Comparing GM’s New 6.6L L5P Duramax V-8 Turbo Diesel To The Competition
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Though not officially announced, we already know the answer to one of the biggest questions of the year: GM’s new Duramax L5P 6.6L V-8 Diesel will be rated at 445 horsepower and 910 pound-feet of torque. Though they look good at first glance, how do the numbers stack up when compared to Ford’s Power Stroke and Ram’s Cummins engines?
On paper, the L5P stacks up quite favorably.
| Vehicle | Engine | Horsepower (hp) | Torque (lb-ft) | L5P +/-hp | L5P +/- torque |
|---|---|---|---|---|---|
| 2017 GM Heavy Duty Trucks | 6.6L Duramax L5P V-8 | 445 | 910 | N/A | N/A |
| 2017 Ford F-Series Super Duty | 6.7L Power Stroke V-8 | 440 | 925 | +5 | -15 |
| 2017 Ram HD | 6.7L Cummins Diesel I-6 | 385 | 900 | +60 | +10 |
| 2016 GM Heavy Duty Trucks | 6.6L Duramax LML V-8 | 397 | 765 | +48 | +145 |
GM’s leaked powertrain guide for the 2017 model year denotes that the L5P figures are SAE J1349 certified, which means that the numbers were derived using the latest standards and specifications in engineering.
So, as it stands, GM’s new oil burner has 5 more horsepower yet 10 fewer pound-feet of torque than Ford’s similarly-new 6.7L Power Stroke V-8. When compared to Ram’s 6.7L Cummins inline-six, GM’s new mill makes 60 more horses and 10 more pound-feet of torque. Finally, the new L5P is 48 horsepower and 145 pound-feet more powerful than the LML Duramax it replaces.
With that said, we feel obligated to note that these are all on-paper measurements. As such, real-world performance of vehicles with the aforementioned engines could vary significantly based on a myriad of factors, from the quality of the numbers issued by Ford and Ram, as well as by other vehicle components with which they integrate, such as the strength and durability of the entire powertrain as well as that of the truck frame itself. And the only way to find out about that is to test the trucks in real-world hauling, towing and driving situations. But until that happens, these numbers will have to suffice.
2017 GM Heavy Duty Trucks Information
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Whatever the numbers are, and all 3 are pretty close to each other, I still think the Duramax/Allison combo is unmatched. It has proven again and again that you can’t beat it. It has been down on hp/tq to competition and still has managed to win every single head to head.
My Duramax killed me on maintenance.
Lots of contractors tell me likewise.
So I ordered the 2017 Ford F250 6.2 gas, fine for my 8,000# trailer.
Until they figure hot how to make them inherently clean I’m sticking with gas.
My Duramax failed head gaskets, fuel injectors transmission locked in 4 gear, etc, etc, etc.
And through all of this they declined to offer me any supplier or employee pricing so I “walked”
Just wait till you are putting manifolds on that Ford at 20k miles…
Dude, you are kidding yourself! GM trucks are way better engineered and built! Get ready to know your Ford service department.
My Duramax has 200k hard miles and has never been touched! Engine, trans, axles all original. I have changed wheel bearings once is all. This is my third Duramax, all the same.
Fords gas engines are rattle traps. Vibrate the crapola out of you. We rented a motorhome with a Ford chassis and gas engine. What a pile of s#!#! Horrible gas mileage too. We had a GM chassis motorhome with us too. It got double the mileage, no BS!
I wanted the gas motor, if I got a diesel the Cummings is the only way to go.
On the 5.4L and 6.8L Ford you are correct, they are junk.
The 6.2L is fully developed, simple and highly reliable.
It has more torque at lower RPM than the Chevy 6.0L.
I had gen 1 Durmax and I’m sure they got it all figured out now but gen 1 2001 version was a complete train wreck.
Had they given me employee pricing I would have considered one but they don’t care at all about any one individual buyer even with my 2″ thick file on my 2001 Duramax.
