Weldon Pumps, VP Racing Offer Maintenance Tips For Oxygenated Fuels


No one’s disputing the power-enhancing benefits of oxygenated race fuels, but these new formulas can cause headaches for fuel system designers and suppliers if car owners don’t pay attention to proper maintenance.

“About five years ago we started noticing the problems,” recalls Jim Craig, racing products manager at Weldon Racing Pumps. “We were seeing excessive oxidation, rust, severe staining and pumps locked up due to lack of lubrication. We started calling back the customers and found out what fuels they were using.”

Oxygenated fuels formulated with ethanol can lead to corrosion in the fuel system if left long enough to absorb moisture.

Blending a gasoline that carries its own oxygen molecules allows the engine tuner to richen up the carburetor or adjust the EFI fuel map accordingly. More fuel equals more power. Depending on the engine and previous fuel, racers were seeing 10 to 80 more peak horsepower and a stronger overall torque curve with just a chance in fuel. The increases were especially noticeable in competition where low-compression engines with stock-style cylinder heads were prevalent – such as bracket racing and sportsman dirt track.

“But I have yet to find any application that doesn’t benefit from oxygenated fuel,” says Jason Rueckert of VP Racing Fuels.

If a vehicle is going to sit for while, you have to take precautions.–Jim Craig, Weldon Racing Pumps

Oxygenated fuel has been around since the ‘50s when regular rubbing alcohol was added to gasoline, not for power but to keep the fuel from icing over. Corn states led an effort in the ‘70s to add 10 percent ethanol to fuel. Remember the “gasohol” rage? Meanwhile, gasoline suppliers turned to methyl tert-butyl ether, better known as MTBE, as a replacement for tetraethyl lead; hence, the launch of unleaded gasoline.

Lead additives were included to guard against detonation, but they were also extremely toxic. MTBE raises the octane level and carries its own oxygen molecule. It was relatively inexpensive and mixed well with gasoline, but when it started showing up in ground water the Environmental Protection Agency pushed for an alternative. The Bush administration preferred ethanol to please the agriculture community and help reduce foreign dependence of crude oil.

Here are the types of problems caused by ethanol left too long in the fuel system.

What are oxygenated fuels?

Ethanol is basically grain alcohol, a fuel usually distilled from corn feedstock, although different types of grasses and even sugar cane can be used. It’s similar to methanol, which is generally produced from a natural gas feedstock, though it could come from coal or even wood. Ethanol is now used in gasoline to raise the octane level and oxygenate the fuel.

VP Racing Oxygenated Fuels

VP Racing Fuels offers a wide range of oxygenated fuels, both leaded and unleaded, for different markets, including racing, powersports, karting and even airplanes. Following are the popular drag racing formulas:


  • Q16 – Versatile with N/A, nitrous and boosted engines;  116 octane and highly oxygenated
  • VP113 – Under 14:1 naturally aspirated engines
  • C45 – For high-compression, naturally aspirated engines
  • VP Import – For small-displacement engines with boost or nitrous


  • VP101 – Oxygenated with ethanol; street-legal in California
  • MotorSport 109 – More power than unleaded premium
  • SV-05 – European Pro Stock racing
One may ask why can’t refiners just “whip” up the fuel with some pure oxygen and not worry about additives? It may be that easy when making marshmallows but not fuel. The formula must include an oxygen-bearing chemical, or the oxygen will simply drift away. Ethanol’s molecular formula is C2H6O. In the heat of the combustion, the oxygen breaks off and effectively leans out the air-fuel mixture.

“The way I like to explain, it’s like having a little nitrous oxide all the time,” says Rueckert.

That begs the question, what could be the downside to oxygenated fuels? Other than higher costs and some sanctioning bodies not allowing them, these fuels can have an increased maintenance factor, especially those formulated with ethanol or methanol. The problem stems from ethanol’s tendency to absorb and hold water. In fact, ethanol has a stronger attraction to water than fuel. When the fuel is left standing for an extended period in the tank, fuel lines, carburetor, fuel pump and other fuel system components, any number of scenarios can occur.

“Fuel pumps are made from tool steel,” says Craig. “Heavy water contamination left in the pump will cause it to rust, and it can be almost immediately.”

Ethanol and methanol can also be corrosive to aluminum fittings if not properly anodized, and steel fittings are susceptible to oxidation when water is present in the fuel. Ethanol is also a solvent, so it can loosen grime, flakes or other leftover particles that can find their way into carbs and fuel injectors, clogging up the fuel delivery.

Guarding against moisture

“Most of our pumps are compatible with E85, methanol, Q16 (a popular oxygenated fuel from VP Racing),” says Craig. “They’ll move the fuel. But if you leave it in there, you could get moisture that comes along with these fuels, and that’s what attacks the working components inside the pump.”

