GM's Duramax diesel goes under the knife, loses weight
GM's new 4.5L Duramax diesel engine promises a 25% increase in fuel economy while providing 310 hp and 525 lb-ft. The new oil-burning powerplant also needs to pass 50 state emissions while providing the efficiency customers are demanding. GM has already provided some details of the Duramax 4.5L, including that the new diesel is roughly the same size as the General's compact small block V8, which means it can fit in more than just trucks and SUVs. The 4.5-liter also reduces the parts count with integrated aluminum cylinder head exhaust manifolds and an integral cam cover intake manifold. GM talked to Automotive News about new features of the lower half of the 4.5L Duramax, and they're just as extensive as the top.
[Source: Automotive News subs req'd]
Diesels run a higher compression ratio than gasoline engines, so components like crankshafts are built heftier to better-handle the enormous pressures of every day use. GM wants to keep the weight of the 4.5L down, though, because a heavy engine leads to heavier mounts, struts and brakes, which adds tonnage to the truck and saps away performance. To accomplish this, engineers started by casting the crank journals into the engine block, which reduces weight and lowers costs while also adding strength and precision. Because the sides of the bearing journals aren't cast into the wall of the cylinder block, the new crank journal design also improves circulation of air between cylinder banks. Better air flow means reduced pumping losses, which improves efficiency. GM has not used this process before, and may build the design into future gasoline engines.
Other noteworthy features of the 4.5L Duramax include a hollow balance shaft that transfers noise to the rear of the engine and into the thick transmission housing, which mutes engine noise. An aluminum upper oil pan that mounts between the engine block and the lower oil pan also stiffens the engine block by 30%, reducing vibration.The 4.5L Duramax diesel is scheduled to see production in fall of 2009 in the Chevy Silverado and GMC Sierra.
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Reader Comments (Page 1 of 2)
Dave 6:40PM (10/21/2008)
Cadillac may get a version of it?
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Slizzo 6:52PM (10/21/2008)
That's what they say. May appear in the CTS. Here's hoping that they slap it in the Pontiac G8 (Holden Commodore) as well.
Gabagool 7:32PM (10/21/2008)
See, there's not a single diesel sedan out there that is made by an American company. They do not show any real desire to build it.
GM already has a fuel efficient engine, Volt's, so they'll probably come out with a Caddy that is electric rather than oil burning.
I believe Ford also has to plans for diesels in sedans and i believe you best bet for an affordable diesel is Honda Accord, i believe it should be in USA either in 2009 or 2010.
Jack 7:08PM (10/21/2008)
GM woke up about 3 years ago and is now getting ready to kick-ass, when the economy gets better and if they don't run out of money.
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MD Drew 9:24PM (10/21/2008)
Here's a dream, based on current rumor-milling: GM gets Jeep from Cerberus, throws the 4.5 Duramax in it with a 6 speed, and I can get great mileage all the way to, over, and beyond the nearest mountain range!
Here's to dreaming...
Paul P. 7:14PM (10/21/2008)
This is the engine I've been waiting for. Put it in half ton Pickups and the Tahoe/Suburban and I'll be ordering a few for my business.
On a side note GM, please make sure this engine is available in stripped out work trucks and SUVs, unlike the Hybrid. I would love this engine in a Tahoe/Suburban, but I don't need, nor want, to pay $60,000+ for it because I can only get it as a package with every interior amenity.
A simple model with this engine, 4x4, G80 rear, tow package, and basic LS interior (cloth) for less than $45,000 would be perfect.
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aaron 7:58PM (10/21/2008)
Wow. I've been begging for a diesel to be put in the Hummer H2 for years and here it is. GM gave up on Hummer understandably but my God this could help them a little and may throw a bone to the dealers. If the diesel is about the same size as the small block, it couldn't be that hard to make them work with the 6-speed in the H2.
To typical Autoblog naysayers and pseudo-experts that populate the comments:
I know it's not that simple but do ya'll have any better ideas? I really honestly think it can't be that hard.
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miles 8:12PM (10/21/2008)
Sure it would fit if it's the same size as a small-block. But packaging isn't the problem - I doubt tat 6-speed auto can take 525 ft-lbs...
why not the LS2LS7? 10:08PM (10/21/2008)
They can say the engine is the same size as a small block all they want, but this one requires you locate an intercooler up front and piping around the engine bay. It's not just a drop-in, even into a ZR1, because this seems to use air-air intercooling, and the ZR1 uses air-water-air.
It would probably need an Allison transmission, which I doubt GM wants to use because they don't own Allison anymore. Does anyone know what transmission the GM pickups will be using?
Thomas 8:12PM (10/21/2008)
Will it fit in the Acadia/Enclave etc.
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Slizzo 8:18PM (10/21/2008)
@ miles
The 6L80 may not be able to, but I'm pretty sure the 6L90 is fine for that. IIRC, the 6L80 is rated to about 450ft.lbs.
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Slizzo 8:21PM (10/21/2008)
Let me fix my previous. The HD version of the 6L80 handles up to 520ft.lbs. 6L90 should be a perfect fit for it.
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Matt 9:39PM (10/21/2008)
Great for GM. Just when Ford is questioning their small diesel, GM just steams ahead. GM will recover quickly from this recession and will prove that they are the strongest automaker. They have the best products of ANY US automaker and the future products will cement their position as number 1.
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Chidfreegearhead 10:04PM (10/21/2008)
If this motor is available in a two wheel drive RCSB (Reg cab shortbed). I'll be putting my order in.
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MBM 1:17AM (10/22/2008)
Would somebody explain the second paragraph. First it states that the crank journals are cast into the engine block and then immediately states "the sides of the bearing journals aren't cast into the wall of the cylinder block". The pic is not very enlightening regarding these seemingly contradictory statements.
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CraigD 2:56PM (10/22/2008)
MBM,
In the picture you can see how the crank bearing caps are clear of the surrounding block skirting. Since the block does not have a cross-web at each bearing journal connecting the journal to the raised (in the picture) skirting, I think they are then saying the "journals aren't cast into the wall of the cylinder block."
Peering at the picture more closely it appears as if the meat surrounding the bearing journal is rather "floating" in space between the cylinder block walls. I don't know how much turbulence is in there or how much aerodynamic pumping losses can be reduced inside the crankcase but sounds like they at least think they found something.
Gardiner Westbound 11:38PM (10/21/2008)
Let's hope GM didn't save 25-cents by substituting a plastic crankshaft for the steel one.
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PiCASSO 1:52PM (10/22/2008)
My fellow Canadian: where the heck is your comment coming from?
Mike 12:47AM (10/22/2008)
Here's to hoping that GM can produce this engine at a reasonable premium over a gas engine($2000 perhaps)and be wise enough to offer it in all models of their full size truck/van fleet. If it is ultra reliable and can get 20 to 25 percent better fuel economy than a comparable gas engine they will most definitely have a winner. If it ends up under the hood of enough of thier trucks, it could help them in meeting future CAFE standards.
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Noah 1:37AM (10/22/2008)
This engine could easily ramp up to more HP/TQ. If it were in a Cadillac, they could easily tune it to 360HP.
Cannot wait for this engine. They should also lop off 2 cylinders for a vortec V6 Duramaxx.
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