Newer Tech= Lower Mileage... WHY?

[Cummins Thunder]

Why does mileage keep getting worse on the every newer model Dodge Cummins truck built?



What I am saying is that when you run down the road doing 1800rpm without a load on flat land why would one 5. 9L get better mileage than one that makes less power? Example: the 555 VS. the 600 Why do the 555's get better mileage?



I would think the main way a 600 is going to go beyond 555 ft lbs is because it can get more fuel, but, it isn't always getting full fuel.

To turn a constant 1800 both programs should give the same amount of fuel, right? Kind of like the P7100 12v VS the 98. 5 24v You would think the newer technology would have improved mileage despite a very slight power gain? With the 12v VS 24v thing, more air flow= improved efficiency, right?



I hope yall understand what I am trying to say...

 

[lmills]

the 600/610 motors have more injections to reduce emissions. That is why some people get worse fuel milage. I have had both a 555 and a 610 motor and have gotten good fuel milage with each. The 555 was a 4. 10 geared dually that gave me 18-19 mpg. The 610 is a 3. 73 SRW truck that has given me a best of 21. 5-22 mpg. each truck and each driver is different.

 

[dhill]

My '97 got on average about 19. 7 mpg. It had an auto and 3. 54 gears. My '05 has a G-56 and 3. 73 gears and is getting better all the time, I only have 7100 miles on it. Here are the hand calcs since new.



14. 4

17. 7

16. 3

18. 0

15. 4

19. 3

20. 5

18. 1

17. 2

18. 6

17. 6

17. 9

18. 5

17. 3

17. 3

17. 9

17. 9

19. 8



MPG

Avg. (all time): 17. 8

Avg. (Last 3 fills): 18. 5

Max: 20. 5

Min: 14. 4



I think the milage would be higher but when I drive to work, it's only 11 miles and I go from 100 ft. ele. to 650 and back to 35 ft. Even if I coast down the hill I can't recoup what I lost going up hill. Every trip I took shows up on the chart with milage over 17. 9.



The '97 had a front axle disconect and this one doesn't. Driving style sure does have an affect on mileage, but in my opinion the new trucks are better.



Dave

 

[Texasrattler]

I've got a 555 and all the 600s get better milage than mine and they haul full time. The best I get is 20 to 22 on the highway and 18 mixed driving normal. My son's 05 is getting 22 in town and 25+ on the highway, no box. I watched it. I talked to other guys hauling and they are getting the same empty some more with an Edge. Pulling about 6K from Houston (109 miles) to Austin I was getting 15. The nice thing is I paid 2. 32 a gallon when I left Austin and paid 2. 54 when I got back. I must have come back thru a parallel universe.



Pete

 

[Texasrattler]

MInor correction, 190 miles not 109. It's late.



Pete

 

[Cummins Thunder]

WOW! you guys must just drive VERY slow... I have a lead foot... well that and I like to hear the Cummins rev I make about 13MPG around town, 17 on the highway.

 

[lmills]

with fuel as high as it is nowadays, who doesn't drive slow? I usually cruise around 70 mph on the interstate.