With over 400 feature wins in Late Model competition, Scott Bloomquist has been on top of his game.
The heightened state of competition requires successful racers to constantly upgrade and get the ultimate performance from every aspect of their program. In the minds of many, there are no huge horsepower gains remaining. When it comes to power, the sport is speeding toward parity like never before. Now, the challenge isn't finding 10 hp; the challenge is finding a single-unit gain in power.
The use of racing fuel is an area where the modern engine builder and racer are turning their attention. The drive for maximum efficiency begins and ends with the fuel's performance.
Competition to provide the fuel is as heady as the on-track action itself. Many of the major touring series do not restrict a driver's choice, even though some of these same series have fuel companies as sponsors. This freedom gives the driver a chance to work with his engine builder to provide the maximum power.
Bloomquist has been using VP Late Model Plus throughout the 2003 racing season.
Changes in the sport have led fuel companies to be on their toes for developments to enhance their products. Steve Burns of VP Racing Fuels said the changing demands of racing applications have been a boost for the fuel maker.
"It has helped us because these changes make you get more and more specific with the product," he said. "Now you're looking for a 1 or 2 horsepower gain. Your fuel has to be specific for its purpose, for the type of racing being done. You have to develop it to suit the exact need.
"We've been doing that with drag racing and motorcycles. We've had to come with 15 different fuels for NHRA classes. In motorcycles, the needs are so different that they give us different ways of looking at things and that can help development. It's like everything: The more sophisticated you can get with it, the better it's going to perform."
A fuel is expected to allow for the engine to provide maximum performance on a consistent basis. In order to do that, the variables need to be reduced or eliminated. Each gallon of fuel has to mirror the gallon before it with tight tolerances.
All of VP's fuel is produced at its San Antonio facility. The company relies on regional dealerships for distribution of fuel and other racing-related products.
Because there are different types of engines with different demands, there are also different fuels to adjust to those demands. This is not a one-size-fits-all scenario.
"To develop a fuel, you have to essentially be a partner with an engine builder," Burns said. "You want the cars to be competitive when they're out there. The fuel needs to have enough octane so there won't be detonation."
Detonation and pre-ignition are the biggest enemies of any fuel's performance. The spark within the internal combustion engine needs to occur at the right time. The perfect time is when the piston is starting its downward stroke. If the fuel ignites too late, the piston has already begun the process and efficiency is reduced. Ignition that's too early will create a force opposite of the piston force, again reducing efficiency.
In the case of detonation, the fuel becomes heated to the point of explosion without the needed controls. A common cause of detonation comes from amounts of uncombusted fuel, still in liquid form, remaining after normal ignition has taken place. When this fuel ignites, it is often out of synch with the expected process and reduces efficiency. By their nature, racing engines can be highly susceptible to detonation, a constant concern of engine builders and fuel manufacturers.
VP Chemist Duane Minazzi conducts a test of a product. These tests are developed in-house to ensure fuels are made according to the proper formula. The tests are performed on established fuels as well as new product lines.
Most fuels are known for their octane number, a point to be discussed in more detail in short order. There are additional considerations in fuel development that must be met in order for the product to make it to market.
A figure sought by engine builders is the burning speed of the fuel. This is the time it takes for the fuel to totally release its available energy. If the fuel is still burning after the peak cylinder pressure has been attained, that fuel is not contributing total efficiency.
"Gasoline does not burn, it vapor-burns. It's a liquid but it must be converted to vapor before ignition," said Burns. "The vaporization helps the fuel release its energy. The gasoline goes through the intake track and never vaporizes. You want the engine to suck in air and the fuel vapor will displace the air. The fuel is vaporizing fast as the piston comes up. Before you set the torch to it, you want it to be vaporized. You have to get the fuel to release the energy and you should have that at 17 to 22 degrees after top dead center. You have to be careful that it doesn't vaporize so quickly that you lose volumetric efficiency and power. Burn speed is an important consideration."
Minazzi uses a gas chromatograph/ mass spectrometer to analyze fuel composition for quality assurance and control. Blending, leading, and dyeing are done at the Texas location.
Another fuel test comes from the energy value; a measure of the fuel's potential. It is measured against the oxygen consumed in the process. It's a delicate balance because there are materials that will enhance the fuel's energy value, but something has to give, and it is often the fuel's octane number. "It's a trade-off," said Burns about energy value. "If you want one thing to go up, something will have to come down."
A final consideration is the cooling effect, directly related to the heat of vaporization. The cooling effect on the intake mixture is better if there is a higher heat of vaporization.
