Cummins Competition Commuter
Upping your game. It’s what diesel drag racing is all about. Once you realize that 600 to 700 hp is just the tip of the iceberg, added power and quicker time slips are soon to follow. After getting his feet wet in the Outlaw Diesel Super Series’ ET Bracket class, Trent Skinner decided to throw another hundred ponies at his ’06 Dodge Ram 2500 daily driver and step up to the faster, 7.70 Index class. Now, Trent runs both ET Bracket and 7.70 Index, which means more passes, more practice and more fun—not to mention that double-classing offers two chances to finish in the money. We recently caught up with him to find out what was new.
Going from 650hp at the wheels to more than 750hp called for a CP3 upgrade, higher volume lift pump, a bigger turbocharger and a few tuning tweaks. To keep those four-wheel drive launches consistent and make 7.70-second eighth-miles repeatable, Trent installed a stand-alone transmission controller, a staging limiter and a Nitto NT420V at each corner. Internally, the 183,000-mile 5.9L Cummins remains untouched, the sole addition to the all-iron I6 being a set of ARP studs to keep the cylinder head glued to the block. So how has everything panned out so far? How about an ET Bracket win against 33 highly talented competitors, third place in the current national ET points chase and persistent trips to the quarter finals (or further) in 7.70?
Running a 7.70 dial-in across two racing categories means Trent is seeing a lot of seat time and constantly accumulating experience. His consistency is also making him one of the most feared drivers in diesel drag racing. If you find yourself lined up next to this red third-gen at the tree or the stoplight, you better be packing your A-game…
Stacking Horsepower On A 14-Year-Old 5.9L
When you’re working with an engine that’s proven capable of handling 1,000hp in stock form, it makes power increases all the more enticing. And when you live right up the road from Firepunk Diesel, it makes the urge to go fast practically irresistible. As a direct result of Trent Skinner’s association with the duly-lauded Plain City, Ohio company, his 183,000-mile ’06 5.9L common-rail Cummins is capable of sending as much as 898hp to the wheels at the present time.
Improved Clamping Force
The ability to contain immense cylinder pressure is what makes powerful diesel engines possible. While the Cummins’ factory rotating assembly can handle plenty of punishment, the stock head bolts can stretch under prolonged periods of exposure to excessive boost. To avoid the possibility of a blown head gasket, and because the engine sees 60 psi of boost on a regular basis, Trent installed ARP head studs before he got serious about modifying the truck.
While a factory Bosch CP3 high-pressure fuel pump used to support Trent’s 650hp, 8.0-second eighth-mile endeavors (thanks to spot-on tuning from Firepunk), it was on the ragged edge of being able to hold adequate rail pressure. To maintain rail pressure for virtually any size injector he could ever want, Trent ditched the stock CP3 in favor of a 14mm stroker pump from Exergy Performance. On the receiving end of what the 14mm CP3 can dish out, you’ll find a set of 60-percent over injectors, also sourced from Exergy.
Feeding the Beast
In order for the stroker CP3 to perform its job effectively, an AirDog II-4G system supplies it plenty of low-pressure fuel. A flow rate of 200 gallons per hour ensures the 14mm injection pump is never short on the fuel it needs to pressurize higher than 24,000 psi. The AirDog system pulls fuel from the factory tank.
High-Flow Turbo & Exhaust Manifold
Forcing more air volume into the engine, Trent ditched the stock appearing turbocharger and factory exhaust manifold in favor of an S467.7 from BorgWarner and a second-gen style Steed Speed manifold. The big BorgWarner unit features a 67.7mm compressor wheel, an 83mm turbine wheel and a T4 turbine inlet flange. At full tilt, the new charger maxes out the 60-psi boost gauge mounted along the A-pillar in the cab.
Stage 1 Golden Nugget
With its proven track record for durability, Trent continues to run a Competition Stage 1 48RE transmission from Firepunk. Often referred to as golden nuggets, these four-speed automatics are capable of holding 800 hp thanks to upgraded internals such as a billet input and output shaft, added clutches, a triple disc DPC converter and a host of other internal modifications. For added peace of mind, Trent tells that in the future he may throw in a billet intermediate shaft, and also that he may have the converter re-stalled to better complement the S400 turbo.
Having precise control over when the 48RE makes its shifts is made possible via a stand-alone transmission controller from Firepunk. Called the Anteater, it replaces the factory PCM and offers three different shift tune tables, navigable on the fly. The Anteater’s in-cab remote (shown above) allows Trent to select which shift tune table best suits his needs and when he wants the converter lock up event to occur. It also provides the ability to disable overdrive if the situation warrants it.
Consistency on the Starting Line
With all drag races being won at the starting line, this staging limiter from BD Diesel allows Trent to launch his truck the same every time. Working off of the brake pedal, the limiter allows a maximum of 20 psi of boost to be built when staging the truck. Once Trent releases the brake pedal, he knows he’s on his way to either a high 1.6-second or low 1.7-second 60-foot each and every pass.
Since EFI Live began its support of the 5.9L common-rail Cummins platform eight years ago, calibrators have been proving that these engines can make more power with better reliably and refinement—and while running much cleaner. Such is the case with Trent’s Ram, which benefits from five custom EFI Live tunes from (you guessed it) Firepunk Diesel. While Trent bounces back and forth between tune number 2 (754hp) and 3 (772hp) to get his trips through the ‘660 as close to 7.70 seconds as possible, tune 3 has sent him through the eighth-mile in 7.58 seconds (11.80’s in the quarter). Tune 5, his hottest file, has yet to be run at the drag strip (although it did yield the previously-mentioned figure of 898hp while strapped to the chassis dyno).
At the end of the line, when what’s left of the power generated at the crankshaft ends up at the wheels, Trent relies on a set of Nitto NT420V tires to get it to the ground. Mounted on 20x12-inch Moto Metal 962 wheels, the LT305/55R20 NT420V’s deliver a quiet ride, solid wet weather performance and ample traction on dry pavement. And, just in case Trent needs his Cummins to move a mountain or two, their F load range makes them the perfect companion for a 750hp to 900hp, daily-driven ¾-ton diesel truck—a vehicle that, while modified, is still expected to do a little bit of everything.
Curious what it takes to build a diesel sleeper? Check out Part 3 of our ongoing series for all the details.