AN INSIDE LOOK AT TRUCK PULLING’S NEW 2.6 CLASS

Love it or hate it, smooth bore turbocharger rules are here to stay in truck pulling. Not only do they eliminate all the rule bending associated with the “gray area” map groove turbos of yesteryear, but they’re much easier for tech of cials to inspect. On top of that—and perhaps most importantly—they help level the playing  eld as far as horsepower is concerned. But even though smooth bore rules have favored the Cumminspowered trucks in the Pro Stock and Limited Pro Stock  elds to date (3.6 and 3.0, respectively), the same can’t be said for one of pulling’s newest classes: the Pro Street Diesel category.

-Advertisement-
-Advertisement-

After the Pro Street Diesel Truck class saw immediate success in the Lucas Oil Pro Pulling League’s Western points series, it was picked up by the Illinois Tractor Pulling Association (ITPA) for the 2017 season. The class mandates a 2.6-inch smooth bore turbo, air-toair intercooler, OEM driveline, and single rear wheel con gurations. Despite the obvious turbo limitation, competitors are still squeezing 800 to 850-rwhp out of their setups, and Cummins, Duramax, and Power Strokes mix it up on a nightly basis. You read that right: even V-8 powered Blue Ovals are competitive in this class.

To give you an idea what it takes to compete in the ITPA’s 2.6 class, we’ve pro led half a dozen of its toprunning trucks below. From P-pumped 12-valves to the steadfast Duramax to the 6.7L Power Stroke, it’s a diverse crowd to say the least.DW

DW-1801-ITPA-02A

DW-1801-ITPA-02B

While the Duramax and Power Strokes that hook in the Pro Street Diesel class are very competitive, like all pulling classes most competitors opt for Cummins power. Drew DeClerck is one such competitor, and he’s built one of the nastier vehicles in the field. His ’97 Dodge sports a built 12-valve 5.9L Cummins, the venerable NV4500 manual transmission, and has been stretched courtesy of a 10-foot bed.

DW-1801-ITPA-03

With the help of R&D Fuel Injection’s Ryan Lenehan, Drew put together a solid parts list for the 12-valve, which was built at his family’s shop, DeClerck Custom Machine. The battle-ready 5.9L utilizes the factory forged crank and rods, forged-aluminum pistons, and ARP fasteners throughout. The head was ported and fitted with oversized valves at Nye’s Automotive, and (due to the Pro Street Diesel class not permitting the use of runner style intake manifolds) Drew designed the one-piece intake manifold you see here.

DW-1801-ITPA-04

Looking for an edge in air flow, Drew turned to Barder Turbo Service for his smooth bore charger needs. The six-blade, 66mm billet compressor wheel unit sends boosted air through a Spearco intercooler on its way toward the engine, and it bolts to a T4 Steed Speed exhaust manifold.

DW-1801-ITPA-05

Not cutting any corners on the fuel side of things, Drew’s engine employs a 13mm P7100 from R&D Fuel Injection, which makes use of an Ag governor. The 13mm pump routes fuel to a set of Hart’s Diesel high-flow injectors. As for low-pressure fuel supply, Drew kept things mechanical there, too. A waterman lift pump (driven off the front cover) feeds the 13mm beast a steady diet of diesel.

DW-1801-ITPA-06

In the cockpit, Drew buckles into a custom race seat fabricated by his father and works the throttle by hand. Power is transferred through an untouched, 315,000-mile NV4500 transmission via a triple disc clutch from Kenny’s Pulling Parts and Machine. The combination of fourth gear, Low range, 4.88 gears, and the engine turning between 4,200 and 4,600 rpm makes for considerable ground speed as Drew’s Dodge storms down the track.

DW-1801-ITPA-07

From old-school P-pump to new-age common-rail, Morgan Primm’s ’11 F-350 is on the cutting edge of what a 6.7L Power Stroke is capable of. As a longtime truck puller and a diehard Ford enthusiast, Morgan has always made it a mission to keep his Blue Ovals at the front of the pack. He was also instrumental in getting the ITPA to take up the Pro Street Diesel class for 2017. Along with competing in the ’11 F-350 shown here (fittingly coined “The Experiment”), Morgan also campaigns a 6.4L Power Stroke, which is driven by good friend, Patrick Marler.

DW-1801-ITPA-09

With ball bearing turbochargers seeming to offer the best reliability in the Pro Street Diesel class, Morgan makes use of a ball bearing unit from Diesel Technology Source. The 2.6 turbo is based on the Garrett GT42 platform, features an 83mm turbine wheel, and sees 45 psi during the course of a pull. It fastens to the back of the lifter valley courtesy of a Midwest Diesel & Auto T4 mounting kit, complete with stainless steel intercooler piping.

