1999 Dodge Ram 2500 Cummins Turbo Diesel - Project Baja Bomber, Part 5Posted in Project Vehicles on September 1, 2005 0) (
When Chrysler packaged the Cummins turbodiesel engine in 3/4- and 1-ton Ram pickups in 1989, the light-duty truck market was changed forever. Not only was it radically heavy-duty compared to other diesels of the era, but it was also the first turbocharged diesel engine to ever grace a consumer pickup. Designed as a mammoth mover, the Cummins was barely working when required to push around a 7,000-pound (light-duty by commercial standards) Ram chassis. As such, extremely heavy-duty internal parts make the Cummins engine a very willing candidate for hop-ups. This is why we chose the Cummins-powered Ram as our starting platform for the Baja Bomber project.
One of the biggest names in the diesel aftermarket is BD Diesel Performance of Abbotsford, British Columbia. BD builds everything from transmissions to injection pumps and has been in business for over 32 years. With a staff of two engineers, a dozen performance specialists, and more than 350 nationwide dealers, BD is a one-stop shop for Ford, GM, and Chrysler diesel performance products. We took a trip up to BD's headquarters for the biannual dealer-training and dyno day event. We spent hours touring the facility and learning about each division of the company, and about the products BD manufactures.
The operation was impressive, and the people in charge were extremely knowledgeable when it came to high-performance diesel pickups. Knowing a good opportunity when we see it, we decided to let them tinker with our resident Cummins-powered project vehicle, the Baja Bomber, to see just what kind of power they could produce reliably and within reason. The results were outstanding, so follow along as we highlight how the guys at BD woke up our oil-burner.
DYNO TEST COMPARISON
|Test 1||Test 2||Test 3||Test 4|
Test 1: Stock turbo, Edge Comp box 5x5, Snow performance 50/50 water/methanol injection.*
Test 2: BD twin turbo, Edge Comp box 5x5.**
Test 3: BD twin turbo, Edge Comp box 5x5, Snow performance 50/50 water/methanol injection.**
Test 4: BD twin turbo, Edge Comp box 5x5, Snow performance 50/50 water/methanol injection, DMH Performance exhaust cut out valve open.**
*Exhaust Gas Temperatures above 1,400 degrees.
** Exhaust Gas Temperatures below 1,150 degrees.
With any diesel engine you must first supply additional fuel to increase power. To achieve this, we decided to try out a set of Mach 2 (105 hp) injectors from Formula One Diesel. We could have sourced bigger injectors from BD. However, the guys at Formula One Diesel happened to be present at a local drag race event when we were ready to install. We won't bore you on these pages with the installation process, but instead illustrate the principle by which they function. Picture a regular run-of-the-mill garden hose, just like the one you'd find in your backyard. Now imagine this hose is turned on just slightly, enough so that water trickles freely from the open mouth of the hose. Though a bit exaggerated, we'll say this is your fuel system at idle. Next, imagine turning on the hose full blast; we'll say this simulates your truck's fuel injectors at wide-open throttle. Now picture a fire hose hooked up to a fire hydrant out in front of the house, and it's not hard to see where this little analogy is going. A set of bigger injectors simply allows more fuel into the combustion chamber, and they also create more efficient atomization.
Unfortunately, Chrysler used a weak lift pump on '94-'01 Cummins-equipped trucks. These pumps are located down low, near the back of the engine on the driver side. Over time, these pumps tend to fail. When they do, they typically take the injector pump with them. This can cost thousands of dollars to repair, so anyone who is looking into beefing up a Cummins-powered Ram should at least install a low fuel-pressure indicator light (PN 1081130) or simply replace the fuel pump altogether with a new higher-flowing unit. BD offers a simple bolt-in replacement unit (PN 1050226) that is good to 600 hp. Retailing for under $265, this is extremely cheap insurance against injection-pump failure.
We expect the Bomber to run competitively in the increasingly popular diesel drag racing circuits. So, we needed a fueling box that could help deliver more than enough fuel to exceed the demands of our new BD twin-turbo intake system. BD recommended the Edge Products Power Edge Comp box, which they stock. This little black box connects to the MAP sensor, injection pump, and a boost source. Once connected, the box is positioned in the cab where the driver can reach the controls. The driver interface on the Comp box is composed of three touch-sensitive buttons. Two of them activate the five different power levels, and one button turns the unit on or off. The box has a display that lights up, indicating which power levels are selected. Essentially the Comp box talks to the injection pump and changes the timing and quantity of fuel delivered to the injectors. Edge claims power gains up to 120 rear-wheel hp with the box on level five. Our dyno test confirms these claims.
Now that we've taken care of the fueling side of the equation, we'll move on to the other side. Without additional air, fuel alone will only create high EGTs and black smoke. So it is necessary to introduce more oxygen into the combustion chamber. The kit shown above was engineered to deliver just that for 24-valve Cummins-powered Rams with modified transmissions. With this setup, a smaller primary turbo feeds a larger secondary turbo, thereby multiplying air volume and head pressure. Back in Part 2 (Sept. '04) we installed a Scotty Air 2 intake system, which gave the Bomber cool-cowl induction via the HVAC intake cavity located just behind the firewall. This intake worked out great for us. However, due to spatial constraints under the hood, we had to abandon the Scotty Air system as it was not physically compatible with BD's twin turbo kit.
