TowRig.com - Diesel Discussion and Tow Tech

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The rumors:
The 6.4L Powerstroke is going to be put in the new SD as the diesel option mainly because of more stringent emissions that go into effect in '07. In addition to some design changes, looks like we may finally get a factory F450 pickup (unofficial).

And of course the twins.

The new engine will have an improved turbo, a new rail fuel delivery system, lower emissions and much quieter than the 6.0L.

Torque and HP will be increased as well.

I kept hearing Twin turbo, has that been dropped?

Edit: yes the twins are still rumored to be 2007

I don't like the rims. They look like 20's.

The taller rims with lower profile tires will offer more lateral stability, which is good isn't it??

The taller rims with lower profile tires will offer more lateral stability, which is good isn't it??Yes, to a point. Too short of a sidewall and the ride will suffer. I would think a 17" rim would be plenty large enough to improve handling. I'm sure it's mainly for looks regardless. A lot of people are going with that bling bling 20" wheel doodoo....not for me. :doah:

While I see drawbacks to 20" wheels I like the fact that the OEM's are being progressive. Factory twins would revolutionize the class, say goodbye to emissions!

Why do you say twins would ruin emissions? More air helps emissions (smoke, particulates, hydrocarbons, etc), it does not hurt it.

Just guessing, but maybe what he means by "say goodbye to emissions" is that it would reduce the emissions and perhaps eliminate the (perceived) need for things like EGR.

Why do you say twins would ruin emissions? More air helps emissions (smoke, particulates, hydrocarbons, etc), it does not hurt it. He means it will help emmissions.

Well twins certainly doesn't eliminate emissions either, not by a longshot. There are so many things that go into reducing emissions it is not even funny. Twins alone won't do much without other pieces of hardware and software to take advantage of it.

I'm completely out of my league here, but these are my thoughts...

Most of the worst emissions are produced under acceleration. By having twins you get much more boost much sooner from the smaller turbo (as opposed to a single compromise turbo), which then phases out to the larger as rpm climbs and time passes. By making the earliest portions of acceleration much more efficient (due to more complete burn resulting from more boost) that would dramatically (I think) reduce harmful emissions. Obviously it also provides for other opportunities to do things with timing and such to improve still more, but just on it's own, properly configured dual turbos should have a rather large effect on total harmful emissions, or so it seems to me.

There is much more to diesel emissions that what you see coming out of the tailpipe. There are things like NOx, CO, and HC. CO and HC as well as smoke and particulates are generally reduced by more airflow. However, the higher airflow and boost effectively can raise cylinder pressures and temps, so it increases NOx, which is the most plentiful pollutant in diesel exhaust. There are things you can do to combat NOx like timing changes and EGR of course, but it is still a problem. What I was getting at earlier in the post was that just because you add twins, doesn't mean you can "say goodbye to emissions". I did, however, misunderstand at first what he meant by "say goodbye to emissions", but either way, his statement wasn't quite true.

I do wonder why they would use twins when they seem to have a VGT that works quite well. It basically does the same thing as twins, but in a much smaller and cheaper package.

Agreed, "reduced" emissions would be better. And I know there is much more than the soot you see, but I wasn't thinking about the increased cylinder temps.

There is much more to diesel emissions that what you see coming out of the tailpipe. There are things like NOx, CO, and HC. CO and HC as well as smoke and particulates are generally reduced by more airflow. However, the higher airflow and boost effectively can raise cylinder pressures and temps, so it increases NOx, which is the most plentiful pollutant in diesel exhaust. There are things you can do to combat NOx like timing changes and EGR of course, but it is still a problem. What I was getting at earlier in the post was that just because you add twins, doesn't mean you can "say goodbye to emissions". I did, however, misunderstand at first what he meant by "say goodbye to emissions", but either way, his statement wasn't quite true.

I do wonder why they would use twins when they seem to have a VGT that works quite well. It basically does the same thing as twins, but in a much smaller and cheaper package.
wow! Looks like I started something I should finish. I both agree and disagree with what you say. Starting with "say goodbye to emissions" come on dude don't take me that serious! First off dodge/cummins, to my understanding met emission standards for 2007 in 2004.5 and they did it without a variable pitch turbo. (thus the reason for Gale Banks to come out with is sidewinder) Just think what Cummins could do with twins to emissions, thus "say goodbye" was born in my little head. Now were I start to loose you. If I remember tech school well enough, HC (hydro carbons) is unburned fuel and I sure see it coming out of my tailpipe. Correct me if I am wrong but NOx is a gas created by high combustion temp. More air psi lower combustion temp... are we on the same page? twin turbos eliminate emissions, nope. Help in a big way.... do you really think international is spending millions of $ in developement to give you factory twins for hot-rodding purposes?

my thoughts
Mike
www.Dunksperformance.com

Sorry for taking what you said so seriously. It sounded like the typical response some people have who know very little about diesel emissions (not saying this is the case with you) and I felt it needed corrected. You are correct in that NOx is formed by higher cylinder temps and that more cool air will lower that. However, just because you add twins, thus more airflow, doesn't necassarily mean that the air going into the cylinder is any cooler, thus it may or may not impede the formation of NOx. Also, timing, pressure, and rate of fuel injection usually make much more difference than the temp of the air coming in. More air, however, does usually mean that you will get lower HC and smoke/particulates because there are less fuel rich areas in cylinder that cause the formation of these pollutants. Notice I do not make blanket statements about the effects of different changes to a particular engine. I have learned there are very few sure things when it comes to emissions, just lots of testing and fine tuning until an emissions compliant engine is produced.

I see yall are assuming the twins will be typical "twin" turbo's.

What about if they use "compound" turbo's.

This would allow lightning quick spool-up, and then a ton of air on the top-end.

This would limit the end-user from "turning" up the truck since compound turbo'd trucks are sensitive to overboosting.

I think the 6.4L will probably use twins just like the Big Cat motor does.

Merrick