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  • 2015 Chevrolet Silverado 2500HD Speed Demon

2015 Chevrolet Silverado 2500HD Speed Demon

Full Circle

Jason Sands
Mar 9, 2018
Photographers: Jason Sands
When Michael Runk bought his ’15 Chevrolet Silverado 2500HD, he immediately liked the power and torque of the 6.6L Duramax LML engine, but he thought the truck could be a little faster. “At one point right after it was new, I had one of the fastest LML-powered rigs in the country,” Michael laughs. “I didn't mean to; it just sort of happened.” Like any diesel enthusiast, Michael started his upgrade process with ECM tuning, then turbocharger swaps.
After conferring with Cody Spaulding and Mike Graves of Hollyrock Performance, Michael then added nitrous oxide and an awesome transmission from Evan Drosehn at Limitless Diesel Performance. “That led to a best elapsed time of mid-12s on fuel—and an 11.46 at 120 mph with nitrous,” Michael recalls.
When we shot photos of Michael's ride, it was dialed back from its 11-second trim. However, “The nitrous is still on there if I need it,” Michael points out. In its current and past forms, the 6.6L engine remains bone-stock, with the exception of a set of ARP 625 cylinder-head studs and a keyed crankshaft. The air and fuel systems, on the other hand, are massaged quite a bit.
Photo 2/25   |   The engine bay in Michael Runk’s ’15 Chevrolet Silverado 2500HD is as clean as they come. Aside from a keyed crankshaft and ARP 625 cylinder-head studs, the 900hp 6.6L Duramax LML long-block is basically stock.
Fuel upgrades start with Michael using Fleece Performance Engineering’s CP3 conversion hardware to ditch the stock CP4 injection pump in favor of more reliable CP3 pumps. He then added a pair of 10mm Exergy Performance CP3s (one in the valley of the engine) using an ATS Diesel Performance Twin Fueler kit. A set of 100-percent-over Exergy injectors was added, as was a FASS Fuel Systems 150-gph lift pump.
The fuel system isn't the only part of the engine that received upgrades, as Michael has gone through several different turbo combinations. The setup presented in the photos is based on an HSP Diesel swap kit that’s highlighted by a BorgWarner S476 turbocharger prepared by Engineered Diesel and Pacific Performance Engineering up-pipes. Exhaust exits through an AFE Power 4-inch downpipe and intake air is chilled by a Mishimoto air-to-air intercooler. Michael doesn't want to have a shortage of nitrous, so he used some of the biggest pieces he could find from Nitrous Express, along with a Maximizer 4 progressive controller.
Photo 3/25   |   A very comprehensive BorgWarner S400 turbocharger mounting kit from HSP Diesel is a big part of the airflow package and features a fabricated ceramic-coated pedestal, cold and hot pipes, 3-inch Y-bridge, boots, and, of course, cold-air intake and airbox.
With a conservatively estimated 700 hp on fuel and 900 hp when nitrous is flowing, the stock LML driveline’s fortifying includes a full competition transmission from Limitless Diesel Performance. The Allison 1000 six-speed automatic on steroids features billet C2 and P2 planetary gears; aftermarket input, main, and output shafts; a shift kit; Raybestos and Alto clutches (in a top-secret combination); and a SunCoast Diesel Transmissions triple-disc torque converter. Michael also went a bigger step toward drag racing his rig by lowering the rear, reinforcing the front end, and adding high-traction Nitto 420S tires.
“The truck only has 19,000 miles on it in three years, because we spent a lot of time running it at the track,” Michael laughs. In the end, though, he says one of the best decisions he made was retaining its street qualities. “It's a great truck for driving when the weather is nice.”
Why retire an 11-second truck? Michael is going all-in, building a Pro Street drag truck. “It should have nearly double the power and weigh about half as much—so it should be just a little faster, right?” Now that its track time is minimal, Michael plans to start driving the ’15 much more. “It's still a great driver, and there were definitely times I wanted to give up, but in the end I'm so glad I built this truck.”
Photo 4/25   |   After a 68mm turbo grenaded, Michael switched to a non-variable-geometry BorgWarner S400-based unit from Engineered Diesel. He figures the big-frame ’charger’s 53 psi of boost helps the Duramax produce power numbers Mike estimates are between those achieved with nitrous oxide and without.
Photo 5/25   |   The stock CP4 high-pressure injection pump is replaced with twin Exergy Performance CP3 units, which are mounted using a combination of Fleece Performance Engineering twin-pump and ATS Diesel Performance Twin Fueler kits.
Photo 6/25   |   Michael dropped nearly a second off his rig’s best dragstrip e.t. with the aid of a healthy Nitrous Express nitrous-oxide system. The custom setup features a Maximizer 4 progressive controller and 0.125-inch solenoids. Michael also added a purge solenoid for consistency.
Photo 7/25   |   Mike has changed the truck’s exhaust several times. The setup shown here is a 4-inch AFE Power turbo-back that terminates in dual SoFlo Diesel Custom Stacks 6-inch miter-cut stacks.
Photo 8/25   |   The Allison 1000 six-speed automatic transmission in Michael's Chevy is extensively upgraded to handle almost any power level. Not only does the Limitless Diesel Performance gearbox have a SunCoast Diesel Transmissions torque converter, it also has a TransGo shift kit, aftermarket shafts, and billet C2 and P2 planetaries.
Photo 9/25   |   We asked Michael if he put Rancho shocks on his truck because it's a popular modification for drag racers. The answer there is “no.” The dampers are stock equipment in Z71 packages, like Mike's ’15.
Photo 10/25   |   Installing a lift pump is typically among the first upgrades a diesel enthusiast adds. Michael uses a FASS Fuel Systems 150-gph pump that consistently supplies the engine with fuel.
Photo 11/25   |   Solid traction is crucial in drag racing. So, to ensure his truck has plenty of grip, Michael uses Calvert Racing CalTracs traction bars.
Photo 12/25   |   Front and rear axles are stock with 3.73 gears in each, save for an AFE Power differential cover in the rear for a little extra heat dissipation.
Photo 13/25   |   Even with the nice bedliner, there's still room for a nitrous bottle. The black tank matches the bad-in-black truck, and it’s outfitted with upgraded bottle brackets and a pressure gauge.
Photo 14/25   |   New GM trucks leave the factory with nice interiors, so Michael doesn't feel there is a need for many upgrades. The mods on this rig’s cabin are either subtle or hidden.
Photo 15/25   |   The typical boost gauge and pyrometer grace the A-pillar pod, but the pieces are far from simple. These cool Elite Series recall gauges from AutoMeter Competition Instruments flash red when preset boost or EGT limits are exceeded.
Photo 16/25   |   Another interior concession to speed is a Dirty Hooker Diesel Dirty Alli-Locker box, which is cleverly hidden in the center console.
Photo 17/25   |   The next interior trick is a BD Diesel Performance staging limiter, which allows Michael to dial in a precise rpm and amount of boost as he leaves the line.
Photo 18/25   |   One of the most popular choices in street-strip tires is the Nitto 420S series. Michael fitted his truck with much larger wheels, along with 305/50R20 Nitto tread.
Photo 19/25   |   Michael likes the way BMF Wheels match his truck, so he bolted a set of 20x10 BMF Novakanes that add flair to the Z71 package.
Photo 20/25   |   The front bumper is stock, but a small Cree lightbar from SoFlo Diesel Custom Stacks is added to the front bumper. Michael also installed a set of SoFlo’s foglights.