More Air = More Cylinder Pressure
Stock head bolts tend to stretch over time and should at the very least be re-torqued with any increase in cylinder pressure. We recommend replacing head bolts altogether with studs to prevent head-gasket failure. Cummins claims the stock head gasket on a 24-valve will typically remain intact with up to 55 psi of boost. Go much over that and you're running on borrowed time. Unfortunately, we learned this the hard way on our trip back to California, when halfway through Oregon our head gasket let loose, leaving us with a huge oily mess under the hood, an expensive tow bill, and a contaminated cooling system. The guys at Cummins Northwest of Medford, Oregon, replaced the Bomber's head gasket with a new OE unit. The repair cost nearly $2,500 and delayed our return home by nearly a week. Luckily, ARP makes a set of studs that can prevent this (shown at left). No doubt another thing we plan to do very soon. Another option is to remove the head from the vehicle and have a machine shop install reliefs around each cylinder for wire O-rings. With O-rings, we've seen Rams with boost levels as high as 100 psi with no problem.
BRING IN THE TWINS
First, the BD technician removed the Bomber's intake system, stock turbo, exhaust downpipe, and intercooler intake tube. Next, the radiator was drained so that the steel coolant line running beneath the exhaust manifold could be modified. A brass compression fitting was used to allow proper alignment of the coolant line once it was reinstalled.
Then the BD technician removed the exhaust manifold from the head of the engine. The center of the three-piece ATS manifold had to be inverted to provide a mounting surface for the new secondary turbo. While the exhaust manifold was removed, the BD technician also drilled and tapped the manifold for an Exhaust Gas Temp (EGT) port and a turbo drive pressure probe. The holes for the original EGT probes on the opposite side were plugged and the mounting base with its four holes was tapped for studs (shown above).
Next the BD technician removed the freeze plug from the lower rear area of the engine block. This required careful attention so as not to let the plug drop into the crankcase. To remove the plug, he first drilled a small pilot hole in the center of the plug. Then he installed a short sheetmetal screw. This created a way to pry the plug from the block with a pair of pliers. Once the freeze plug was removed from the block, the BD technician inserted an aluminum fitting to provide a return drain connection for each turbo's cooling oil line.
The secondary turbo was then fitted to the exhaust manifold. This was followed by hooking up the oil feed line and drain to the appropriate ports. Then the primary turbo support bracket was installed just behind and slightly lower than the secondary turbo. This impressive bracket is brake-formed from 316 stainless steel.
Next, the primary turbo was mounted to the above-mentioned bracket. Once mounted, all appropriate oil lines were connected with associated fittings.
Once both turbos were installed, the BD technician moved on to the intercooler tube assembly. First, the cast-aluminum elbow and intercooler tube were secured to the secondary turbo outlet. Next, each turbo inlet was fitted with 4-inch silicone boots and heavy-duty 4-inch band clamps. This provided connection points for the remaining turbo ducting connections.
Then the primary turbo intake tube was installed. Once in place, the oil filter was reinstalled and checked for proper clearance. As you can see, the 4-inch intake tube is positioned very close to the oil filter. In some cases, a slight depression to the oil filter body may be required for proper clearance (arrow).
Once all the turbo ducting was replaced with the parts included with the BD kit, the new exhaust downpipe was installed. To do this, they removed the entire exhaust system from its rubber hangers. The new downpipe was clamped to the primary turbo outlet (arrow). Next, the exhaust system was attached to the downpipe. This step required two people under the truck to manipulate the exhaust system.
Once the exhaust system was done, the BD technician moved on to the cold-air intake setup. This kit utilizes a slick piece of polished stainless steel to isolate the filter element from the rest of the engine compartment. A large AFE seven-layer filter provides tons of surface area to ensure ample air supply to the engine. The setup is shown here with the optional screen pre-filter, which is said to extend filter life by nearly 40 percent. We found it also cut airflow by about 30 percent. This little guy will likely stay tucked away in the glove compartment until the Bomber hits the silt beds of Baja.
Are Twins Too Much?
Not all Cummins owners actually need two turbos underfoot. At least they don't think they do. For those people, we suggest driving a truck equipped with twins first - you'll know right away if it's the right thing to do. We did. For others, though, the twin system might be a wee bit expensive to justify. Luckily, BD has solutions for tight pockets too. This one is called the Super B single replacement turbo and it retails for about half the price of twins. With this kit you get a 75- to 125hp increase with acceptable EGT levels, and the best part comes later down the road; if you decide to upgrade to BD's twin kit, you already have half the system installed.
Did you know each time a turbodiesel is shut off, turbo bearing damage can occur? It's true - when a hot diesel engine is turned off without a proper cool-down period, the bearings that are cooled by engine oil get a boiling-hot oil bath, which leads to premature bearing failure. One way to avoid this expensive mishap is to install one of BD's turbo cool-down timers. This little unit is wired-in under the dash to provide logic that delays engine shutdown until the turbo has reached suitable temperatures. It takes some getting used to because you have to remind yourself when you remove the key from the ignition that it's "OK, the truck will turn off when it's good and ready." A simple tap on the brake pedal will override the turbo timer, killing the engine instantly should the need arise.
Still Need More?
Snow Performance builds the ultimate add-on for those of you looking specifically at quarter mile times. The technology has been around for years - drag racers swear by it. It wasn't readily available, however, until Matt Snow, the owner of Snow Performance, developed a bolt-on kit for diesel pickups. It's called water-methanol injection. We tried it out and were very impressed with the results. We're talking 50 to 95 rear-wheel hp, depending on the ratio of water to methanol. It works like this: a simple bulkhead fitting goes in the bottom of the windshield washer fluid reservoir. From there, a special pump forces the water/methanol mixture into the intake plenum. Two small atomizer nozzles fog in the juice as the turbo boost level comes up. The electronic controller meters the amount of water/meth injected proportionally to boost levels. Cooler EGTs are an added benefit with this system. The kit retails right around $500. Check out www.snowperformance.net for more info.