I was told by esr to run half race gas half premium in my 250r, i was wondering two things, is it ok to run aviation gas fromt he airport instead of race gas, and if not, where do i get high octane race gas?

 

Why do you need to run such high octane? How much compression do you have. It seems to me that many people think that running higher octane fuels makes them faster but in fact slows you down unless your motor requires the octane to prevent detonation. If they think you only need premium 50/50 with race fuel you are probably only in need of around a 100 octane. I would not go any higher than what they recommend unless you just like to spend money.

 

go to vpracingfuels.com and locate your region. Email them and they will give you the closest dealer. I would just go to the closest speed shop and ask them where they buy there fuel.

 

i agree on saving money, but they said run that and they know what they did to my engine, and esr knows what they are talking about usually, ill check into that website, thanx for the help

 

Run race fuel and premium not Aviation fuel, which is for high altitudes and different conditions than here on earth!

 

if you go with the cheaper avaition fuel, you'll need to run a top lube I have heard, or at least mix a little marvel mys. oil, some people do, but results are still out, best bet is to run a decent race grade or alky.

 

there are alot of people who believe av fuel is bad or not as good. I dont know for sure,but If they run it in a turbo charged 12 cylinder I think It will be ok in a quad but I would just spend the extra buck and buy normal race fuel.

 

Aviation gasoline or "av gas", is blended specifically for use in small aircraft. It's also commonly used by many high performance engine owners because of it's high stated octane rating (usually 100-110) and the relatively low price compared to racing fuel. Unfortunately this fuel is not all it appears to be. Avgas octane is rated on a different scale than gasoline's intended for ground level use. What is 100 octane "av", is not necessarily 100 octane "ground level". Besides this, there is also a big chemical difference. Normal ground level race fuels are made up of gas molecules that have a "light end" and a "heavy end". The light end of the molecule ignites easily and burns quickly with a low temperature flame (as a piece of thin newspaper would burn). The heavy end of the molecule is not so easily ignited, but it burns with a much more intense heat (as an oak log would). This heavy end of the gasoline molecule is responsible for the hotter, more powerful part of the combustion process.

Small aircraft are constructed as very weight conscious vehicles. That's because their somewhat weak engines often have difficulty taking off with any extra weight. To help reduce this weight problem, aviation gasoline's are blended with no heavy molecule end. This makes a gallon of avgas weigh substantially less than a gallon of ground level fuel. Since small plane engines turn very low rpms and produce so little power, the omission of the heavy end is not a horsepower issue. However, for high output MX racing engines, there is defiantly a compromise in power. This, despite the fact that many mx owners experience the desirable cooler operating temperatures that avgas offers. In addition, some blends of avgas will quickly separate from some oils used in premix situations.

Despite all this bad news, running avgas (accepting the slight power loss) is usually a better choice than burning down a high output engine on regular pump gas. In this situation, the best choice is usually a 50/50 mix of pump and avgas. That provides "some" heavy molecule ends for the engine.

 

Do a search alot of people run it in drag cars they can tell you the pros and cons. There are different kinds of av gas some are like 130 octane. I know some guys that run on it. If you run av gas and tune to run on it you will be fine but if you tune for race gas and run av you can run into trouble. Jetting plays a huge part.