511 Rear-Wheel Horsepower for Only $25,000Posted in Vehicle Reviews on November 10, 2004 Comment (0)
Diesel performance used to be an oxymoron. Then "diesel-heads" (generally considered to be morons by the performance industry) began playing with these farm-bred engines. Today, their power claims seem way too good to be true: 700-plus rear-wheel horsepower, 1,600-plus lb-ft of torque and 11-second quarter-miles in 7,000-pound smoke-belching pickups?
A 500hp Challenge
Recognizing the huge bang-for-the-buck performance potential in late-model oil-burners, two diesel-performance specialists, Edge Products and Diesel Dynamics, hatched an idea: Buy a slightly used diesel truck and build it to reliably (some smoke, but no mirrors) put out 500 rear-wheel hp for less than the cost of a new vehicle. Real-world output would be approximately 200 horses more than an off-the-lot '04 and nearly 300 hp greater than the used truck's original rear-wheel numbers.
A '01 1/2 Ram was chosen for the challenge. This vehicle is good raw material because Dodge introduced the 245hp/505-lb-ft H.O. (high-output) 24-valve Cummins ISB (engine code ETH) in 2001; rear disc brakes were added mid-year. This engine is mated to the NV5600 six-speed. Compared to the five-speed NV4500 and four-speed automatic offered behind the 235hp standard-output Cummins, the NV5600 offers additional gear(s) to better keep the engine in its powerband, especially when towing. This trans is nearly bulletproof, even when subjected to high horsepower. (For drag-racing applications, a more-expensive-to-modify auto-trans setup would be used.)
Diesel Dynamics purchased a 36,000-mile '01 1/2 Quad Cab longbed 4x4 for $20,000. Baseline performance numbers were promptly generated on the company's specially constructed Dynojet chassis dyno.
Extensive testing by Diesel Dynamics has spawned package combos that balance more power with tailpipe smoke considerations. While most of these aftermarket upgrades make gains on their own, the overall package output is greater than the sum of the individual parts: These combinations account for each modification's effect on exhaust-gas temperature (EGT). Lowering exhaust heat opens the door for power-making fuel and timing enhancements. Here's an overview of Diesel Dynamics' Cummins ISB H.O. 500hp package:
|500 hp Power Package |
|Part ||Price |
|Edge Juice WithAttitude module/controller ||$810 |
|Jammer Stage 3 fuel injectors ||$700 |
|Therminator 4-inch exhaust system ||$550 |
|HX-40 Max-Boost turbo kit ||$1,200 |
|Big Fuel Line kit ||$180 |
|Pusher fuel pump kit ||$200 |
|Clutch upgrade ||$995 |
|AFE Funnel ram intake kit ||$249 |
|Total ||$4,884 |
Here's the Dynojet rear-wheel proof: 218.1 hp stock, 511.5 following a day's worth of bolt-on modifications. Even more impressive are torque numbers: 444.4 lb-ft before, 1,052.2 after. Diesel Dynamics purpose-built this dyno bay by digging a crater into the ground to accommodate the 48-inch drums necessary to handle these torque loads.
Engine Module and Monitor
The single-best bang-for-buck diesel modification is an engine-control module. This job used Edge Products' new Cummins Juice With Attitude system. It offers five different power levels that add 50 to 120 hp and 150 to 350 lb-ft on "standard" Cummins ISB ETC applications, and 40 to 95 horses on H.O. ETH trucks. The Juice black box intercepts the signals between the truck's computer and the engine to maximize efficiency and power by controlling fuel supply, timing, and turbo boost.
The system's Attitude in-cab controller serves two functions. First, its backlit LED readout replaces aftermarket EGT (exhaust gas temperature) and boost gauges. Combined with its thermocouple, the Attitude can be programmed to defuel the engine at preset EGT levels for idiot-proof durability. The Attitude switches among the Juice's five power levels on the fly to accommodate towing, cruising, or flat-out hauling ass as needed.
Diesel Dynamics has tested countless Cummins high-flow fuel injectors over the years--so many that they can now swap out a set in as little as 14 minutes. The engineering challenge here is to maintain proper fuel and cylinder pressures, so simply hogging out the nozzle orifices isn't the answer. In the past, substituting injectors intended for other applications has made power, but now there's a higher-tech solution: Diesel Dynamics' Jammer injector line combines OE Bosch injector bodies with precision-machined nozzles having eight orifices instead of the stock seven. The manufacturing process also matches flow rate to within about 1 percent among injectors. (The stock injectors can vary as much as 11 percent per set.)
