The 2023 Chevy Silverado HD Duramax and 2023 GMC Sierra HD Duramax are set to receive engine updates with a boost in power. Now, one rumor has the total output from the upgraded diesel powerplants at nearly 1,100 pound-feet of torque, along with more than 500 horsepower.
Back in May, GM Authority was the first to report that the 6.6L V8 L5P turbodiesel Duramax engine equipped by the 2021 Chevy Silverado HD and 2021 GMC Sierra HD was due for an update, likely introduced in conjunction with the heavy-duty pickups’ full model refresh / mid-cycle enhancement. The new powertrain update could send final output numbers as high as 1,085 pound-feet of torque and 505 horsepower, according to a recent report from TFL Truck.
That’s a significant boost over the current 6.6L V8 L5P turbodiesel Duramax power and torque figures, rated at 910 pound-feet of torque at 1,600 rpm, and 445 horsepower at 2,800 rpm. That means the new rumored figures represent increases of 175 pound-feet and 60 horsepower.
As a reminder, the 2021 Chevy Silverado HD and 2021 GMC Sierra HD are also offered with the naturally aspirated 6.6L L8T gasoline engine, rated at 401 horsepower at 5,200 rpm and 464 pound-feet of torque at 4,000 rpm. The gasoline engine connects to a six-speed automatic, while the diesel connects to an Allison-branded 10-speed automatic.
Per the original GM Authority report made in May, it’s expected that both gasoline-powered HD models and diesel-powered HD models are in store for updates with the upcoming full model refresh. However, when those updates will be applied is still somewhat uncertain.
When GM Authority first reported on the powertrain updates, the refreshed models were expected to arrive with the 2023 model year. However, as a result of numerous delays and setbacks, including the COVID-19 pandemic and ongoing global microchip shortage, it’s possible the refreshed Chevy Silverado HD and GMC Sierra HD will not arrive until the 2024 model year.
Check out the table below for more info on the heavy-duty pickup truck powertrains currently on sale, including rivals of the Chevy Silverado and GMC Sierra.
| Vehicle | Engine | Fuel Type | Aspiration | Valvetrain | Horsepower (hp @ rpm) | Torque (lb-ft @ rpm) |
|---|---|---|---|---|---|---|
| 2021 Chevy Silverado HD | 6.6L L8T V8 | Gasoline | Atmospheric | OHV 16-valve | 401 @ 5,200 | 464 @ 4,000 |
| 2021 Chevy Silverado HD | 6.6L Duramax L5P V8 | Diesel | Turbocharged | OHV 32-valve | 445 @ 2,800 | 910 @ 1,600 |
| 2021 Ford Super Duty | 6.2L Boss V8 | Gasoline | Atmospheric | SOHC 16-valve | 385 @ 5,750 | 430 @ 3,800 |
| 2021 Ford Super Duty | 7.3L Godzilla V8 | Gasoline | Atmospheric | OHV 16-valve | 430 @ 5,500 | 475 @ 4,000 |
| 2021 Ford Super Duty | 6.7L Power Stroke Scorpion V8 | Diesel | Turbocharged | DOHC 32-valve | 475 @ 2,800 | 1,050 @ 1,600 |
| 2021 GMC Sierra HD | 6.6L L8T V8 | Gasoline | Atmospheric | OHV 16-valve | 401 @ 5,200 | 464 @ 4,000 |
| 2021 GMC Sierra HD | 6.6L Duramax L5P V8 | Diesel | Turbocharged | OHV 32-valve | 445 @ 2,800 | 910 @ 1,600 |
| 2021 Ram HD | 6.4L HEMI V8 | Gasoline | Atmospheric | OHV 16-valve | 410 @ 5,600 | 429 @ 4,000 |
| 2021 Ram HD | 6.7L Cummins I6 | Diesel | Turbocharged | OHV 24-valve | 370 @ 2,800 | 850 @ 1,700 |
| 2021 Ram HD | 6.7L Cummins I6 HO | Diesel | Turbocharged | OHV 24-valve | 420 @ 2,800 | 1,075 @ 1,800 |
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Comments
If those numbers are true I pray to God GM has a fleet option to have a lower HP and torque option. When you put a driver in one of these trucks who has a ‘I don’t own it’ attitude….. it’s just too much (and has been for a while).
