What We Know About GM’s New L5P 6.6-Liter Duramax Turbo-Diesel V8 Engine
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As we were first to report just a few days ago, the 2017 Chevy Silverado HD and 2017 GMC Sierra HD are getting a new Duramax diesel engine to replace the 6.6L Duramax V8 LML. In the days following the discovery, we’ve compiled a list of things that we know about GM’s new HD diesel, and what we don’t.
First, here is what we do know about the powerhouse, courtesy of various sections of the official order guide:
- It is assigned GM RPO code L5P
- It displaces 6.6 liters
- It is B20 compatible (20% biodiesel and 80% petroleum diesel)
- Like its predecessor, it remains mated to the Allison 1000 6-speed automatic transmission
- It works in conjunction with the new intake system on the 2017 GM HD trucks
- It is available across all trim levels of the 2017 Silverado HD and 2017 Sierra HD
What we don’t know is the juiciest, most important details: the power and torque ratings. Yes, we have seen the “rumored” (or perhaps speculated) figures of 445 horsepower and 850 pound-feet of torque floating around various websites. Whether those figures are true or not will be seen when GM officially announces the motor and its 2017 Heavy Duty trucks.
2017 GMC Sierra HD Denali
However, we feel responsible to note that GM’s outgoing LML makes 397 horses @ 3,000 RPM and 765 pound-feet of torque @ 1,600 RPM. In addition, Ford’s 6.7L PowerStroke Turbo Diesel V-8 in the 2017 F-Series Super Duty is rated at a whopping 440 horses @ 2,800 RPM and a segment-leading 925 pound-feet of torque @ 1,800 RPM. Those figures allow it to tow a maximum of 27,500 pounds from the fifth wheel, which is 4,300 pounds more than the 23,200 pound fifth-wheel rating of the 2016 Silverado 3500 HD/Sierra 3500 HD. Moreover, the gooseneck trailer rating for the F-450 Super Duty is an astounding 32,500 pounds.
Here’s to anxiously awaiting official figures and specs of the new L5P, as well as the capabilities of the 2017 Silverado HD and and 2017 Sierra HD. When all of those show up, you can bet that we will be here to cover it stat.
More On 2017 GM Heavy Duty Trucks
2017 Chevy Silverado HD
- 2017 Silverado HD information
- 2017 Silverado 2500HD information
- 2017 Silverado 3500HD information
- Chevy Silverado sales numbers (including Silverado HD)
- Chevy Silverado news
2017 GMC Sierra HD
- 2017 Sierra HD information
- 2017 Sierra 2500HD information
- 2017 Sierra 3500HD information
- GMC Sierra sales numbers (including Sierra HD)
- GMC Sierra news
- Sweepstakes Of The Month: Win a 2023 Corvette Z06 Convertible. Details here.
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Hoping for 450/950. I know it’s being very optismtic, to say the least. But, GM needs to start pushing more heavy duty pickups out.
I know they dominated the segment with the LML, but I don’t think they will be able to keep up with the updated Power Stroke. I know real world performance is more important, but hp and torque numbers are a big marketing boost.
Really hoping, although very unlikely, GM updates the front fascia with the LEDs, much more practical and in my opinion better looking.
What function can the truck do with 450hp that it can’t do now?
If you really want to tow 30,000#, a medium truck with air brakes is better suited. Typical medium duty trucks (class 5-7) have 225-325hp, those are up to double the gross weight of even the heaviest pickup. More power will make the rig easier to drive with a max weight trailer, but as a work vehicle it just adds costs.
From a marketing perspective, GM needs to come up with a hp/torque rating around that of the others. For actually using the truck, reliability and maintenance costs are more important.
http://gmpowertrain.com/assets/docs/2017-US-Product-Information-Guide.pdf
445 hp and 910 lb/ft
not bad at all
When will we find out about the New L5P?
I expect it to be either in August or September.
A good guess would be the Stare Fair of Texas, which runs September 30 – October 23.
Now
http://gmpowertrain.com/assets/docs/2017-US-Product-Information-Guide.pdf
445 hp and 910 lb/ft
Needs the new 10 speed.
Actually, no it does not. I would not advise going away from the Allison 1000 as it was designed and set up for the Dmax. The new 10-speed is a light duty application transmission. If they go away from the 6-speed, it better be to a 8 or 10-speed Allison only.
An alternative would be that the new 10 speed was developed with heavy duty applications in mind, and could have a variant for high torque applications such as the HDs.
That alternative would make theoretical sense since the new 10-speed auto was co-developed with Ford, which also has a use case for an HD application in its Super Duty trucks.
All the power is great, but I have owned three Duramax’s with the Allison trans. in most cases they have all the power one needs to be pulling with the normal 250/350 frames.. What I would love and I think most Diesel owners would love to see is for GM to hold it’s power and try to raise the fuel economy by 3-5 mpg… This would sell more trucks than trying to see who had the most HP/Torg. ….
I currently own a 2011 LML. And agree it can pull more than its fair share. But I really doubt customers are looking for MPG while buy heavy duty pickups.
Why wouldn’t anyone not care about what kind of mileage it makes.. I drive mine up and down the road just as many times pulling nothing as I do pulling my camper, stock trailer or what ever.. I kind of appreciate getting out on the interstate and have my truck make 22-24 mpg.. After all, I do consider my truck as good as driving my car… And as far as not caring about the mileage, so if you’re pulling something up and down the road and one truck makes 2-3 more mpg that doesn’t mean anything to you ???
2017 2500 HD hood scoop !
What about going through car washes ??
Carroll — they thought of it.
Go here:
http://gmauthority.com/blog/gm/chevrolet/silverado/2017-silverado/2017-silverado-hd/
… under the “Confirmed Changes & Updates section, see the subsection entitled “Clean and Dry”.
In summary, there is a pretty extreme air/water separator as part of the new intake system.
When will the 2017 be ready for purchase from the dealers ?