If it's a repost, I apologize.... it's too cool.
I can already predict some of the responses, too bad, here it is....
As taken from the September Diesel Power Magazine:
David Kennedy writes:
It's finally here. As we were going to press, General Motors announced an al new 4.5L, V-8 Duramax diesel engine for it's 1/2-ton trucks in 2009. At this point, I have more questions than answeres about the little Duramax, but one thing's for sure: This engine will redifine the diesel market. Here's what I know so far.
Power Output
The official word is this engine will make in excess of 310hp and 520 lb-ft of torque. Trust me when I say those numbers asre sure to increase the closer GM gets to production, especially as Dodge and Ford release specifications on their 1/2 ton diesel engine programs. If I were a betting man, I'd say you'll see the 4.5L Duramax debut at 240hp and 590lb-ft while meeting the tough new '10 Tier 2, Bin 5, and LEV 2 emissions standards to they can be sold in all 50 states.
Engine Block
GM powertrain engineers seem to have been highly motivated to make this engine compact. Their goal was to fit the new diesel in the same overall package size as the GM current 5.3L gasoline V-8 To do that, the "V" of the 4.5L Dmax is narrower than the 6.6L Dmax's 90-degree cylinder angle. The new engine appears to use a 60-72 degree cylinder angle to keep the top of the engine as narrow as possible.
To keep weight down and increase strength, this engine will use a compacted graphite iron (CGI) block with fractured main caps. CGI is a premium material that's more common in expensive heavy-duty European diesel engines. It's lighter and stronger than the gray iron that's used in the current Cummins, Dmax, and Power Stroke. I'd expect all the upcoming 1/2-ton diesel engines to use CGI blocks. It may also forecast a possible V-6 or V-10 version of the engine in the future.
Cylinder Heads
Just like on the big 6.6 Dmax, the 4.5 heads will be aluminum and feature 32 valves. The interesting part is these heads use dual overhead camshafts (four cams total) and flow inlet air and exhaust in the opposite direction from what we're used to. The new 4.5 routes the exhaust from the inside of the engine's "V" to the turbocharger, while the intake air from the turbocharger is split and routed to the outside of the engine through what appear to be composite plastic valve covers/intake manifolds.
Turbocharger
It looks to be a Garrett turbocharger. I'm surprised to see a single variable geometry turbo, but it looks as though adding a second turbo (possibly for a high-output version?) would be pretty easy.
Injection system
Your guess is as good as mine as to which high pressure injection system will be used. It could be Bosch, Delphi, or even GM's own stuff. I know it will be common rail, possibly use piezo injectors, and have the ability to do up to five injections per combustion event. I won't be surprised if injection pressures exceed 30,000psi. One thing of note is the computer on the driver-side valve cover looks like a glow-plug controller, but I see no glow plugs. Could that be GM's new ECM?
What's next
The new 4.5L Duramax will be built in GM's Tonawanda plant in New York. Tonawanda is the world's largest engine plant and produces more than a million engines per year. Based on the number of 1/2-ton trucks sold today, the 4.5L's production volume could be doble that of the current 6.6L engine. Going forward, I really don't see GM dropping the 6.6L Duramax that's built in Ohio, but I don't see why this new engine couldn't be configured as a 3.4L V6, 5.6L V-10, or 6.8L V-12. A V-12 Duramax.... I like the sound of that.
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