Fast Facts

Year/Make/Model: ’15 Chevrolet Silverado 2500HD
Owner: Michael Runk
Hometown: Sykesville, Maryland
Odometer: 19,000 miles
Engine: 6.6L Duramax V-8, keyed crankshaft, ARP 625 cylinder-head studs
Fuel: FASS Fuel Systems 150-gph lift pump, twin 10mm Exergy Performance CP3 injection pumps, 100-percent-over injectors, Fleece Performance Engineering CP3 swap kit, ATS Diesel Performance Twin Fueler system
Air: BorgWarner S400 76mm turbocharger prepared by Engineered Diesel, HSP Diesel turbo-swap kit, PPE up-pipes, Mishimoto air-to-air intercooler
Exhaust: AFE Power 4-inch downpipe, SoFlo Diesel Custom Stacks dual 6-inch stacks
Programming: EZ Lynk with tuning by PPEI
Transmission: Allison 1000 six-speed automatic by Limitless Diesel Performance; billet P2 and C2 planetaries; aftermarket input, main, and output shafts; Pacific Performance Engineering deep pan
Horsepower: 900 hp
Torque: 1,500 lb-ft
Tires: 305/50R20 Nitto 420S
Wheels: 20x10 BMF Novakane
Suspension: McGaughy's Suspension 2-inch drop shackles, one leaf removed, CalTracs traction bars, Cognito Motorsports tie-rod braces, pitman-and-idler-support kit
Axles: 3.73 gears, AFE Power differential cover
Body: SoFlo Diesel Custom Stacks Cree LED foglights and lightbar
Interior: AutoMeter Competition Instruments recall gauges, Dirty Hooker Diesel Dirty Alli-Locker, BD Diesel Performance staging limiter
Fun Fact: The Silverado’s best 60-foot time is 1.63 seconds, which is pretty good for a 7,600-pound truck! Michael says the good launch is the result of perfecting his technique over many dragstrip passes.



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