It will make you wallet lighter! I have read on here before that running race gas on a stock motor is a waste. The ideal octane is the lowest possible without knocking.

 

4 stroke compression vs octane fuel rating.

9:1 - regular 86/87
11:1 - premium 93/95
12:1 - racing 104/110
13:1 and up - racing 114+

Just the guidelines ive accumulated through research and testing. Feel free to disagree.

 

That seems to be a safe line up.. Heres one example

Vp website:VP RED
A great standard grade of racing fuel. Used in any high compression race engine up to 13:1, off-road racing, marine engines, motocross, karts and personal watercraft.

• Color: Red
• Leaded
• Motor Octane: 105
• Specific Gravity: .730 - .745 at 60° F

I.M.O, 114 on a 13:1 piston may be a little overkill, but you cant be too safe to avoid that terrible knock in the motor or holes in piston...

Maddog56 what comp do you run? Everyone I know thats at 14:1 seems to be running 110. I personally think different motor builds like different kinds of fuels and octane levels, especially in different climates.

 

I've run 93 octane pump gas on 11.5:1 and 12: 1 pistons for years in atv's. I've never had knocking or detonation.

222

 

maddog56, it seems those #s are a good rule of thumb, but the newer motors seem to be drifting away from that. I know the Z400 has a stock CR of 11.3:1 and the recomended octane in 87. I am currious how suzuki achieved that, is it it just timing? or has to do with head design?

 

where i live in michigan, 104, 108, 110, and 114 are all usually about 3-4 bucks a gallon. for that close of a price, i try to run the higher octanes when i have a 12:1+ cr. You could get away with 93 with that compression, but i wouldnt do it if there are other major modifications and/or a lot of wot racing. And face it, if you are running that high of a cr, you did it to beat people. I would never run premium 93 in a built 13:1, but if it works for you, who am i to cut it down.

My current raptor has 11:1, but is getting a 13:1 or so lift over the summer.

 

Maddog, I agree with you... Your right about other mods and WOT.. I just wish I didnt have to pay $8 a gallon, but it is good fuel.