New Clean Diesel Engine Developed by GM for Silverado/Sierra and H2
Diesel is a hot topic for many automakers, especially the North American ones. The big three have offered turbodiesel engines for quite some time now, but only for their industrial-strength vehicles. Having one under the hood of your hauler involves opting for a heavy-duty three-quarter ton truck or SUV. Unfortunately, not everyone can afford such a vehicle, or has the space or patience to park and maneuver it. So, General Motors has taken it into their own hands to develop a brand new turbodiesel engine specifically for its smaller trucks, the very popular GMT900-series half-ton pickups, plus the Hummer H2.
For those who may not be in the know, GM’s “Duramax†branded diesel engines are the core of its heavy-duty lineup. This series of V8 engines, ranging from 6.2- to 6.6-litres in displacement are used to power everything from the heavy-duty vans such as the Express/Savanna, the large pickups, the now deceased Hummer H1 Alpha, and the Chevrolet Top-Kick and GMC Kodiak. These engines were engineered in collaboration with its Japanese industrial partner, Isuzu.
This new turbodiesel engine, while branded Duramax, was developed completely in-house by GM and is on the cutting edge when it comes to technology. Its head is made out of lightweight aluminum, and the engine features dual overhead camshafts with four valves per cylinder, features that you generally don’t expect to see on a workhorse turbodiesel. Likewise, we’re surprised to see that General Motors invested the money in a variable vane turbocharger on an engine like this, but we’re glad they did as it enables the 4.5-litre unit to produce more power, more efficiently. GM designed the engine so that it’s as compact as its regular small block V8, which is impressive since the General’s “big†V8 turbodiesels have always been in the six litre or larger displacement range.
Since the engine is still under development, its output isn’t written in stone, but at the minimum it is expected to turn out 310 horsepower and 520 lb-ft of torque. GM says that the engine will use 25-percent less fuel, and produce 13-percent less carbon dioxide, and cut the harmful NOx emissions by up to 90-percent compared to its current gasoline engines. Amongst the other impressive claims that GM is making is that the new diesel is at the noise, vibration and harshness (NVH) levels of its current gasoline V8 engines, which really impresses us.
It may take a couple of years to finish, with production scheduled for 2009, but the addition of a clean diesel to the Silverado/Sierra and Hummer H2 will certainly help slipping sales due to the rising price of fuel. With its compact size, we wouldn’t be surprised if GM eventually spread this engine into the smaller Colorado/Canyon pickup truck range, as well as to the Hummer H3.