As stock car racers, we often fall into the trap of believing that as long as the engine idles and runs at full throttle, the carburetor is giving us all it's capable of. The reason cannot be a fear of complexity-not compared to the problems of determining roll centers or measuring dynamic caster gain, which most racers handle with no problem. For some of us, it's because we concentrate solely on tuning the suspension and leave everything between the air cleaner and the oil pan to the engine builder. For others, it may be because we've given a custom carburetor builder $3,000 to tweak a stock carburetor within an inch of its life, and now we are afraid to touch it.
Regardless of the reason, if you fall into this category, you may be missing out on the track. When tuned properly, a carburetor can be used to help control how fast the engine puts the power to the rear wheels and, in essence, becomes a legal traction device. This is true regardless of what brand you are using.
According to Barry Grant's Doug Schriefer, tunability is the key: "If you race the same track every week, and your setup is pretty good at getting you through the corners, but you are getting too much wheelspin, it doesn't make sense to start automatically swapping shocks and springs. If your setup is good, then leave it. Let me help you control the wheelspin coming off the corners with the carburetor."
Since it began manufacturing its own line of performance carburetors in the early '90s, Barry Grant has concentrated on giving the racer lots of tuning options in its line of Demon carburetors that can be performed easily and quickly. Granted, many circle track stock car divisions require a specific Holley part number, but if your track or division has no restriction on the brand of carb you can run, a Demon carburetor should at least be considered.
Because it shares most of its basic architecture with a Holley carb, a Demon isn't an alien piece of technology for most racers. We're still talking about boosters, venturis, float bowls, and throttle plates in all the positions you would expect. The differences are finer, but they may turn out to be quite important to you on the track and in the pits.
One of the newest advancements Barry Grant has added to its Demon line is a unique set of quick-release throttle cams that allow you to tune how quickly the secondary butterflies open up. Known as the Traction Master baseplate assembly, this can be quite useful on slick tracks or in divisions where the engines are more than a match for the tires. On a high-bite track, where you have all the traction you need, use the 1:1 cam that opens the secondaries normally. But on a slick track, where hooking up the rear tires on turn exit is a problem, you can switch to a throttle cam that delays the opening point for the secondary throttle blades. The effect is to give the driver the feel of a longer throttle pedal. Many drivers believe they can be gentle enough with the throttle pedal to keep wheelspin to a minimum regardless of the track conditions, but few are actually that good. Schriefer says almost every driver he has worked with is able to improve their lap times using the Traction Master baseplate assembly, because less wheelspin means more forward bite, and more forward bite means better acceleration on turn exit.