It's official! 6.7L: 350/650 and 68RFE

[jwilson610]

Actually, the fact is that the G56 runs in medium duty trucks all over the world, but we in the US/Canada fell for the power wars. Look at the Sprinter - here's a van whose GVWRs range from 8550 to 10,200 pounds, and it gets the job done with a 2. 7L 5-cylinder turbo diesel that puts out all of 154 hp and 243 lb-ft... and it gets an honest 25 mpg, according to DC and several commercial clients - FedEx and UPS are buying Sprinters by the bushel. So here are DC and Cummins offering an engine that's more than double of displacement, hp, and torque for the same GVWR range in the Ram pickup. And that Sprinter engine is used with no problem in many other countries, as is the G56.



In a nutshell, the rest of the world manages power with gear ratios, we do it with engine output. DC chose to go in-house for the HD manual 6-speed and the G56 was the best they have for the job of the Ram 2500/3500.



You have to ask... will Joe Average really notice the difference between 610 lb-ft and 650?

I like the Sprinter and it is great for loading up with 4000lbs of parcels to deliver, but that little engine will not tug a 15000lb trailer around. I looked into getting one and pulling a 20' tag trailer, but they are only rated at 5000lbs for towing. It may have the same GVWR, but the GCVWR is about 1/2 of what the 1 ton trucks are(you can buy a F350 off the lot with a 26000 GCVWR). So, yeah- a 5 cylinder 2. 7L turbo diesel may be fine for a 12000lb GVWR, but no where near the 23K-26K GCVWR that the US 1 ton truck market is built for.

 

[Cummins Cowboy]

what I find very strange is there are 2 different auto trannies available. This kinda flys in the face of everything DC does, like giving us a small 4 door without an extended cab model, usually DC tries to make a once size fits all model so to speak. Just like my 06 with auto trannie, it has the stupid floor console that collects dust, and there is just a small square tray where the 6 speed shifter could come through the floor if my truck had been made a 6 speed,

 

[Plowboy]

I'm sure all of the performance chips will negate the derated engine on the standard.

 

[jwilson610]

I'm sure all of the performance chips will negate the derated engine on the standard.

Plowboy, I'm sure it will. I do software for most german cars(including volvo). The 1. 8T was the most popular engine to upgrade. It didn't matter what the factory specs were- they all had ~205hp when chipped wether it was the 180hp version in the VW Golf/Jetta- The 170hp version on the Audi A4 or the 150hp version on the VW Passat- they all had 205hp when chipped-only exception was the Beetle which had hardware differences in the fueling system.

 

[KCJackson]

I like the Sprinter and it is great for loading up with 4000lbs of parcels to deliver, but that little engine will not tug a 15000lb trailer around. I looked into getting one and pulling a 20' tag trailer, but they are only rated at 5000lbs for towing. It may have the same GVWR, but the GCVWR is about 1/2 of what the 1 ton trucks are(you can buy a F350 off the lot with a 26000 GCVWR). So, yeah- a 5 cylinder 2. 7L turbo diesel may be fine for a 12000lb GVWR, but no where near the 23K-26K GCVWR that the US 1 ton truck market is built for.

But the 215/440 12-valve could move a large 5er, just not as fast as a 325/610. That Sprinter is handling the same jobs as the Powerstrokes and Duramaxes in the Ford and GM full-size vans. Heck, Winnebago is making RVs on the Sprinter cutaway.



My point is, there comes a point where you're raising the hp/torque numbers just for marketing without increasing the basic ability of the truck. If they raise this new 6. 7 from 350/650 to 400/700 for 2008, will it really do the job that much better? Probably not.

 

[daytripper63]

I might have to order a new truck now...

If the Aisin transmission in the new Dodge/Cummins is built anything like there other trans I would not expect ANY problems, I would love to have a 6 speed behind my little 6 cyl

Am I reading this right? is the 68rfe not an Aisin? what do I need to do to get the Aisin

 

[KCJackson]

I might have to order a new truck now...

If the Aisin transmission in the new Dodge/Cummins is built anything like there other trans I would not expect ANY problems, I would love to have a 6 speed behind my little 6 cyl

Am I reading this right? is the 68rfe not an Aisin? what do I need to do to get the Aisin

Pickups get the Mopar 68RFE, chassis-cabs get the Aisin AS68RC.

