2008 Dodge Ram 2500 Cummins Four-Digit Fuel Mapping - Diesel Tech
A quest for 1,000 hp from a 6.7L Cummins
When a truck already has two giant turbos, a fire-ringed head, and Extrude-Honed injectors, you might think it's already "maxed out," but that wasn't stopping the team at Bud's Diesel. They realized this 900hp 2008 Dodge Ram 2500 was still thirsty for more fuel, so they came up with a unique system that combines dual CP3 injection pumps with dual 165-gph lift pumps to provide enough fuel for new 58-lpm injector nozzles. With the proper tuning, the team is looking to break 1,000 hp at the rear wheels, and here is how they plan to get it done.
Not Exactly Stock
You may remember this 2008 Dodge Ram 2500 as the Mr. X truck from the September 2014 issue of Diesel Power. While the owner prefers to stay low-key, the upgrades made to his truck are dramatic. The engine received a full work over by Industrial Injection with upgraded pistons, a Stage 3 camshaft, a machined block, and a fire-ringed head to handle the output from both a Silver Bullet 66 turbo and an 80mm BorgWarner S400 turbo. Before this new set of fuel upgrades, the ¾-ton already had a single 85-percent-over Dragon Fire CP3 injection pump and 45-lpm injectors from Industrial Injection, and a single AirDog II 165-gph lift pump—but that wasn't enough for the crew at Bud's Diesel.
The first step in providing more than enough fuel for 1,000 hp was the installation of a second AirDog II 165-gph lift pump that will run in parallel with the one that was already installed. Since the truck is equipped with AMP Research motorized running boards, the pumps were mounted on the inboard side of the framerails. Both pumps have a water separator, a 2-micron fuel filter/air separator, and a powerful 165-gph gerotor pump for quiet and predictable operation up to 75 psi. Each pump was fitted with ½-inch id nonconductive and nonflammable fuel lines with secure quick-connects, and fuel pressure gauges were installed inline so the owner can make sure both CP3 pumps are receiving fuel.
The next step was adding another CP3 injection pump under the hood to complement the existing 85-percent-over Dragon Fire pump. This will reduce wear on the pumps and ensure enough fuel is available for the souped-up engine. The dual CP3 kit from Industrial Injection comes with everything needed for installation and a Duramax-spec CP3 that flows more than a stock Cummins pump. With a smaller idler pulley for the front of the engine and a large-diameter wheel on the second CP3, the system is designed so both pumps share the work of delivering massive amounts of fuel for the hungry 6.7L. An electronic controller splits the signal from the engine computer and feeds the pumps with instructions so they can work in harmony with each other and the rest of the powertrain.
The Ram was already fitted with Dragon Fly injectors by Industrial Injection with Stage 1 Race nozzles rated at 45 lpm, but the team wanted to go even bigger. To take advantage of all the available fuel, the injectors were fitted with higher-flowing, 58-lpm Stage 3 Race nozzles that were custom ordered for this build. The injectors used in this truck are remanufactured genuine Bosch units from a 5.9L engine that were Extrude-Honed twice by Industrial Injection using its in-house EDM machines.
The folks at Pusher Intakes provided a bright green version of their Mega intake for this segment of the upgrade. The unit has a 3.5-inch inlet that feeds into two 3-inch mandrel-bent tubes to provide 49.4 percent more airflow than the stock Dodge manifold. The manifold is fully TIG-welded and has four ports for injectables, such as water-methanol or nitrous—even though this truck will be running on diesel fuel only…for now.
Programming for Power
The truck was already fitted with an H&S tuner with programs to run the two-turbo setup with 45-lpm injector nozzles along with the RevMax Signature 1000 68RFE transmission. To achieve the goal of 1,000 hp, a new tune had to be drawn up by the engineers at Draconian Diesel. Once the programs for the new engine setup and transmission were electronically delivered, the team at Bud's Diesel uploaded them to the H&S Black Maxx programmer and began prepping the truck for a trip to the chassis dyno.
The Dodge was already capable of making 900 hp at the rear wheels before the fuel system was further upgraded. That's pretty close, but sometimes making the jump from three to four digits in horsepower takes a lot of work. Now this 6.7L Cummins seems to have everything it needs. Unfortunately, the dyno facility we planned to use had one dyno out of order, and the other would not fit a ¾-ton truck with 325/50R22 Nitto Trail Grappler tires, but we will post the results on dieselpowermag.com as soon as they become available.
