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i was just reading the owners manual, and it says "your engine is designed to meet all emissions regulations and provide excellent fule economy and performance when using high quality unleaded gasoline having an octane rating of 91. The purchase of higher octane is not recommended".... now up here in RI, i have been getting 94 octane from sunoco.... that isn't bad right? why would they not recommend you go higher then 91 octane.... that doesn't make any sense to me.... :?:
 

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I'm trying to find 91 oct here in my area. They are all 93 so far. I wonder if I even feel any difference anyway.

Up the boost + 93 (or 94) oct. = better??? :?:
 

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What they mean is you do not need any octane higher than that for the car to perform as designed. They started saying higher not recommended so folks wouldn't buy into the crap that higher octane ($$$) means better performance.
I know idiots putting 91-94 octane is Ford Escorts. Those engines don't need it.
My 89 & 99 Blazers get 87 octane, the GLHS and SRT-4 get 93 (91 not sold here) .
 

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I didn't think octane had anything to do with power. Higher octane means the gas is more stable and less likely to spontaneously combust during the cylinder compression stroke (knocking, bad). Higher octane gas is not needed in most everyday cars because their engine compression ratios aren't high enough to cause lower octane gas to spontaneously combust.

High performance cars typically have higher compression engines and therefore need higher octane gas to prevent knocking. Turbos also increase the compression occuring in the cylinder so also need higher octane.

If you aren't running higher boost than factory, you don't need higher than 91. If you use higher, you won't get anything out of it except less cash in your pocket.

Now add a boost controller and up the boost and you may want higher octane gas just in case.

Anyway, that's what I understand octane to mean.
 

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Correct!!!! Underpants wins the gas knowledge award. For next week, check in for our tires question. Any doubters, take three minutes to do a search on octane.
 
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