BLACK MAGIC

From Work Truck to 942 Rear Wheel Horsepower Beast

A lot of people buy diesel trucks knowing that they’re going to load them up with aftermarket parts as soon as they leave the lot. Looking at Daniel Dillon’s outrageously powerful Duramax, which has put down 942 rear-wheel horsepower and 1,858 lb-ft of torque, we figured he was one of those all-out kinds of guys. But that wasn’t the case. A couple of years ago, Dillon ordered a brand-new Duramax straight from the dealer with the intent of leaving it alone and using it as a normal work truck.

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In December 2012, after finding the exact LML-powered Duramax that he wanted at a dealership in northwestern Illinois, he jumped in with a buddy to go pick up his new ride. “I found myself going home empty-handed,” he says. When Dillon showed up at the dealership to pick up the nearly new truck, he found out that it had thrown a check engine light for low DEF and couldn’t even be driven. “The dealership replaced the sensor and delivered it to me the next day,” he adds. “But by then I was already online looking.”

Addicted to Modifying

Since Dillon had experienced emissions gremlins earlier than most owners (in fact, before he owned the truck), he scoured the Internet high and low for parts that would make his truck stronger, faster and more reliable. Within weeks, he 2011 had an H&S Mini Maxx, an MBRP 5-inch exhaust and an all-important FASS 150 lift pump.

“I was happy with it for a while, but the more I drove it, the more I wanted it to go even faster,” Dillon admits. He was on the prowl for even more power and soon had an upgraded transmission, along with a BorgWarner 75mm S400 out in front of the stock turbo. Since the truck was pulling plenty of air, he also put on dual CP3s to keep up with the fuel demand, running on what he calls a “risky 3,000 pulse width tune.” Dillon put a couple of thousand miles more on his truck before he decided to go with a full build.

“I noticed that Wehrli Custom Fabrication was introducing some pretty cool parts for the LML platform, so I decided to give them a call,” he says. “I’m not sure if Jason [Wehrli] believed that I was going to build up the truck as much as I wanted because it was still so new and it was running perfectly fine. But he always returned my calls right away and talked me through all my plans, so within a few months it was at his shop.” What they had planned for the truck was big, with the engine, transmission, and chassis all receiving modifications. In fact, the LML engine itself (which was still running fine) was unceremoniously yanked out of the truck, signaling the start of the big build.

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The Duramax engine in Daniel Dillon’s 2011 Chevy is quite a piece. Built by Wehrli Custom Fabrication, the powerplant puts down 942 hp to the wheels. It was assembled from the bottom up with a stud girdle, ARP main studs, Carrillo connecting rods and Mahle pistons. The heads were also lightly ported by Wehrli and got a set of upgraded valve springs and pushrods.

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Special attention was paid to keeping the exhaust side from frying the firewall. The turbo piping from the small to large turbo snakes along the back of the engine and is heat-wrapped to reduce under-hood temps.

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The custom compound turbo kit was also built by Wehrli Fabrication and features an Engineered Diesel S366 turbocharger. A billet wheel improves both reliability and flow.

Concrete Foundation

Since the LML blocks are already so strong from the factory, the block itself received very little work other than a girdle and main studs, which replaced the factory bolts. The crankshaft was also left stock, but the connecting rods were replaced with much stronger Carrillo versions and the pistons are Mahle oval-bowl designs. The engine also had a set of ARP head studs installed and the factory cylinder heads were ported, polished, and fitted with performance valve springs. Once upgraded, the engine was reassembled by Wehrli Custom and stuck back in the truck. The focus now would be on making some serious power.

Compounds and Twins

Because the factory-sized injectors can only spray so much fuel before they just start making heat, one of the major steps in the build was adding a set of Exergy Engineering 80% over injectors fed by twin CP3 pumps modified by Wehrli. That way fueling wouldn’t be an issue, even as power approached 1,000 rear-wheel horsepower. The stocker/S475 compound turbo setup wasn’t going to cut it either, so two billet-wheel turbos from Engineered Diesel were secured, one 66mm S300 and the other an 84mm S400. Again, it was Wehrli who built the outrageous orange piping to funnel the charge through an AFE intercooler.

THEY SAY IT WILL NEVER END, AND I’M OKAY WITH THAT.

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The larger of the two turbos in the compound setup was supplied by Engineered Diesel and measures 84mm in inducer size. The S400 frame charger breathes through an aFe air filter and combined with the small turbo produces a massive amount of boost.

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Plenty of fuel is available thanks to a Wehrli custom dual CP3 kit, which feeds a set of Exergy Engineering 80% over injectors. Tuning for both the ECM and TCM was handled by Motor OPs.

Transmission Work

The transmission also received appropriate modifications in line with the engine upgrades and was built by, you guessed it, Wehrli Custom. The Allison was equipped with both billet input and output shafts, a billet hub and planetary gear and Raybestos clutches. A SunCoast converter is the final piece which helps put the power to the ground.

With some final engine and TCM tuning by Motor OPs, the truck was sent to the dyno and then put on the road. With nearly 60,000 miles to date on his ride, you might think that Dillon is happy with the current state of things—but no. “I’m very happy with my truck, but there’s still work to do,” he claims. “It’s going back to Wehrli this winter for driveline upgrades and a little more under the hood.” As he contemplates even more for his truck, his last line puts it all in perspective: “They say it’ll never end, and I’m okay with that.”

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While making crazy power is fun, getting it to the ground reliably is even better. Again, Wehrli was tapped to build a transmission for Dillon’s truck, using a combination of his own recipe along with a Sun Coast converter and PPE deep pan to dissipate heat. The Allison 1000 has been reliable so far.

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Four Fuel Hostage wheels give the truck a solid stance, and are wrapped in 305/50R20 Nitto 420S tires for traction.

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To control axle wrap and help the truck somewhat hook up in two-wheel-drive mode, a set of Cal-Tracs traction bars were added to the otherwise-stock suspension.

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The exhaust is a simple and free-flowing MBRP 5-inch design that runs from the turbocharger back to over the rear axle.

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Lots of engine monitoring is available thanks to both analog gauges and an H&S monitor. Boost, rail pressure, transmission temperature and EGT can all be logged under full-throttle conditions.

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The LML was left in its factory black color, but the corner lenses were replaced with cool smoked LED lights.

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The grille was kept stock aside from a clean, blacked-out Chevy bowtie.

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Even considering the Chevy’s wide stance, you’d never know it was packing such serious horsepower. It’s a sleeper for sure.

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942 REAR-WHEEL HORSEPOWER AND 1,858 LB-FT OF TORQUE.

Specifications

2011 Chevy Silverado 2500HD 4×4

Owner: Daniel Dillon
Engine: 6.0L Duramax V8, Mahle pistons, Carillo rods, main girdle, main and head studs, ported and polished heads, performance valve springs
Air: Compound 66mm S300 & 84mm S400 turbos,
AFE BladeRunner intercooler
Fuel: Dual CP3s modified by Wehrli Custom Fabrication, Exergy Engineering 80% over injectors
Exhaust: MBRP 5-inch
Tuning: Custom tune by Motor OPs
Transmission: Custom built by Wehrli Custom Fabrication, billet input and output shafts, billet planetaries, billet hubs, Raybestos clutches, SunCoast torque converter, PPE deep transmission pan
Horsepower: 942 rwhp
Torque: 1,858 lb-ft
Wheels: Fuel Hostage, 20×12
Tires: Nitto 420S, 305/50R20
Extras: Cal-Tracs traction bars, H&S monitor