RE:Chevy '08 Duramax - Montana Owners Club

Crossthread · 10-13-2007, 09:08 AM

With all the discussions about the new '08 Fords, a little about the Dodges, whats the word on the '08 Chevys? Any problems with the new emissions, ect. with them? Not flaming any brand, just interested in the results of the emission/ problems with them. Mpg towing, empty... Bill

Montana Sky · 10-13-2007, 04:52 PM

Bill,
Join dieselplace.com That is a great forum all about the GM diesels.

dscott · 10-14-2007, 01:54 AM

Bill,
I have a new 2500HD it has 1900 miles on it.The mpg on the e-way is about 19, towing about 13,regentration takes about 15 min.have to run about 30 mph, mpg drop when regentration to about 10. Lots of power, fun truck to drive.ONSTAR keeps a close eye on the truck for any problems they tell you,even if a tire has low air.Great article in oct. issue of DIESEL WORLD on the big three thrucks compete heads up.

mail2us · 10-14-2007, 04:11 AM

When is regeneration "kick in" or does the vehicle owner have to do this? on the Chevy diesels?

HughM · 10-14-2007, 05:42 AM

No. It's automatic. You sometimes won't notice regen unless you are looking at your mpg on the dash. It's not the big deal that some people are making of it... Just drive it.
Hugh

dsprik · 10-14-2007, 06:11 AM

HughM, what about the 30 min at 30 mpg requirement for regen - or is that a myth? Hard to imagine an engine with those kind of requirements...

dscott · 10-14-2007, 09:09 AM

dsprik,
I worded that wrong about the 30 mph,you drive at aleast 30 mph,mine has regenterated,maybe 3 or 4 times while I was driving 65 mph.The only way you know it's doing it the mpg drop to around 10 mps then goes back up to 18 or 19 on the e-way.

dsprik · 10-14-2007, 09:15 AM

Can you feel any power loss?

dscott · 10-14-2007, 09:26 AM

No,but I was not towing at the time.I will be able to give you more info after I pull to Florida in Dec.[

dscott · 10-14-2007, 09:27 AM

No,but I was not towing at the time.I will be able to give you more info after I pull to Florida in Dec.[

Chip · 10-15-2007, 09:49 AM

Mine has 4000 miles on it. Ive only noticed it in regen while towing. The rpm's are up and you can hear it. It last about 20 to 30 minutes. Acts like it is not upshifing all the way. My mpg while towing in regen mode drops only a couple of mpg, 12 drops to 10, then right back up. I am sure it has regen not towing but I haven't notice it yet.

Was very concerned about the new emssions, but so far it seems to do what it is suppose to do. Time will tell.

Seems to be a great truck.

Chip
Drew

HughM · 10-15-2007, 11:26 AM

If you have an exhaust gauge you'll notice a rise in temps. No severe loss of power. Mileage drops very little.
Regen is nothing but burning the particles out of the exhaust with higher exhaust tempertures.
Just drive and enjoy your duramax, there's nothing better to pull with.
I traded a Power Stroke Ford for mine.
Hugh

sreigle · 10-17-2007, 10:23 AM

Guys, mine is not a GM but a Dodge but I'd bet from everything I've read the regen behaviour is very similar in all brands. I have read this process has been used in Europe for some time now so apparently it's only new in this country.

As said by others in this thread, I also cannot tell when a regen is going on except the mpg is dropping when I would not expect it to. When done, the mpg starts back up. How much it drops is all relative, however, because if I just hit reset five minutes ago it's going show a more precipitous drop than it would if I haven't reset the computer in a couple hundred miles. Same concept as shoving your foot in it going up a steep hill. MPG drops big time shortly after a reset and just a little if long after a reset.

Dsprik, I cannot feel any performance difference. If it's there I can't tell it. We have 16,200 miles on this truck in 4 months and 10 days. Almost half of that is towing, including mountains in PA, VA, New England. I see no performance difference when a regen is going on.

Please forgive for my intrusion in your GM thread. I just wanted to add my observations since all the brands are using the same process. As someone on the prior page said, it's not a big deal. Just drive it.

Crossthread · 10-17-2007, 10:42 AM

No intrusion at all. Its all information that helps me, and possibly many more. Thanks to all that has posted, and I welcome all info. Bill

sreigle · 10-25-2007, 08:56 AM

Bill, all three majors use the same procedure with the dpf and the regen. So far, all the problems I've heard about were cured by reprogramming the computer. A learning curve for the mfrs. There have been a couple of instances where a faulty fuel injector put too much fuel into the process causing flames out the tailpipe. From what I've read that happened on three Ford trucks and two GM's. I haven't heard of Dodge doing that yet but maybe nobody's telling. In any case, that's darn few problems.

Most of the problems I'm hearing about have to do with using low sulfur diesel instead of ultra low sulfur diesel. That's a sure recipe for problems with that system and the mfrs say warranty will not cover that.

lwcdg · 10-26-2007, 09:08 PM

Steve I only wish the mileage on the Chevy would be as good as the Dodge Cummings. that said it is better than my "old" Ford.-)) And definitely has better stopping capabilities with this turbo.

There is a ton of talk over on the Diesel Place boards about better fuel mpg with the programmers and other mods. I only wish I was more confident in making that jump. I can't get beyond the thought of warranty issues. I don't need anymore power just more mpg so I'm saving at the pump would be nice.
Chuck

richfaa · 10-27-2007, 02:25 AM

During regen the EGT temps on our 08 Ford will increase by 200/300 degrees and the MPG will drop drastically. The regen has lasted as long as 5 mins. We can tell when it starts and stops by the EGT temps. We note no loss of power but then we have not gone into regen pulling the 3400 on a long steep grade....yet.. It seems to regen more frequently in "city" driving..just my observations thus far.

quarrles · 11-04-2007, 01:08 AM

Took delivery of our 2008 Chevy 3500HD DRW 4X4 Duramax with the Allison 6spd Tranny on Oct. 30th. We had it out yesterday to get those break-in miles suggested by the book. I noticed, among other good things, that this transmission runs the engine well below my 2004 GMC Duramax dually with the 5spd Allison. At 65 mph rpms are about 1500-1600 well below the 2000 the old rig did.

I have consistently tried to keep my towing rpms @ or about 2000 with the 2004 GMC. The new Chevy seems to have to use less to achieve the same mph. When we start to tow I will post again with the mileage and rpm facts. This truck runs really nice and the ride is much improved over the old one.

I am not mechanically knowledgeable enough to give any technical info but will post my results. We are having a PullRite 18K Super Slide installed overa Rhino sprayon bed liner tomorrow using the Universal rails. Even though we have an 8ft bed I like having the extra manuverability of a slider. We will tow our 2008 Montana Big Sky 340RLQ with the new TV.

I was impressed with the smooth shifts of the Allison Tranny. The Chevy has the built in trailer brake and Ally has the "M" mode which I am looking forward to try with our camper in tow.

Happy Trails to all

Diesel@ $3.19 Tifton, Ga 11/03/07

sreigle · 11-04-2007, 04:25 AM

I do not yet have an EGT gauge on our Dodge so have to identify a regen by watching the mpg on the computer. I have not noticed a regen while towing (almost 6,000 miles of towing with this truck). I suspect exhaust temps run high enough when towing that no system-initiated regen is necessary. But that's just a supposition. I have no basis in fact.

richfaa · 11-04-2007, 04:56 AM

I have been told the same thing that keeping the exhaust temps high will result in less frequent or no regeneration. we have been using this 08 Ford as a daily driver since we got it just to run up some miles before we leave for the winter and it DOES regenerate "frequently" in city driving.

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