Fuel is fuel, right? After all, regardless of the brand you choose it's all leaded race gas, right? Wrong! Fuel is not just fuel. Fuel is the food for your engine. As silly as that might sound it couldn't be more true. And just like the food we eat, the gas you put into your race car can affect the engine in ways both good and bad. Consider this, how many times have you eaten a monster, fat-laden meal only to feel pretty bad afterward, almost like you need a nap? Garbage in, garbage out-and the same holds true for your race car. Put in substandard fuel or the wrong fuel and you'll have problems . . . guaranteed.
So How Do You Go About Choosing the Right Fuel?
First off unless you run a series that requires a specific fuel be used by all teams such as ARCA, NASCAR, or Pro Cup, your fuel choice is yours and yours alone. There are some sanctions that have a fuel sponsor for their series and require teams to buy a specific amount, say 5 gallons, per race. In cases like these, teams that do not want to run the sponsor's fuel will sometimes buy that set amount for a friend's team, thereby fulfilling their obligation to the series while leaving themselves free to run their chosen fuel. But in the end what you put in your tank is up to you.
Between the two largest racing fuel suppliers in the U.S. there are more than 30 different fuel blends just for oval track racing applications. More than 20 of those belong to Texas based VP Racing Fuels.
Chart A: This chart shows...
Chart A: This chart shows the fractional distillation of crude oil. At the bottom is where you'll find greases and heavy lubricants. Near the top (Light Straight Naphtha) is where you'll find the origins of gasoline. -Courtesy Carnegie Mellon University
Why so many different fuel blends? "Why do you have so many camshafts?" quipped VP's founder Steve Burns when asked that question. "Seriously, it suits the application. Because of growing up in an environment where 2 horsepower means something, I got to develop fuels with some of the best engine guys in the world. It taught me that one or two fuels don't fit every application. And that has become our philosophy."
Obviously to find out the type of fuel that is best for your car or application you need to consult both your engine builder and your chosen fuel manufacturer. VP has a nifty color coded icon system on its website that identifies the different fuels based on your racing application (off-road, drag, circle track, and so on). Beyond that, specific decisions such as octane rating can be handled by talking with your engine builder as well as VP's Technical Support Department. But before you do there is some information that you'll want in your back pocket.
Motor Octane Versus Research Octane
There are actually two different ways to rate the octane of fuel; Motor Octane rating and Research Octane rating. Simply put, the Motor Octane rating of a fuel is arrived at through a test that involves putting an engine (and the fuel) through a heavy load test that simulates "severe" driving conditions such as hard acceleration. On the other hand, the Research Octane test simulates cruising conditions with lighter loads and less stress. The Research Octane rating will always be higher since the test conditions are generally milder. Think of it this way, easier test . . . better grades.
The most economical way to...
The most economical way to purchase your race fuel is a 55 gallon drum, just be sure you have a good pump to get it into your containers. -Rob Fisher
Because the Motor Octane rating test simulates heavy load conditions that is the rating we, as racers, want to pay closest attention to; highway cruising is just something we don't do unless of course we're heading to the track. VP has even modified its in-house motor octane test rig to more closely simulate race conditions rather than just relying on standard heavy load testing. Bottom line: Always look at the Motor Octane rating.
When you switch race fuels,...
When you switch race fuels, you'll likely have to change the jets in your carb. Here Circle Track Dirt Late Model driver Bobby Clark begins by removing the four bolts that hold the primary fuel bowl assembly on the main body. Note the metal bowl to catch any fuel that might drip out. -Rob Fisher
Now the simple reason you should care about the octane rating is that it shows the resistance of the fuel to uncontrolled combustion; such as knocking, pre-ignition and detonation all of which, at a minimum, reduce the efficiency of your engine. The higher the octane of a fuel the greater its ability to withstand cylinder pressures before uncontrolled combustion takes place.
Meth vs. Gas; Which is better?
Another fuel debate often heard in the pits around country is, should I run methanol or gasoline? To delve deeper into this subject let's first go back to school and look at the differences between the two.
Gasoline is one of the resulting products from the Fractional Distillation of crude oil. Various components of crude oil have different molecular sizes, weights, and boiling temperatures. Simply stated the refining process separates those components by heating the crude oil to the boiling point. As the oil boils the resulting vapor enters the bottom of a long column called the fractional distillation column which is filled with trays or plates. These trays have many holes or bubble caps (like a loosened cap on a soda bottle) in them to allow the vapor to pass through. As the vapor rises through the trays in the column, it cools. When a component in the vapor reaches a height where the temperature of the column is equal to that substance's boiling point, it will condense to form a liquid. That liquid is in turn collected. As you can see from Chart A, gasoline is collected at the top of the fractional distillation column.
With the bowl detached, he...
With the bowl detached, he can remove the metering body. -Rob Fisher
On the flip side, Methanol (also known as methyl alcohol) is an alternative fuel made from woody plant fiber, coal or natural gas; it is used primarily as a supplement to gasoline. It can also be harvested from the methane gas in landfills in addition to fermented waste products such as sewage and manure. To digress into the environmental world for a minute methanol is one of those fuels that can be sustainably produced depending on its origins. Converted from methane gas captured from landfills it can be a source of constantly renewable energy. Taken as the by-product of natural gas production (a fossil fuel) it's no more green than standard gasoline.
Environmental lessons aside, pure methanol is primarily used as racing fuel. One of the major pros of methanol versus gasoline is that it has the ability to run at higher compression ratios than gasoline, translating into more power. As any Dirt Late Model racer who favors a methanol-fired engine will tell you, the primary reason they run it is more power. It also tends to run cooler than gasoline.
