Get More from your Truck - MPG

[Tomassend]

Wondering if any of you out there could assist with handling this topic, I am very pleased with the modifications I have done thus far and just trying to finish the upgrades with focus on getting more fuel efficiency out of the vehicle.

 

Vehicle Current State:

 

2006 Dodge 5.9 2500 Mega Cab

Edge CTS Tuner - Low Boost Setting on 1

4" Exhaust from Turbo back with 36" resonator

Stock Wheels and Tires

Stock Airbox - This should be good to 450 Raw HP

 

Currently we are doing heavy amounts of traveling with a 9.5 foot Cab Over Camper and 4 Place snowmobile trailer through pretty mountainous terrain. All the infrastructure is in place to handle these items from a airbag, tie down, and steering perspective. This allows the truck to remain in good riding height while traveling....which is normally around 70 mph as we are slightly inpatient

 

Current MPG Loaded - 13/14 MPG

 

Any insights you have is appreciated.

Dave

 

 

[MnTom]

Most guys would love to get that kind of mileage loaded. If you want better mileage your best bet is to slow down. Just to give you an example, my truck with my 28' fiver on and a GVW of approx.17k gets 14 mpg at 60 mph, 12 mpg at 65 mph, and 10 mpg at 70 mph. Speed will kill more mileage than anything.

[Mopar1973Man]

Absolutely. Speed is the number one killer of MPG's numbers. But when you math out speed and time you'll be surprise how little it effects.

 

Like a trip to Boise, ID for me is 180 miles. Answer below are typical MPG empty (Gross weight 7,600#).

 

55 MPH = 3.2 hours = 23 MPG

65 MPH = 2.7 hours = 18 MPG

 

Now with the Jayco (GCW 16,820#)

 

55 MPH = 3.2 hours = 13 MPG

65 MPH = 2.7 hours = 9 MPG

[Tomassend]

Totally understand the speed to fuel economy relationship, as we have performed tests mush like the ones listed above on our trips. Driving habits are huge, will never disagree with you on that.

 

Although I will say, I drove to WY from WA without the Edge Tuner, I got 10 MPG @ 55 mph without overdrive. I don't ever want to drive a stocker 5.9 Cummins ever again, LOL.

 

However, to keep the title of the post relevant to modifications......are there any recommendations to elements which can improve Fuel Economy performance?

[mopartechnician]

Camshaft helps alot. Gets rid of the egr lap that is used with the stock cam.

[dorkweed]

Manual or automatic???  2WD or 4WD???  Highway tires, AT tires or mud tires????  Ginger or Mary Ann???

[Tomassend]

Kelly Safari ATR Tires 265/70, 4WD, 4 speed auto.

 

Mopartechnician - What type of benefit can you see by camshaft changes?

[Mopar1973Man]

I would turn up the Edge as much as possible. The highest main level that doesn't cause issues with your transmission and the highest sublevel (low boost setting) without excessive smoke.

 

You could think of trying 2 cycle oil in the fuel (200:1 ratio) so like it and others don't. But typically the lower cetane levels produce better MPG's.

 

Proper tire inflation helps a bunch.

http://articles.mopar1973man.com/general-cummins/35-exterior/354-tire-inflation-formula

 

Tonneau cover or a canopy will help a bunch if you can cover the bed of the truck.

 

Another thing if you go the fund is hook up with a Dyno event locally and find out where your torque is at for your current setup. Then you know exact what RPM's does the most work for the buck.

[AH64ID]

Ditch the Edge and get a Smarty, better yet get a Smarty with custom UDC tuning.

 

You probably won't see a huge gain, but a little should be had.

[JAG1]

Count me crazy, I saw a quite a mileage increase on my stock engine/truck by doing some simple mods.

 

I'm not sure if it caused the computer to work more efficiently or what, here's the things I did;

 

Ran a ground wire from the alternator housing to pass. battery because I found weak grounding thru the alt mount bracket.

 

Ran a ground from the ecm mounting bolt to the drivers side battery. negative

 

Placed nylon washers behind the ECM on mounting bolts to help isolate from engine block heat.

 

Retorqued the intake manifold bolts.

 

Made a bracket out of fiberglass to isolate stock fuel filter housing off of engine heat.

 

Made my next 1400 mile run (I do this same trip often) thinking my fuel guage was going bad because mileage increased by at least 10%.

 

I was very surprised and like said before, I thought my sender was going bad but when I filled up at the same place as always it took a lot less gallons.

 

I don't know.... maybe 75,000 miles means the Cummins is just breaking in.

 

I'm also running with a 0216 code for 2 years now.

Edited April 11, 2014 by JAG1

[dorkweed]

The best additive for improved mileage comes from a "soft right foot"!!!  Whether it be "stock"...."modified' or anywhere in between!!

 

 

 

 

But stock ain't no fun!!!!!

Edited April 11, 2014 by dorkweed

[Mopar1973Man]

It can be done by a 12V truck I'm sure many of other trucks can too.

http://www.dieselpowermag.com/tech/general/0708dp_1997_dodge_ram_3500_dualie_cummins/viewall.html

[Tomassend]

What about injector changes.....has anyone out there had good luck with changing out of stock injectors?

[mopartechnician]

If your overhead reads way off of hand calculated than you have injectors leaking a little extra fuel each time. How many miles do you have?

[Tomassend]

If your overhead reads way off of hand calculated than you have injectors leaking a little extra fuel each time. How many miles do you have?

 

The overhead was never really accurate from when I purchased the truck. Hand calculation seems to be the most accurate methos of measurement.

 

No leaking injectors, they were all tested and 99% score in relation to one another. I also recently ran a fuel system cleaner through it as well.

 

Truck has 145,000 miles.

[AH64ID]

If your overhead reads way off of hand calculated than you have injectors leaking a little extra fuel each time. How many miles do you have?

 

Not really true on a 3rd gen. They are very inaccurate to begin with.

 

The way the 3rd gen calculates is also different, you could be leaking a lot of fuel and still have the same reading. The calculation is based off of commanded mm3, which is a function of rail pressure and injector open time. It should be VERY accurate, but it isn't.

[dorkweed]

Not really true on a 3rd gen. They are very inaccurate to begin with.

 

The way the 3rd gen calculates is also different, you could be leaking a lot of fuel and still have the same reading. The calculation is based off of commanded mm3, which is a function of rail pressure and injector open time. It should be VERY accurate, but it isn't.

 

My last tank of fuel...............the overhead read 25.1mpg .......................I hand calculated the mileage and it was 20.2mpg.

[Tomassend]

Not really true on a 3rd gen. They are very inaccurate to begin with.

 

The way the 3rd gen calculates is also different, you could be leaking a lot of fuel and still have the same reading. The calculation is based off of commanded mm3, which is a function of rail pressure and injector open time. It should be VERY accurate, but it isn't.

 

AH64ID - What mileage are you seeing with your travel trailer?

[mopartechnician]

The last 4 guys that i did injectors on their pickups actually keep track of thier mileage and they all were 5-6 mpg off of overhead. After the install they are within .5-1mpg off now. I talked to erick at brown's diesel and he said that is what he looks for too and he told me the reason was for the extra fuel that is getting by each time it fires/closes. That my personal experience

[Tomassend]

The last 4 guys that i did injectors on their pickups actually keep track of thier mileage and they all were 5-6 mpg off of overhead. After the install they are within .5-1mpg off now. I talked to erick at brown's diesel and he said that is what he looks for too and he told me the reason was for the extra fuel that is getting by each time it fires/closes. That my personal experience

 

What install are you referring to?