Which Fuel is Right

The Four Key Properties of Fuel

Too often, racers focus only on octane when evaluating the quality of a fuel. Octane is certainly important, but it’s just one of several key fuel properties that should be considered when evaluating and selecting a fuel. It’s entirely possible to generate more horsepower with a lower octane fuel if it’s designed properly with respect to its other key properties. It’s also possible for two fuels to have the same octane rating, but perform very differently due to their other key properties.

1. OCTANE: Octane is simply a rating of a fuel’s ability to resist detonation and/or preignition. It is not so much an indication of a fuel’s ability to make power, but rather a fuel’s ability to make power safely, i.e., without blowing your engine. Octane is rated in Research Octane Numbers (RON), Motor Octane Numbers (MON) and Pump Octane Numbers (R+M/2). A Pump Octane Number is the number you see on the yellow decal at gas stations, representing the average of the fuel’s RON and MON. (See below for a more detailed explanation of how octane numbers are derived and what they represent.)

VP relies on MON numbers because the MON test more accurately simulates racing conditions. Don't be fooled by high RON or R+M/2 numbers. Many companies use these simply because they look higher and are easier to come by because of the test methods. Also bear in mind that the ability of fuel to resist detonation is more than just a function of octane.

2. BURNING SPEED: This is the speed at which fuel releases its energy and is partially a function of a fuel’s vaporization qualities. At high RPMs, there is very little time (real time - not crank rotation) for the fuel to release its energy. Peak cylinder pressure should occur around 20˚ ATDC. If the fuel is still burning after this, it’s not contributing to peak cylinder pressure, which is what the rear wheels see. Because VP’s fuels are designed with a particular focus on vaporization characteristics, most of VP’s fuels—oxygenated or nonoxygenated—vaporize much better than comparable competitive fuels. This means it cools the intake charge, burns faster and yields more efficient combustion. As a result, the “effective” octane rating of VP’s fuels is even higher than the octane test indicates, and they will prevent detonation better than competitive fuels with similar MONs.

3. ENERGY VALUE: Energy value is an expression of the potential energy in fuel. The energy value is measured in BTUs per pound, not per gallon. The difference is important as the air/fuel ratio is in weight, not volume. Generally speaking, VP’s fuels measure high in BTUs per pound and thus, have a higher energy value. This higher energy value will have a positive impact on horsepower at any compression ratio or engine speed.

4. COOLING EFFECT: The cooling effect of fuel is related to the heat of vaporization. The higher a fuel’s heat of vaporization, the better its ability to cool the intake mixture. The superior vaporization characteristics of VP’s fuels make cooling effect one of their key advantages. A better cooling effect can generate some horsepower gains in 4-stroke engines and even bigger gains in 2-stroke engines. VP’s superior cooling effect can also ensure circle track racers maintain power in the longest races and harshest conditions. In virtually any application, the cooling effect of VP’s fuels will help extend engine life.

Understanding these key properties of fuel will better equip you to evaluate fuels for your application. By clicking on your application to the right,
you’ll find a list of VP fuels designed with you in mind, along with the fuels’ relevant characteristics.

Leaded/Oxygenated Fuels

U4.4™
If you’re not bound by fuel rules, this leaded fuel is the best choice for virtually any powersports application, offering the biggest gain vs. cost of any performance part you can buy. The latest generation of our U4-based fuels, U4.4 makes up to 6% more power than pump gas across a wider range of applications than its predecessors. It yields no sticky residue and is more resistant to heat. Designed as a direct, pour-in replacement for pump gas, it will require modest jetting changes, i.e., +2 main jets or +2 pilot jets at most. With its higher octane rating, U4.4 is designed for use in stock and modified 2-stroke and 4-stroke applications. U4.4 passes fuel rules for AMA Pro/Am, CCS, WERA, AFM, NMA, WORCS, SCORE and Best in the Desert as well as club level racing and more.

TYPICAL VALUES
•   Color: Light Green
•   Motor Octane: 103
•   Specific Gravity: .763 at 60° F

Tech Tip: When using U4.4, to keep your fuel cool and prevent vapor lock on hot days, e.g. 90 ° or higher, we recommend:

Always go out with a full tank – the more fuel you have the cooler the fuel will stay
Insulate the bottom of your fuel tank:
- line the underside of the tank with heat reflective tape and/or
- install a CV4 Fuel Kool Gas Tank Barrier
It will also help to keep your fuel container wrapped in a RACEPRO “Cool Fuel” Ice Jacket prior to dispensing in your fuel tank.

New! VPR™
VP's latest fuel for 4-stroke powersports applications, VPR, bridges the gap between pump gas and race fuel. The ‘R’ is a nod to ‘riders’ of motorcycles, quads, UTVs, & SXSs that may not require professional grade race fuel, but are looking for performance that is economically practical. Offering 1-2% more power, better throttle response, increased consistency and long-term savings over pump gas, VPR is clearly what your stock (or slightly modified) bike needs. Ethanol-related problems will not be an issue with VPR and you can expect better vaporization, plus a cleaner, more efficient burn than that of street gas. VPR will extend the life of your engine, increase the time between rebuilds and lower your long-term costs, preventing corrosion problems in EFI or carbureted fuel systems in the process.

TYPICAL VALUES
•   Color: Pale Green
•   Motor Octane: 101
•   Specific Gravity: .732 at 60° F

VP113™
Offering substantial power gains at a competitive price, VP113 is oxygenated to street gas levels. Formulated for naturally aspirated engines with CRs up to approximately 14:1. VP113 makes up to 2% more power than competitive 110 octane fuels, with gains of 3-4% in engine applications with poor or marginal fuel vaporization qualities. VP113 burns cooler, ensuring power is maintained throughout the longest races and harshest conditions. May require a tuning change, including increase in jet size for optimum performance.

