GM Posts (then Deletes) New 6.6-Liter Duramax Turbo Diesel Power Specs

gm posts then deletes new 6 6 liter duramax turbo diesel power specs

A document containing official horsepower and torque numbers for General Motors’ new 6.6-liter V8 Duramax turbo-diesel was found buried on the GM Powertrain website — before the company quickly deleted it.

GM’s new 2017 heavy-duty pickup trucks will wade into the nuclear torque war with a whopping 910 lb-ft of twist, with peak torque coming on at just 1,600 rpm. Horsepower is up by nearly 50 to 445 hp at 2,800 rpm — thanks in part to a new turbo design — while the 103 mm bore x 99 mm stroke remains identical.

The L5P’s 910 lb-ft of torque puts it midway between the Ford Super Duty’s 925 lb-ft and the Cummins-powered Ram at 900 lb-ft, however, its 445 hp rating leaves GM with the horsepower crown (versus Ram’s 385 hp and Ford’s 440 hp).

Thew new L5P Duramax is slotted for production at the GM-Isuzu plant in Moraine, Ohio, and will see action in both Heavy Duty Silverado and Sierra twins.

The accidental release comes just days before GM’s new HD trucks are set to officially debut at the 2016 State Fair of Texas, where we should receive transmission and towing specs.

[Image: General Motors]

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  • Lou_BC Lou_BC on Sep 26, 2016

    I've seen similar quick disappearances of numbers in the past. Since the peak numbers for these trucks can easily be tuned by the factory they all tend to wait to the last minute when releasing specs. They want bragging rights but so far GM has chosen to stay out of the "peak numbers" game with HD's. It is rare to see anyone tow max loads with any of these trucks. Experienced buyers tend to build in some leeway. GM who has chosen not to play "peak numbers" claims that the average tow load for a HD diesel is 10k. Ram who chooses not to play peak numbers with 1/2 tons claims that peak average for that class is 5k. That does tend to fit with what I usually see. There are guys towing 10k trailers with 1/2 ton p/u's but ironically most I see aren't max capacity Ford or GM trucks. I do see guys towing massive 54 ft long tri-axle toy haulers but that is fairly rare.

    • Drzhivago138 Drzhivago138 on Sep 26, 2016

      Any toy hauler or fifth-wheel camper with three axles almost always requires a Class 4 truck, which is only offered in pickup form by Ford (and yes, I know some years of F-450 pickups are just heavy Class 3s).

  • on Sep 26, 2016

    I have a 2015 2500HD SRW 6.0 with 68k miles and make multiple runs across the US towing 10k with a pop up camper in the bed at 19k CGVW. Pulled that weight up the Ike at 35 mph at 4K Rpm's. There is no reason when towing, to run up the Ike at the posted limit than to stress your motor. Chevys 6.0 is perfectly capable, has done everything I've asked and while the tranny is not an Allison it holds downhill speed within 2 mph. Gets 9-11 miles per gallon towing at 60 miles per hour. The only reason I would be interested in a diesel is range. 36 gallons gets 290-330 miles with gas the Duramax would be close to 500 miles. When gas was 30% less than diesel the cost per mile for gasser was 1.5 cents more than diesel. Crunched the numbers recently and noted I would save a total of 45 dollars a month with the diesel. Not enough for me to switch.

    • Stuki Stuki on Sep 27, 2016

      The range discrepancy is, in practice, bigger than that. Larger aftermarket underbody diesel tanks are plentiful and fairly cheap, while aftermarket gas tanks are either flat out illegal, or at least exceedingly rare.

  • DenverMike DenverMike on Sep 27, 2016

    The time is right for a return of big blocks. Or at least twin turbo versions of the Hemi, Coyote, etc, for HD pickups.'

    • See 2 previous
    • Lou_BC Lou_BC on Sep 28, 2016

      @DenverMike - you do know that no one makes a true "big block" anymore? Ford's 6.2 is regarded by some as a "mid block". GM's 6.2 is a small block and so is the 6.4 hemi.

  • Snail Kite Snail Kite on Sep 27, 2016

    Is that enough power to tailgate people in the left lane while going 80mph and hauling a trailer after you install a 10" lift and big chrome wheels and off-road tires? The people of Georgia need to know.

    • Scoutdude Scoutdude on Sep 27, 2016

      That reminds me of what I saw last night. A lifted SRW GM HD pickup with a trailer carrying a DRW 3500 GM truck, poorly tied down from the looks of it. Of course it was lifted to the point that even with a big drop ball mount the trailer was at a good angle. He was merging on to the freeway and I took one look at the seriously hurting rear axle trailer tires and put the hammer down to put some distance between us. I looked into the rear view mirror to see the trailer wagging the dog almost into the car that had been behind me. The next glance back showed him pulling over to the side of the road.