DIESELS ARE TORQUE MONSTERS. WHILE A FULL-BLOWN RACE CAR MIGHT MAKE 1,000 LB-FT OF TORQUE, THAT NUMBER CAN BE ACCOMPLISHED WITH A STOCK OR NEAR-STOCK DIESEL.
STEP EIGHT: Getting Power to the Ground
For vehicles that aren’t heavy-duty in nature, the rear axle can be quite a task if performance is involved. Remember when we said that a diesel makes the torque of a race engine? Well, your rear axle won’t know the difference, so don’t expect a stock truck or car 10-bolt or GM 7.5, or anything else of that nature, to live long behind a diesel powertrain. Custom front and/or rear axles can be required if jumping, off-roading or drag racing is involved. Try to think about your needs and price margins, as light axles usually aren’t cheap, and cheap axles usually aren’t light. If you’re building a truck, you may even be able to grab an axle from your donor vehicle—something heavy duty like a Dana 70 or 80 or AAM 1150.
STEP NINE: Cooling & Other Ancillary Systems
We know of one less-than-bright enthusiast who had almost completed his project and decided he didn’t need a transmission cooler just for driving around. Instead of finding and running one, he just looped the lines and fried his transmission. Take a moment here and make sure all your cooling, steering and add-ons (like air conditioning) will work well with your diesel engine. Diesels don’t make much heat at idle, but under load it’s a different story. Both engine and transmission heat are something that must be factored in on a build (especially on a modified engine) and it’s better to be safe than to skimp. Items like NASCAR-STYLE aluminum radiators or oversize transmission coolers are still relatively cheap considering the cost of a new engine or transmission.
Probably one of the harder swaps we’ve ever seen was built by David Hackett, who somehow managed to stuff a 1,300-pound 7.2L CAT into his GMC. Note how much he had to modify the firewall for this swap, and it’s still right up against the radiator.
Need to fit something in a tight package? Merchant Automotive’s Duramax-powered sand rail doesn’t use a diesel transmission—it uses an ATI lock-up Powerglide with an M&M converter. It’s also been from zero to 100 mph in only 3.5 seconds at the sand...
It’s a little less common now because of the cost, but putting a Cummins engine into a 6.0L-powered F-250/350 used to be a very popular swap. Since a 6.0L is a diesel to begin with, much of the cooling system and drivetrain can be retained.