Going fast on 10.5-inch wide tires has been a phenomenon that swept the drag racing community off its big tires since the early '90s. The concept was made famous during the early days of Fastest Street Car racing in a popular category called Super Street. The class was the little brother of the ultra-quick and prestigious Pro Street eliminator. Pro Street catered to the big-money guys and several ex-Pro Stock and Pro Mod racers with tube chassis cars and giant slicks. Super Street, on the other hand, was the heads-up racing class where street racers found a home with their real cars and true 10.5-inch tires. As time evolved, so did Super Street and it turned into a class that caters to back-half rides with unlimited power under the hood and 10.5W (measuring 11.5-inches wide and 33-inches tall) rear tires. Today, the Super Street cars hardly resemble the late-night, grudge-racing machines from those early years.
The street racing roots have long been forgotten in the Super Street category-but history often repeats itself. During the NMCA reorganization, which started in 2001, the folks at Pro Media Events saw the need to build a category to bring back the popular Super Street-type vehicles from the original days of the street legal drag racing organization. The solution was Xtreme Street, sponsored by Vortech Superchargers, and it emulates the popular category from its humble early years. Vortech Xtreme Street contains the most identifiable cars in the heads-up racing portion of the NMCA sanctioning body due to the cars being real with pragmatic engine combinations. This year the times are mostly in the low 8-second range, with a few competitors eclipsing the 7-second barrier in good conditions. We've noticed a wide variety of combinations this season with big-blocks, small-blocks, nitrous, blowers, and makes and models of all kinds-making the class fun and exciting.
The rulebook calls for a maximum of 10.5-inch wide tires, stock framerails front-to-back, any rear suspension, and stock-style front suspension. Under the hood, NMCA officials have restricted the engines to conventional-headed small- and big-blocks and put a limit on the power adders (nitrous and centrifugal blowers only). The limitations are meant to prevent a severe escalation like with the original category. Some might think the handicap is under the hood, but the real limiting factors are the suspension restrictions, namely the lack of wheelie bars, and true 10.5-inch tires. Tuning the suspension becomes a delicate balance between spin and hook. "The biggest thing is that these cars are heavy and powerful. The big-block cars, like what Cameron Coble and others run, are hard to get moving on a small tire at that weight. Some of them are 3,575 pounds or more. Controlling tire spin is key. The Xtreme Street cars are allowed stock suspension, ladder bars, or a four-link. It's nice to run a four-link; it helps control the hit and the power applied to the tire. That is good when you deal with the tire size and lack of wheelie bars," said Steve Matukas of Matukas Motorsports Race Cars (matukasmotorsports.com). The Kentucky-based chassis shop has built several cars for many top players in the high-stakes game of true 10.5 racing.
Tuning the suspension on these cars is certainly not a "set-it and forget-it" type of deal. Track conditions change from round-to-round as the surface temperature fluctuates and bald spots form. Shock adjustments, tire pressure, and frontend limiters are the most popular components to compensate for varying track conditions. "Having the right chassis is critical in getting the car moving and hitting the tire. It's a balancing act of how much you can apply to the tire. With a four-link you can do so much more. You can hit the tire harder and the chassis will absorb it," said Matukas. He continued, "shocks like Santuff, Afco, and Penske are all great stuff to use. We run mostly the Santuff and Afco for our customers. A good double-adjustable shock is essential and very critical to performance."
Jake Holdrege, who is crew chief and partners with Jamie Stanton on a new entry, built their 2002 Camaro specifically for the category. He operates Pentagon Race Fab and chose to run a four-link rear suspension. Holdrege and Stanton rely on a custom set of frontend travel limiters and they constantly adjust the Strange double-adjustable shocks and struts to get the fourth-gen Camaro down the track. In the nasty heat and slick track conditions at the NMCA event at zMax, he still managed to tune the Camaro to a 1.32 short time. Stanton's best e.t. so far has been an 8.07 at 175 mph, which was coupled with a 1.25 60-foot-the team's best shot in Xtreme Street competition. "On a bad track, we will loosen the frontend limiters and loosen the rear shocks to let it hit harder. We also vary the tire pressure, so it doesn't fold the tire too hard. Our new car is better than our old Chevelle because we can move ballast in the car. The old Chevelle had the weight in all the wrong places. The placement of weight is very important to get the car right," said Holdrege. We prodded him about the four-link and whether or not he changes it often. The team keeps it in the same location, as long as shock adjustments and tire pressures allow the car to bite on the starting line. But if that doesn't work then they adjust the four-link as a last resort.
In addition to chassis tuning, racers also turn to various pieces of equipment like electronics to help control wheelies and tire spin. Finding the proper balance between the driveline and chassis is what has been separating the men from the boys. "Tuning the starting line on an Xtreme Street car can be a handful at times-it is what makes the Xtreme Street class such a fan favorite. You just never know what's going to happen on a run," said class veteran Bob Curran who competes with a '96 Corvette Grand Sport. He continued: "After being in the class since 2002, you put on both bulbs and you're always thinking about what is about to happen once that tree drops. One never knows what the starting line is going to be like at the tracks we race on. But with the technology out there today, (progressive nitrous controllers and MSD Programmable ignitions) getting a handle on consistent 60-foots is getting more common. Driving a power-adder car with true 10.5-inch tires and no wheelie bars is a blast." Matukas also threw in his two cents on the subject, "A big part of it is timing, like the MSD 7531 that everyone runs. When running as heavy as 3,600 pounds it gets tough. Some have tried progressive nitrous controllers, but a lot of us don't like the pulsing of the solenoids. We use the timing controls in the MSD digital ignition system." The MSD 7531 digital ignition system allows racers to build a complete timing curve for each gear. Racers will run less timing in First gear to get the car moving, and then bring in more as the car moves down track.
As veteran NMCA racer Steve Cagle once told us: "You cannot get too greedy with the power." The cagey veteran not only turned to Matukas this year to help get his chassis sorted out, but he also changed his nitrous system around. The rules allow engines to have a single-stage fogger setup or a two-stage plate system. There were a few reasons for Cagle's swap to the nitrous plate and one of them was the ability to stagger the power. It has helped him get into the 8-teen range with his '70 Nova. Matukas also told us that torque converter selection plays into the equation. Some combinations can get away with a tighter-than-normal unit to help prevent too much power from hitting the 10.5-inch slicks. Matukas said the big-block entries are the opposite and need a looser one because of the heavy weight they run.
Matukas summed it up best, "Xtreme Street is tough but it is fun. I think it is one of the best classes out there."