ILLINI OUTLAW DIESEL BUCKS THE PULLING TREND
In the age of purpose-built, competitiononly pulling trucks, many enthusiasts like to harken back to a time when things were simpler. You know, when you could pull your truck on Sunday and then drive it to work on Monday. While those days are likely gone for good, a few diehards are still able to win in the dirt with a truck they regularly drive on the street.
Andrew Karker of Illini Outlaw Diesel is one such believer. A longtime truck puller and Duramax guru, he entered the sport at a time when your daily driver doubled as your puller—and that work-andplay mentality has never left his mind. As you can imagine, when his local sanctioning body (the Illinois Tractor Pulling Association) introduced a streetbased truck category for 2017 Karker immediately got to work building something that could compete.
Coined the 8,000-pound Pro Street Diesel Truck class, key limitations entail a 2.6-inch smoothbore turbocharger rule and single-rear-wheel configuration. And although the field of trucks in this class can theoretically still be driven on the street, everyone knows that nine out of ten won’t be. Making a conscious effort to buck this purpose-only trend, Karker made sure each and every component that made its way onto his ’02 Chevy Silverado 2500 HD served two purposes: It would give the truck an advantage both in the dirt and on the pavement. The parts recipe employed in this build will likely result in a truck that makes close to 800 rwhp, competes at the front of the new Pro Street Diesel Truck field, and can run low 11s at the drag strip. Follow along for an inside look at the truck’s First Place-caliber powertrain, chassis, and suspension setup.
From the front of the frame rails to the hitch, no area of Andrew Karker’s ’02 Chevy Silverado 2500 HD went untouched. With the body still sitting in the paint booth at the time of our photo shoot, we were able to get up close and personal with a chassis that had been spec’d to perform at the top of the newly-created Pro Street Diesel Truck class within the Illinois Tractor Pulling Association (ITPA).
A remote turbo mount moves the charger out of the lifter valley and makes swapping turbos a seamless process (and luckily for Karker it’s allowed in the Pro Street Diesel Truck class). Having the ability to change out a charger in a timely manner is ideal in the truck pulling world—where turbo technology is always improving and you can literally hook to the sled just about every other night. The remote mount system was built by Wehrli Custom Fabrication in Sycamore, Illinois, and utilizes a T4 mount/pedestal, 2-inch stainless steel up-pipes, and reverse flow 3-inch intercooler pipes.
At the heart of the ground-up build rests an Lb7-based Duramax that’s reinforced with Wagler Competition Products connecting rods, Diamond Racing pistons, a Wagler alternate-fire camshaft, and ARP fasteners from top to bottom. To keep the engine efficient (and ultimately, street friendly), Karker elected to run non-de-lipped, factory-compression pistons. The heads are stock (and were sourced from a Kodiak, ironically enough) aside from a set of Performance valve springs from Hamilton Cams and Merchant Automotive heavy duty chromoly pushrods.
To keep the potent LB7 anchored between the frame rails, Karker fabricated a set of stainless steel motor mounts. It’s important to remember that without properly battening down a high-torque diesel engine it will twist in the chassis, which can lead to damaged motor mounts, excess wear on the transmission mount (and transmission case), or both.
The LB7’S rotating assembly was balanced by “Bert” at River City Diesel in East Peoria, Illinois, and topped off with an ATI super damper. A billet flex plate from BD Diesel, rated to handle 1,500 lb-ft of torque, also made it into the balancing process.