i run nothing less than 91 in mine my book says to use premium only higher octane is better if it wasnt then unleaded would cost more [img]i/expressions/face-icon-small-wink.gif[/img]

 

I always just run the highest octane they have. Usually "nonoxygenated" though I don't know what difference it makes. I just have been told that it is better for it so that is what I put in it.

Ryan

 

I just checked the book for my rappy 350 and it said to run anything from 86 octane up, so i guess some of my VP 120+ race fuel will work wonders

 

Its only $13 a gallon from where i get it.

 

WHERE THE HECK DO YOU LIVE?

 

Ok guys, waste your money. If you dont choose to believe that an engine makes peak power running on the lowest octane on which it does not ping, then you go ahead and shell out money for higher octane gasoline.

 

I agree. I can't beleive how many people waste their money on high octane fuels when their machine doesn't need it. It also makes the machine harder to start in cold temps.

 

I am quite curious why would a high octane number fuel cause hard starting ? It make a lot of sense from the financial standpoint alone to run the cheapest fuel you can purchase that does not cause detonation .

gman

 

You are 100% correct.

My reasoning for running 91 throught the wolverine is this: It has pinged before (knocked) on 87. That is the day I switched. There was no power incerease or fuel milage decrease. Just almost certanty I will not fry my piston.

Running VP or anything above 91 is a waste. There is such little compression in the combustion chamber to cause pre detination.

Higher octane fuel as stated above, is just plain hard to fire. Here is an example:
I drive Jeeps. Bother have low compression pistons. One is carbed, the other is FI. I will always run 87 in them. Why? They are low compression engines. But I have run 91 in each before. The YJs economy went from 12mpg to 8mpg, and the Rubi went from 16mpg to 13mpg.
However, in hi-compression engines sometimes 91 is not enough to stop pinging. Example is our 68 Camaro. The BB will ping under load with 91. Stick octane booster and it is not so bad. Run VP and it purrs like a kitten.

I am not sure what the wolverines compression ratio is, but I will always run 91 through it. Nothing more, but possibly 89 (when in Colorado).

 

The octane rating refers to the fuels ability to resist ignition. The higher the octane rating, the harder it is to ignite. The higher octane fuels are necessary to resist auto-igniton (pinging or knocking) before the spark from the plug ignites the mixture. In a cold engine(like our canadian winters)you need a mixture which is easy to ignite. I admit the difference (for starting) is very slight and/or undetectable in most situations.