Diesels used to tow your race car. Now they are the race car. That’s not to say that heavy duty diesel trucks no longer perform mundane, utilitarian duties. After all, someone still has to haul Miss Piggy down to the bacon factory. However, the diesel aftermarket is doing a Krakatoa. These days, 7,000-pound street trucks are running 10-second elapsed times, and electronic diesel tuners—which add hundreds of horsepower and pounds-feet at the push of a button—are becoming as common as a diesel’s trailer hitch. Throw in the astonishing fuel mileage a diesel delivers in the wake of relentless spikes in gas prices, and it seems like only a matter of time until the diesel revolution launches its foray into traditional hot rodding.
How Diesels Work
From a performance standpoint, the fundamental design of a diesel has significant advantages that gasoline engines just can’t touch. A gasoline engine relies on fuel and ignition spark for combustion; a diesel operates on the principle of auto ignition. In lieu of spark plugs, the extreme cylinder pressure and heat produced by a diesel’s staggering compression ratio (between 17:1 and 20:1) initiates the combustion process. Detonation beats up bearings, pops head gaskets, and blows holes through pistons, but without ignition spark, diesels live happily in a world where detonation doesn’t exist. Combine all this with a turbocharger and the result is tremendous bottom-end torque.
Thanks to factory boost levels in the 24-30psi range, GM’s 6.6L Duramax cranks out 650 lb-ft at 1,600 rpm, Ford’s 6.0L Power Stroke produces 570 lb-ft at 2,000 rpm, and Chrysler’s 5.9L Cummins churns out 610 lb-ft at 1,600 rpm. “Since diesels aren’t limited to octane as with a gasoline engine, they can handle enormous boost pressures, making them exceptional ultra-high performance platforms to build upon,” says diesel tuner Gale Banks of Gale Banks Engineering.