On the downside, while it's not as volatile as gasoline, it does burn with an invisible flame, making it hard to tell when you're on fire. It's also highly corrosive meaning that your post race maintenance schedule is going to take longer than with a gasoline engine. Your biggest trade off is that it has a 50 percent energy ratio-that means it produces half of the power content of gasoline. In other words, you need to consume more methanol to generate the same power as gasoline. Still, the additional power produced by a methanol engine is enough to make many racers run the colorless fuel.
The old jets require a flat...
The old jets require a flat screwdriver to remove, which could cause damage. -Rob Fisher
Burns boils it down to this, "Racing fuels in the past weren't all that good and many people felt methanol made more power. But today's good race gasolines can make as much if not more power than methanol."
Our Project Dirt Late Model team recently made the switch from a 112-octane race gas to VP's 113. We chose the 113 for a couple of reasons. First off VP does race fuels and only race fuels. Second, VP's 113 vaporizes extremely well and equalizes out exhaust gas temperatures. Think of your engine as eight individual motors (the cylinders). Each "motor" doesn't have the same cooling efficiency because of the water jacket design. If you could somehow even out the air/fuel ratio out among each cylinder then you can theoretically achieve a more consistent burn throughout the engine. The good vaporization characteristics of 113 would achieve just what we wanted.
Change those Jets
VP's Technical Director Freddie Turcza told us that once we made the change to 113 we needed to change the jets, because the octane rating of our new fuel is different than the old fuel. Changing the jets on a carb is probably one of the easier things you can do on a race car. But if you've never done it follow these simple steps. You may want to keep a metal bowl handy under the carb to catch any fuel that might spill out. Simply remove the four bolts and pull the primary fuel bowl assembly back resting it on the metal bowl, then you will be able to remove the metering body, exposing the jets. Removing the old jets on our carb required a flat head screw driver. But our new jets from Comp Cams would use a hex driver.
Here's a close up of the new...
Here's a close up of the new jet on the right and the old one on the left. -Comp Cams
Conventional jets are mass...
Conventional jets are mass produced with a wide tolerance, and then plated. Many of these jets use the same orifice size with the only difference being different angle tapers that supposedly change the flow-rate characteristics. -Comp Cams
These mass produced jets also...
These mass produced jets also use a "slot" that requires a special, expensive tool to install, but most people just opt for a flathead screwdriver. Using a screwdriver on these jets can cause damage that creates a turbulence that severely affects the fuel flow as much as 50 percent. -Comp Cams
Here's a close up of the Comp...
Here's a close up of the Comp Cams Max Jet, note the 5/16-inch brass hex design that makes installation and removal a snap. -Comp Cams
The nut driver design results...
The nut driver design results in zero damage to the bowl. -Comp Cams
The new jets from Comp Cams...
The new jets from Comp Cams use a 5/16-inch nut driver, a much safer design. -Rob Fisher
That's right, I said Comp Cams. Among the general racing population the fact that Comp makes carburetor jets is not that well known. In fact, it's a pretty well kept secret, although not intentionally on Comp's part. In any event, Comp's virtually indestructable Max Jets are produced with 5/16-inch hex-stock brass that delivers a solid jet that can be installed with no damage to the inlet bowl.
Conventional jets are mass produced with a wide tolerance, and then plated. Many of these jets use the same orifice size with the only difference being different angle tapers to change the flow-rate characteristics. These mass produced jets also use a "slot" that requires a special, expensive tool to install, but most people just opt for a flathead screwdriver. Using a screwdriver on these jets can cause damage that creates a turbulence that severely affects the fuel flow as much as 50 percent. Max Jets' hex-stock brass uses a simple 5/16-inch nut driver resulting in zero damage to the bowl
With the old jets out of the carb and the new jets in, we can now replace the metering body, fuel bowl and put the bolts back in. Do not forget to change the jets in the secondary also.
The Future of Race Gas
Since we were changing fuels,...
Since we were changing fuels, we also took the opportunity to install a new inline fuel filter from All Star Performance. A couple of AN fittings is all it took. -Rob Fisher
The future for race gas is pretty wide open at this point. Some sanctions like IRL and ALMS are pushing full steam ahead with alternative fuels while others like NASCAR have recently made the switch from leaded to unleaded. In the short track world, fuel choice is still largely up to the racer. But what is clear is that technical development will continue on into the future.
"Every three or four years we go through this cycle of thinking we've topped out in terms of technology for race gas," says Burns. "Then some time passes and we develop several new formulations and say 'how come we didn't think of this three to four years ago?'"
About VP Racing Fuels
Founder of VP...
Founder of VP Racing Fuels
Incorporated in 1975, VP Racing Fuels was the brainchild of drag racer Steve Burns who saw room from improvement in the race gases at the time. When he was 19 Burns headed to Washington, D.C., and the Library of Congress where he checked out books on fuels and how they work in a quest for power gains for his own racing endeavors. Over the course of time he became a self taught chemist. Armed with the info he was looking for, he began mixing fuel formulas in his parent's garage. Those initial formulations led to C12, a fuel that he convinced Warren Johnson to try back in the early years. Over time C12 became the most popular fuel in NHRA.
In the 1980s, Burns and VP began delving into other fuels with each one having its origins from a custom formulation. Their sole focus has always been race gas and the company's driving philosophy is that one fuel does not fit all. To date they have almost 70 blends.
In 2000, VP became the spec fuel of NHRA but before that drag racers had a choice. The growth of VP's drag racing business led it down the path of developing fuels for other markets such as circle track and motocross.
In the process of developing formulations for specific applications VP will often adapt one to another. For example, during the development of its Late Model Plus which targets Dirt Late Model applications, engineers found that the fuel blend was well suited for off-road racing because of the similar environments faced by the racers.
Now distributed internationally, VP plays a significant role in the landscape of oval track racing. Constantly innovating and developing new formulations for an ever widening marketplace.