91 octane?

goofy · Nov 6, 2009

I have always ran 91 octane in my revs and rt, but was talking to a well known engine builder and said because of running at 8-10,000 feet there is no need for 91 octane and actually you will get more horse power out of med grade? do any of you believe this or is he full of sh**?

DaveB · Nov 6, 2009

True story. One of my buddies used to fill his sled with farm 87 octane all the time and his engine always seemed to out pull the rest of us with the exact same sled....at elevation. On the trail in and out he had to baby it to avoid deto.

onlyrotax · Nov 6, 2009

I don't know about the horsepower thing but here in the Black Hills our unleaded regular is only 85 octane, I used to use it but I was always having problems getting our sleds started after they were hot, since I switched to 91 octane the hot starting problems have disappeared. When we go to the other side of the state and fill up our Tahoe with 87 octane I can really notice the difference in power and the "pinging" is gone too.

kodpkd · Nov 6, 2009

goofy said:
I have always ran 91 octane in my revs and rt, but was talking to a well known engine builder and said because of running at 8-10,000 feet there is no need for 91 octane and actually you will get more horse power out of med grade? do any of you believe this or is he full of sh**?

Your "well known" engine builder is smart... The most power is from the lowest oct rating without pinging.. Higher oct,,, has less power... The reason the higher oct,,,,, is only to stop the detonation, not for more power... Go back to him and listen...

High Voltage · Nov 6, 2009

I would stay away from any ethanol fuel, which alot of lower octane gas pumps have.

jpxp154 · Nov 6, 2009

true. but its kind of hard to baby it at lower elevation well for me it is

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91 octane?

goofy

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DaveB

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onlyrotax

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kodpkd

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High Voltage

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jpxp154

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