Hello all--

I own a 2006 4X4 Quad Cab 325/ 610/ 48RE/ 3.73 gears. Am very pleased with the truck-- except, it is thirstier on fuel than I had hoped based on pre-purchase conversations that I'd had with other Dodge Cummins owners. I have about 7500 miles on it, and as expected, it is gradually getting better. Best ever yet is about 19.5; worst ever is about 14.1, both hand calculated. I do live in hilly terrain (1000 ft elevation gain from work to home) and much of my regular driving consists of short trips (7 miles from home to job). I have hauled some heavy loads with it, but not on a daily basis. I do try to use the "tow mode" selectively to lock the converter when I am in the 30-40 mph zone and going uphill (usually ease off the throttle before locking it). I do not drive like a granny, but neither do I drive like a teenage racer. I do really long to join the ranks of those of you who get around 20 mpg. I do not want to drop vast $!$! on performance mods, or void the warranty. So-- what are people's recommended hints on how to break it in the rest of the way without excess wear and tear, and maximize MPG. Thanks!

 

PS to the above message-- the 19.5 was a rare exception, more often, I am hovering in the 14-16 range.

I know this is not an economy vehicle. And I am still pleased. My last truck was an '02 Toyota Tacoma V6 AT 4X4 that really didn't do any better than the Dodge (except that gas is cheaper than diesel around here these days) and wasn't a quarter of the usefulness that this CTD is.

I'd just be doing the happy dance all day long if I could get average MPG up closer to the 20ish range as it sounds as if some of you do.

I know that the 325 610 3rd Gen is not famous for economy as much as some of the earlier versions.

Also, would a boost gauge help me drive for MPG? I used to have a vacuum gauge in one of my previous gasser vehicles. With an A/T, does the boost gauge really let you do much, as you can't shift?

Thanks all

Trevor in VT

 

This seems to be a recurring theme, but I think it's gonna be tough with the auto - nobody I know with one is doing much better than you are; with the manual you've just got more control over the operating conditions. I drive mostly highway, mostly fairly reasonably but including a daily commute over a 1400 foot pass, last tank was 20.1 and change, including a couple of hours of bumper to bumper city traffic - this was hand calc, and it's pretty repeatable with the tank vent mod. (cpu said 21, which was atypically close...)

Note that it's pretty easy to drop into the high teens if I get on it much, i.e. accelerating up the daily pass... try to reserve that for passing a string of gravel trucks or rv's!

I'd say enjoy your really cool truck and don't sweat the extra 25% or so you're paying to drive that auto, and maybe back off a bit gping up the hills to see if that helps!

 

I drive 20 miles each way to work and average 19.4. When I pull my 12,000lb
5th wheel she burns around 12.5.

2005 4X4 Quad cab short bed 6sp.
Volant cold air
issipro boost and pyro

 

Its those shot trips. It takes the cummins a while to warm up. The motor isn't at is best performance when it still cold. so dont expect the best performance from it. I have the same problem when I use it to go back and forth to work. The next time you go on a long trip do your calculations then. Also how you treat that right peddle makes a big differance.

 

I too have run into this problem. I feel it is in the major slip in the T.C. A upgraded converter I feel would help greatly.

JRG

 

I commute 75 miles a day. 25% rural, 50% expressway, 25% city. I can fool the overhead into thinking we're getting over 20mpg with ultra-conservative driving, but can't fool the calculator. Sensible or ultra-conservative is still 18-19. Playtime is 16. Towing is 12. Will hit 50k in a couple weeks. If it ain't broke in by now, I need to carry more bricks in the trailer.

 

just filled up toninght and it was 11.9 by hand. This was all city with and idle time in the morning getting the kid ready. I have gotten 19.6 hwy.

 

I just did a cat back system and all it did was make it sound better, no change in mileage, taking off my 315(D) to 285(E) gained 2 miles a gallon(she rolls much better, the drop in filter made a little more torquey(was towing so I couldn't tell the difference in mileage), the Cap was worth a 1 mpg... All mileage test were on the same road.

Funny, tonight at 61 mph mileage was 19.8, at 64 it was 18.8 and at 67 it was 20.4 on the over head with the cruise on and on the same road.

At 10000 after traveling to Indy to cali to Indy I got terrible mileage and changed the fuel filter and the power and mileage came back... Now I drive to Flying J to get fresh fuel and avoid the small ma/pa service stations..

With my 01 and using Stanadyne I got 2 extra miles per gallon, got some on order...

The low sulfer fuel really hit me hard about a 17% loss in mileage...

good luck in your findings

Gary

 

Forgot to say, if you use a light throttle and keep it under 2k on the shifts that really helps all the way around...

 

Put an xzt tow module on and watch your mpg jump considerably. Mine did anyway. But mine is a stick, however it went from 14-15 to 18.25, and that was with several WOT accelerations with new power, couldn't resist.

 

Thanks all--

I am experimenting with throttle modulation. In the past have generally always tried to go really light on the throttle, but the last couple of days have realized that perhaos some combination of torque converter slip and being out of the torque band may be hurting mpg. So while I am not jack-rabbit starting it, I am trying to take the RPMs pretty quickly to the center of the torque band (1600-1750), bring it up to desired speed quickly in that RPM zone, and then back off and let it float. I know that the overhead is notoriously inaccurate, but I assume that the overhead does reflect mpg in the relative sense, and judging by its readings, this driving style does seem to be causing rising mpg compared to simply trying to go exceedingly light on the throttle all the time.

 

I agree that the short trips are hurting your mileage. It takes my truck 15 minutes to get to operating temperature. And stop and go traffic also hurts my mileage.

I drive very slowly and I usually get in the 20’s. My wife drives the truck kind of fast and gets high teens.

 

If one could only ELIMINATE that 3rd injector event on our trucks, that would help A LOT!

 

I just use cruise control locked at 55mph and let the truck do the rest. All I have to do is steer!! This will usually give me about 20-24mpg depending on terrain.