From Homegrown, Pro Stock Duramax To Triple-Turbo, Mechanical Monster

It’s been on the scene since 2008, in one form or another. From Pro Stock to Super Stock, a big single turbo to compounds and then triples, and common-rail to mechanical injection, the name Cummins Killer is one of the most recognized names in competitive truck pulling. If you’ve been to a national-caliber event in the Midwest over the past decade, chances are you’ve seen it in action. Some of the biggest names in the Duramax aftermarket have been onboard with the truck’s various parts combinations over the years, and its crew has enjoyed a host of dramatic wins—along with its fair share of on-track carnage and unexpected setbacks. Through it all, they’ve kept forging ahead, often even reinventing the game…

We recently sat down with Wes Kusilek and driver Craig Dickey to look back on the truck’s storied past. From revving up the fans with its contentious name, to innovating and pioneering their own components, to pushing the vertical limits of the Duramax platform, along with making in-depth repairs in the pits, there is zero idle-time in the Cummins Killer camp. For 2021, the team has plans to grow even more comfortable with the new, triple-turbo, P-pump’d Duramax under the hood of version 3.0. If you have time this summer, make it a point to come out and witness this one-of-a-kind machine storm down the track. Believe us, everyone deserves to see this cut-tire’d monster tear through dirt.

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The original Cummins Killer was the brainchild of both Wes Kusilek and his father, Chris. Believe it or not, and as is evident from this photo taken at the 2009 Scheid Diesel Extravaganza, the O.G. Cummins Killer was essentially nameless (although the Kusilek’s often referred to it as “Homegrown”). Built to compete in the Pro Stock diesel truck class, which allowed a single map groove 3.0-inch inducer turbo at the time, the truck was always up against stiff Cummins competition.

