Spied! 2010 Chevrolet Silverado 1500 4.5-L Duramax Diesel V-8
By: Mike Levine Posted: 07-09-08 08:00 PT
© 2008 PickupTrucks.com, Brian Williams for Brenda Priddy & Co.

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The price of diesel fuel is at a record high but that's not deterring General Motors and other light-truck manufacturers from introducing all-new diesel engines in their half-ton pickups by 2010.

Pay no attention to the 2500 HD badges on the doors of the Chevrolet Silverado engineering mule in these pictures. The six lug wheels (instead of eight, like the real 2500 HD) give away that it's actually the 1500 series pickup and the exhaust-cooling Venturi tailpipe out the back is GM's diesel powertrain signature.

Under its hood is GM's revolutionary new dual-overhead cam 4.5-liter Duramax diesel V-8. The four-valve engine was designed with six dozen fewer parts than a conventional diesel. Separate intake and exhaust manifolds have been eliminated and integrated directly into the engine. Airflow is reversed, so fresh air enters through the outer portion of the cylinder heads and exhaust gases are dumped inboard, directly into a variable-vane turbocharger and EGR cooler that sit in the valley of the 72-degree V-8.

Removing hardware and rearranging key components also reduces the 4.5-L Duramax's footprint compared to conventional V-8 diesels with similar displacements, so the 4.5-liter Duramax can fit in the same space as GM's 6.2-liter small-block gas V-8 (see picture below).

GM officially says it expects the 4.5-liter Duramax with a six speed transmission to deliver class-leading horsepower and torque, with ratings in excess of 310 horsepower and 520 pounds-feet of torque. Fuel economy is expected to be 25% higher than a comparable gas engine. It will also meet stringent 2010 light-duty emissions in all 50 states, using a diesel particulate filter to remove soot and urea selective catalytic reduction to scrub nitrogen oxide.

Even though it shares the Duramax name with the heavy-duty 6.6-liter V-8 -- which has been engineered and produced in partnership with Isuzu Motors -- the new diesel is 100% designed by GM and will be built without Isuzu's involvement.

When it arrives, the 4.5-liter Duramax V-8 will be competing against similar engines from Ford and Chrysler. Earlier this year we saw Ford's 4.4-liter V-8 in 2009 F-150 test mules and on the floor of Ford's dealer convention. The 2010 Dodge Ram 1500 is expected to offer both V-6 and V-8 diesels built by Cummins.

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