Once you have a train wreck truck and no consideration from supplier it makes it impossible to go back.
Why does it need to be employee pricing and not the Costco program or even just in relationship to invoice. Either of those are excellent prices for these vehicles. They probably had rebates along with it that brought you to just about what employee pricing is. But individual dealerships run themselves whether it is Ford, Gm or anyone. So you bought your second choice because it isn’t labeled “employee pricing”? Also Ford has had far bigger issues in the last 15 years or so with their diesels than GM by a large margin.
Really a 01 Duramax. Your kidding, right. Let see 6.9, 7.3, 6.0, 6.4 and 6.7 not to mention 5.9 w/o cam bearings, they did add them years later. You go for it
Had the 2011 LML used as a hot shot vehicle pulling a 9k lbs trailer with loads from a couple K to 16K in 220k miles I blew two engines. No thanks on the LML. Love chevy but they need to do something. I hope the 17 LP5 is better. The perfect combo if you’re serious about hauling is getting a cummins mated to the allison tranny. Hey chevy go talk to Cummins and make that happen.
I’ve had three Duramax/Allison trucks, currently have a 2015 HD2500, I have had no Maintenance problems with any of the trucks I’ve owned.. Every truck has become a better truck than the one I have before.. I’ll admit, I have not put a lot of milage on them like some do, but I pull a 36′ fifth wheel camper, and a 20’boat and trailer behind that and have no problems with power what so ever.. I also pull a 24 livestock trailer loaded with cows and usually, unless a windy day, never know I have anything behind my truck.. I also make usually 11-14 mpg while doing this.. I hear of Ford/Dodge owners telling how much better they do, but I tell them to follow me with the same load and then I’ll believe you…
I have a 2012 F350 Powerstroke with 58K. Zero failures of any part. Insane power. Tows 8500 lbs and gets 12 mpg even up and down the Colorado mountains. Was going to buy a 2017, but…
I’ve always been a Chevy guy. They ride better, and my butt is getting old. So, I will check them out and see how they compare. Ford has a lot of great technology out for 2017, but I won’t use half of it.
It gets down to price. All the manufacturers make a solid product, but it is distasteful to hear them brag about how profitable truck are, and then see sticker prices of $60, 70, 80K for a pickup truck. I will die first, or preferably go without, before I get conned into that kind of price tag.
I only pull 8,000# so I went with the 6.2L in the 2017 as it has OK torque for my needs that comes on at lower RPM than Dodge or Silverado gas engines.
I drive some short trips in winter too so diesel will drop to millage of gas around town in winter anyway.
People I talk with like the 6.7L powerstroke, even the original versions.
The new one is very nice, gave it a try.
Still worry about particulate filters and selective catalytic reduction units.
Current back end cleanup on Diesels (all of them) remind me of cars in the 70’s where they put a lot of addons to motors which were inherently dirty.
Ford owners be like since when did chevy make engines with less litres and around the same power as ford engines? Clues less ford owners don’t even know that dohc and pushrods are completely different engines
Lmfao. Since when is the duramax a gmc made engine? Ford is the only one with enuff brains to make thier own diesel engine!!
This is true but look at the 6.4 that is crap and the power stroke is not Ford, better look a little closer.
7.3, 6.0 and 6.4 are International engines, not Ford built.. The code name for the 6.7 (which is a Ford engine) is Scorpion but Ford decided to stick with the powerstroke name. In fact the 6.7 power stroke is such a good engine that Ford decided to use it on their new F650 and F750.
U better look a little closer. 2011 and newer powerstroke is a ford built in house diesel engine. 6.4 was not a ford built engine but an international engine. I agree the 6.4 were not very good but the ford built diesel powerstroke is definitely 1 of the best available
Ford did not build their engine ,they call it a power stroke but it was originally built as a Detroit an used in Chevy trucks ,so Ford bought out Detroit an started putting them in their trucks,,,thats when GM started running the Duramax,, I know because I work on diesels for GM.
