Can the new 600 be de-tuned to increase fuel mileage? I tow a 6000 LB Travel Trailer and 450 ft/lbs of torque would be plenty for me. As I use the truck for business, I'd rather have more MPG than power.

 

As with all CTDs, the mileage will get better once the engine breaks in.

You can de-tune it by keeping your foot from mashing the go-pedal! (If you can!!)

 

I talked to a guy that bought the same type truck as I did EXCEPT it was a 555 instead of the 600. He gets 17mpg...I get 13mpg with the same miles on the clock (5000) and same driving style. These 600's are, like I have said before, 4 to 5 mpg worse than the 555's.

Both trucks are 4x4 DRW QC Auto / 373's

 

Just for the recored on my 555 QC 4X4 I'm getting 19mpg around town..... However, If I pushed the gas pedel under acceleration another 1/4 of an inch, it would drop to about 15 or 16........ If I didn't keep a steady pace (not off and on the gas at all times) it would easly be 14 to 16 mph the way I drive it. The Cummins is very PICKY if you want to get good miliage. If your making your truck even slightly accorate, your MPG is in the tubes! Milage is made up by keeping the truck a steady speed just off idle (around town).... If you not doing this or your driving conditons don't allow it, it's no wonder to me your seeing the milage you are.

Play around reseting the over head a bunch under different driving conditions. It will give you an idea of what your truck like's.

Rich

 

If I drove like you think I am I would get 11 to 12....Thanks for the comment though.

I didn't buy a diesel to drive like a grandma...but I did buy it for longevity,personal preference,and to get better mileage than a gasoline powered truck.

 

I don't think you can really make that statement unless you are the only one that drives both trucks. My dad just got a 600 with and auto and 4.10's that looks to be getting about the exact same milage as my 555 did when it is new.

To think that the new 600 is getting 4-5 worse then the 555 is just wrong.

 

There is no possible way to get my hand calculations or my overhead to read even 15mpg. That is on the interstate driving 60 to 65 mph for 100 miles or more. I have done way too much testing and there is a huge difference.

Don't forget that I paid alot of money for my truck. I didn't buy it just to be a "600" basher.

 

I don't have my truck yet so I can't comment on what mileage I get (will get).

However, using common rational and some engine dynamics 101, the general statement that "the 600 gets worse mpg then the 555" is a VALID conclusion! How much worse is the question of the year!

Some "general" statements:

1 - To obtain more power without major mechanical modifications you need to burn more fuel.

2 - A combustion cycle with 3 injection events consume more fuel then one with 2 injection events (assuming the amount of fuel injected per event is equal).

3 - Adding emission control devices (i.e. converters) will decrease power. To regain some of what's lost, the engine must be retuned. (see note 1 above)

4 - The goal of the new 600 motor was to increase power output, lower emissions, and decrease dB output level. Nothing about being less fuel efficient.

So, I guess everyone can make there own conclusion if this is true or not. In my opinion, I believe the 600 will consume more fuel then the 555 - period! How much will depend on driving style, fuel, and every other variable thrown into the mix. I don't think anyone can dispute this conclusion, or prove it wrong otherwise. That is unless their willing to strap two engines on a testing machine that can simulate identical conditions for the duration of the test.

These are just my opinions on this whole MPG debate so don't throw me into a corner here. If anyone wants to prove me wrong, lets see some hard documentation with charts, 3"x5" pictures and a paragraph behind each one explaining otherwise!

 

You have to remember that a diesel engines power is made by fuel. That said it take no more power to push an 03 down the road then an 04.5. The only time you are making power above the old 555 is when you got your foot far enough in the throttle to feed it enough fuel to make that power. So all things being equal a 600 should be feeding no more fuel then a 555 crusin down the road in identical trucks.


Thats the real simple version.

Now if your 600 is really getting that bad of milage maybe something is wrong with it. Only 5000 miles is not alot, have you done any heavy towing, that brakes them in faster. Fuel leaks? Was yours one of the trucks that needed the reflash done to it?

 

It has been to the dealer for the reflash but I am not sure if they really did it...at first they acted like they didn't know what I was talking about...until I gave them the TSB number. So maybe I need to try another dealer. I read somewhere that the dealer is required to put a sticker on it stating that a modification has been done to the truck when they perform a TSB but I cannot find ia sticker anywhere. It does say on the ticket that they did it but there was no change.

 

Ok so i had an 03 ho 48re 4:10 4wd that was bought back .They ordered me a new truck than there was that big production delay.Igot stuck with a 600 equiped exactly as the 03 was. Im the same driver . The 03 got 16 to 18 The 600 gets 9 to 11 mpg it truly seems to get worse with every tank full The early reflash took care of it running poorly, for a while .I now have 4k on it and the exact same hesitation is coming back woo boy are we having fun yet or what ..Im sure it will all get resolved Just kind of frustrating being a mechanic and having a truck thats not right and there isnt much i can do about it .Its all computer /software issues

 

Yeah, just trade with me. An S.O. for the 600...you can't go wrong. Mike

 

Im a Newbe here. Love the site! I just got my 600 a month ago. I have 1200 miles on it. I found if I keep it at or under 1800 rpm (67 mph), my overhead tells me I average 17 mpg. And if I go slower, my mpg goes up. Thats on a flat straight road for 75 miles. All I can say is, so far so good

 

See sig for truck and mods

If you think the 600's are bad check this out...

15 mpg in town

14-15 mpg on highway at 75mph

Here's the KICKER!

6800 lb Enclosed gooseneck cargo trailer...


1500 mile return trip from the manufacturer...


75 mph (on the rare occasion that it would do it)...


7.4 mpg average


I'm going to hang my head in shame now...

 

That sound right on course you know. It is that 75mph that is killing you. Drop that down to 65 and you will see a big jump, I have tried it. I get about the same that you are at the same speeds running 4.10's

You have to remember that wind it the real killer and not weight. That enclosed goosneck is like pulling a big sail down the road. And when you try pulling it faster the drag goes up fast.

I have a 40' gooseneck that I put 2 lifter off road trucks on that sits way up in the air. When I load the same trailer with building material of similar weight that sits low I will gain 2-3mpg.