how to imprve mpg on an 04

[ScottK]

MPG

I doubt anyone is going to go from 13 to 21 mpg... . just ain't gonna happen. With 2000 miles on my 04 I could squeeze 20+ at 70 mph... .



This can and will happen. Check all you air intake hose clamps, to and from intercooler. I check these at each oil change. I went from 15 to 19 mpg, not as much as listed above. (this was w/ my Y2K)



Also, I now believe that you must work your truck!!!!

I watched this site for 3 years, they all said to pull it hard. My first two trucks was poor to moderate.

My '03, I gave it @ 500 miles of easy driven', then I hauled a bob cat and Lake Erie boat (27 ft) around for only (approx) 200 miles.

Power and milage jumped, I get 18-19 w/ a heavy foot(M/T)

Loaded it is @ 14 mpg, but after I run run it loaded for 50 to 200 miles, the next few tanks get great miliage (21+)



Just my 2 cents



Scott

 

[draymorris]

GSatler

I installed a tornado in my 01. It was cracked in about 6k miles, the crack was at the base of one of the fins. Watch it, if a piece comes off... . ?!!!?? Besides, I saw no improvement in MPG and the thing was also eating into the vibration joint.



As for my input on the MPG discussions, the overall summary seems to be that these trucks vary, A LOT, from driver to driver. It seems that some people say they get mid to upper 20's, that is almost unbelievable, but I am not calling anyone a liar. But, are those figures calculated or do they come from the overhead console. How critical is the fill up point on the tank - I can keep topping mine off and add another gallon to the fill - this will change the MPG calcs drastically. When running test on machinery, one needs to remove as many variables as possible, - that is sometimes hard to do.



As for my truck, it hung around 13. 7 for about 40k miles, then I decided to put synthetic(Amsoil) in everything front to rear, except the power steering. I saw as much as 3 mpg better, at times. Since then I have put in a TAG, and have seen an improvement in moderately loaded average MPG. The easiest MPG increase has been using a cetane booster fuel additive - again I have seen a 2-3 mpg increase with a moderate load. So far I have been able to get a max of 17. 6 with the cetane booster. Without it, mid 15's to mid 16's. I beleive that air flow mods are the best mods and some chips help also. But remember some of the mods are synergistic.



As far as driving hard to break it in - I hauls 4 loads that grossed at around 37k 2 days after I bought mine, within a month hauled similar loads hundreds of miles and drive it pretty hard - you really cannot drive loads that heavy without gettin on it. My mileage at 13. 7 was not very good for a Cummins IMO.



I wish TDR would make a MPG page to record all the relevant facts and MPG on each member who wished to participate. Making the page where you could sort by model, year, etc. so that we could compare apples to apples a much as possible.

 

[SSnider]

Originally posted by draymorris

GSatler

I installed a tornado in my 01. It was cracked in about 6k miles, the crack was at the base of one of the fins. Watch it, if a piece comes off... . ?!!!?? Besides, I saw no improvement in MPG and the thing was also eating into the vibration joint.



As for my input on the MPG discussions, the overall summary seems to be that these trucks vary, A LOT, from driver to driver. It seems that some people say they get mid to upper 20's, that is almost unbelievable, but I am not calling anyone a liar. But, are those figures calculated or do they come from the overhead console. How critical is the fill up point on the tank - I can keep topping mine off and add another gallon to the fill - this will change the MPG calcs drastically. When running test on machinery, one needs to remove as many variables as possible, - that is sometimes hard to do.



As for my truck, it hung around 13. 7 for about 40k miles, then I decided to put synthetic(Amsoil) in everything front to rear, except the power steering. I saw as much as 3 mpg better, at times. Since then I have put in a TAG, and have seen an improvement in moderately loaded average MPG. The easiest MPG increase has been using a cetane booster fuel additive - again I have seen a 2-3 mpg increase with a moderate load. So far I have been able to get a max of 17. 6 with the cetane booster. Without it, mid 15's to mid 16's. I beleive that air flow mods are the best mods and some chips help also. But remember some of the mods are synergistic.



As far as driving hard to break it in - I hauls 4 loads that grossed at around 37k 2 days after I bought mine, within a month hauled similar loads hundreds of miles and drive it pretty hard - you really cannot drive loads that heavy without gettin on it. My mileage at 13. 7 was not very good for a Cummins IMO.



I wish TDR would make a MPG page to record all the relevant facts and MPG on each member who wished to participate. Making the page where you could sort by model, year, etc. so that we could compare apples to apples a much as possible.

 

[SSnider]

I went 150 miles today all highway and used almost 8 gallons.

This is the best mpg I have gotten (19) up from 15 . I don't know why it went up . I will check it again later. almost 5 k on the truck. I will post mpg again later .



Steve

 

[R.M.THOMPSON]

Whats your avg. speed(miles/hours) . Just for conversation sake!

 

[SSnider]

sorry guys, I was driving between 60-70 most of the time . When I started the post I was getting around 14 highway. So it really improved over the last 2k . I tried to fill tank the same before and after the trip but with all the foam it can be hard to judge. Even if it was off a little it would have at least been 18 mpg. which I would be happy with.



Steve

 

[Blufrog]

I have about 8k on the truck and when it was new I was getting about 16 pretty steady, even watching the overhead gauge. I have been jackrabbiting off the line more and really getting into the truck after hanging around this board. Yesterday took a fairly long trip hwy @ 60mph and got just over 20mpg but that is going by the trip gauge on the overhead, but I also noticed I have 200 miles on the trip meter and the fuel gauge is only down 3/8th as apposed to the half tank mark which is where it used to hit at 200 miles on the meter. So guessing at having a 1/8th tank more than usual the fuel milage has gone up somewhat. Can I trust the gauge in the overhead, probably not, but the fuel gauge is higher than normal. When watching the overhead and calculating milage when getting fuel (total miles/gallons) it was always within 1mpg difference than what the overhead said I got on average so I would guess it is pretty close to 20mpg now.



So like these guys say, drive it like you stole it and it helps! It's working for me.

 

[XcumminsX]

im gettin 13. 2 mpg 80% city driving w/ 4. 10 gears 35's and the 48re. Sound normal?

 

[Blufrog]

I have 4. 10 gears with stock tires on it and 48RE myself. My old 98. 5 got that for milage and that is why I traded it in on the newer one. could be the oversized tires on your rig that are hurting you, plus did you recalobrate the speedo to make sure it is correct? I don't know if they recalobrate on thier own after installing larger tires? That might be something to look into as you could be going further than the speedo tells you.

 

[SSnider]

xcumminsx.

I think that sound right for gettin into it around the city. That is what I get in the city with 3. 73 rear.

Steve

 

[sfr1047]

MPG

I just got through my third tank full on my 04 3500 6 speed. Went 726 miles and put in 40. 6 gallons. The overhead said 17. 3 mpg. I took along a 5 gal can just in case I ran out. That works out to 17. 88 mpg. It was half city ,half freeway. The tank before when my fuel light came on I put in 34. 5 gallons so I wanted to see just how much it would hold.

 

[R.M.THOMPSON]

Whats your avg. mph,we have to start there to know/find the rest of the equation !!!