I’m sorry but I really don’t care where u work and I don’t believe that for a sec. It couldn’t be more farther from the truth as far as I’m concerned. U will need some facts to convince anyone of something that stupid
Lmfao. Since when is the duramax a gmc made engine? Ford is the only one with enuff brains to make thier own diesel engine!!
Umm duramax is fully built by gm which build gmc and chevy trucks so yes they build thier own diesel.
U should wait to comment till u kno what ur talking about. Duramax is an Isuzu diesel. Gm has a contract with them and own a small share of it. Gm made thier own diesel prior to 2001. 6.2 and 6.5. Yes. They were garbage to that proves they’re not capable of building thier own
No gm owns the plant that engine is built in isuzu helped develop it but it is not a contract engine never was.
Dustin, I think that Allen’s point is “who designed this diesel, Isuzu or GM?”.
There are lots components to design, number of head bolts, metal thickness at head machine surface, expansion calculations, unforeseen owner abuse, ease of maintenance, etc.
Ford had trouble with Navistar on the 6.0 and than went their own way.
I do not know who designed the latest Duramax, GM engineers would need to respond to that.
All I know is that the new Ford is pretty nice, tests will bear that out though.
U are exactly rite. Isuzu engines have been out a long time are used in alot of trucks. Gm looked to Isuzu for help. They do own a share of them but it is still an Isuzu engine
GM global engineering team designed the Duramax from 2016 and back. It is produced by DMAX, a joint venture between Isuzu and GM. The 2017 Duramax is completely redesigned and the only similarities from the old is the bore and stroke. Gale Banks, of Banks Engineering, and other top diesel engineers helped design the new Duramax.
You mean how the new 2017 camaro 6.2 makes 455 horsepower and the 2016 ford gt350’s 5.2 makes 526 horsepower? No wait, that’s completely opposite of what you just said. A whole liter less and makes 71 more horses. GM is always playing catch up. Not to mention they now have the worst interior of all three big truck brands. The current Ram 2500 with a solid axle has a better ride than chevy or gmc. Haven’t ridden in a new 2017 F250 but I’m sure it rides the same or better too.
Just drove all the new 1 tons. Ford rode the best then ram and chevy was last. I was shocked that the chevy didn’t ride as good as the ram.
I have driven my 2017 F250 for 2,000 MI and yes, it does ride better than the Chevy.
I think it’s because the Chevy has torsion bar and less travel than the coils on the new Ford.
Mileage on the 6.2L gas motor is not as good as I had hoped @ 14 to 14.5 highway @65 but may get better with more break in.
I expect 9 when towing my 7,700# enclosed race car trailer, will report this summer on that.
I hear real good Mileage numbers on the Dodge 6.4L many claiming 18+.
I still think the Diesel is way to complicated, cannot even get your hand under the hood.
I will have to say it would be diesel for me but I have heard good things about the 6.2 gas engine. We just got back to Pennsylvania tonight from our wk of visiting relatives in Nebraska and I became friends of a farmer out there that has a 2011 f350 6.2 gas and really likes it. He does quite a bit of towing with it and said he has over 215k trouble free miles. I don’t kno about gas mileage but I find it very hard to believe that the 6.4 dodge will get better milage
Yeah the ford gt 350 makes more power but it runs the 1/4 mile in 12.4 with 526 hp and the Camaro ss with 455 hp and a auto runs 1/4 mile in 12.2 so what do you have to say about that gm has always made a better engine ford just started making something that can even come close to what they have been making for years
I’ll stick with my unicorn 2007 Classic GMC LBZ. 260k miles towing 8 to 10k trailers, camper, boat and 25′ travel trailer! Do the maintenance and drive it. Only part replaced….power steering pump! I don’t need to win a race up a hill just get there RELIABLY!!!