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So what kind of parts did the Kusilek’s Pro Stock Duramax engine sport back in the day? In 2008, one of the recipes included a GT42-based 3.0 charger, SoCal Diesel heads, a belt-driven Industrial Injection Grand Poobah CP3 on top of a stock CP3, and 105-percent over Industrial injectors. “Industrial Injection gave us a lot of parts to test back in the day,” Wes recalled. As the years progressed, Wes and crew switched from a GT42-derived turbo to a GT45-based one, then got onboard with Precision Turbo & Engine. Literally always trying new things, here you can see one of the two exhaust manifolds the Kusileks pulled from a 4500 series Duramax after a set of fabricated headers didn’t produce the results they were after.
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Having been in the truck pulling game for well over a decade now, Wes and Craig have lived through a host of rule changes—some of the biggest of which have been turbo-related. Back when map groove limits were just starting to be enforced, Wes found that while a .250-inch map groove had to be run in one organization, they didn’t have to be in another. “So, we pulled the .250-inch charger after the first pull, changed to a no limit map groove turbo in the trailer on the way to the next hook, and put 50 feet on everybody that night,” he told us. “But back in those days that was 100-percent legal.”
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Always finding new ways to win with common-rail injection, Wes and company showed up to the 2010 TS Performance Outlaw event with a triple CP3 arrangement—a wild innovation for the time. A one-off gearbox the Kusilek’s designed themselves, and driven off of the crank, allowed the system to work, and also provided room for growth if even more CP3’s were needed later. All three CP3’s employed here were 10mm stroker pumps from Exergy Performance. One 10mm CP3 is known to support 800-rwhp…
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As fate would have it, Wes ended up taking the Pro Stock 3.0 win at the 2010 TS event, edging out 11 of the toughest-running Cummins-powered trucks in the nation. But on top of that, it was the first event that the GMC donned the name “Cummins Killer.” There could not have been a bigger statement made, and pulling fans either loved the truck instantly, or loathed it completely.
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A few years down the road, the need to keep up with massive common-rail injectors demanded the CP3 arrangement be grown to include five pumps. In 2018, when this photo was taken, Cummins Killer II was in the midst of one of its best years in service. The overspeed issues had been ironed out with the big single and the engine proved highly reliable at 2,300 to 2,400 hp. In fact, Craig told us he only had to adjust the valves once the entire season.
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On to Super Stock they went, big single turbo and all. Thanks to Wagler Competition Products’ billet-aluminum air-to-water intercooler, which essentially replaced the factory intake (and in this case was port-matched to the heads), a Pro Stock tractor turbo was mounted in front of the engine. The compact packaging eliminated the lengthy intake piping and complexity that is traditionally associated with most air-to-water units. Over the course of the next four years, everything from a 5.1-inch to a 5.5-inch charger would be tried, the massive snails coming from either Columbus Diesel Supply or Wimer Fuel Injection & Turbo.
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In the upper tiers of competitive truck pulling, people take notice when you win —especially the competitors you beat. When Wes rolled into a major event with arguably the most aggressive DOT tires on the market under Cummins Killer, Nitto Mud Grapplers, everyone else thought he was nuts. In a sport where convention wisdom at the time dictated that all-terrain tires were the “only way to win,” it appeared to most that the Kusilek’s were setting themselves up for failure. Long story short, they were wrong. Wes won, and opened a lot of eyes in the process.
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Version two of Cummins Killer blasted onto the scene in 2012. The GMC body was obtained through the purchase of a rollover, and was pieced together with dealership parts from there. This era would also mark the point in time when Jeremy Wagler entered the picture. After trying a set of his cylinder heads, Wagler (and many of his future innovations) became an integral part of the Cummins Killer engine program.
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So what got Wes and Craig and the guys interesting in bumping up from Pro Stock to Super Stock? After competing at local events that allowed them to run cut tires, they found that—even though they were underpowered in their class—the tremendous bite the cuts provided kept them neck-and-neck with the competition. Of course, the ability to run cut tires wasn’t the only reason they made the move. When we asked Wes what the determining factor was he laughed and said: “We bumped up to Super Stock because we’re always willing to try different things. Plus, when everyone said we couldn’t win in Super Stock or with a single turbo we knew we had to try it.”
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So what was life like running a 5.5-inch turbo that’s normally reserved for 680 cubic inch IH and John Deeres? How about 110 to 115 psi of boost, 6,500 rpm, and a Wagler DX460 that would eventually turn out 2,980 hp on the engine dyno! “You didn’t want to pull it down below 4,800 rpm,” Craig said, but at full song it was positively nasty. With this parts recipe and when the conditions were right, Cummins Killer was always poised to pull off an upset in the Super Stock class, despite being considerably underpowered.
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Not only did the Mud Grappler gamble work back in 2013, it started a trend. “A weekend later, everyone had them on their truck,” Wes told us. “But it wasn’t just the tires…we had a great year that year in 2013.” It’s worth noting that in the years leading up to the Pro Stock class switching to cut tires, virtually every competitor ran a set of Mud Grapplers at one point or another.
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This is one major reason why the DX460 Duramax in Cummins Killer was nearly able to push common-rail injection to 3,000 hp. The Bosch MCRS (Module Common Rail System) injectors out of a Cummins QSK60, a 60.2L V-16 used in mine haul trucks and commercial applications, moved copious amounts of fuel volume with very low duration. They were also capable of supporting 2200 bar (or roughly 32,000 psi) right out of the box. Once S&S Diesel Motorsport got their hands on a set, they were made to work in the DX460 and several hundred more ponies were brought to the table.
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According to Craig, who took over most of the driving duties in 2016, the first full year in Super Stock was rough on turbos. “We were overspeeding them all the time that first year,” he told us. “But after we put water in front of them it helped to slow them down, and we quit overspeeding them.”
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In 2019, the team turned to a compound turbo arrangement to get them down the track. The Pro Stock tractor turbo was combined with a 4.4-inch charger, both from Columbus Diesel Supply. Here, you can also see the shielded driveshaft that extends from the crank to the CP3 gearbox positioned well forward of the axle.

Stuff 

You Just Can’t Make Up!

In addition to being infamous for trying unorthodox, out-of-the-box things, the Cummins Killer crew is also well-known for making last-minute repairs that somehow, some way allow the component to hold up for one last hook.


