine.

Earlier this year I tried 93 octane for a few downstate tanks in the Celeb. I noticed no difference in mpg.

Winter daily driver, parked most days right now

Summer daily driver
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