The old adage that there’s “no replacement for displacement” isn’t technically true, but it’s seemingly part of the logic behind the company’s massive new 8.3 liter Duramax diesel.
GM’s huge new engine offers more horsepower and torque than Ford’s 6.7 liter Powerstroke and RAM’s 6.7-liter Cummins. To be specific, that’s 555 horsepower and 1,230 lb-ft of torque, compared to 500 horsepower and 1,200 lb-ft from Ford and 430 horsepower/1075 lb-ft from RAM.
Obviously, the block and internals need to be robust to handle this kind of output. GM says the block is made from “compacted graphite iron” while the internals feature a fully forged crankshaft and connecting rods. There’s also a variable geometry turbocharger forcing air into the thing and upping the power.
The huge V8 is surprisingly tech-forward
While a massive diesel engine can seem a little brutish, GM’s latest effort actually has a good amount of technology behind it. In thermal terms, the engine uses a dual stage air to water charge cooler to keep the temperature down. An integrated intake design, advanced combustion system and crankshaft isolation hardware are all there to reduce noise and vibration. A new aftertreatment layout targets emissions, making sure the gases coming out of the back of it are pretty clean.
An Allison 10-speed 10L1000 transmission sits between the block and the wheels. The gearbox comes with “advanced shift logic” which is designed to smooth out acceleration, keep the vehicle sitting in its power band, and make heavy trailers easier to handle.
A lot of the tech is aimed at improving the towing experience. The cooling system means you can haul a heavy load a longer distance without issue. That journey should also be smoother and quieter.
The new engine puts GM ahead of both Ford and RAM when it comes to raw power and displacement. However, despite the diesel’s immense size and ridiculous amount of torque, the Ford Super Duty still edges it out when it comes to towing capacity.
With a gooseneck hitch, a truck powered by the new Duramax V8 can haul a staggering 38,000 pounds. But Ford says the Super Duty can still pull up to 40,000. If you’re towing conventionally, the Duramax maxes out at a still impressive 20,000 pounds.
The hardware around the engine has also received a bit of an upgrade. There’s new rack and pinion electric power steering, and a new electronic brake boost system built on heftier 14.6 inch rotors and four point piston calipers.
The new 8.3 liter Duramax engine is being built for the Silverado 3500 HD and Sierra 3500 HD, and it is a pretty clear statement of intent from GM. Between people who tow things commercially,
There is also a gas option, if diesel prices are a worry. The Enhanced 6.6L gas V8 GM has made available in its heavy duty trucks is also best in class when it comes to torque, though the 427 lb-ft is way below what a diesel will give you.
