Details of GM's new 4.5L DuraMax diesel V-8
At the General Motors Powertrain Technology show, ABG learned more about the upcoming 2009 Duramax 4500 diesel V-8. GM made some unusual design choices in order to improve the efficiency and get the engine to fit in the same package size as the traditional small block V-8.
GM started off by choosing a 72 degree bank angle rather than the typical ninety degrees making the engine narrower. Most V-8 engines traditionally have had the intake manifold in the V between the cylinder banks with the exhaust manifolds on the outside of the heads. The new Duramax places the exhaust manifold in the valley along with the turbocharger.
Continue reading about the new Duramax 4500 after the jump.
Placing the exhaust and turbo in the V allows for very short exhaust runs and minimal heat lost from the exhaust gases. That means more of the energy in the hot exhaust can be used to spin the turbo and the response is quick. The intakes are on top of the cylinder heads directly over the intake valves. The outer sides of the cylinder heads are devoid any appendages which allows for easy assembly line installation.
Downstream of the turbocharger comes all the hardware to make the new engine fifty-state legal and Tier 2 Bin 5-compliant. A diesel particulate filter cleans up the soot while excess nitrogen oxides are addressed by a urea injection system. The urea will need to be replenished periodically, but it should last longer than the oil change interval.
Overall, the Duramax 4500 should provide a great, fuel-efficient option for the light duty trucks while improving towing capability. The possibility of installing the new engine in passenger car applications certainly exists thanks to the packaging, but whether it happens will depend in part on how well other new diesels are accepted in the market in the next couple of years.
Reader Comments (Page 1 of 2)
James 2:55PM (2/03/2008)
This news of a new design DuraMax 4500 diesel turbocharged with direct injection is very exciting news to me. I have a '97 GMC Sierra that is still in factory new condition but optioned with the Vortec 4300 L35 gas engine. Oh the engine is wonderful and still runs like new but it's not a diesel. I have considered many options to re-power this chassis but it all comes down the weight and size issues. The DuraMax 6600 TDI is a wonderful engine but way too much motor for what I use my pickup for. Since this new DuraMax 4500 TDI will mount and hookup to existing small-block infrastructure this means little or no major mods will be needed to mount in current chassis and mount to existing 5-speed manual transmission. Why would I want to pay $30K to $50K for a new truck with this engine combo when I can use my existing infrastructure and have a brand new 1997 GMC Sierra SL repowered with the DuraMax 4500 TDI for less than $10K. Chevy/GMC finally did something right when they built a vehicle that doesn't rust or fall apart after 10 years. Repowering my existing chassis will allow vehicle life to be extended to more than 1 million miles or 20 to 30 years before replacement. Who would've ever thought such a thing possible 40 years ago.
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Guenther 9:56AM (2/15/2008)
mexglx- SCR is the only proven, economic way to make a LARGE diesel pass T2B5 regs. I realize Dodge/Cummins isn't going that route, but there may be problems down the road. MB cannot seem to get there with the 3l Bluetec. SCR is not such a bad thing.
James- You might be able to find a good 2.7L from a sprinter to use. It would fit real easy and get awesome mileage.
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manymilesayear 12:40AM (3/10/2008)
I am no where near understanding what most of you are talking about, however, I have purchased a 08 Suburban on lease waiting for the new diesel engine. I owned a HD2500 with the larger duramax and loved it, however, here are my un-tecnical questions maybe some of you can answer:
1. What MPG might the new engine get?
2. Since the Oil companies are now killing us with
the fuel costs, will this run on Biodiesel?
3. Will this engine use the same cylinder shutdown
mode?
3a. Why can't the cylinder shut down mode stay in
4 cylinder mode when on cruise control and not
pullng a trailer? I put 40thousand miles on a
year in the midwest and hope GM makes the
computer stay in 4 cylinder mode. Give us
drivers the opportunity to use the mix using
geography and trailer/no trailer modes.
4. Will this motor go in the regular Suburbans?
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Dennis Turner 5:02PM (4/04/2008)
300 plus horsepower!!! I love my 2500 HD Duramax but now that I am retired I wish I could buy a 1500 with a 150 Horsepower Duramax that might give 30 milers per gallon. I need 300 HP twice a month sell me a 150 horsepower full sized pickup. They sold them for years now we all need 300 HP!! Bull.........
We need to save fuel now not tomorrow.
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2007 Sierra Classic 5:36PM (5/08/2008)
I think that GM is doing a good thing here. However I do agree with those here that have made the comment that they can't understand why so many cylinders and the related. In the old days those who are interested in power used to say there is no replacement for displacement; now a days that is not the case- the person who made the comment about the Formula 1 4 cylinder cars sparked a good point. In Canada with our diesel being more than gasoline for over a year now I would hope that this/ these engines would have to be like 30mpg(imperial)+ to be viable. Also with the price comment made by some here if General Motors kept the price reasonable and the engine proves to be good performer in the sense of long lasting I would bet they would sell millions easy(and numbers would make their bottom line for years if an actual GM employee happens to be reading this). Maybe General Motors is a little late with this. I know the good old 6.2 liter of the early nineties more than exceeded expectations, what took them so many years to bring back smaller diesel again is my question. One last point I would like to make is yes as far as transmission goes a 5 or 6 speed automatic as a standard option would be my choice. Don't get me wrong I like the manual transmission but it's the 21st century now and the automatic transmission in my mind is far superior now and why shift gears if you don't have to. I know I am going to get hate mail over that comment as some will still want to shift those gears but now a days put a good tow/haul mode on it that really controls well on hills(diesel could include some kind of built in engine brake like the commins) and I'm sold.
