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.
Turbo Timer
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.