frequently asked questions

The length of time the fuel will stay fresh in a sealed drum depends on the fuel itself. A non oxygenated fuel such as C12 should be used within a couple years. I personally have tested some that was eight years old and was fine. As far as an oxygenated fuel I would like to see these fuels used within a year or so. This way you know the oxygen content is still within spec. Both oxygenated and non oxygenated fuels will most likely last longer than I have stated, but I feel that to ensure the best performance following these recommended guidelines will be to your benefit.

I would personally use it within 2 to 4 weeks. A plastic container is designed for fuel transfer, not storage. If you are going racing for a week or weekend, it’s OK to put your fuel in the plastic containers. I just recommend that when you get to your shop you put the fuel back in the drum and seal it. This will keep it fresh. Plastic is porous. Even though the liquid fuel doesn’t leak out, the light ends of the fuel can evaporate out of the plastic. Plus the sun’s UV rays can penetrate plastic and the lead may drop out. Again, plastic containers are designed for transfer, not storage.

One of the most frequently asked technical questions company get at VP involves the difference between Motor, Research and R+M/2 Octane Numbers. The next most frequently asked question is why some fuel companies represent their fuels with Motor Octane Numbers, while other companies use Research or R+M/2 Octane Numbers.

Realize first that octane is a measurement of a fuel’s ability to resist detonation—nothing more. The two types of machines used for testing octane—a Motor Octane machine and a Research Octane machine—were designed in the 1930s. They were designed to test for octane numbers from the 0-100 range, therefore, any number above 100 is an extrapolation.

Both of these machines are dinosaurs and are not adequate for today’s high tech fuels or engines, but they’re the only means available for testing fuels. These machines are one-cylinder engines with an adjustable head that can move up or down to increase or lower the compression ratio while the engine is running. The Motor and Research machines are the same in this respect, but they differ in several other characteristics. As you can see, the Motor Octane machine runs at a higher RPM, higher temperature and more timing. This machine puts more stress on the fuel than a Research machine and more accurately simulates a racing engine. VP Racing Fuels always includes Motor Octane Numbers when promoting its fuels because our fuels are used exclusively for racing applications.

The Research Octane machine will always produce a higher number for the obvious reason that it does not put the same amount of stress on the fuel. This number is used by some fuel companies to trick the racer into thinking the fuel is rated higher, i.e., higher quality, than it really is. The “R+M/2” Octane Number is the average of the Research and Motor Octane numbers for a fuel and is the number displayed with yellow labels on retail level gas pumps.

When comparing fuels for racing purposes make sure to compare Motor Octane Numbers because these are the ones that count in your racing application. Focusing on the MON of each fuel will help ensure you’re comparing apples to apples with regard to octane.

But bear in mind, a fuel’s ability to prevent detonation is a function of more than just octane. For example, VP’s fuels—oxygenated or nonoxygenated—vaporize much better than competitive fuels with comparable octane ratings. This means VP fuels cool the intake charge, burn faster and yield more efficient combustion. As a result, the “effective” octane rating of VP’s fuels is even higher than the rating generated by the octane test. As a result, VP fuels will prevent detonation more effectively than competitive fuels with comparable MONs.

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.

Before making a final fuel selection, company encourage you to consult with your VP regional distribution center or VP’s Technical Support Staff. Be prepared to answer the following questions:

• Is your engine naturally aspirated, turbocharged, blown or using nitrous oxide? • What is the compression ratio (CR) of your engine? • Does your engine have O2 sensors or CATS? • In what series or sanctioning body will you be racing? • What are their fuel rules, e.g,. are any fuels illegal or do they allow oxygenated fuels? • In which class will you be racing?

You can be confident that once company understand your application, we’ll find the fuel that will make the most power for your engine!

Yes you can over octane an engine. Generally you will get sluggish throttle response. Also you may get fouled plugs and deposits in the exhaust ports and headers. When an engine is trying to burn a fuel that has too much octane, the burn rate is incorrect and all of the fuel won’t be used up. This excess usually gets left as a deposit or gets pushed out the exhaust. It is important to match your engine’s needs with the correct fuel.

It’s OK to spray nitrous to Q16. I wouldn’t recommend multiple kits but single stages up to 500hp or so. When you spray multiple kits, you are introducing all the oxygen, i.e., nitrous, the engine can handle. This is where you want a fuel that will help reduce detonation, and where VP’s C23 is perfect. An oxygenated fuel hasn’t proved to be a benefit in these applications yet.

Generally on a single 4-barrel application, 2 to 3 Holley jet numbers richer is sufficient. I have experienced many instances of over jetting with this fuel, where it works great on the dyno, but on the track the car is a pig. What I’m finding is most people are already rich, so when you go up another 2 or 3 jets you are way out of the ballpark. Most applications run best about 2 jet sizes richer from their previous fuel on the track. This is approximately 8% more fuel. If this still seems to be rich, you may need to increase the high speed air bleed .003 or so. This will get you to approximately 6% more fuel volume. This is where I have seen Q16 perform the best. Regarding air fuel ratio, I have seen the best power on a naturally aspirated engine around 12.8 to 1 to 13.3 to 1. This seems a bit on the rich side to me, but the engines like the extra fuel volume. Remember – every engine combination is different. It will take experimentation to get the desired result. All I can guarantee is the horsepower will increase and your ET’s will decrease.