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While Wes, Craig, and all parties involved weren’t able to realize the full potential of S&S’s MCRS injectors (said to be 3,500 hp), that was not the only reason behind the switch to mechanical injection. Among many holdups, a key sticking point was the Bosch Motorsport MS15.1 stand-alone ECM not quite having enough electric current to fire the injectors at the rate they needed them to. “We aren’t mechanical guys. We still aren’t,” Wes stated. “But it was an uphill climb to constantly keep the common-rail guys innovating. Do I think common-rail can be made to compete? Absolutely. It just needs the right amount of R&D, money, and time poured into it.”
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Running on the ragged edge has always been everyday life for Wes, Craig, and everyone else involved in Cummins Killer, which at times means they’re very busy in the pits between hooks. Since entering Super Stock, they’ve encountered a host of issues and setbacks, including blowing injectors out of the heads, killing turbos, melting or damaging pistons, cracking blocks, and one time even exploding the bearings in the drop box. Despite being deck-plated when they were running the factory Duramax block, crankcase failures proved both common and crippling. “When you’re competing at 2,600 to 2,700 hp on the factory Duramax block everything is fine,” Craig said. “But any time you try to make and compete at 2,800 or 2,800-plus the block splits right at the oil galley by the mains.” We captured this image at the 2019 Scheid Diesel Extravaganza, where Craig was knee-deep in a sleeve and piston replacement on the DX460 engine in order to make the call that evening.
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Before the mechanical DX460 debuted in the fresh Cummins Killer chassis at the track, its new engine was on display at the 2019 PRI Show. Complete with a gigantic turbo, a hulking P-pump in the valley, and a floating core air-to-water intercooler out front, show-goers and those on social media were just as floored as everyone else in the motorsports industry. Deservedly, Wagler Competition Products earned the JE Pistons Masters of Motors award for the all-billet Duramax.
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Lurking behind the P-pump at PRI sat a massive Wimer Pro Stock tractor turbo. Seeing this, attendees had reason to believe that, in addition to the mind-blowing decision to switch to mechanical injection, Cummins Killer would be back to running a big single in 2020. This would not be the case, as three turbos would make the cut.
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By the time the DX460 Duramax was dropped into the new Super Stock GMC, the massive near-6-inch Pro Stock charger was replaced with a triple-turbo arrangement. Each Holset-based, T6 charger was sourced from Wimer and features a billet, 4.1-inch inducer compressor wheel. Two 4.1’s serve as one large atmosphere unit in the two-stage configuration, while the high-pressure 4.1 resides beneath them, and slightly forward along the tube chassis.
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The massive, billet 8-cylinder P-pump in the valley was built by Wimer Fuel Injection & Turbo. It was rumored to be sporting 16mm plungers at the 2019 PRI Show, but Wes and Craig disclosed that a 17mm pump was in charge of fueling the engine when Cummins Killer III debuted last summer.
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The 17mm Wimer pump feeds fuel to eight John Deere-based injectors. Also built by Wimer, the John Deere units feature billet, triple-feed bodies, and 5-hole nozzles. How big the holes are we don’t know—but the 17mm pump is currently set to flow 1,080 cc’s of fuel. There is one thing Craig is very sure of, and that’s the fact that the mechanical Duramax isn’t as fuel efficient as the common-rail. It consumes a whopping four gallons of diesel per pass vs. the common-rail only using two.
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So how much different is the driving experience with triples as opposed to a big single? Craig Dickey told us that, thanks to their ability to recover or re-light after engine rpm drops, they make the truck much easier to drive. “Triples are easier to run because throttle response is better. I can start the pull at 5,000 rpm, hook up to the track and bog the engine down to 4,300 and then bring it back up. The single would never let you get that low. It would snuff or fall off and never come back.”
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As you can see from this angle, the air-to-water intercooler core was packaged on the passenger side of the engine. With three turbos and 148 psi of boost involved in the truck’s full-pull efforts, it’s this elaborate cooler’s job to make sure intake temps and EGT remain at reasonable levels. Of course, by chilling the engine’s incoming air, it’s good for a solid horsepower contribution all on its own, too.

“One year at Scheid’s, pieces of a Busch Light can were used as shims in the rear pinion yoke. We took third place that night!
—Wes Kusilek

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Though it’s not exactly normal for the Kusilek’s to outsource work, they did turn to Randy Kleikamp and the pulling experts at Performance Pros for the IFS tube chassis and tilt body setup on Cummins Killer III. Kleikamp and his crew responded by building a chassis that looks as good as it performs. As for the body, it’s one of the the only steel versions in the Super Stock class. Hey, at least there aren’t any fake headlights or tails (they hate those)!

 

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