DW-1801-ITPA-08

As the owner of Midwest Diesel & Auto, Morgan built the 6.7L Power Stroke long block in-house, using some of the best parts on the market. The short block sports rods from Wagler Competition Products, a Midwest billet stage 3 cam, and ceramic coated pistons. Up top, the heads were treated to port work and various valvetrain upgrades before being anchored to the block by ARP studs. A Midwest ported intake manifold offers boosted air a restriction-free path into the worked over, reverse flow heads.

DW-1801-ITPA-10

Thanks to a set of 100-percent over piezoelectric injectors from River City Diesel, Morgan has enough injector to support 1,000-rwhp. The task of maintaining rail pressure is left up to a ’15 model year 6.7L Power Stroke CP4 in the factory location and a belt-driven Fleece Performance Engineering 10mm CP3 up top (shown). Low pressure fuel supply comes by way of a 150-gph Titanium series FASS system feeding the CP3, while the factory lift pump supplies diesel to the CP4.

DW-1801-ITPA-11

Pro Street Diesel class rules mandate that trucks remain equipped with the OEM dash, front door panels, and firewall, but that aftermarket gauges can be used. As you can see here, Morgan has robbed the extended cab of its rear seats and passenger seat, which most competitors in the class do. Other interior rules dictate that all factory glass be retained, and that windows be fully functional (be they electric or manual).

DW-1801-ITPA-13

Now in its third season of use, the buildup of the original LLY took place at Calibrated Power Solutions. The competition engine build entailed a SoCal Diesel girdle, Carrillo rods, Fingers oval bowl cast-aluminum pistons, 3388 SoCal cam, and light porting of the heads. Heavy fueling comes courtesy of Exergy Performance, in the form of 100 percent over injectors, a 12mm CP3 in the valley, and a belt-driven Sportsman pump up top, mounted via one of Wehrli Custom Fabrication’s dual CP3 kits.

DW-1801-ITPA-12

Once a truck that dominated the local Work Stock scene, Lee Stiltz’ ’05 Chevy Silverado makes use of what is arguably the most proven chassis in the Pro Street  eld. And not only is it one of the more consistent trucks in the class, but as we went to press Lee’s Duramax had only  nished outside of the top two spots on one occasion, and was the current points leader. No matter the track or the pulling order, this Bow Tie always seems to claw its way to the front.

DW-1801-ITPA-14

A one-off S400 mounting kit from Wehrli Custom Fabrication allows Lee to mount a T4 flanged 2.6 turbo from Diesel Technology Source in the valley. The ball bearing charger is very similar (if not the same) as what we found under the hood of Morgan Primm’s Ford. It produces between 45 and 50 psi of boost, depending on the track, and forces compressed air through a Mishimoto intercooler.

DW-1801-ITPA-16

No standard-style hitches are allowed in the Pro Street Diesel truck class, only draw bar style units. Per the rules, this hitch was designed and fabricated by Wehrli Custom Fabrication, and it places the hook point 24 inches above the ground (the maximum hitch height allowed in the class). Also notice the sled stops, which are mandatory items as well.

DW-1801-ITPA-15

With OEM axles being mandatory, Lee went the extra mile to ensure his rear end never lets him down. The 11.5 AAM Hybrid axle assembly from Proformance Pros is equipped with a spool, gundrilled 300M axles, and trusses. Up front, the book has been thrown at the 9.25 AAM IFS, including an Eaton E-Locker, an RCV axle set (custom-lengthened to accommodate the truck’s lift), and Fleece Performance Engineering TufShafts. Linking the axles to the engine is a full billet Allison 1000 automatic built by Illini Outlaw Diesel with a high-stall Precision Industries triple disc converter.

DW-1801-ITPA-17

While it’s not uncommon to find Cummins-swapped Fords in any pulling class, Coltyn Du Pre’s ’85 F-350 is anything but a run-of-the-mill conversion project. After spending most of its life as a 6.9L-powered farm truck, it was taken down to a bare frame, sand-blasted, painted, and outfitted with a nasty 12-valve Cummins, an NV4500, and an AAM 1150 courtesy of Dermody Diesel of Murrayville, Illinois. And, with the old body style (’80-‘97) Fords being so light, Coltyn can hang nearly a dozen suitcase weights up front, while adding a handful more in the bed.