Generally on a single 4-barrel application, 2 to 3 Holley jet numbers richer is sufficient. I have experienced many instances of over jetting with this fuel, where it works great on the dyno, but on the track the car is a pig. What I’m finding is most people are already rich, so when you go up another 2 or 3 jets you are way out of the ballpark. Most applications run best about 2 jet sizes richer from their previous fuel on the track. This is approximately 8% more fuel. If this still seems to be rich, you may need to increase the high speed air bleed .003 or so. This will get you to approximately 6% more fuel volume. This is where I have seen Q16 perform the best. Regarding air fuel ratio, I have seen the best power on a naturally aspirated engine around 12.8 to 1 to 13.3 to 1. This seems a bit on the rich side to me, but the engines like the extra fuel volume. Remember – every engine combination is different. It will take experimentation to get the desired result. All I can guarantee is the horsepower will increase and your ET’s will decrease.

This fuel is the nuts for intercooled applications. We’re seeing huge increases in these applications. I haven’t seen any issues with detonation when they follow the 6% rule. This is richen your fuel system 6% over C16 (which is the fuel 90% of these applications are using now) and you should be close to the air fuel ratio you were at before the Q16. This is where Steve Petty (Dyno master) picked up 107Hp to the tire on a twin turbo 588 ci application. The Q16 isn’t responding as well in non-intercooled applications. I recommend that in these few instances, you should stay on C16. Heck, most of these applications have enough HP as it is.

I recommend that you drain the fuel out of the car if it is going to sit more than a week. Not because of gumming or corrosion of the fuel system, but because of the oxygen and the fuel evaporating. This fuel is made up of many light materials, and it will evaporate quickly. You spent good money for this performance part. Keeping it fresh will ensure a more consistent result. In a perfect world, you should drain it every night. This won’t happen if you’re like me, because company racers are lazy (haha). If you have an aluminum cell, you can cap the vent and it should be fine for week to week storage. I do not recommend storing this fuel or any fuel in a plastic jug or container. Keep it in a sealed VP drum and it will stay good indefinitely.

I’d use regular methanol like VP’s M1 for the injection. This is what I personally use. All you are using the injection for is to cool the air charge. This is how you get more power, because you can add more timing or boost with a cooler charge. M3 has a hydrocarbon in it and won’t pull the heat like M1. M5 has a hydrocarbon and a combustion additive. I would definitely not use this. It could have bad results by combusting in the air inlet tube between the turbo and the throttle body. M1 is your best choice.

M5 contains nitroparaffins, which are relatives of nitromethane in the same chemical family.

So far M5 has worked in every application I have tried it in. From a single cylinder Briggs JR dragster to a Brad Anderson blown hemi. If you’re adamant about running methanol, there is no reason you shouldn’t run M5. It’s more consistent, you’ll use less, and it makes gobs of Hp.

This fuel seems to be very friendly in jetting. Steve Petty dynoed a 1000 rear wheel Hp vehicle and increased the jetting 15% and the car made 1080 to the tire. He reduced the jetting to 7% and the car went 1079 to the tire. This is an 8% tuning window. I recommend you jet up 10 to 12% to start and then you can back down from there. Al Brown (Antron’s father) did a back to back test with M5 vs. M1. His combination is a 540 ci injected big block Chevy running Top Dragster. With no difference in jetting, the car picked up .11 seconds and 6 mph. Again, every combination is different and you’ll need to run the tests to determine what your combination likes.

As with Q16, so far I have left the timing alone. Run what timing you had with regular methanol. Here’s my thought. The hydrocarbons in the fuel help vaporization, so you SHOULD be able to retard the timing a bit. But the fuel also contains nitroparrifins, which generally need the timing advanced to start the burn earlier. Since they are both in the fuel, they almost seem to cancel each other out, hence the timing will stay the same. Weird huh?

No, M5 already has enough upper lube in it. While VP’s M2 is excellent for use for straight methanol, I don’t recommend adding it to M5. I have seen injection nozzles clog up because of the extra lube.

I recommend the same as Q16. If the car is going to sit for a week or so, drain it out and put it back in the drum. Also, the fuel will not separate.

Unless you’ve already tried M3 with success (and M3 works great in many applications), I’d go right from regular methanol to M5. The range of applications that can benefit from M3 is slightly more limited than M5, while M5 will pick up virtually any application you put it in.

In two words, BETTER VAPORIZATION. Regular methanol doesn’t like to vaporize in the combustion chamber. It likes to stay in liquid form. In the combustion chamber on the combustion stroke, the engine needs to burn 2 things, fuel vapor and oxygen. If the fuel doesn’t vaporize well, then you will have wasted fuel going out the exhaust. The hydrocarbons and nitroparrifins in M5 help to vaporize the fuel more efficiently. This way there’s more fuel vapor in the combustion chamber and in turn the engine will make more power.