The diesel engine horsepower race gained speed reported the journal Automotive News on December 5, with General Motors announcing a power increase for its hot-selling 6.6-liter Duramax V-8. GM says that starting in January, the diesel engine, which is optional in heavy-duty models of the Chevrolet Silverado and GMC Sierra, will make 310 hp and 590 pounds-feet of torque. That’s an increase of 10 hp and 70 pounds-feet of torque, compared to its current version of that engine. The move comes just days after Dodge announced a new high-performance version of its Cummins turbodiesel, which makes 600 pounds-feet of torque and 325 hp. That engine is optional in the Ram heavy-duty pickup. Ford Motor Co.’s 6.0-liter Power Stroke V-8 available in F-250 and bigger trucks and the Excursion SUV, is rated at 325 hp and 560 pounds-feet of torque. GM, Ford and DaimlerChrysler have been slugging it out for the title of most powerful diesel truck engine for more than two years. All three automakers recently have replaced their diesel engines with new models and have boosted horsepower or torque — which increases a vehicle’s towing capacity — numerous times. All three automakers’ diesel trucks sell at near sticker price and are highly profitable. The diesel-powered trucks typically are bought by consumers who use them to pull heavy loads and drive tens of thousands of miles per year. GM also says the re-tuned Duramax will run cleaner. The engine, developed with Isuzu Motors, features a new turbocharger, updated fuel injectors and a revamped engine computer. GM and Isuzu engineers also installed an electronically controlled exhaust gas recirculation valve, which helps cut emissions. Tom Stephens, GM’s vice president of global powertrains, said the automaker is weighing a decision to boost production of the Duramax engine from its current level of about 150,000 per year.