There are lots of things about stock car racing that are sexy or cool--but filters definitely aren't on that list.

Still, like a driver's license, running water and clean underwear, filters for your race car are something you can't do without--even if you don't give them much thought. Just swap 'em out every so often and get on with your life, right?

Well, maybe, but there are ways you can improve your racing program by taking a close look at how well your filters are working. Your oil filter can even give you vital clues to your engine's health and help you spot problems before they lead to engine failure.

The Next Generation Fuel Filter

Let's face it, carburetors can flow some pretty large pieces of junk without clogging. At least compared to fuel injection, that is. And that's why for years most racers have gotten by using an inline fuel filter that uses a wire screen to filter the fuel. It's not ideal in most cases, but the design is functional and the limited filtering ability helps promote lots of flow. But the racing landscape is changing, and the old-school wire screen filters may not be the best option for your racing situation any longer. For example, longtime engine builder Keith Dorton told us not too long ago that after races he began noticing that many teams running his engines had a buildup of a black substance inside the carburetors that could only be described as "gunk." The cars were able to finish the race with this build up, but some experienced stumbling problems when the stuff got into the accelerator pumps. Dorton says he finally figured out that a change in the fuel being used was causing the inner liner of some of the older fuel cells to literally degrade into the fuel. Newer fuel cells had updated liners that didn't react with the fuel, but that didn't help the race teams suffering from the problem right then.

The solution Dorton found was a new type of fuel filter from FST Performance. This filter looks a heck of a lot like a remote oil filter system but it's actually designed specifically around the requirements of filtering gasoline. For its spin-on filter systems, FST uses an oil filter style steel canister because they are effective, durable and incorporating the same design saves costs. But the interior of the can is packed with a special cellulose filter (you might call it "paper") that can filter very fine particles while still allowing lots of flow.

"For years when it came to fuel, especially in the performance industry when running a carburetor, everything was all about the amount the filter could flow," explains FST owner Rick Rolling. "Get as much fuel through the filter as quickly as possible. Actually filtering the fuel was secondary. So the standard with the wire screen media they've been using is around 40 microns. Anything smaller than that gets right through."

Forty microns--or anything labeled as a "micron" for that matter--seems pretty small, but Rollins says in the real world it's unnecessarily large. "Now that the Cup guys have switched to fuel injection, if a 39-micron particle gets past the filter and lodges in the injector, that injector is dead. So we've developed the cellulose filter, and our biggest filter can filter down to 3 microns and flows over 350 gallons per hour which will service over 2,000 horsepower."

FST is able to achieve such incredible filtering and flow numbers because the spin-on design allows for acres of surface area for the filtering media. Where most fuel filters have around 60 square inches of surface area at most, Rollins' design has 579 square inches--nearly 10 times the surface area.

For NASCAR approval, Rollins has also developed an inline filter that looks like a conventional fuel filter. It also utilizes the cellulose filter media but the smaller canister means the filter media's surface area is reduced--but still an outstanding 122 square inches. To keep the flow up around the 350 gallons per hour rate, this media filters down to four microns.

The FST filters are also disposable. After purchasing the billet aluminum remote mounts, replacement spin-on filters sell for 24 bucks or less. Rollins says he has a Dirt Late Model racer using his smallest filter, which sells for $16.99 and racing well with it. The inline filter uses replacement units that sell for $39. "I've had racers tell me that it's more economical to use the screen filters because they can clean and reuse them," Rollins says. "But then I ask them what they are cleaning them with, and how clean is that, and they tend to get real quiet. If you are cleaning your screen filter in the parts washer, it's probably coming out with more trash in it than when you started. By using a replacement filter you know you are getting the best filtering possible every time you spin on a fresh filter."

Another unique factor with the FST filters is that they are also effective at filtering water. A screen filter poses to obstacle to water contamination in race fuel, but FST's cellulose media blocks it. Also, unlike a real paper filter, the cellulose material doesn't absorb the water. Instead, Rollins says his filters are all designed with a "quiet area" where the water can collect. In the spin-on filters, it's in the bottom of the can. For the inline filter, Rollins designed a canister that's 8 inches long and a filter that's just 6.5 inches. By mounting the inlet side of the filter slightly lower than the outlet side, any water that's separated out of the fuel by the filter media settles below the filter and allows the fuel to pass safely by.