Weldon inline fuel pumps are not recommended for E85 and ethanol — not because of construction or materials issues with the pump mechanism, but due to the incompatibility of certain electrical components in the motor.

The severity and frequency of the problems vary due to different racing conditions, changing weather and intervals between races or engine startups.

“If a vehicle is going to sit for while, you have to take precautions,” warns Craig. “If you’re using a ‘funny fuel,’ you don’t want to let that stuff sit in your system over time.”

The most thorough solution is to drain the fuel system, especially if the car is scheduled for a long break. An application of lightweight oil to critical parts, particularly moving parts in the fuel pump, will also protect against oxidation.

“Then close up the pump completely,” adds Craig.

“It’s not the fuel itself that’s causing the problem,” says Rueckert. “It’s when the fuel evaporates. If you’re in a situation going from hot to cold or in high humidity, the fuel will attract moisture if it sits for too long. Then it will evaporate out of a fuel pump. That water will oxidize on the vanes. You’ll also see it in fittings and carb bowls – a white powder residue. You don’t run into these issues if you plug up the system and close off the vents in the carb and tank.”

Weldon pumps that isolate the motor from the fuel are compatible with ethanol, methanol and oxygenated fuels. These pumps should be flushed out and the internals coated with a light oil if the vehicle is not racing for an extended period.

There’s an element of mystery that doesn’t help the racing community with regards to oxygenated fuels. By now, most pump gas is oxygenated up to 10 percent (labeled as E10) with ethanol. Late-model vehicles have fuel-line components that are compatible with ethanol, and drivers rarely let their cars sit for extended periods. Oxidation issues, therefore, aren’t prevalent on the consumer side, except in situations with classic vehicles. A number of gasoline additives are available to help minimize E10’s impact on older cars.

Race fuels, however, do not carry an ingredients labels. The fuel may be sold as an oxygenated fuel, but different oxygen-bearing chemicals can be used as the additive besides ethanol or methanol. These include, but are not limited to, MTBE, propylene oxide, ethyl tertiary butyl ether (ETBE) and tertiary amyl methyl ether (TAME). Some of these chemicals do not have the same water-absorbing tendency as ethanol, but again, it’s difficult to tell what’s in a race fuel. Also, the amount of oxygenation varies from two to 10 percent in different oxygenated fuels. That percentage, however, is not a direct correlation to power increases.

Oxygenated fuels are formulated using many different chemicals, so check with your supplier to make sure you know what's going in your tank.

“Some fuels have only two percent oxygen but have other chemicals that make power,” explains Rueckert. “Vice versa, other fuels have 10 percent oxygen but a less powerful base stock.”

Some fuel-system components may not be designed for ethanol or methanol fuels, while are others are designed specifically for those fuels. Check with all suppliers to ensure compatibility.

Selecting an oxygenated fuel comes down to the application, and talking to the fuel supplier representative is the best course of action. Some fuels exhibit similar properties but are actually formulated for specific applications. For example, VP Import is less than three percent oxygenated and may work as well as Q16 in some applications.

“But VP Import will handle higher air temperature and a little more timing,” says Rueckert. “Even though it has less oxygen, tuned correctly it could make more power than Q16 in certain applications.”

Preventative maintenance

Regardless of the oxygenated fuel recommended, it’s a good idea to guard against oxidation in the fuel system by following basic preventative maintenance. In addition to the suggestions already mentioned, the fuel should be kept in a UL-approved containers that limit exposure to outside air. Keep them stored in a cool, dry place and out of direct sunlight. Also, be aware of the fuel’s recommended lifespan.

Race fuels have a different shelf lives, so consult with the supplier about storage suggestions and longevity.

Many racers are purchasing oxygenated fuel in small containers rather than drums. But Rueckert says if stored properly the drums will work. A racer himself, Rueckert says he takes only what’s needed for the weekend out of the drum, then seals it back up.

“Fuel life still depends on the type of fuel,” adds Rueckert, “so check with the supplier.”

Warning signs that oxidation may have already affected a fuel pump include fluctuations in fuel pressure, peculiar noises, a fuel injector gets hung up or a higher-than-normal amp draw at the pump.

“That’s an indication the pump has to produce more fuel pressure to push through a clogged or restricted filter,” warns Craig.

Fuel system components should be flushed and checked when using ethanol fuels if the vehicle is inactive for an extended time.

Bottom line: in addition to retuning the vehicle to take advantage of oxygenated fuels, racers need to take added precautions between races and certainly during the off season.

“The guys who have don’t have problems seem to do the same thing,” sums up Craig. “They cap off all the vents and always make sure they use fresh fuel.”

Article Sources

About the author

Mike Magda

Mike Magda is a veteran automotive writer with credits in publications such as Racecar Engineering, Hot Rod, Engine Technology International, Motor Trend, Automobile, Automotive Testing Technology and Professional Motorsport World.
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