pete97

Anyone have any suggestions on how to get better MPG with the current set up that I have. Thanks

xtoyz17

Increase the timing.

Dartmouth 12V

There are ways to modify your rig but the biggest thing is driving habits. Slowing down will make a huge difference. If you can drive at 60mph on the highway, your mileage will increase greatly. Windage is approximately proportional to the square of your velocity at highway speed so slowing down a little will help mileage a lot, not to mention you will be running lower revs. Also, anticipation is huge. Coasting up to traffic lights and not flooring it off the line are really helpful. Since you have a manual, shift points are important. Most people understand that running too high of an rpm will get poor mileage but a lot of people don't realize that lugging the motor is just as bad.

As far as actual vehicle modifications go, there are three things to work on: powertrain, windage, and rolling resistance. As far as the powertrain goes, you have a pretty darn efficient one. If you have a tendancy to use a lot of throttle, backing the plate off will definitely help you with mileage. Also, don't disable your AFC or your truck will have the ability to be quite inefficient. As mentioned above, you can get a slight gain out of a small timing advance. Adjusting your valves will also give you a small increase in efficiency. Also, make sure that you have good synthetic oil in everything like your differentials, transfer case and transmission.

Windage is the most important factor. Doing things like taking racks off when they are not being used is really important. Lifts, tall tires and wide tires are all really bad for mileage. There are some more drastic modifications with smoothing out the trucks shape (like covering over all the gaps in the body work) that you can do and there will definitely be a mileage benefit.

Rolling resistance is a smaller factor than windage but it is an easy area to improve in often. Tires are really important. Aggressive tread patterns tend to have high rolling resistance. Also, underinflated tires will be really inefficient. The final thing to do is make sure that the truck is aligned properly.

The only other thing that I can think of is putting your truck on a diet by taking any unnecessary stuff out of it. I realize that this is pretty general but you have a truck that should be relatively efficient(for a 4X4) to start with.

infidel

Much good info here http://www.everytime.cummins.com/eve...Whitepaper.pdf

pete97

Thanks for the info. What kind of mileage do you guys get?

Dartmouth 12V

I average around 21mpg running empty on B20. Most of my miles are highway and I set the cruise control on 65mph. I could probably take at least 500lb of stuff out of the truck and I might get another 1mpg. The highest I have seen is 24mpg and I consider it a really bad tank if I get below 20(unless it is winter fuel)

Towing, the worst I have gotten was 12mpg. I tend to tow high windage but fairly light(4k) trailers and usually see 16mpg or so.

What are you getting for mileage pete97?

pete97

About 16-17 around town. I put 285's on and I figured the mileage by adding 10%. I need to change the speedo gear. Plus I hardly ever fill it up completely since it costs too much!!!!!!!!!!!!!!!

DennisT

Pete, If you figured your mileage and then added 10% because of your 2.85 tires, would I add 5% with my 2.65 size tires? (Figuring you are up two sizes from stock and I'm half that).

??

Dennis

pete97

If you can find out the original tire diameter and the new tire diameter you can go to this web site www.ricksontruck.com/speedometer.html and put the info in and it will tell you how much your speedo is off. That is how I figured it was off 10%. Pete

xtoyz17

Here's a good calculator that even tells you the percentage you're low.
http://www.miata.net/garage/tirecalc.html

Pete97, you're calculating about 2% too high. If you figured 17 with the correction, you're really getting about 16.7 mpg. If you figured 16 with the correction, you're really getting about 15.71 mpg

The correction factor for Pete97 should be 1.08, and Dennis I'm assuming that the tire size you are running is 265/75/16 which would make your correction 1.039. A different sidewall height will change that though.

Shawn

pete97

Yes it is a good site. The problem I have is that the specs on the General Grabber AT's that I got say that the diameter of the tire is 33.1 with 630 revs per mile. When I used the calculator it says that for 285/75/16's that the diameter is 32.8 with revs per mile being 614. So which is correct?

xtoyz17

If it were me, I'd measure the actual tire height and go from there.

wcbcruzer

If your engine and drivetrain are working like they should, and you're driving conservatively, the other best thing I see in improving fuel economy is lightening the weight of the truck. Heavier tires will hurt mpg's. Having 4 tires that are each 20 lbs. heavier is a lot different than having 80 lbs. of load in the truck. Also, get synthetic oils.

pete97

Thanks for the info!!!!!!!!!!!!!

lobes1985

i dont know if any of you guys get diesel power but they had an article in there about a thing you can put in your fuel line and it gives you better mileage, cant remember what its called though