General Motors has finally taken the wraps off its new Duramax 4.5L V8 turbodiesel, with several innovative features that separate the new mill from the previous generation design. Last year GM showed off the top half of the engine, which showed the turbocharger positioned where the intake manifold is normally found. Now, full details about the engine have been revealed, with claims that it is both lighter and more fuel-efficient than the outgoing powerplant.

The chief goal with the updated Duramax engine was not only to make it lighter and more efficient but also to give it similar performance characteristics to a petrol V8 engine. Discussing the "death spiral" of weight gain for modern cars, GM's diesel engineers have avoided this through some innovative techniques.

The crank journals in the new Duramax that hold up the crankshaft have been cast into the block using fracture splitting, resulting in greater efficiency, strength and precision, while at the same time bringing costs down. The new technique for constructing the crankshaft case also allows air to circulate more readily between the cylinders, reducing pumping losses. Additionally, the engine block is 30% stiffer thanks to an aluminum cradle, which allows the block to be subjected to higher pressures.

The end result is a 310hp (231kW) and 520lb-ft (704Nm) of torque output, reports Automotive News.

While GM wouldn't reveal how much cheaper the new Duramax will be to construct with these innovations, it is known that GM plans to sell the one design throughout all 50 states. This means that it will comply with tough Californian emissions standards, and GM is confident that the new Duramax should also be able to show a 25% gain in fuel efficiency over a similarly-sized petrol engine.

GM plans to use the new engine in more of its lineup to help improve its fleet-wide fuel economy and to boost the attractiveness of some of its bigger vehicles. The first models it will appear in are the Chevrolet Silverado and the GMC Sierra pickups, and then several SUV models. There’s also a rumor that it could appear in the new CTS sedan, with reports suggesting the 4.5L Duramax fits in the same space as the 6.2L LSA V8 of the CTS-V.