Jerad Wittwer owns Performance Diesel and feels it's very important to know and use the products sold in his St. George, Utah, store. "We built this Mega Cab to really push the envelope of performance and find out how much power the common-rail 5.9L Cummins engine can produce," Jerad says. Soon after purchasing the truck, Jerad and his technician, Kelly Evans, began the modifications. The first phase of the project included a set of twin turbos, a Bully Dog Triple Dog programmer, an ATS billet transmission, and bigger injectors. With these mods, Jerad was able to crank out 860 hp and win the 8,500-pound sled pull at the '06 May Madness in Las Vegas. Most owners would be satisfied with these results, but Jerad knew the truck had more potential.
You're looking at close to...
You're looking at close to $30,000 in engine modifications. The extensive power upgrades began with a complete engine teardown and rebuild with custom pistons for a lower compression ratio, stronger connecting rods, and 14mm head studs.
Engine Internals
After Jerad returned from May Madness, the technicians pulled the engine out of the truck and spent several months modifying the internal components. Some 13.5:1 compression pistons were ordered from Arias and mounted on upgraded connecting rods; the pistons had to be specially fly-cut to clear the larger intake and exhaust valves. The head was ported and O-ringed, and 14mm head studs were installed. The modifications to the motor were complex because almost all the products had to be custom made. Jerad estimates he has roughly $30,000 invested in the Cummins. Once all the internal engine modifications were finished, it was time to work on providing the diesel with the right combination of fuel and air.
A second beltdriven CP3 injection...
A second beltdriven CP3 injection pump was adapted from a Duramax kit to keep the rail at maximum fuel pressure when using the modified injectors.
Dual CP3 Pumps
A second beltdriven CP3 injection pump was added to feed the Bosch common-rail fuel system with enough diesel for 1,000-plus horsepower. The second CP3 came from a Duramax engine application and uses a PDI-built bracket to mount it on the Cummins. With dual CP3s, the rail pressure stays at a fairly constant 26,000 psi. A Bully Dog Triple Dog stacked with a Dr. Performance module handles the electronically controlled fueling. ATS provided a set of custom eight-hole EDM'd injectors, and a FASS fuel kit keeps the dual CP3s supplied with plenty of diesel.
 A custom water-injection kit...  A custom water-injection kit is used to cool air going into the engine. One stage of water is injected between the two turbos via a small copper line. The second stage is injected just before the intercooler. |  Peak boost pressure and EGT...  Peak boost pressure and EGT levels are stored during each pull. The 79 psi of boost is impressive, but the EGT is cooking at 1,600 degrees F. |  On the dyno, the 5.9L pounds...  On the dyno, the 5.9L pounds out 1,008 hp. Note the custom upper radiator hose routing to clear the second CP3 injection pump-you can see it bulging out from the high pressure. |