After all that is out of the way, the exhaust rocker arms are removed and set aside so they can be reinstalled in the same locations.
The intake is removed to provide access to the fuel-supply tubes inside the engine head, which are pressed into the sides of the injectors.
Once those tubes and the final two bolts are removed, the injectors can be pulled.
The injectors are put aside in the same order to make sure they’re reinstalled in the same cylinder locations. This will reduce the chance of leaks once the system is under pressure—and hopefully they won’t need to be removed again.
This layout shows how fuel travels from the common-rail into the injector. The high-pressure fuel lines send fuel from the rail to the fuel tubes mounted inside the head. Fuel then enters the injector and then eventually exits through the holes in the injector nozzle holes.
Tom uses a razor blade to loosen the crush rings that provide a seal between the injector and the engine. Once they’re broken loose with the blade, it’s easy to wiggle the parts off and discard them.
It takes a bit of elbow grease to break loose the retainer that holds the nozzles in place. Tom carefully places the injector in a vice, making sure only the mounting-bolt housing is squeezed, and not the actual injector. After the new nozzles are installed, they’re screwed into place with the amount of torque specified by Cummins.
Care should be taken while removing the injector nozzles because there are small parts that can be easily lost.
Out of the six injectors, only one came apart like the one in these photos, but when it did, a tiny spring retainer popped out and was nearly lost.
Maybe it was just bad luck that part popped out, but if you’re working in a shop with no spare injector parts around, losing something like this could mean “Game Over” until you can find a replacement.
Before the injectors are put back into the engine, Tom fits them with new crush washers that are included with the Industrial Injection nozzles.
The O-rings on the injectors and fuel supply tubes are lubricated before they are reinstalled.
Tom says it’s best to remove parts from front to back and then reinstall them in the reverse order. That way, you will have the fewest number of parts in your way while you work. Following the Cummins specifications, Tom first torqued down the injectors to 44 lb-ft, then he made a second pass and tightened the injectors down with 89 lb-ft of torque. This ensures the injectors are seated properly and securely.
This 3.5-inch Mega intake will route the air from the turbos and the AFE intercooler into dual 3-inch mandrel-bent tubes. Pusher Intakes says that on a stock 6.7L Cummins, this intake can reduce EGT by as much as 200 degrees and add up to 1 mpg. The Mega intake has a detent to make room for the stock #1 injector feed line and can be ordered in eight different colors, or bare so you can choose your own look.
The billet-aluminum bracket for the new CP3 pump mounts directly onto the pedestal, next to the intake manifold and above the location of the existing 85-percent-over Industrial Injection Dragon Fire CP3. Mounting was pretty straightforward, but after fighting with the bottom bolt a couple of times, Tom says he remembered an “old man trick”: using a piece of scrap paper to keep the nut secure until the threads catch the bolt.
he dual CP3 kit includes a reduced-size idler pulley. When combined with the oversize pulley, both pumps run at about half of their normal speed.
This greatly reduces wear and assures the pumps will not be maxed-out when the engine needs fuel at critical times.
The AirDog II lift pumps come with ½-inch fittings for the CP3 pumps that are significantly larger than the stock units. Fuel lines for the system are Goodyear Insta-Grip ½-inch 300-psi WP tubing with SAE J2044 OEM-style quick-connects that make installation quick and secure with an audible click when the connection is made.
It was decided to run dual return lines with the existing one going directly back to the fuel tank, and the second one routed into the fuel filler neck above the tank, which meant the tank would not have to be dropped a second time.
The dual CP3 kit also includes a polished tube that routes coolant around the new pump’s location.
It has a bracket designed to mount to the stock manifold, but since that’s long gone, Tom uses a piece of ABS plastic to fabricate a mount to keep the coolant tube secure. The Pusher intake features a special bracket to keep the oil dipstick in place, so Tom used that as his mounting point.
With everything in place, the 6.7L Cummins should have plenty of fuel to reach the goal of 1,000 hp at the rear wheels. Now there is a new high-volume CP3 mounted above the existing 85-percent-over Dragon Fire CP3 that sits in the factory location. Each CP3 is fed by its own dedicated 165-gph AirDog II lift pump. All the fuel from this new setup goes through Dragon Fly injectors with 58-lpm nozzles, and airflow for all the added fuel travels through a 3.5-inch Mega intake by Pusher Intakes.