Slamnasty

A Ford F250 diesel-owning friend of mine says the Duramax is an uber-powerhouse. He said you can chip it up to 800hp/800tq really easy, but the tranny would then need attention because of the output level.

Either way, I've never heard anything really bad about the Duramax-equipped Chevy.

mbilderback

You guys are missing my point on speed. The engine speeds are slower, diesels make power low in the RPMs. And it says the turbos spin at 120000rpms for these diesels. That would make for MUCH higher RPMS on a higher redlining engine. I do not think a diesel is a slow engine, with 6+ liters of displacement, are you kidding?

Most diesels I see redline before or around 5k, can the turbos spin fast enough for something like a more std 7k rpm gasoline engine?

I NEVER said diesels were slow. Just that they redline slower in RPM terms.

Sr2oD3

I understand that, and most diesels won't make that much power at redline, 90% of their engine power is created around idle or <2500rpm.

Variable geometry turbos can run at 120,000rpm because the size of the turbo housing can be adjusted to act like a small turbo(for fast spool up and low end power), and then open to a larger trubo diameter( to create power at higher engine and air intake speeds). This way, GM was saying that there wasn't a need to wind the engine out at high rpm, (which is useless anyway with a diesel) to make efficient power.

Elistan

Like I said, it doesn't matter how fast the engin spins - there's no belt connecting it to the turbo. It's all based on the exhaust gas flow. A 6.6 liter engine at 3200rpm moves just as much air as a 3 liter engine at 7000rpm. So no, the turbo would NOT have to spin faster on a higher rpm engine.

mbilderback

Point made, but is the exhaust coming from all 8 cylinders? I mean, that's a lot of exhaust flow, and the turbo would have to sit after the Y connector, or it'd have to be dual turbos to get the exhaust from all 8 cylinders. I'm just curious.

And Sr2oD3, I know they make their power down low, it was Elistan's answer I was looking for.

rockville

Mbilderback,
If the turbo can

Elistan

The turbo sits on top of the engine - from what I can tell there's only one, and all eight cylinders do feed in to it.

Also - I just read that the Duramax engines are made in Ohio by Isuzu.

CG

I had a chance to drive one of these monsters today and it's very safe to say that I liked it. The changes under the hood are obvious. The air filter is much larger, very thick and round. The turbo setup looks different also. The six speed has the option of shifting manually by a thumb lever on the much thicker shifter. The shifting in drive was as smooth as the 5sp. and the "tow mode" worked the same. In the manual shift mode the shifting was quick and I actually broke the back end loose and got a little sideways on a shift from 1st to 2nd. The redline on the tach is also 5500 rpm's. In the tow mode it seemed to quick climbing about 3500 to 3700 rpm's. The added power is always on hand and the turbo seems to come on very quickly. It would be very easy to do a big burn out with the stock truck.

The truck was a well equipped LT very much like my 03. There are some changes to the "info" center on the dash. If the truck still shows the instant and overall fuel mileage I couldn't find it and I think it's been deleted. That I can't understand because I find it very useful. They have added a water/fuel filter life % to the info center which I did like.

One major change is the sound of this engine. In my truck you don't notice the diesel sound as long as the windows are up but pull up to a drive up window and you've got to shut it down to talk. In the 06 Chevy the engine makes very little more noise than a gas engine and that's a big change.

The window sticker on this truck was blank except for saying, This vehicle not for sale. This vehicle not for display. The dealership had no idea of what the horsepower was or what changes to expect other than the 6sp. They weren't even real sure what they were doing with a "not for sale, not for display" truck. The dealerships sales product trainer is a buddy of mine so we were able to take the truck out and play with it.

I liked this truck very well, two thumbs up!

jwkim

VGT for diesel has been around since early 90s.

mbilderback.

Turbos used in Diesel cars have much bigger exhaust housing so it can spoon at much lower RPM.
They also use very small turbine compare to engine displacement.