If you're among the thousands of enthusiasts wearing the DSM badge, you've probably heard of David Buschur. Buschur has been racing DSMs for the past 12 years and has eclipsed more milestones in the Diamond Star arena than anyone in the sport. The Buschur Racing team was the first to break the 12-, 11-, 10-, 9- and most recently, the 8-second barrier down the quarter.
Buschur's passion for the sport thrived into a highly successful Buschur Racing specializing in Diamond Star performance. Buschur and Buschur Racing have developed many innovative products that proved to be key to a lightning quick DSM. We caught up with Buschur so he could show us his new tube-frame racer that's about to break another milestone--the 7-second barrier.
As you all know, Buschur was racing a back half Talon, which debuted in July '98. The Talon would eventually post a 9.43 at 147 mph before it was sold in late '98. In late 1999, Buschur felt the need for speed again and built a full tube-frame Talon. He knew the old back-halved car was too heavy, weighing in at a hefty 2,450 lbs and all the power from the engine was wasted on pushing the tank down the track.
Buschur got the ball rolling by purchasing some aftermarket fiberglass pieces for a 1998 Eagle Talon and dropped them off at Gary Reese Chassis shop. Starting from the ground up, Gary Reese and Doug "Buzz" Johns built the chassis with an array of chrome-moly tubes carefully bent and meticulously welded in place. The chassis meets NHRA and IHRA 25C-1 specifications for up to 6.00-second e.t.s.
Strange components are found throughout the Talon, as the DSM uses Strange shocks up front, while Strange dampers are on call out back. Heavy-duty Stange disc brakes and calipers are in charge to bring the eight-second sled to a stop with the help of a Straude drag chute out back.
While the chassis was being built, Buschur was busy building the powerplant. A 4G63 bottom-end was disassembled and cleaned before sending the block to Wakeman Auto Parts for boring, honing and decking. The block was bored .010 inches over to accommodate 9.5:1 low-compression JE Pistons. Eagle rods replace the heavy stockers and swing on a custom-prepped crankshaft. The factory crankshaft retains the stock stroke, but has been knife-edged and balanced for reduced rotating weight and quicker revs. Buschur blueprinted the bottom-end using Hasting rings and all-new components. A custom built Buschur Racing oil pan seals the bottom-end up.
Up top, a Buschur Racing Stage four cylinder head was ported for maximum flow. To enhance flow, resist valve float and handle 9500 rpm shifts, the head was stuffed with heavy-duty hardware. The stock valves were replaced with 1mm-oversized stainless steel valves from SI Industries for increased airflow. Ensuring the valves don't float at high rpm, stiffer HKS springs and lightweight Crower titanium retainers were added to the mix. Conducting valvetrain orchestration is a pair of HKS 272-degree billet bumpsticks.
A cast-iron HKS turbo manifold directs exhaust gases to a single turbo, where it propels the turbine wheel of a T-61 O-trim turbocharger. On the strip, the 4G63 is regulated to 35 psi by a HKS Racing wastegate and an HKS EZ electronic boost controller. An extra large Spearco front-mount air-to-air intercooler chills the charge air as it's fed through 3-inch stainless-steel I/C piping into a custom Buschur Racing sheet metal intake manifold. At the manifold, it's channeled through the short runners where it's combined with high-octane juice from four 660cc injectors. Mounted in the trunk is a three-gallon race cell and Weldon fuel pump, which supplies juice to a Buschur high-flow fuel rail for the thirsty injectors. The engine management on the Talon was a big surprise, as the DSM runs a factory ECU combined with HKS VPC and GCC piggyback computers.
Although the DSMs are known for great powerplants, the driveline is a real heartbreaker. Many of the top DSM racers in the country have experienced transmission failure more times than he'd like to remember and Buschur was no exception. Having spent enough money on transmissions to make any bank account dwindle, he decided to use a more stout aftermarket piece. Since the engine in the Talon was mounted in-line and was running in RWD trim and not AWD, Buschur utilized a two-speed Powerglide. His old back-halved car also used a Powerglide with great success. David enlisted the help of Janis Transmission in Akron, Ohio to help set up the two-speed Powerglide. Vince Janis worked his magic and the result is an extremely consistent pass each and every time down the track. The Powerglide uses a Multi-Performance 5500 converter and Hurst 1/4 stick shifter.
As this article goes to press, the Talon has already run a best of 8.04-sec. at 172.8 mph, which is far from the car's full potential, according to Buschur. From reviewing the Edelbrock on-board data-logger, he found that the converter was slipping a whopping 24-percent from the flywheel to the driveshaft. Buschur feels if he can work the bugs out of the converter, the Talon can run deep into the sevens.