They’re 8000+ lb trucks with mediocre traction. The 0-60 in a current Duramax is in the high 6’s. That’s over a second slower than a current Honda Accord Sport (5.5 s) and around a quarter second faster than a base Accord (7.2 s). It’s even beaten by a 2.0 L Ford Escape (6.3 s).
Anyway, companies that do care have telemetry via OnStar and third party solutions.
An Class 8 truck is even slower the the current Dmax, it doesn’t need more power stock to show off to everyone, that’s what the aftermarket’s for.
Small Enos committee members rejoice!!!
Interesting fun facts: The original LB7 Duramax diesel engine was released with 300 hp and 520 lb-ft torque. Compared to the rumored 505 hp and 1085 ft-lbs that’s an increase of 205 hp and 565 ft-lbs of torque (double+ on torque!) Also interesting that the 2022 2.7 T four cylinder gas engine has 10 more hp and within 100 ft-lbs of the original LB7 Duramax!
Turbochargers, and Injection (engine management computers) have come a long way since 2001
Those numbers for the original LB7 are EXACTLY my dream numbers for the 3.0L I6 Duramax in the half-tons
A week later Ram and Ford announce over 510hp and 1100 ft/lbs. Same old song and dance. Does it really matter at this point. Are people towing skyscrapers with these things?
I laughed too hard at this..
But yes paper wars are old. It’s only good for the non-enthusiast and commercials. Which I mean they make good money on advertising I guess. But real world performance is where it matters. I wished they advertised those types of comparisons instead of just powertrain output.
Nah Ram never comes close in the horsepower department, only torque.
I have a 2022 Freightliner Sport Chassis M2-112 with a Detroit diesel DD13 its 505 HP, and has 1850 lbs of real torque and has a real 4000 series Allison transmission , not a Fake branded one like GM. these funny number’s the big 3 truck producers come up with are nutts.
My Abrams Combat Chassis M1A2 has a Honeywell AGT1500 gas turbine engine it’s 1500 HP, and has 3754 lbs of “real torque” and has THE real X1100 Series Allison Transmission pushing 70 Tons off road while firing it’s 120mm M256 Cannon, not a civilian purposed medium duty flatsfaulter.
You do realize GM owns Allison?
even the new 2021 Ram 3500 Cummins HO with Aisin Transmission has 1075 lb torque , but its a very reserved transmission and your now going to beat on the truck hot rodding it. it pulls and pulls any thing you want to put on its back , but as a everyday driver the truck is much slower than Gm or Fords HD trucks . Ram has the advantage with the rear air bags system on Ram 3500’s cause it picks the load back up level, and it works well.
This diesel will be on both 2500 and 3500 series trucks.. not solely in the 3500 like that Ram. The 2500 Ram still falls behind with under 400hp and barely 850lb-ft .. but still diesels come a long way.
I was hoping GM would release an updated version of the 8.1 vortec V8 or a new big block gas motor with the Allison trans.
Does that mean you can get to the Dunkin Donut’s drive through 20 seconds faster ?
These numbers mean nothing. Last time I looked all the brands limited their power in the first few gears. So flooring it from a stand still or slow roll will have limited lower and at higher speeds the truck will down shift into the lower gears and higher RPMs so these insane torque numbers are never actually seen by the transmissions never makes it to the ground outside of a dyno.
No thanks I’ll keep my 2021 HD gasser thank you very much , I don’t pull trailers anyway and I can get fuel on every street corner
RAM Inline 6 is the only naturally balanced diesel out there. Nuth’n to sneeze at.
Pretty sure the 3.0l duramax in the half tons is also naturally balanced.
How can this stunning news not be followed by more details. Complete silence during the last three months. Will it come at all?