 

[daytripper63]

Pickups get the Mopar 68RFE, chassis-cabs get the Aisin AS68RC.

That BITES the... . Aisin builds an excellent unit and Dodge probably figured out a way to do it CHEAPER with cheaper components... I hope I am wrong but time will tell, if it was an Aisin I would probably get a new truck with one but i think I will sit on the fence for a bit on this one

 

[jwilson610]

But the 215/440 12-valve could move a large 5er, just not as fast as a 325/610. That Sprinter is handling the same jobs as the Powerstrokes and Duramaxes in the Ford and GM full-size vans. Heck, Winnebago is making RVs on the Sprinter cutaway.



My point is, there comes a point where you're raising the hp/torque numbers just for marketing without increasing the basic ability of the truck. If they raise this new 6. 7 from 350/650 to 400/700 for 2008, will it really do the job that much better? Probably not.

I had a 96 180/400? cummins dually that got 18mpg on the highway at 75mph- that would pull a big fifth wheel just fine- just not that fast up the hills. My point is why not bring the power up to the 325/610 that my 06 has if you can do it with todays fuel systems/turbos(I liked the variable nozzel/vane turbo on my 04 and 05 ford- just like the VW TDI started using in 1999. 5) and get the same miles?



Now the sprinter you bring up is a different story- Yes, it is sold a a camper, but the frontal area is still not very large. Not much strain on that little engine. I would be fine with a 3. 0L 4cyl CTD in 3500 if I never had to trailer anything I'm sure they could make it with 300ft/lb and 175hp(cycle those smaller cylinders faster). That 2. 7CDI would not last long(compared to the 5. 9) pulling 5th wheels around. It's just not designed to put out full power all the time.

 

[KCJackson]

I had a 96 180/400? cummins dually that got 18mpg on the highway at 75mph- that would pull a big fifth wheel just fine- just not that fast up the hills. My point is why not bring the power up to the 325/610 that my 06 has if you can do it with todays fuel systems/turbos(I liked the variable nozzel/vane turbo on my 04 and 05 ford- just like the VW TDI started using in 1999. 5) and get the same miles?

Well, I had as closely comparable a pair of trucks as you could have - 4x4 extended cab dually, tallest ratio, auto trans. My 96 with the 180/420 12-valve got 24. 3 mpg over a tank of highway and rural 2-lane driving. My 05 325/610 has never broken 19 over a tank, and will only show over 20 on the overhead if I reset it while I'm driving at exactly 52 mph. That's a 20% drop in fuel economy.



Almost every power increase over the last 10 years has been in response to something that potential consumers weren't necessarily going to like, usually an emissions equipment change. Then there was thre quiet change from 325/600 to 325/610 just because GM raised the Duramax to 605... no actual change to the Cummins.

Now the sprinter you bring up is a different story- Yes, it is sold a a camper, but the frontal area is still not very large. Not much strain on that little engine. I would be fine with a 3. 0L 4cyl CTD in 3500 if I never had to trailer anything I'm sure they could make it with 300ft/lb and 175hp(cycle those smaller cylinders faster). That 2. 7CDI would not last long(compared to the 5. 9) pulling 5th wheels around. It's just not designed to put out full power all the time.

Wasn't all that long ago that the dually's standard engine was the 5. 9 gas V8, and the power wasn't a whole lot more than 175/300... especially when looked at over the rpm range of a diesel. I'm not disputing more grunt leads to a higher tow rating. But



Here's one thing we can probably agree on, though...



In January, the diesel engines will essentially eliminate themselves from the Big 3 competition. We will have:

- Duramax 360/650

- Cummins 350/650

- Powerstroke 350/650

The 10 extra horses by the Duramax are negligible... you can gain or lose that much with a dirty air filter or a particularly well-assembled engine. It will actually come down to the trucks again.

 

[GHarman]

Why?

Howdy all, I guess I like the B-series engine. All the H. P. and torque capability is already there. Why is the extra displacement necessary for a 3/4 or 1-ton truck? The new transmission is another story. Why cant DC marry the AISIN transmission (Or an ALLISON for that matter) to the SO or HO 5. 9L Cummins and be glad that their first attempt at installing a diesel in a light truck was an excellent choice, 3 generations notwithstanding. DC, Ford and GM all like us to see shiney new paint. before the paint dries on our last purchase. For some - thats OK. For me just improve on your successes and I would consider buying just one more truck before my part in this drama is completed. In the meantime I'll stick with my old ugly 1st gen. GregH.

