"Everybody has a sense that diesel engines can pull stumps," says Gale Banks, "but most people don't understand that we haven't even begun to scratch the surface of what diesels can do." A prime example of that is his custom tube-chassis GMC Sierra road racer equipped with a modified 6.6-liter twin-turbo Duramax diesel. The vehicle is limited to 650 horsepower and 800 pound-feet of torque right now, but Banks says there's no reason why the block couldn't put out 20 percent more if tuned differently. For now, he's content to keep it down and take it to the track. Not sure we'll ever see it run against the R10 or pulling a fifth wheel, but this could open a whole new frontier as diesels make their way into the hearts and minds of more than your average hard-core truck guy.
Without giving too much away, Banks Engineering has modified the block and oiling system and uses a seven-stage, 16-quart dry-sump unit. There's a custom crankshaft, 4340 billet connecting rods, 14.5:1 compression racing pistons, a billet oil pan, and custom-cut roller camshaft and lifters.
The front end uses a conventional double A-arm configuration with coilover shocks and helper springs.
Wheels and Tires
The front of the truck is held in place with 25.5x12.0R17 Goodyear Racing Eagle tires mounted on 17x13.5-inch Bogart Racing aluminum wheels. Rear rubber is 28.5x14.0R17. For stopping power, Banks uses Wilwood six-piston billet-aluminum calipers, clamping on 13-inch rotors with modified cooling vanes.
This is all race dress. After a lot of trial and error, Banks settled on a Weismann Quickshift six-speed transmission that uses an internal oil pump and external oil cooler. All they'll tell us about the clutch is that it's "experimental." The bellhousing is magnesium.
The cab and roof of the body are made of steel and retain the GMC look; however, the remaining body panels are carbon fiber. Banks also had to custom design a rear wing and undercarriage pan to keep the massive amounts of air being pushed around and under the truck flowing.
Banks decided to go with a Speedway Engineering-prepped full-floating Ford nine-inch rear axle, which uses a race-tech internal oil pump and external oil cooler. The race suspension is a modified three-link with Koni coilover shocks.
Massive twin Honeywell turbos sit underhood from the racing division of Garrett. Banks had to design a custom stainless-steel tube exhaust, electronically controlled wastegates, and a one-of-a-kind twin intercooler system.
Called by some the heart of any current-generation turbodiesel, the fuel injection system is a staggering example of Bosch-supported experimentation. The high-pressure common-rail system is capable of delivering enough fuel to the cylinders to produce more than 900 horsepower.