Cooling effect is seen as one of the advantages of the fuel. Dirt Late Model racer Scott Bloomquist switched to VP's Late Model Plus fuel in early 2003. "The cooling effect allows us to run at lower engine temperatures," Bloomquist remarked. "That's important because our engines have high compression, a lot of power, and we operate real close to the edge. It's more forgiving under extreme conditions and gives us a greater safety blanket against detonation."
Octane numbers are common knowledge, but there are more numbers than those seen on the yellow stickers on the gas pump. The common octane number is the product of two designations and is actually the average of these two numbers.
The Octane Engine Laboratory allows VP to find the correct Motor Octane Number for the fuel. VP uses the Motor Octane Number, which differs from both the Research Octane Number used by some companies and the octane numbers seen on gasoline pumps for passenger vehicles. The Motor Octane Number provides a better indication of a fuel's performance in a racing application.
Octane is the term given to a fuel's ability to resist detonation. The numbers are derived from standard testing. A Research Octane Number and a Motor Octane Number are added, then divided by two to give consumers of gasoline for everyday driving a measurement of fuel performance with respect to detonation.
"We look at the Motor Octane Number," said Burns. "The Research Octane test is one used to simulate cruising, which isn't what race engines are built for. Race cars understand the Motor Octane Number better.
Burns added that some companies will sell their products based on the Research Octane Number, which is generally the higher of the two numbers.
An important consideration of an octane number is how it relates to your engine. Once you arrive at the octane number that will prevent your engine from detonation, there is no need to deviate. A higher octane number will not increase performance.
Most of the oval track world continues to use leaded racing fuels. A person new to the sport might wonder how that can happen. In the same sense, they may wonder how long it will stay that way.
Burns was asked if unleaded racing fuels, which do exist in some forms of the sport, are the future of oval track racing. It's a yes or no situation.
Users need to make sure the barrels are resealed after use to prolong the life of the product.
"It's yes in some ways because people think it's coming and has to happen," said Burns. "But, think about this. Airplanes are designed to run leaded fuels and there's no move to get planes to run unleaded. Leaded fuels provide a bigger window against detonation and pre-ignition problems. We're running carburetors on many of the engines being used in racing. It isn't the sophisticated systems that carmakers have been building. Unleaded fuels are good for those applications, but they're not good for carburetors and the types of engines we're running in oval track racing.
"The Clean Air Act gives race cars a fuel exemption. We can build racing cars to use leaded fuels because it's not covered. The engines used in closed-course applications are treated differently.
"There doesn't have to be a change in the regulations. Airplanes are built to fly with leaded fuels and you can't change planes overnight. It would take years. Why spend money on something that's not broken?"
Also, the sport is in no hurry to bring about the change. In the past, issues such as noise suppression have been addressed in anticipation of pending government involvement. The sport is not likely to voluntarily look into the idea of unleaded racing fuels. Canada, though, has mandated unleaded racing fuel as of last December.
The barrels of fuel are filled and tightly sealed for their trip throughout the United States or around the world.
Time and sunlight rank as the biggest enemies to a racer's fuel supply. Gasoline has a limited shelf life, so it's important to give it proper care.
"Don't let ultraviolet rays hit the fuel," said Burns. "It will cause the lead to fall out of the composition. Take some fuel, put it in a jar, and set it in a window. You'll see how quickly the lead separates from the fuel."
For that reason, storing fuel in clear containers is never a good idea. Many racing product suppliers sell plastic fuel jugs, usually red or some other opaque color, for storing fuel.
Keeping the fuel fresh also requires using it soon after you acquire it. You cannot expect the fuel you purchased at the beginning of the year to have the same efficiency at the end of the year. The lighter elements of the composition will be gone by the time you get around to using it. The best teams calculate fuel usage and buy accordingly. Fuel should also be kept in sealed containers for obvious reasons and stored in areas not susceptible to moisture. Like the UV rays, temperature can be harmful to a fuel's efficiency, so a cool storage area is helpful.
Like most fuel manufacturers, the products offered by VP are available in different colors. The color has nothing to do with the performance capability. "We dye it," Burns said. "It takes one pint of dye for every 25,000 gallons. It was the surgeon general's idea some time ago. Now, it just helps identify it. You can tell a fuel by its color and smell, and the smell will change at different temperatures."
The fuel supplier and engine builder work together in product development, and that partnership extends all the way to the track. "The fuel supplier needs to know everything, like how hot or cold the car runs, the rpm range that's expected, and so on. The things that determine vaporization of fuel need to be addressed to make the car perform," said Burns.
Racers looking for the best performance need to know that the fuel supplier and engine builder are on his side. After all, their products are being put to the test the instant the driver turns on the engine.
