Remember when you were a kid, dragging a sled up a hill for a wild downhill ride in the snow? Well, what if the fun part was pulling the sled instead? That's the case with Clint Cannon's '02 Chevy 2500 HD 4x4. Light the fuse on this juggernaut, and it's virtually unstoppable, with 970 horses straining at the reins, pumping furiously at more than 5,000 rpm. Of course, more important for the task at hand is the amount of twisting force on tap.
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Cannon's engine compartment is far from stock. That's 970 hp and 1,781 lb-ft of twin-turbo LB7 Duramax power staring back at you when you pop the hood. |
Got torque? Yeah, in spades. The twin-turbo Duramax delivers an astounding 1,781 lb-ft of torque. That's enough to drag a 43,000-pound sled the length of a football field and spike the ball in the end zone too. And when it's not towing, this rip-roarin' rig cuts and runs through the quarter-mile in 11.4 seconds at 119 mph.
Just how did Cannon load up his pickup with so much firepower? Well, it helps that he's the owner and founder of ATS, a company that makes all sorts of diesel drivetrain upgrades, so he has access to the full resources of his shop and can pick all the needed components right off the shelf. And Cannon's truck serves as a test bed of sorts for his company's products (though we suspect that he also really enjoys dropping the hammer too).
Getting the LB7 6.6L Duramax to produce such a prodigious output is no simple task, however. A tremendous amount of testing and innovation went into this rig. And it's not merely about mondo power either, because an equal amount of engineering went into the chassis setup so the truck works smarter, not just harder.
Starting with the engine block, the innards needed to be both stronger and lighter to handle twin turbos that boost intake pressures to more than 80 psi. About 10 pounds of material was removed from the crankshaft alone, which then had to be shot-peened and cryogenically treated. Also, the counterweights were knife-edged for reduced resistance at high revs, and the entire rotating mass is precision-balanced. Fitted to the billet connecting rods are low-compression pistons (15:1 instead of the stock 17:1).
In addition to porting, the heads have oversized custom valves and springs with titanium keepers and retainers. The high-lift roller camshaft was custom-ground to ATS specs. Keeping the engine from tearing itself apart required 240,000-psi head studs and main bearing studs.
The turbocharger pair is an ATS Aurora Compound Turbo System. For quicker spool-up on the low end of the powerband, there's an Aurora 5000, and a prototype turbo handles the midrange and above. A 2-inch, high-flow wastegate with regulated balance keeps the boost and backpressure in concert. The boost control module controls the wastegate to elevate pressure and also backpressure to get air out of the engine. A fine balance between these two variables is required, with the backpressure slightly lower if possible.
Additional diesel fuel is provided by a second CP3 pump mounted next to the A/C compressor. In many high-horsepower Duramax applications, the common rail fuel pressure falls off quickly under heavy load. Not anymore with this setup. | 
Multiple stages of water injection are used to cool the intake air and keep the EGT around 1,000 degrees. | 
Other safety equipment includes an air shut-off plate that immediately blocks air to the big turbo in the event there is a disconnect from the sled. |