Aftermath - Diesel World

Inside Adam Foltz’ 5.90 Index Second-Gen

Diesel drag racing isn’t what it used to be. The engine and chassis setups of yesteryear wouldn’t cut it in today’s four and 5-second eighth-mile world. Even the current crop of 5.90 Index trucks are faster than the nastiest Pro Street vehicles running the circuit just six or seven years ago. With 15 drivers signed up to run the Outlaw Diesel Super Series’ 5.90 class in 2020, the class has already doubled in size since debuting in 2018. As for the competition? It’s fierce—but mostly common-rail. Adam Foltz is looking to change that with his ’02 Dodge, a P-pumped 24-valve he refers to as the Aftermath.

Once a daily driver, and even a truck the local Duramax’s and 6.0L’s used to pick on, Adam ditched the VP44, the original frame, suspension, and interior long ago. Trust us, no one is laughing now. Adam’s P-pumped 24-valve second-gen is one of the fastest mechanical Cummins in the country, and in the pages that follow we’ll highlight the parts and pieces that could make it a top 5.90 contender in 2021. From its overbuilt, 6.7L-based Cummins to its exceptionally light chassis, and its top-notch fabrication to its clean-burning, single turbo over nitrous arrangement, Adam is looking to make the P-pump relevant again.



At only 4,100 pounds, Adam Foltz knows he doesn’t need crazy horsepower to be competitive in the 5.90 Index class, which is probably why he has fueling on the P-pump pulled all the way back and has focused more on dialing in the chassis lately. “With a small nitrous tweak we went from 6.50 to 5.80,” he told us. “But once we know it’s going to go straight every time, we’ll be shooting for low 1.2’s on the 60-foot (on the trans brake).”


For a 4,100-pound truck looking to go 5.90, less than 1,100 hp is required to propel Adam’s Dodge down the track—which makes the Predator series Cummins from D&J Precision Machine positively overkill. The balanced and blueprinted engine consists of a 6.7L wet block fitted with 4.125-inch bore sleeves and machined to accept fire-rings. An HD girdle, billet main caps, and 9/16-inch ARP main studs lock down the crankshaft, while D&J’s FSR pistons and X-Beam connecting rods have zero problems standing up to cylinder pressure. A Hamilton cam, billet Hamilton tappets, and D&J 7/16-inch pushrods handle valvetrain operation.


A D&J Stage 2 head that’s also been cut to accept fire-rings fastens to the 6.7L block via 9/16-inch ARP head studs. The head has seen 5-axis CNC port work, benefits from D&J’s XL exhaust seats and intake seats, and also has HD valve springs with titanium retainers. Garofalo Enterprises supplied the mirror finish, billet-aluminum valve cover.


A single turbo and nitrous has become a common theme in the top tiers of diesel drag racing in recent years—and it’s because it works. For a high-flow charger that could be brought to life quickly, Adam entrusts the 5-blade compressor technology from Stainless Diesel. Though a Stainless T-6 S480 is shown here, it has since been replaced with the company’s T-6 S485. Best known as the Godfather, the S485 sports a 5-blade billet compressor wheel with an 85mm inducer, and a 96mm turbine wheel inside a 1.32 A/R exhaust housing. Also notice the EGT probes in the exhaust manifold collector, the first of which reads exhaust temps in cylinders 1, 2, and 3, while the rear probe picks up EGT for numbers 4, 5, and 6.


In conjunction with the ported Stage 2 cylinder head, a Stainless Diesel Competition T-6 exhaust manifold—with its full length, 1.65-inch internal ports—helps drive the big single turbo very efficiently. Even the ¾-inch thick center section is treated to CNC porting for the smoothest exhaust flow possible. Here, you can also see one of the 26 9/16-inch ARP head studs that keeps the fire-ringed head glued to the block.


For all the fuel he could ever need (and then some), Adam turned to Northeast Diesel for a 13mm P7100. Though it’s capable of flowing 1,000 cc’s worth of fuel, the reins are currently pulled all the way back to 550 cc’s. Timing checks in at roughly 30 degrees of advancement. On the opposite end of the injection lines, you’ll find a set of dual-feed injectors from Haley Speed Innovations, which have been fitted with 6 x .018 nozzles.


A billet front timing cover from Keating Machine integrates the engine’s gear-driven Waterman fuel pump. The 500-gph Waterman unit never fails to maintain 50-psi of fuel supply pressure to the hungry P-pump.