Write an article on how hideous that truck is. The numbers don’t matter at this point, you’ve got 900ft./lb. but you can’t fix those hideous current gen gm full-size truck bodies.
Myself, I don’t much care what they look like as long as they perform trouble free.
One exception is the Nissan XD, looks horrible, like a “bug eyed ford”.
I drove the 2016 Cummings & Duramax and the 2017 F250.
On ride and overall quality the F250 is very obviously a notch above. You have to expect this given it’s drive line is fully developed on previous models and that it had 12 million miles of testing.
I’m still totally amazed that Chevy did not give me employee or supplier pricing given my fully documented 2001 train wreck Silverado Duramax.
They don’t give a dam about loosing 5 to 10 truck sales in the past/future with me.
I haven’t talked to anyone that has driven the new Ford F250 and the Chevy HD2500 Duramax that said the Ford rode better, each one said the Chevy was the best riding of the two.. Don’t know about the Dodge, so I can’t compare.. I do know my Sun in Law had 2015 F350 with the Diesel engine and he got rid of it because he said that truck was the biggest lemon he had ever had.. In fact he traded down a couple of years for a Duramax Dually..
I’m not sure how meaningful this is but I looked at Silverado 1 ton and the torsion bar sits right on it’s limit of travel, rubber to metal making the rubber stop an integral part of the suspension tuning. This was a crew cab 8′ box
The 2017 Ford diesel has about 2″ of travel before it’s stop making the springs and shocks the dampening and ride components.
Ford suffers in my opinion needing to be too high for all but serious off road stuff
The above comments are subject to challenge because the Chevy front suspension works through a pivot point so small travel at bump stop equals big travel out at wheel.
The only diesel I would buy is a 2007 or older cummings 5.9L, it has little, if any, back end cleanup and sensors.
I will have to say the 2017 ford does ride better then the chevy. I have not drove a newer dodge so I don’t kno about them. I guess some people prob have different likings to different things but I would definitely choose the ride quality of a 2017 f250 over the 2017 chevy 2500. Since I’d have to say if u are serious about buying a new truck test drive them urself and see what u like.
I haven’t driven either of the 2017 models, I’m not sure many have, but the 16 models that I’ve rode/driven, the Chevy had the best ride of the two… But I’ll agree, it’s which one you’re in favor of, and that will usually make the difference in one’s opinion…
I have personally drove both 2017 models and I think they are both good but my personal choice is the ford. There is a dealership not far from where I live. C-Harper ford and C-Harper cheverlot the sell both so it’s nice to compare there.
I currently own a 2001- 2500 Duramax 275K, 2004 3500 Duramax 125k and a 2014 Duramax 80k. Have had Zero trouble with the drive train on any of them and they are easy on fuel. The 2014 had the DEF tank and filter replaced. We work the heck out of these trucks pulling equipment and hauling material all day everyday. I’m waiting for 2017 to come out so I can buy it. I’m sure the Ford and Dodge are dependible, but I will stick with what know to be proven, dependable. I also run the gas versions 6.0 have 2- 2001’s and one 2006. I have only rebuilt the transmission on the 06. The others are all original drive train with 200k plus miles. These trucks last if they are cared for properly.
I’m really interested if your 2001 was built late in the year?
Mine was early, some specifications and problems:
Two piece drive shaft, check yours, I had to convert mine to one piece with no center bearing at 2/3 my cost eventhough it was design flaw cause low speed vibration.
Blown head gaskets, at Coyne Chevrolet in Escanaba MI for 7 weeks. Could not get new head bolts from factory.
So called HD allison trans locked in 4 gear requiring three trips to various dealers because we were on road pulling race car.
One quart of oil every 1,000 miles.
Leaking injectors.
Now, I got full documentation on this including case number which I can share.
I think the new motor may be very good but would you buy one after this experience?
I’ve owned two Dodge Hemi since since then and traded the last one on 2017 Ford HD, 6.2 L gas which I do not yet have.
