A 1,000-HP Diesel in a Military Wrapper
Steve Ortner, of Belleville, Michigan always wanted a Hummer. When he finally got the chance to buy a ’94 civilian-spec Hummer H1, he was ecstatic. But there was a problem. “The Hummer had a naturally aspirated 6.2L engine, and it was so, so slow,” Ortner exclaimed. “There were times on hills when I was unsure if it would make it up to the speed limit!” He definitely had the vehicle he’d always wanted—but it was powered by the wrong engine.
“I had always liked stuff with power and reliability, so the 5.9L 12-valve Cummins was an obvious choice,” Ortner said. After acquiring the engine from an old Fed-Ex truck, he was off to the races. Since he knew he wanted a lot of power, he started with the engine block and worked his way up. The Cummins block was fitted with 14mm ARP main studs and a modified girdle, based on an Industrial Injection Gorilla Girdle. He kept the factory crank, but added connecting rods from Wagler Competition Products. A 188/220 camshaft from Hamilton Cams was also added, and the block was machined to accept 14mm head studs. After the bottom end was assembled, Ortner opened up the Hamilton Cams catalog to search for street heads, a valve spring package, and pushrods.
While a single turbocharger would’ve been the easy way to go, Ortner was more concerned with response and power, directing him more towards a compound turbo. With a high-rpm capable engine, Ortner went with a 66mm turbocharger as his smaller turbo and a monster 88mm BorgWarner SX-E for the larger turbo. He built a custom intercooler from a bare core and jacked the fuel to the stratosphere with a Farrell Diesel Service 13mm P7100 pump, Power Driven Diesel 5×0.025-inch injectors, Scheid Diesel 0.120-inch injection lines, and a FASS 220-gph lift pump. Estimated horsepower is somewhere around 1,000 hp even with the 13mm pump turned down.
Transmissions can be a troublesome part of diesel swaps, but in this case, Ortner lucked out. A GM 4L80E easily fit in the transmission tunnel, and he was able to adapt the Cummins engine to the transmission via an adapter plate of his design. A Cummins-to-GM flexplate was also used as the final piece to hook everything together. GM 4L80E transmissions are desirable for diesels because they use an overdrive gear, they’re relatively light, and they’re extremely durable. For a racing gearbox that could handle the engine’s immense torque, Ortner dropped the electronic “E” and went with a J&H full manual valve body and performance transmission. The 4L80 features raised line pressures, aftermarket shafts, as well as a tough Yank Performance torque converter that stalls at about 2,200 rpm. Used in off-road race trucks, this converter is one that’s built to handle abuse.
The suspension was another area where Ortner turned to the off-road racing industry, considering most parts stores don’t carry lift kits for Hummers. He wanted his H1 to be fully capable, so he went with a Rod Hall Products long-travel spring and shock package. It was designed to give the truck a couple of inches of lift along with useful travel. The rest of the drivetrain was also reinforced, with a transfer case from an armored Humvee and ARB front and rear air lockers that work with the factory gearing. Ortner also up-sized in the wheel and tire department with 37-inch Pitbull Rocker XOR tires mounted on 17×9-inch Method Race Wheels beadlocks.
When he finished building his innovative Hummer, Steve Ortner now had enough power to pass cars on the highway—and just about everything else. He spends a lot of time in the sand where the Hummer shines, as its independent suspension, huge wheels, massive tires, and immense diesel torque form the perfect combination. So what’s next? “I need to find a four-wheel-drive dyno in the area and start leaning on it,” he described. Ortner also attracted enough interest in his personal Hummer conversion that he’s now building examples for customers. “I had a lot of friends help out with this one,” he replied. “Casey Curtis, Ed Larsen, Carl Sparks, and Chris Reiter. We all decided we wanted to do more. There are about three in the shop right now—and I don’t see things slowing down any time soon.”
Estimated horsepower is now somewhere around 1,000 hp.
ARB 4×4 Accessories
AutoMeter Competition Instruments
Farrell Diesel Service
FASS Diesel Fuel Systems
Industrial Injection Diesel Performance
Method Race Wheels
Pit Bull Tires
Power Driven Diesel
Rod Hall Products
Scheid Diesel Service
Wagler Competition Products