In high-horsepower applications, an air-to-air intercooler serves as a fail-safe measure just as much as a method of cooling EGT—and that’s exactly the way Adam looks at it. Should a turbo failure ever occur, it’s highly unlikely any compressor pieces will make it into the engine. As for cooling, Adam tells us his On 3 Performance unit keeps peak EGT between 1,700 and 1,750 degrees F, an amount of heat he feels makes his Cummins perform the best. EPMAN Racing V-band clamps have no problem containing the roughly 50-psi of boost the turbo and intercooler system see. All intercooler plumbing, along with the masterful velocity stack, were fabricated by Blake Miller of J&J Auto and Truck Service.


In addition to all of the cutting and gutting that took place on the truck, Adam’s 25.6 SFI certified chassis and roll cage was built using Docol steel. Lighter and stronger than chromoly, Docol is also easier to work with than traditional chromoly and is said to rank higher in crash safety. Like much of the rest of the truck, Adam’s good friend, Blake Miller, pieced together the chassis from 1-5/8-inch od, 0.040-inch wall Docol.


For utmost bite, four-link suspension systems are employed front and rear. All of the linkages and brackets were pieced together by Blake Miller at J&J Auto and Truck Service. Thanks to Miller’s skillsets, pinion angle remains constant and axle wrap is non-existent during Adam’s boosted four-wheel drive launches.


Surprise surprise, Blake Miller also fabricated the truck’s fuel cell at the back of the chassis. The tiny cell holds just 2 gallons of diesel, but thanks to only burning a half a gallon per pass, there is no fear of running it dry. In fact, Adam leaves the pits with the cell 75-percent full.


AFCO coil over shocks tie the chassis in with the axles and feature double-adjustability. While Adam tells us he has the chassis performing close to how he needs it to at this point, subtle rebound and overall travel tweaks are still being implemented to fine-tune the truck’s launches.


The truck’s original Dana 80 can still be found in the rear, although it’s been graced with Yukon axleshafts, a Yukon ring and pinion, and a locker. For added support and gear oil capacity, the Ultimate-80 diff cover from LPW shown here was added. To shed even more weight, Adam is considering swapping to a done-up 9-inch over the winter.


Believe it or not, the Dana 60 up front is the same bone-stock version that’s been under the truck since it left the factory in ’02. Like the Dana 80 out back, it sports 3.55:1 gears.


M&H Racemaster slicks measuring 30×14.0-16 are tasked with applying the truck’s power to the track, and staying glued to it on the back half, when all three stages of nitrous can really pour some power on. They’re mounted on 16×10-inch American Racing wheels for now, although Adam may switch to bead locks prior to the start of the 2021 season.


You’re looking at a lot of late nights and long weekends when you peer into the cockpit of Adam’s second-gen. Like much of the rest of the truck, Blake Miller was in charge of building the roll cage, which also entailed making the cab as safe as it is functional. While the truck sports a lot of its original body parts, it’s all new both inside and underneath.


After launching at 3,300 rpm (roughly 20-psi of boost), the Pro-Comp series tachometer from Auto Meter registers 4,800 rpm before the 1-2 shift occurs. Subsequent shifts take place at roughly 4,600 rpm.


This is one of the reasons Adam’s P-pumped 24-valve is so clean running down the track. With three stages of nitrous, as part of a Nitrous Express Maximizer 5 kit, Adam tells us his 15-pound bottle of N2O lasts three passes before it’s time for a top-off. First, a .52 jet comes on at wide-open throttle, then a .96 jet kicks in shortly thereafter, followed by a .136 jet on the big-end.


All of Adam’s driving is conducted out of this 55 series Pro Street Drag seat from Kirkey Racing. And when he straps into the Crow Enterprizes 5-way restraint and heads for the staging lanes, he’s all business.


When you’re up against a common-rail nine times out of 10 in the 5.90 class, you’re going to keep track of the ones you beat… In time (and hopefully sooner rather than later if you’re him), Adam hopes to run out of room on his RaceQuip helmet to log common-rail kills. Can you blame him? “As many common-rail guys as there are out there, you can bet I’m gonna keep score every time I take one out,” he told us.


AFCO Racing


D&J Precision Machine

Firepunk Diesel

Goerend Transmission

Haley Speed Innovations

Hamilton Cams

J&J Auto and Truck Service

Keating Machine

Northeast Diesel Service

Nitrous Express

On 3 Performance

Outlaw Diesel Super Series

Stainless Diesel