If I got a Diesel, I would probably have gotten the 1 ton Ram with HD Aisin auto.
But all of the big three have extremely complicated back end cleanup compared to gas so so went with Ford gas.
One other comment, I take extreme care of my trucks and cars.
Drove 1982 Audi 4000S4E for 370,000 miles.
Current Subaru Forester (2005) has 260,000 miles and runs like now but did have to do head gaskets at 186,000.
If I find a good truck, I’ll keep for 10 years.
Dodge Ram had weak front end requiring new wheel bearings, CV joints, tie rod ends and upper/lower ball joints every 50,000 MI, very expensive. These were 3/4 ton Hemi’s.
I hate to say it but dodge would definitely be my last choice. Don’t get me wrong. I really like the cummins engine (witch is not part of dodge) But the rest of trucks just simply aren’t put together very well. I have a 1995 f350 crew cab 4×4 with 300,000 miles and it’s my daily driver. I also pull it at the fairs. (Sled pulling ) and that thing is a tank. Until I upgraded it i had zero problems with it. Now I have around 450 hp at treatment rear wheels according to the dyno. So every now and then there are small things that I have to replace. But I beat the cap out of that truck. I do keep the oil changed. I don’t have anything against the chevys but if I was to buy a new truck it would be the 6.7 powerstroke. But I think I will just buy a used 1 at half price ( that’s out of warranty ) and delete it. That’s the reason for all the problems with the new diesels. Everyone of them. They can’t breathe. Get rid of the emission garbage soon as the warranty runs out. You will get better mpgs also. Just my 2 cents. Lol
Allen, can you reprogram the ECM to work OK without all of the inputs?
You are right on Dodge, on mine I had to replace entire front end, twice.
I think the Silverado still has grease fittings, I always liked that.
It doesn’t matter too much witch diesel truck you buy, or who it was made by its a diesel. Price is a factor and over all I rather have a stripped down diesel over a gas perty much any day of the week regardless on the manufacturer. All trucks of all models have flaws.
It doesn’t matter too much witch diesel truck you buy, or who it was made by its a diesel. Price is a factor and over all I rather have a stripped down diesel over a gas perty much any day of the week regardless on the manufacturer. All trucks of all models have flaws, I have had many good and bad trucks by the same manufacturer. And I’ve had them all it’s just matanence and if you lucky to get a good one.
I kind of agree, once you have a diesel and pay the extra price the first time you have done the pain of the extra cost, from there on out the diesel will be a better value when you go to trade it off, especially if you don’t have a huge amount of miles on it.. I have had four Chevy Duramax’s, usually put around 60K-75K on them.. I know most say they aren’t even broke in yet, well I like to drive a new Truck and I always get a huge trade-in value for mine, in fact when I order my new truck, my dealer has mine sold before I get the new truck..
The one thing I’ve seen is the difference between a Ford and a Chevy diesel, everyone I talk to says the Duramax gets the best mileage other than that both trucks are good trucks.. I’m sure the Dodge is good as well, I’ve just never been a Dodge kind of guy..
Report on my F250 crew cab 6.2 gas motor.
Truck weight on title is 6,215# (full 4 door, almost like mega cab dodge and 6.5′ box).
This truck will challenge some garage spaces, should be available with 5.5′ box like Dodge and Chevy. (250″ long)
Frame is incredible, integrated 2.5″ hitch is very robust and rated at 1,500# tongue weight.
Front CV are about twice the size of my Dodge and have grease fittings.
Ride is solid and very quiet but steering is slow and heavy (I could not get variable steering on the XLT as originally ordered as Ford changed that option to Lariat, King and Platinum models only)
With only 500 miles on truck and in Northern MI winter I did two millage checks @ 62 MPH and got between 15 and 16 MPG.
If I get 10 pulling 7,800 enclosed trailer I will be happy (54 sq ft area).
More to report after pulling SCCA spec Miata this summer.