Jammers make more power through better atomization, faster fuel flow, and an enhanced spray angle. Diesel Dynamics offers them in five performance stages, ranging from the 60hp Stage 1 to the 175hp Stage 5. Stages are distinguished by orifice diameter, spray angle, pop-off pressure, and price. For this buildup, Stage 3 Jammers were chosen to add about 150 hp when triggered by the Edge Juice module. Another reason that Cummins Rams are popular diesel hot-rodding raw material is that the injectors are easily accessible; mechanically inclined Cummins owners should be able to swap out their injectors in two hours or less.
Max-Boost Turbocharger and Manifold
Doubling the stock power also requires a bigger turbo. The Cummins H.O. ETH is factory-equipped with an HX-35 turbo in a 10cm2 housing for faster spool-up than the standard-output engines. To increase airflow and thus reduce EGT in 325- to 500hp buildups, Diesel Dynamics uses its HX-40 Max-Boost turbo.
The turbocharger is preassembled with a restrictor elbow and wastegate spring to mechanically regulate boost pressure to 40 psi. It's also clocked for bolt-on installation and fitted with a 4-inch downpipe. The turbo bolts to the ATS manifold, OE intercooler, exhaust downpipe, and lower oil line. The unit must be primed with oil before the upper oil line is connected.
This unit receives a modified bearing package for durability, and Diesel Dynamics mechanically regulates the escargot's wastegate to open at 40 psi (compared to the OE 21 psi). Increased airflow drops EGT by about 250 degrees F and adds an extra 25-plus hp and 50-plus lb-ft. Between the turbo and engine is an ATS exhaust manifold, which uses a three-piece design with expansion joints to handle near-instantaneous temperature variations between 700 and 1,400 degrees F. The manifold is engineered to reduce backpressure and improved turbo spool-up.
A common misconception is that fat diesel exhaust systems make power. More accurately, they complement other components by reducing exhaust backpressure, which lowers EGT by 100 to 150 degrees F. Diesel Dynamics developed a 4-inch Therminator turbo-to-tailpipe system for the Cummins. It's made of 16-gauge aluminized steel with mandrel bends and a straight-through-style Walker industrial-application muffler.
The Therminator system bolts up to the turbo's 4-inch downpipe and is designed for better flow and faster turbo spool-up. Each kit includes enough tubing for Quad Cab and longbed applications, so the straight piece must be cut to length for shorter trucks. All necessary clamps and hangers are included, and Diesel Dynamics reinforces all joints with welds on its in-shop installations.
Bigger Fuel Line and Pusher Pump
Applications in excess of 350 hp need greater-than-stock fueling capabilities. Diesel Dynamics solves the problem with its Pusher fuel pump kit and Big Fuel Lines. The Pusher pump is a standard Carter unit, but testing several part numbers revealed the one that supplies enough juice to pump out up to 750 hp and 1,500 lb-ft at the rear wheels. The fuel-line kit eliminates OE restrictions caused by ID fluctuations and banjo fittings to increase fuel flow and keep the diesel cooler in the process.
To a Higher Power
If 500 hp isn't good enough, Diesel Dynamics offers packages that go to nearly 800 ponies and more than 1,600 lb-ft of torque. The company's proprietary 24v Performance Camshaft increases durability by improving cylinder fill at low and midrange rpm. Other characteristics include a 40 percent increase in airflow, turbo spool-up, and smoke abatement. Testing has also shown that this cam provides a 2 to 3 mpg increase in mileage and a 150 to 300 degree F drop in EGT. Diesel Dynamics' over-500-hp power packages can include a ported and polished head that has more than 28 percent better flow per cylinder, race-only Mega Mental fuel injectors, and even nitrous oxide.
Air Intake Box
This 500hp Cummins package includes an AFE "Funnel Ram" intake. The system supplies a 250 percent increase in airflow (820 cfm versus the stock 377 cfm), which helps lower EGT and decrease spool time. Another benefit is AFE's lifetime-warranted washable, reusable filter.
South Bend Ceramic-based clutches have been durability-tested in high-horsepower Cummins 4x4 drag trucks (see video clips on Diesel Dynamics' Web site). This clutch has also proven its worth in 25,000-pound towing tests; the increased holding power comes with a grabbier feel. For five-speed heavy-duty towing applications, Diesel Dynamics offers the South Bend clutch with an OE five-speed flywheel that has been redrilled to accept the six-speed 13-inch clutch and pressure plate. The six-speed NV5600 comes with the 13-inch clutch stock, and the South Bend offering for these have been tested to more than 700 hp. All of these clutches require surface-grinding the flywheel for proper holding power.
Possibly the most impressive part of this buildup is that it's based on glorified tractor parts. Diesel Dynamics can do all of these modifications in a day, and the competent home mechanic could conceivably button them up in a weekend. Compare the overall outcome to a new '04 1/2 Dodge with the Cummins 600 engine at 325 crankshaft hp, 600 lb-ft of torque, and a $36,000-plus MSRP.