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OK I'm still working on the dealer before I sign on the dotted line..... but i was curious to know what kind of gas everyone is running. The dealer says the 05 GTO needs 93 octane. Right now I have an 04 Dodge Ram with the HEMI and I was specifically told I should not put 93 in it. It will run fine on 87 and I usually put 89 in it. But at $2.00 a gallon and even higher in some places, does the LS2 really need it ? I realize it may not make 400 ponies on 87 or 89, but is anyone running that octane without any problems ?

Thanks

Joe
 

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I switched to 87 for a while to see how my 04 auto ran. Personally, didn't notice a performance difference. The one thing I quickly noticed was my gas mileage. On average with premium, I can usually get 17.5 miles to the gallon. With 87 octane, I was losing at least a mile to the gallon.

So at the end of the day, it was costing me about the same. So I am stictly running premium now.
 

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112-116 leaded octane, for my old gto. Live 13 miles from Sears Point where they have 112, 116, and 118 leaded on pump.

For my new gto, 91 octane only. I also will use only 76, sunoco, or mobil gas in the car.
 

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I had a cadillac service advisor recommend reg even though cadillac said hi test. I have run reg in an accura and a vette and noticed no difference or pinging. I'm in Florida and he said gas was reformulated in the south. I heard lincoln dealers were telling ther people the same. This was in 1997. My friend just started running reg in his olds which also was supposed to run hi test no problem. He said above georgia to run hi test.
 

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I've done extensive testing of different octanes since I got my GTO last year. Nothing truly scientific, mind you, but enough to satisfy me. Basically, I couldn't really tell the difference in performance between 87, 89, and 93. But I definitely found a difference in mileage. I get the worst mileage, 17ish, with 93, 18ish with 87, and 19ish with 89. I also found that 87 will cause some knocking when I initially start the car, that doesn't happen to me with either 89 or 93.

So really only use 89 now as I get the same seat-of-the-pants performance as 93, the best mileage of the three, and it's a good comprimise in price between 93 and 89.

Hope that helps yoU!
 

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I put 93 in my 05. the car's computer says i get 18.9mpg. the owner's manual says the car will run on 89 or 87 octane, but power and mileage will be less (i'm assuming the car's computer detects the detonation and retards the timing to compensate for the lower octane gas). bottom line, if you're spending $30k+ for a new car, and you want the full 400hp, spend the extra 30 cents per gallon and put in 93 octane.
 
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