2008 GMC Sierra: Fit For A Foreman

Even though 99 percent of North America’s population chooses to drive gas-powered vehicles, you can still find select areas where diesels dominate the landscape. Take the oilfields of the Great White North for example. Nils MacArthur resides in the oil-rich province of Alberta, Canada, makes a living in the oil industry, and (as is the norm in this region) drives a diesel. “There aren’t too many gas jobs running around up here,” he told us. “Anywhere there’s oil, there’s diesel trucks.”

Fit For A Foreman Modified Duramax Engine

The ground-up LMM engine build took place at Empire Diesel Performance. Billet main bearing caps, Empire main studs, R&R Racing Products’ billet-steel connecting rods, 15.5:1 hard-anodized Ross Racing pistons that feature Empire’s proprietary bowl design, and an Empire Stage 1 camshaft round out the bottom end. Up top, the heads were treated to mild street porting, upgraded valvesprings and push tubes, 100-percent-over injectors from Exergy Engineering, and H-11 head studs. One of PPE’s Dual Fueler CP3 systems was installed to support the larger injectors, and a FASS Platinum series fuel system takes care of low-pressure fuel supply. Replacing the factory intercooler is an all-aluminum version from PPE.

The ground-up LMM engine build took place at Empire Diesel Performance. Billet main bearin

Because Nils’ ’08 GMC Sierra is his lifeline out in the field, he initially built it to better handle the type of terrain it was often subjected to. Then, once the suspension lift, air springs, and mud terrain tires added the off-road functionality he was after, he focused his attention on the powertrain. As it turns out, through his longtime readership of Diesel Power, he was intrigued by the kind of work Empire Diesel Performance was doing (Aug. ’09 and Feb. ’11) and decided he wanted a quick-spooling, high-powered truck.

After making the 1,300-mile journey to Empire’s Iowa-based facility, the LMM Duramax was transformed into a rock-solid version of its former self, the Allison transmission was bulletproofed, and the truck left with a 900hp-capable package under the hood. With a compound turbo arrangement sourced and fabricated by Empire and a modifications list that reads like a PPE catalog, it’s now a completely different animal.

Fit For A Foreman 2008 Gmc Sierrra Drivers Side Front Three Quarter

With the DSP5 switch set to its second hottest performance position and the 37-inch BFG mud terrains on the truck, Nils’ big Duramax still made an impressive 890 rwhp on a chassis dyno. Adding some boost to the mix via wastegate tuning could yield well north of 900 rwhp.

With the DSP5 switch set to its second hottest performance position and the 37-inch BFG mu

Back on oilfield duty, Nils says the truck fits right in. “At any given time, you can have four to five heavily modified diesels on one jobsite, so I enjoy it,” he told us. In the end, what’s not to like about a truck that can go anywhere, do anything, make 900 hp, and break the tires loose at 80 mph? Now fully submerged in the diesel performance culture, Nils plans to retire the truck from the oilfields next year and turn up the wick even more.

For those who don’t know, oilfield work often requires people to live in remote areas for days, weeks, or even months at a time. And as you can imagine, lodging options (and paved roads for that matter) aren’t exactly abundant in the middle of nowhere. As a completions consultant in the oil industry, Nils uses his off-road-capable Sierra as a rolling office, which almost always has a 28-foot recreational trailer in tow. Needless to say, even at power levels approaching 900 hp, it’s still used to work, day in and day out.
For those who don’t know, oilfield work often requires people to live in remote areas for
Intake air first passes through this atmospheric charger from Precision Turbo and Engine. It features a ball bearing center cartridge and was fitted with a billet, 88mm compressor wheel. Thanks to the staged turbo arrangement and the ball bearing cartridge, it spools surprisingly well for its size. The plumbing was derived from PPE’s Twin Race kit, which required a few minor modifications in order to bolt up to the Precision turbos.
Intake air first passes through this atmospheric charger from Precision Turbo and Engine.
The high-pressure turbo in Nils’ compound system also came from Precision Turbo and Engine, and it too utilizes a ball bearing centersection. Its billet compressor wheel has a 71mm inducer. A 46mm external wastegate, also from Precision, bleeds off excess drive pressure and (for now at least) limits overall boost pressure to 70 psi on the street.
The high-pressure turbo in Nils’ compound system also came from Precision Turbo and Engine

Not cutting any corners, the six-speed Allison 1000 was treated to PPE’s top-of-the-line, Stage 5 transmission rebuild kit. The triple-disc torque converter and valvebody recalibration kit, along with a host of upgraded internals, makes the unit good for supporting more than 1,000 hp at the wheels. For extra fluid capacity and improved cooling, PPE’s aluminum deep transmission pan and performance transmission cooler added the final touches.
Not cutting any corners, the six-speed Allison 1000 was treated to PPE’s top-of-the-line,
Resting on a 6-inch suspension lift from BDS and Firestone air springs, Nils’ GMC sports a set of 37x12.50R17 BFGoodrich KM2 mud terrains on 17-inch American Eagle wheels. For extended range, Nils replaced the factory fuel tank with a 52-gallon cell from Titan.
Resting on a 6-inch suspension lift from BDS and Firestone air springs, Nils’ GMC sports a
Here you can see where the 4-inch MBRP exhaust system culminates in a custom, dual-exit setup, complete with two 5-inch tips. On another exhaust note (no pun intended), a set of PPE’s high-flow, ductile-iron exhaust manifolds and stainless steel up-pipes open up the exhaust track leaving the engine, bound for the turbos.
Here you can see where the 4-inch MBRP exhaust system culminates in a custom, dual-exit se