An 800+ Horsepower Twin-Turbo Daily Driver

Chase Dunnavant purchased his standard cab ’03 Dodge Ram 2500 HD with just under 100,000 miles on the odometer for a great price since it had a rebuilt title. The Lynnville, Tennessee, marine engineer had plans to make some simple modifications to the truck then enjoy it as his daily driver. He installed a Bully Dog Power Pup programmer, 5-inch exhaust system and a cold-air intake system and was happy with the truck and had every intention of leaving it that way.

While attending a diesel event, Dunnavant ran the truck on the chassis dyno and was pleased with the 393 horse-power and 831 lb/ft of torque that his truck put to the rollers. Nearly 400 horse-power was a good number for a daily driver and Dunnavant planned to move on to his other project truck, a ’93 Ford F-250 that he wanted to outfit with a Cummins. Not long after, he made a dramatic change to his plans. The catalyst for change was seeing Jason Epling’s Mega Cab make 733 horsepower and max out the torque capability of the dyno. When speaking with Epling, he was told that the truck was a daily driver work truck that also was used for sled pulling, so a new goal was set for his Dodge.

After realizing that modern diesel trucks can make huge amounts of power and still be driven daily and worked hard during the week, and compete on the weekends, Dunnavant sold the F-250 to get the funds together so he could get serious with the Dodge. After the original turbo broke, he went with a BD Diesel R700 compound turbo kit to start making some real power. To support the additional performance he was planning on wringing out of his 5.9L Cummins, he also installed a Banks Power intercooler and went under the valve cover to install Crower valve springs and a set of head studs. To support the fuel system, he installed an AirDog 150 pump and filter system and an Industrial Injection dual feed line.

Dunnavant drove the truck in this configuration for a few months but then he started to desire even more power. He heard that Epling was upgrading his compound turbo setup so he purchased the take-off setup. He installed this turbo with a set of 230-hp MCN injector nozzles to complete the next round of upgrades on his truck. Unfortunately, within a week of the upgrade it blew the head gasket. This led Dunnavant to consult with Mark Newton of MCN Diesel Performance and Keating Shelly of Keating Machine to develop a game plan to make big power and still allow the engine to live with daily use. They suggested the use of Fire Rings and Dunnavant pulled the head and sent it to Keating for the necessary machine work.

While the head was being machined, Dunnavant developed a coolant bypass system using two bypass valves, one installed in the head and one in the block that returns the coolant to the system into the upper radiator hose after the thermostat. He also ordered up some more high-performance parts while waiting for the head. This included a PPE Dual Fueler kit using a Duramax CP3 for additional fuel volume, a Fluidamper balancer for the crankshaft, a Smarty programmer and a new South Bend dual-disc clutch with ceramic pads. When all the new parts and the machined head arrived, he went to work putting everything back together, getting it ready to tackle the dyno again.

Strapping down the truck to the same dyno that started his quest for more power showed that perseverance pays off. On his first pass with this combination, he put down 776 horsepower and pegged the torque reading. Then Dunnavant and Newton decided to push it a little harder for the second and third power pulls, which yielded 783 and 793 horse-power respectively, making this DIYer a very happy man.

After driving the truck more and sled pulling with it several times, the clutch was having difficulty holding the power. This led to the installation of a Kenny’s triple-disc clutch with sintered iron discs to hold the power. Then, with the clutch holding well, Dunnavant stepped up the top turbo to a T4 chassis mounted on an ATS T4 manifold with a 66/73/.91 turbo to work with the 80/96/1.32 turbo.

With the combination running better than ever, Dunnavant ran it at the 2010 TS Performance Outlaw event on David Dunbar’s Diesel Performance Motorsports chassis dyno. He recorded his highest numbers ever at 843 horsepower and 1,472 lb/ft of torque on the first pull before blowing apart an injector and overfueling the engine. Fortunately, the only damage was to the injector.

The potent Cummins is backed by a NV5600 manual transmission with the aforementioned triple-disc clutch to get the power to the wheels. Duunavant fabricated and installed front and rear U-joint shields to protect the truck in the event of a joint failure. To help the truck put the power to the ground, Dunnavant installed a set of CalTracs traction bars on the rear springs. Then, to level the truck, he installed Hell Bent Steel leveling spacers in the front.

For wheels and tires Dunnavant chose to run 17X9-inch Dick Cepek DC1 wheels wrapped in the ever-popular BFGoodrich All-Terrain T/A tires in 285/70R17 size front and rear to fill the fender wells and provide good traction on the pulling tracks. For more help in the traction department up front while pulling, he fabricated a weight rack to hang tractor weights when he hooks to the sled. He installed a set of air bags for load leveling as well as a gooseneck mount under the bed to make towing duties easier..

Finishing off the truck that he dubbed an SRT6, Dunnavant installed an SRT10 hood and sport bumpers, and then ordered SRT6 badges from the Dodge dealer and installed them on the leading edges of the doors. Moving inside the cab, Dunnavant installed a combination of DiPricol and ISSPRO gauges with three mounted in an A-pillar pod and two in a pod above the steering column. The factory-matched white-face gauges help him keep a close eye on the performance of his high-horsepower Cummins under the hood. He also installed a Pioneer DVD receiver with a flip-up LCD screen in the dash with a Kicker amp and sub mounted behind the center section of the split bench seat.

After successfully building his SRT6 dream truck with tons of power to compete on the dyno or on the track and still be able to be driven when he wants, Dunnavant has decided to sell it. You can still expect to see the SRT6 at diesel events and competitions with a new driver behind the wheel. Dunnavant plans to resume chasing his original dream to build a Fummins and has started with a 1995 F-350 that will have a Cummins and even larger turbos and more fuel in hopes of breaking the 1,000 horsepower barrier. UDBG

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