What kind of fuel should I use in my UTV?

A common question on Side-by-Side forums is, “Can I run race gas?” or “If I run race gas will it give me more power?” With so many riders looking to get as much power as possible from their engines, race gas or high octane fuel seems like an obvious choice. But does it actually make a difference?

What kind of fuel can I run in my UTV?

You should run what ever fuel the manufacture recommends. According to Polaris, most of their off-road vehicles should run 87 octane while the RZR Turbo and Pro XP models require 91 octane. They also warn not to use fuel with more the 10% ethanol. For the Maverick, Can-am states a minimum 87 octane but 91 is recommended. They also advise against using more than 10% ethanol fuel. Other manufactures fall in this range as well. If you’re unsure what to run in your stock UTV, consult the owners manual or ask the dealer.

What is a fuel octane rating?

To understand how high and low octane fuels effect an engine, it’s important to understand how an engine works and what the octane rating means. In an internal combustion engine, fuel in the engine is ignited by a spark plug and the ignition of the fuel and oxygen inside the combustion chamber forces the piston down. The rate at which the fuel burns is very important. If it burns too fast, detonation inside the combustion chamber can occur. Detonation can be very damaging to an engine. The burn rate of gas is effected by several factors such as heat inside the combustion chamber, ignition timing and the amount of compression inside the engine. The octane rating determines the rate of burn and the anti detonation properties of the fuel. It is important to have the octane rating matched to your engine.

What happens when you use lower octane fuel than your engine needs?

If you use fuel in your Side-by-Side that is lower than the required octane rating of the engine, serious engine damage can occur. Using a low octane fuel can cause detonation inside the combustion chamber which is basically shockwaves inside the engine. These shockwaves are very damaging and can destroy pistons.

If you have a high performance engine you might need to run high octane fuel like premium or even race gas. The engine builder or company that did the work on your engine will tell you what fuel you should be running.

A turbocharged engine will require 91 octane or higher. If your Side-by-Side has a factory turbo consult the owners manual for the correct octane. If you have an aftermarket turbo kit contact the manufacture of the kit.

What happens if you use high octane fuel when you don’t need it?

Using a higher octane fuel than your engine needs will not improve horsepower. In some cases it can cause worse performance due to inefficient combustion. Using premium in an engine that recommends regular will also have no effect. Run whatever type of fuel and octane rating the manufacture recommends. The only thing you will do is lighten your wallet buy running higher octane gas than your engine needs.

Some people believe high octane gas lasts longer than lower octane gas. This is not true. It is possible for certain blends of gas to have different additives that may increase shelf life but octane rating alone does not make gas last longer.

Can I run race gas in my UTV?

Race gas in a stock UTV engine will not make it any more power. Unless you have a high performance engine with high compression or advanced timing there is no need to run race gas. Considering how expensive it is and the lack of engine performance, race gas has no place being used in a stock engine.

Using too high of an octane can cause poor throttle response and leave left over fuel deposits in the engine and exhaust. It can also foul your spark plugs.

Even mildly modified UTVs usually don’t need a higher octane fuel. An aftermarket exhaust or intake won’t require your machine to run anything more than the manufactures recommended octane.

The exception is if your vehicle has an ECU tuner. While this isn’t considered an extreme modification, most ECU tuners require 91 octane on their high power levels, but not race gas.

What engine UTV engine modifications require higher octane fuel?

While a stock engine won’t run better with premium or race gas, engines with certain modifications may require more than 87 octane. ECU tuners may require 91 octane or higher since they usually advance ignition timing to improve engine performance. Big bore kits and engine performance kits that include high compression pistons might also require at least premium gas. Turbo kits will require more than regular pump gas because the increased compression requires higher octane fuel. Most kits recommend 91 or higher octane.

Can I use gas with ethanol (E10) in my UTV?

Most likely you have been running E10 in your UVT unless you happen to live near a gas station that serves ethanol-free gas. Check out pure-gas.org/ to find ethanol free gas stations in your state.

E10 fuel is gas that has 1 part ethanol to 10 parts gasoline, meaning 10% ethanol. Most pump gas is now E10, or even higher in the midwest. Most UTV manufactures advise against running fuel with a higher concentration than 10% ethanol. E10 is the most ethanol they recommend.

One of the disadvantages of ethanol gas is that it attracts and bonds to water in the air. Ethanol will pull water vapor from the air. If you store ethanol gas it should be in a tank or container that is full and tightly sealed. The more air in the fuel container, the more likely water vapor is to be drawn into the gasoline.

Can I use Av gas in my UTV?

You should not use Av gas (aviation fuel) in a UTV. Av gas is made for low rpm aircraft engines not high revving UTV engines. AV gas also contains lead which is damaging to catalytic converters and oxygen sensors. Leaded fuel can leave lead deposits inside the engine.

Aircraft engines are very different from those found in a Side-by-Side and therefore require a much different type of fuel.

How to properly store gas for your UTV

To get the most out of your gas and achieve a longer shelf life there a few simple tips:

  • Whether in a gas can or gas tank, keep the container tightly sealed.
  • Make sure the container is as full as possible. The less air the lower the chances of condensation.
  • Store gas in area the doesn’t experience extreme temperature fluctuations.
  • Use a metal container or opaque plastic one to prevent contact from the sun’s UV rays.
  • Use fuel stabilizer when storing gas for long periods of time.