GM Shelves Innovative New 4.5 Liter V8 Diesel
By Chris Haak
GM had been expecting to begin production of its all-new 4.5 liter Duramax light-duty truck diesel (pictured at left) at its engine plant in Tonawanda, New York this fall, but has now put those plans on hold, according to Automotive News. The company blamed its deteriorating financial situation for the decision, and has noted in the past that all product decisions are up in the air at this point. If GM ends up re-starting the program, it will take a year from the program’s re-initiation for the engines to reach Job 1. One problem that GM has traditionally had over the past few years, and has become worse lately as it’s hammered on all sides by bad news, is that it repeatedly starts and stops projects, which adds significant time and expense to them.
The new engine was to have produced 310 horsepower and 520 lb-ft of torque, while returning highway fuel economy in the mid-20s. The initial application for the new engine was to have been the Chevrolet Silverado and GMC Sierra full-size pickups.
It really is a shame to see what was seemingly destined to be one of the best engines in GM’s history shelved – and quite possibly cancelled permanently at some point. The engine is a clean-sheet design that is able to fit into the space normally occupied by the very-compact small-block gasoline V8. That meant that as long as the transmission application could handle its 510 lb-ft of torque (not necessarily a given), it could fit into nearly any medium to large GM car, truck, or SUV. Possible applications that had been in the rumor mill from time to time included the Lambda crossovers (Enclave et al), Zeta cars (Pontiac G8, Chevy Camaro, Holden Commodore), and even the Cadillac CTS. The new engine’s small footprint was attributed mostly to the intelligent way in which its exhaust and intake plumbing was reversed from the norm; instead of the exhaust exiting the engine on the outside of the “V,” it exited in the valley, and the turbocharger could be nestled between the cylinder banks for a much more compact design.
As we noted in our “Diesel Invasion” article way back in 2007, many manufacturers had plans or were at least considering selling diesel-powered cars and trucks in the US, hoping that bad memories of self-destructing Oldsmobile diesels from the 1980s were a distant memory for most consumers. Since then, fuel prices shot up significantly, and diesel fuel prices exploded to more than $5 per gallon in most places. Of course, the ensuing global economic collapse pulled diesel and gasoline prices down to lower levels, but seeing diesel prices last summer certainly didn’t help make the case for more diesels in the US. Honda has shelved its US diesel plans for the Acura TSX, apparently because of emission worries, and Jeep is no longer selling the Grand Cherokee CRD that I enjoyed last summer.
There is another hope for the Duramax 4.5 liter diesel as well. GM Powertrain spokeswoman Susan Garavaglia told Automotive News that it’s possible that rights to the engine could be sold to another company. Auto writers who have sampled prototype vehicles powered by that engine have said that it was as smooth and quiet as a gasoline engine, and there are plenty of companies looking for new light-duty diesels for their half-ton truck applications – Toyota among them.
With the sales of GM’s expensive two-mode hybrid pickups and SUVs showing some pretty pathetic numbers, GM could have had better-performing, more-efficient vehicles in the light-duty truck class, while probably selling the 4.5 liter Duramax option for less than the nearly $10,000 premium the hybrids are going for, and for less than the $8,000 price difference the larger and more powerful 6.6 liter Duramax adds onto the price of a gasoline V8 in the three-quarter and one-ton GM pickups. The Duramax 4.5 liter will probably turn into an interesting footnote in GM’s history, and yet another example of the coulda, shoulda, woulda that afflicts this company so consistently.
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