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bob d 9:04PM (9/04/2008)
i would like to see mileage figures with different gear ratio's and would like exact dimentions to see if it would fit in my 65 chevelle 2 door wagon. I think it would get great mileage and performance
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jg3 10:15AM (8/25/2007)
I hope they drop this in the Tahoe/Yukon/Suburban. I'm interested to see the mpg ratings.
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Tim 10:48AM (8/25/2007)
There has to be a better way! It’s hard to believe that after all this time GM can’t do better than the reciprocating piston engine. http://peswiki.com/index.php/Directory:Engines
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fadetoblack51 11:00AM (8/25/2007)
seems like some very innovative solutions for getting a bigger diesel in where a smaller gas engine would typically reside
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GoodCheer 11:53AM (8/25/2007)
Am I missing something in engine design? Why is it that there are so many cylinders? In a gas engine you are limited in the size of the combustion chamber because the flame has to propagate from one point (the spark plug), but in a compression ignition cylinder the whole mass erupts into flame when the pressure gets high enough. And since power generation goes up with volume, but parasitic heat loss goes up with surface area, I would think larger combustion chambers would be more efficient.
The lumpy power delivery probably isn't much of an issue, all you need is a big fly-wheel (which you need anyway).
Is it just that Americans think a 4-cylinder is for wimps?
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Mike 12:19PM (8/25/2007)
It's pretty obvious by now that the next generation of motors will be electric. That being the case GM is unwilling (as they should be) to spend 5 years on new ICE engnes, and tooling for such when in 10 years serial hybrids and all electrics will rule new production.
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Travis Rassat 12:51PM (8/25/2007)
GoodCheer,
I'm not an engineer or anything, but I had a couple of thoughts about your comments - I thought maybe the advantage of having more cylinders rather than bigger ones is that it provides more combustion cycles per revolution and therefore could maybe provide for a smoother running engine with less vibration, or perhaps that it would make overcoming those issues easier?
Another thought that came to mind is heat dissipation.
Those were just a couple of things that came to mind, but I don't really know one way or the other. I'm sure those issues can be overcome by good design.
I also think you are right about the perception about more cylinders being better - I see more and more cars on the road with badges proudly displaying their V6 or V8 status. Formula 1 cars have a 2.4 liter V8 that makes somewhere in the neighborhood of 800-850 horsepower, yet it's smaller in displacement than many 4 and 6 cylinder engines out there. Of course, it's all marketing - there are people who have no idea how big the V8 is, but they want it.
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MikeW 9:52PM (8/25/2007)
Flame propagation isn't too much of a problem for low revving production engines.
F1 engines would benefit from triple spark plugs, but the rule nannies say no. They operate up to a governed 19,000rpm. Before the rules forced a 98mm bore maximum, 20,000 rpm was achieved with larger bore/shorter stroke V10s.
http://www.epi-eng.com/ET-PistonExcit.htm
An engine needs 7 cylinders for net positive torque, but who makes one of those? 5 cylinders for gross positive torque-the firing interval is 144 degrees, but at a crank/rod angle from 36 degrees from BDC the torque out is almost 0, and the longer crankshaft and harder exhaust manifold over an inline4, are real disadvantages for the Inline5 (they fit transversely, that is why volvo uses the)
An inline3 is best because of ease of exhaust manifold design/manufacture, firing interval 240 degrees, and camshaft duration (no crosstalk in exhaust manifold)
So you double that up for an inline6, boxing 6, or V6. Double an inline6 for a V12.
Having net positive torque reduces potentially damaging torsional oscillations, reduces lugging which can damage bearings. But semi tractor trailers operate with Inline6s.
But modern manual transmissions have dual mass flywheels, and automatics have continuous torque converter clutch slip, and have isolator spring (ZF was really proud of the dual spring isolator on the new ZF 6HP21,28,34 models)
and people's (great?) grandfathers liked the sound of a crossplane crank V8 L R L L R L R R.
It was noise, not power. But they liked it never the less.
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bioburner 10:41AM (8/26/2007)
Guys this is a diesel engine. Flame propagation-in a diesel. Combustion starts after the fuel is injected. The more cylinders the smother the engine runs. The more cylinders the engine has the easier it is to sell.
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scappy 7:05AM (8/27/2007)
More cylinders probably helps with emissions as well.
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sean 12:12AM (8/28/2007)
do you think it can fit in a 1997 s10
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Don 9:49PM (9/02/2007)
I read nothing in the GM release about the Dynamax 4.5L being available in a Chevy 3500 Express Van which are used by many Class B RV manufacturers. Do you think it would fit in place of the current 6.0L gas engine? What would the increase in cost be and what transmission would they couple to it? Many thanks. Don
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Sam Abuelsamid 11:12PM (9/02/2007)
Don, The "Duramax" 4500 is specifically designed to fit in the same package dimensions as the small v-8. Anywhere the current V-8 fits, so will the new diesel, including the vans.
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gough 6:01PM (9/06/2007)
Well I hope GM uses a six speed and drops the stupid four speed. Having my 4th GM product, 4 speed is not the best for towing. Six is so much smoother though the final gear ratio is the same between 4 and 6.
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marvin 11:20PM (9/09/2007)
The 72-degree cylinder block angle was chosen for more than just compactness. A 72-degree block angle is optimum for a V-10 engine. GM intends to create a new diesel engine family, not just the 4.5 version. In so doing, GM has chosen the same path as Mercedes, whose V6 diesel is also 72-degree block angle and therefore easily expandable to a V-10.
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