For release: Aug. 21, 2006

TEAM HUMMER H2 EXEMPLIFIES THE 'STOCK' IN STOCK-CLASS RACING

RENO, Nev. - In grueling off-road racing, simply finishing a race can be a rewarding experience. The Team HUMMER H2 racing vehicle has done more than finish races - it wins them. In fact, the H2 - piloted by driver of record Josh Hall - won every race entered during 2005. This impressive record is even more amazing when considering the H2 racing vehicle competes in "stock" classes, which demand few deviations from production vehicles.

The 2006 Team HUMMER H2 is racing again in the challenging Best In The Desert (BITD) and SCORE off-road racing series, including the prestigious Baja 1000 race in Mexico. It competes in the BITD 4100 and SCORE Stock Full-Size classes.

"The HUMMER H2 is well suited to off-road racing," said Thad Stump, engineering liaison for Team HUMMER. "It's a tough vehicle that holds up well in the stock class because it's built to handle off-road driving."

Following the rules of BITD and SCORE stock classes, the H2 racing vehicle is based on a regular production model and altered only in ways to make it conform to safety regulations and other open areas of the rules, such as shocks, springs and tires - items that don't alter the fundamental layout, design or performance of the vehicle, but enable it to withstand the rigors of racing long distances at high speed.

"It's remarkable just how much of the H2 racing vehicle is unchanged from production models," said Stump. "There are even items that the rules allow to be changed, but we've kept with production parts because they're either stronger or perform better than specialized components."

Experience gained from using stock parts on the racing vehicle has resulted in changes to production models that have enhanced the H2's performance and durability.

At first glance, the Team HUMMER H2 looks like a production model, but is outfitted with graphics and decals. The body is stock, but the windshield and other window glass are removed - allowing increased frontal ventilation during a race and an easy exit in case of a crash. Side door windows have Plexiglas inserts and the rear side windows are covered. Reinforcements are made to the underside of the front-end sheet metal to provide additional support and protection of the radiator and other vital components that are in the first line of fire when bounding over jumps in the desert.

The H2 racing vehicle also features an impressive bank of HID lamps that literally light up the desert during night racing. The tail lamps, markers and brake lamps are functional. The H2 also carries mandatory amber and blue lamps on the rear of vehicle, which are always illuminated during a race. The amber light is carried by all competitors for increased visibility and the blue light is required for the H2's racing class.

Although the racing lights and graphics give away the H2's intentions, it still "sits" like a production model. That's because the suspension and ride height are not significantly different from stock. Even the wheels are factory pieces, not specialized racing rims.

Conforming to the rules, the chassis and suspension on the Team HUMMER H2 are very close to stock. No frame enhancements are allowed, so the racing vehicle rides on the same, sturdy ladder frame as all production H2 models. The racing vehicle also uses the factory control arms, front and rear axles - including axle ratios - transfer case, E-Locker rear differential, power steering system and brake system. The antilock feature of the brake system is disabled for racing.

"The rules allow the rear axle to be reinforced, but we didn't do it on the H2," said Stump. "It didn't require reinforcing."

Racing shock absorbers can be used and different springs can be used, as long as they are the same type as stock, i.e. leaf springs, coil springs, etc. For the Team HUMMER H2, special Fox Shox hydraulic racing shocks with external fluid reservoirs are used. The front racing shocks are considerably taller than stock versions, requiring modification of the mounting location on the control arms. One shock is used with each front wheel, while four shocks dampen the rear axle.

"Racing shocks are an absolute necessity because of the heat generated after only a few minutes of high-speed racing," said Stump. "Stock shocks, even though they're designed for off-road driving, are not designed for the sustained high-speed driving that occurs during racing - it's simply two different types of driving."

As for the springs, the Team HUMMER H2 uses stiffer front torsion bars from heavy-duty GM trucks; the rear springs are the factory-installed H2 parts. The team experimented with other aftermarket racing and off-road springs, but the stock springs proved to be the best performers for the racing vehicle. The shocks and springs combine to provide a ride height that is very close to stock.

The racing H2 rides on stock 17-inch wheels that support 37-inch-tall BFGoodrich racing tires, which are based on the company's production Baja T/A tires.

Per the rules, the racing H2's engine is based on the production 6.0L small-block V-8 engine. Minor internal revisions are allowed, as long as the engine retains the production-type cylinder block and heads. To this end, the racing vehicle's engine receives a slight boost in compression, which helps it produce about 345 horsepower - a 20-horsepower jump over stock. Interestingly, the engine relies on the stock air cleaner system, not a racing intake system.

"We tried some aftermarket systems and were able to prove the stock system made the most power," said Stump. "The stock air cleaner system is a great design."

A racing exhaust system is used, replacing the stock system. The 6.0L engine is connected to a stock Hydra-Matic 4L65 four-speed automatic transmission, which receives only minor calibration changes over stock. Also, stock engine and oil coolers are used. A larger-capacity radiator is used, owing to the demands of high-speed, hot-weather racing in the desert.

Perhaps the area of the racing H2 that is the most noticeably different than stock is the interior. That's because it has been stripped of all its upholstery, trim and convenience features and replaced with a purposeful racing cockpit. The trim panels, carpeting and other accoutrements are removed in to help offset the weight of a custom, protective roll cage, which snakes throughout the cabin. A fire suppression system and fire extinguishers are located throughout, too, and the only thing carried in the cargo area of this H2 is a 55-gallon fuel cell and spare parts.

The stock front and rear seats are replaced with two front racing seats - one for the driver and the other for the co-driver. Racing five-point safety harnesses also replace the factory safety belts (the air bags are deactivated for racing). The instrument panel is stock and all the gauges function as original, but the climate control/radio stack at the center of the dashboard has been replaced with a custom control panel. Also, the factory gauges are augmented by a PI Research data logging system, which provides feedback on key powertrain operations. A tracking system provides real-time positioning information that allows race officials and anyone with an Internet connection to track the vehicle during a race. This helps ensure the vehicle accurately followed the course and provides location information in case of a crash.

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Nick Richards
HUMMER Communications
Phone: 313-665-9292
E-mail: nick.richards@gm.com