alan1

I have seen a certain amout of info on the egr system and how it works. However, will we gain some improvement with the Holset Variable Geometry Turbocharger? Faster response and some engine braking? Maybe with the good (vgt) it will offset the bad of the EGR?

JKE

VGT is a bonus if done properly...I know there are quite a few gear heads here the do not want it, but,,,,,,,,,you can achieve max boost at low rpm and control boost throughout the rpm range...very little lag. Guys that I know in the business are excited about VGT. However, that does not mean it is better than snuff and half as dusty.

EGR is a whole nother subject best left for individuals that know more than I. However, do not confuse this egr set up with the widely hated VW egr. There are some things that are still being tested.

I am glad I got an 03. If not, good luck. EGR can work if designed properly for stock trucks. If you bomb, buy older truck and have fun.

doug

Cummins is actually claiming, last I knew, a small fraction of a mpg improvement with the EGR/VGT combo. that is certainly due to the VGT which by itself is really pretty cool -- bascially what JKE said.

The only credible arguments against VGT are:

1. cost. dern things are very expensive
2. more difficult and expensive to bomb. VGT is controlled by the ECM so it will be very interesting to see how these new trucks respond. The downside of VGT is that a whole new body of research needs to be undertaken by the fueling box companies to deal with VGT realities -- for example, Lawrence at DD told me that in his work with the Fords, by the time you detect the need for an effectively larger exhaust housing (say, you mash it off the line), the turbo has already spun out of control. So this is purely conjecture (because Holset does things differently and probably better...) but it appears to me that the ECM has to back off to give the VTG time to respond. This may be no worse than waiting for a larger turbo to spool up, however! VGT may actually have more to give in the boost department, but the fueling boxes will have a more difficult time protecting them from overspooling.

so yea, I frankly would not be concerned about VGT, especially if you stay stock in which case it will be a good thing. Indeed, the shortcomings of EGR will, for the stock truck, be made invisible by VGT in my opinion. Of course, the bombers will have to wait for the frontiers to clear first 'cause nobody's done an EGR/VGT CTD.

And, just because VGT comes with EGR, the whole issue of emissions tampering comes up and starts to sound messy. truth of the matter is that we really don't know ;D

BigBlue

So the 04+ Cummins will have a VGT turbo on them? That's pretty sweet.

doug

well, maybe or maybe not. we think that the 2004.5 RAMS will have EGR/VGT because thats what the motorhomes and busses use today.

But really, guys, we don't know FOR SURE. for all we know, Cummins and DC may have figured out a way to avoid this additional cost. So we gotta be honest with ourselves and allow for the potential for a big surprise come January.

But without regard to that, the 2004.5 trucks will have big brother watching them!

JKE

also, and I may have mentioned it, we supply EGR systems for the volvo diesels...I think . Their performance is/will be an indication of things on trucks like ours. Not sure how the Volvo's are getting along with it .

we have good relations with cummins.

Maybe someone from Europe can add to this.