 

[KCJackson]

The displacement change was a Cummins decision, not by Dodge/DC. Cummins felt the extra displacement would assist in emissions control.



Dodge was supposed to get the Allison 1000 years ago, but DC and GM got locked up in a lawsuit over the Hummer grille (DC claimed copyright infringement on the Jeeo 7-slot design, which was only licensed to AM General and the original Hummer H1), and GM retracted the offer of the Allison.

 

[backroad]

The 6 speed Allison Auto is truly an awesome transmission. My 98 35ft Allegro Bus runs one behind a 275 horse 24 valve. Do either of the auto's that DC plans to use, have any sort of hydraulic retarder built into the transmission like the Allison. I must add that I am NOT a GM fan, but... ... ... ... .

 

[klenger]

All of the discussion I have seen on rv.net about the Allision 1000 leads me to believe that the Allison 1000 trans used in the Chevy pickup trucks does not have any kind of built-in retarder. The only function the trans provides is downshift and lock the TC. All of the braking effect comes from the engine, which does not have an exhaust brake.

 

[Yo Hoot]

All of the discussion I have seen on rv.net about the Allision 1000 leads me to believe that the Allison 1000 trans used in the Chevy pickup trucks does not have any kind of built-in retarder. The only function the trans provides is downshift and lock the TC. All of the braking effect comes from the engine, which does not have an exhaust brake.

That is correct.



Also the Allison 1000 did not exist in 1998

 

[RustyJC]

The 6 speed Allison Auto is truly an awesome transmission. My 98 35ft Allegro Bus runs one behind a 275 horse 24 valve.

Yours is a totally different unit than that used in the GM pickups.



Rusty

 

[Yo Hoot]

In January, the diesel engines will essentially eliminate themselves from the Big 3 competition. We will have:

- Duramax 360/650

- Cummins 350/650

- Powerstroke 350/650

The 10 extra horses by the Duramax are negligible... you can gain or lose that much with a dirty air filter or a particularly well-assembled engine. It will actually come down to the trucks again.

Isuzu uses "PEAK" hp like Electrolux uses to rate vacuum cleaners :-laf

 

[JasonCzerak]

Well, I had as closely comparable a pair of trucks as you could have - 4x4 extended cab dually, tallest ratio, auto trans. My 96 with the 180/420 12-valve got 24. 3 mpg over a tank of highway and rural 2-lane driving. My 05 325/610 has never broken 19 over a tank, and will only show over 20 on the overhead if I reset it while I'm driving at exactly 52 mph. That's a 20% drop in fuel economy.

Are you sue your 96 had the same curb weight as the your 3rd gen? I'm sure 1000# would count for 20% in fuel millage.



at 7400# in my truck if I keep her at 60 with 33" tires I can do 24mpg. What am I doing right and what are you doing wrong? I average 18 city highway, blowing soot all over the place... .

 

[Spooled-up]

My friend has a VW that has an auto that you can shift manually - and not just 1st and 2nd. You can drive it like a manual through all of the gears in the transmission. Is there some reason that DC couldn't make our transmission's do this so we have the benefits of a manual with the drivability of an auto? This would be the best of both worlds if it was engineered well.



I think I'll write to Dr. Z again!



Dear Dr. Z,



I'd like you to build me a 1 ton Mega Cab with an 8' bed and an Aisin trans that I can drive like a manual. Please overbuild mine so nothing breaks when I add the inevitable horsepower upgrades and offer it with no warranty so I can pay as I go.

 

[KCJackson]

Are you sue your 96 had the same curb weight as the your 3rd gen? I'm sure 1000# would count for 20% in fuel millage.



at 7400# in my truck if I keep her at 60 with 33" tires I can do 24mpg. What am I doing right and what are you doing wrong? I average 18 city highway, blowing soot all over the place... .

I don't discount that the 05 weighs more. I meant comparable in terms of configuration (extended cab 4x4 dually, tall gears, automatic, OEM tire size). But if I could swap powertrains between the 2 trucks, the heavier 05 with the 12 valve would still get better mpg. The fully mechanical fuel system was far more efficient than the three-shot EFI. I'm sure plenty of people would trade the quiet for a few more miiles per gallon.