DW-1801-ITPA-18

After the folks at Dermody Diesel somehow convinced the Duramax gurus at Wagler Competition Products to build a competition-ready Cummins, Coltyn wound up with a bad-to-the-bone 12-valve stroker motor. A girdle, shot-peened stock rods, forged-aluminum Ross Racing pistons, Hamilton Cams camshaft, and extensively ported cylinder head highlight the hard-part upgrades. Bringing plenty of fuel to the table is a 13mm P7100 feeding six 5×18 injectors, both sourced from Scheid Diesel. Coltyn’s smooth bore turbo of choice is also the GT42-based, ball-bearing charger from Diesel Technology Source. It bolts to an ATS Diesel T4 exhaust manifold and ultimately routes boost through a Waglerbuilt, one-piece intake manifold.

DW-1801-ITPA-21

Featuring a little bit of everything from the Midwest Diesel & Auto catalog, the 6.4L Power Stroke incorporates billet rods, ceramic-coated Diamond Racing pistons, a Stage 2 cam, ported heads with (+1mm) oversized Inconel valves, ARP head studs, and a ported intake manifold. Fuel delivery begins with a 260-gph FASS system, is pressurized courtesy of twin K16 high-pressure pumps, and makes it in-cylinder through 150 percent over injectors from River City Diesel. Cooler EGT and minimal boost drop are experienced thanks to a Precision Turbo & Engine intercooler.

DW-1801-ITPA-20

Capitalizing on the potential of the 6.4L Power Stroke, Patrick Marler pilots an ’08 F-250 on behalf of Midwest Diesel & Auto. On any given night, this truck has what it takes to win, and it’s perpetually in the the thick of things at the front of the field. As we write this, Patrick sits in third place in the overall standings, just one point behind second and four points out of first.

DW-1801-ITPA-22

In case you hadn’t noticed, most Pro Street Diesel competitors are sold on the 2.6-inch smooth bore turbo from Diesel Technology Source—and this 6.4L is no different. The DTS snail mounts in the lifter valley thanks to a Midwest Diesel & Auto T4 turbo kit and is driven in part by a set of BD exhaust manifolds and up-pipes. Roughly 50 psi worth of boost makes its way toward the engine after passing through intercooler piping provided by No Limit Fabrication.

DW-1801-ITPA-19

Knowing how well it holds up in Duramax-powered GM’s, an AAM 1150 from an ’05 donor was bolted under the rear of the truck. The 11.5-inch ring gear axle sports a spool and 4340 chromoly axle shafts from Yukon Gear & Axle, along with 4.88 gears. A Yukon locker and 4340 chromoly axles also made their way into the Dana 60 up front. The truck’s custom four-link traction bars and blocked suspension were built by CWC Fabricating, along with the burley draw bar hitch out back.

DW-1801-ITPA-23

T he Dana 80 that replaced the original 10.5-inch Sterling was built in-house at Midwest Diesel & Auto and conceals 37-spline axle shafts and a spool from Yukon Gear & Axle. A Detroit Truetrac is housed in the front Dana 60, which makes use of 1480 series Spicer U-joints and sports chromoly axle shafts. One Up Offroad long-gusset traction bars, blocked rear suspension, and dual-shocks up front help quell axle wrap, axle hop, and keep the truck smoothly digging through the dirt.

DW-1801-ITPA-24

In the truck pulling game since 2004, Andrew Karker has kept pace with the constantly-evolving diesel performance world—and he always seems to be one step ahead of everyone else. Over the past 13 years, Andrew has proven his personal trucks can beat purpose-built pulling rigs at their own game and still drive them on the street. His latest creation is no different. Once a high-mile basket case of an ’02 2500 HD, it was taken down to a bare frame and rebuilt from the ground up. After joining the Pro Street Diesel field late in the season, the truck’s first hook yielded a third place finish, and Andrew followed it up with a win at the very next event.

DW-1801-ITPA-27

The five-speed Allison 1000 is laced with Sun Coast’s GMax-5R-1 Raybestos rebuild kit, a billet C2 hub, and a billet P2 planetary. A triple-disc converter from Goerend Transmission incorporates a billet stator and a 2,700 rpm stall, while a remote-mount Earl’s Performance transmission cooler keeps ATF temperature stable. The A1000 is topped off with a mandatory transmission blanket, this particular one coming from DJ Safety.

DW-1801-ITPA-25

Assembled at Andrew’s shop, Illini Outlaw Diesel, the LB7-based Duramax is graced with Wagler connecting rods, stock compression Diamond Racing forged-aluminum pistons, a Wagler alternate fire cam, and unported heads fitted with Hamilton Cams valvesprings and Merchant Automotive heavyduty pushrods. A remote mount turbo system from Wehrli Custom Fabrication positions a DTS 2.6 charger over the passenger side fender well, which entails reverse flow intercooler pipes and stainless steel up-pipes.