TYPICAL VALUES
•   Color: Green
•   Motor Octane 109
•   Research Octane: 118
•   R+M/2: 113
•   Specific Gravity: .718 at 60° F

MRX01™
Recommended for 2- and 4-stroke applications. Delivers up to 6% more power than pump gas and any basic nonoxygenated racing fuel. Can be mixed with MR9 to raise octane level for specific applications. Clean burning — leaves intake and exhaust valves virtually free of deposits for maximum airflow and performance from start to finish. AMA legal except Supercross and Outdoor Nationals. Prior to AMA’s change in fuel rules, MRX01 fueled numerous champions in AMA Supercross and Outdoor Nationals. MRX01 also passes fuel rules for AMA Pro/Am as well as NMA, WORCS, SCORE, Best in the Desert, club level racing and more.

TYPICAL VALUES
•   Color: Pink
•   Motor Octane: 98
•   Specific Gravity: .717 at 60° F

Tech Tip: When using MRX01, to keep your fuel cool and prevent vapor lock on hot days, e.g. 90 ° or higher, we recommend:

Always go out with a full tank – the more fuel you have the cooler the fuel will stay
Insulate the bottom of your fuel tank:
- line the underside of the tank with heat reflective tape and/or
- install a CV4 Fuel Kool Gas Tank Barrier
It will also help to keep your fuel container wrapped in a RACEPRO “Cool Fuel” Ice Jacket prior to dispensing in your fuel tank.

MR12™
VP’s best fuel yet for 4-stroke applications that can tolerate lower octane values, makes more power for powersport applications than any fuel on the market. Dyno tests proved up to 5% more power than VP’s MR9 and up to 6% more power than VP’s MRX01! Although currently not legal in AMA Pro Racing, MR12 passes fuel rules for AMA Pro/Am, CCS, WERA, AFM, NMA, WORCS, SCORE and Best in the Desert as well as club level racing and more.

TYPICAL VALUES
•   Color: Light Green
•   Motor Octane: 87
•   Specific Gravity: .733 at 60° F

When using MR12, to keep your fuel cool and prevent vapor lock on hot days, e.g. 90 ° or higher, we recommend:

Always go out with a full tank – the more fuel you have the cooler the fuel will stay
Insulate the bottom of your fuel tank:
- line the underside of the tank with heat reflective tape and/or
- install a CV4 Fuel Kool Gas Tank Barrier
It will also help to keep your fuel container wrapped in a RACEPRO “Cool Fuel” Ice Jacket prior to dispensing in your fuel tank.

Leaded/Non-Oxygeneated Fuels

VP-110™
Not your "standard" 110! Highest rated MON of any 110 fuel on the market. Formulated for use in naturally aspirated engines with CRs up to approximately 12:1-13:1. Good lower cost alternative.

TYPICAL VALUES
•    Color: Purple
•    Motor Octane 107
•    Research Octane: 113
•    R+M/2: 110
•    Specific Gravity: .720-.735 at 60° F

C12™
The best all around racing fuel made. Recommended for CRs below 15:1, satisfying the needs of 75% of today's race engines. One of the winningest fuels in racing history, including AMA, NHRA, Modified Tour, GNN, D.I.R.T. and Indy Lights, as well as other local and national championships across the U.S. and around the world.

TYPICAL VALUES
•    Color: Green
•    Motor Octane: 108
•    Specific Gravity: .717 at 60° F

Unleaded/Oxygeneated Fuels

Motorsport 109™
Recommended for applications with CRs up to 15:1. In engines that can run on pump gas, MS109 is a direct replacement that produces up to 5% more horsepower than premium unleaded. In fact, MS109 makes more power than any other unleaded fuel on the market with the exception of VP’s MR-PRO4.1, which is used by most top teams in AMA Supercross and Outdoor Nationals. Compared to other unleaded fuels, MS109 offers better detonation protection as well.

TYPICAL VALUES
•    Color: Clear
•    Motor Octane: 101
•    Research Octane: 109
•    R+M/2: 105
•    Specific Gravity: .722 at 60° F

NEW! MR-Pro5™
Our newest unleaded fuel for motocross and supercross, engineered to generate maximum horsepower in 4-stroke applications in conformance with AMA Pro Racing rules. Makes more power than any other AMA-legal fuel on the market, delivering up to 2% more power than VP’s own MR-Pro4.1. Requires minimal jetting/mapping changes, although we do recommend going leaner than MR-Pro4.1 on a carbureted bike. Notably, MR-Pro5 will not require radical changes in ignition timing like other fuels on the market.

TYPICAL VALUES
•    Color: Clear
•    Motor Octane: 86
•    Specific Gravity: .760 at 60°

Motorsport 101™
This 101 octane (R+M/2) fuel makes more power than StreetBlaze 100, along with better throttle response and better detonation protection. It contains no metal compounds and won't harm catalytic converters or oxygen sensors.

TYPICAL VALUES
•    Color: Yellow
•    Motor Octane: 99
•    R+M/2: 101
•    Specific Gravity: .800 at 60° F

Motorsport 103™
MS103 offers performance gains greater than MS101 but less than MS109. Provides detonation protection equivalent to some leaded fuels. Also contains no metal compounds and won't harm catalytic converters or oxygen sensors.

TYPICAL VALUES
•    Color: Red
•    Motor Octane: 99
•    R+M/2: 103
•    Specific Gravity: .743 at 60° F