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Question: I own an '06 Dodge Ram 3500 Quad Cab and I have invested a decent amount of money in it. It has a BD Diesel R700 twin-turbo setup, intercooler, transmission, and flexplate. It also has a Fluidampr balancer, AirDog 150-gph lift pump, FS2500 bypass oil filter, 50hp injector nozzles, ARP head studs, and a Smarty/TST stack for programming.
The maximum horsepower I have been able to make on a mustang dyno is 570 hp and about 1,200 lb-ft of torque before experiencing loss of rail pressure, which I hear is a common problem at my power level. I want to know what path to take next, a modded CP3 pump with more flow over stock, or a dual CP3 setup?
I have heard both good, and not-so-good feedback about the modified pumps, and I am not sure what to believe at this point. I do drive long distances on the highway, totaling about 12,000 miles a year, so mileage and reliability are also concerns for me.
Robert Tom
Vancouver, British Columbia, Canada
Answer: Modified CP3 pumps can be bought from a few different companies, including Industrial Injection, Wicked Diesel, and Floor-It Diesel. It turns out that all of these modified pumps work-it just depends on the power level you're looking for. At 550 to 600 hp, Industrial Injection's Bag of Parts CP3 upgrade or Wicked Diesel's Arson kit will help steady your rail pressure. Beyond that, it's time to go to a fully modified pump. The modded pumps will get you enough fuel to support larger injectors and can support about 700 to 800 hp. The nastiest pumps are not always the most streetable, because they ramp up rail pressure so fast.
| Nick D'Amico found out he needed two modified CP3 pumps to keep his rail pressure up after shifts. Part of the issue here is that Nick's Duramax shifts at an outrageous 4,800 rpm. A lower-rpm engine might be able to get by with two stock pumps, or even a modified single CP3, but lots of fuel, lots of engine speed, plus big injectors will almost always require modified pumps.
For us, if you're looking for about 650 hp, running a modified pump will get you where you need to be. Dual CP3s will get you up to about 900 hp, and anything past that, you'll need dual modified CP3s. Another trick to keeping rail pressure up is supply pressure. Increasing lift pump pressure to 30 to 40 psi is a good way to prevent pump cavitation, which will also help keep your rail pressure from dropping.
Question: This past June I purchased a '97 F-250 crew cab shortbed from a friend. He'd done quite a few upgrades over the years, addressing nearly all its inherent shortcomings. It currently has a Tuff Country 2-inch leveling kit, air springs in the rear, older Rancho RS9000 shocks (five-way adjustable), 33-inch tires on stock wheels, and a Dana 60 solid axle from a mid-'80s F-350 under the front end. With the shocks on the lowest setting (softest), I get a lot of bouncing or wallowing over bumps, and if I make the shocks stiffer-particularly the front ones-it rides like a brick. What are my options if I want a softer and better-controlled ride? I love everything else about the truck but would love to improve the ride.
Jeff Addington
Via Email
Answer: Suspension tuning can often be a difficult problem to address. Before you mess with the shocks too much, try adjusting your tire pressure. You can vary it by about 10 to 15 psi without sacrificing too much in terms of wear or fuel economy. If you still can't find a happy medium between floating and jarring, our last choice would be to install some double-adjustable shocks, where you can change both compression and rebound separately, or some shocks that are valved specifically for your truck. A high-quality mono-tube shock with diesel-specific valving from a company like Bilstein will run you about $60 to $70 a shock-not a bad price for something you'll notice every time you drive the vehicle.
| Since diesel trucks are usually pretty nose-heavy compared to their gasoline counterparts, specially valved shocks can be a real asset in ride comfort. One company that makes such a shock is Bilstein, which carries a full line of diesel-specific shocks for Fords, Chevys, and Dodges.
Question: I recently had my transmission go out in my '97 Ford Power Stroke, and I was wondering if it would be worth switching over to a stick. If it is, then what are my best bets on getting it done? If it isn't, what do you recommend for an automatic?
Jackson Kunz
Santa Cruz, California
Answer: We get this question a lot, especially from Dodge and Ford guys. Oddly enough, most of the Ford guys want to switch to a manual transmission, while the Dodge owners are looking to switch to automatics. While it is possible to switch transmissions, it is always the cheapest and easiest route to stick with what you already have. The only way we would contemplate doing a transmission swap over to a different type is if we had a donor truck, a lift, and a lot of spare time on our hands. The little stuff is what will drive you crazy in this type of swap. Aside from the transmissions, there will be brackets and linkages to contend with, which is why having a donor truck is so important. Even if you think everything will fit perfectly, we'd also expect to do some minor fabrication work. In your case, since your transmission is already toast, it makes even less sense, considering you can't sell your original automatic to recoup the monetary losses of the swap. If it were us, we'd just talk to a few people in the area and see if you can get yours rebuilt (at a reputable shop). If you prefer to do some of the work yourself, you can always just order a new transmission from companies like Sun Coast, ATS, NADP, or even smaller shops like John Wood Automotive and Brian's Truck Shop.
| Many diesel enthusiasts who get into drag racing opt to swap out their manual transmissions for automatics for faster elapsed times, but that doesn't mean all manuals are slow. Back in 2001, Jeff Prince ran 12.1 at 119 mph in the quarter-mile in his manual transmission dualie—a record that stood until this year, when it was beat by a high 11-second manual transmission GMC.
