Engine/Transmission (1994 - 1998) average mpg?

[PSInt]

Mileage

I wish it were that easy... I've relpaced my calipers three times (thanks to Autozone and their lifetime warranty ), and changed to the 1 ton wheel cylinders. Didn't affect the mileage though. If the timing doesn't help it, I'm buying a VW diesel... They get about 50 mpg on the highway... . Problem with that is, they don't make noise and they don't smoke... .

 

[Ahopper]

now i do not for sure know what the prob is with my truck on wendesday i took a 210mile trip to mexico and on the way down i figured out how off my spedo was with my gps. my miles are off by 8%. so i figured that was why my milage was so low because i really wasnt calculating it right but NO! i filled up and i got 13. 2 mpg. that was with the cruise set at 70 (really 75 acording to my gps). my rpm was 1950 my temp was 800-900egt and my boost never went below 10psi. i changed filters on the way between my K&N and my stocker. no difference. im in mexico right now and im going to fill up on mexico diesil ( its only 2. 10 a gallon!! i wish i had a auxilary fuel tank:-laf )

 

[LarryWard]

When shop rotated tires recently I noticed the fronts do not spin freely. How freely should 4x4s front wheels manually rotate when fronts are disengaged?



Do the calipers have need of some routine freeing up? Larry

 

[CumminsPower98]

When shop rotated tires recently I noticed the fronts do not spin freely. How freely should 4x4s front wheels manually rotate when fronts are disengaged?



Do the calipers have need of some routine freeing up? Larry

They should spin freely. Remove the calipers and clean and lube all the pins. Also take a wire brush and emery cloth to the eds of the calipers and the abutments on the steering knuckles. If this doesn't help then the pistons could be sticky and you may need to replace the calipers. This probably won't affect mileage much but will surly have some affect on brake pad life.

 

[PSInt]

Running down the wrong road....

Any brake caliper that's dragging enough to affect the fuel mileage will be smoking and the rotor will be a nice shade of blue. I'm thinking that a dragging brake can be ruled out as much of fuel mileage issue.

 

[VVielmas]

my 02 2500 4x4 long bed with 4"exhaust(planing to get 6" dual stacks)with about 154,000 miles with kn cai,and my truck has 245/75 r16 (had 285/75) now im getting around 19-22 mpg. at 65 mph do you used a fuel treatment like lucas you might want to changed your fuel filter every 30,000 miles that will help you get better mpg.

 

[PSInt]

??

I'm having a hard time understanding how changing your fuel filter more often can affect your mileage...

 

[MMcCallie]

I had hoped that once the truck was rolling at a consistent speed, that the Cummins wouldn't care how much weight it was moving, that it would just humm along at a low RPM and get great fuel economy. On my last long distance trip, my EGTs floated 600-800, and boost down into high single digits, up to low teens. I had heard that 600 is the best EGT for fuel economy. I hope 15 mpg is not as good as it will get. Anyone have suggestions?

Will a bigger turbo bring in more air at cruising RPMs so that fuel economy will increase? I had figured taller tires would lower RPMs at speed and burn less fuel but it looks like those who are getting better highway economy run shorter tires and slightly higher RPMs. What is the most efficient RPM for the Cummins? If i add a GSK could my fuel economy increase?

 

[EKlem]

I had hoped that once the truck was rolling at a consistent speed, that the Cummins wouldn't care how much weight it was moving, that it would just humm along at a low RPM and get great fuel economy. On my last long distance trip, my EGTs floated 600-800, and boost down into high single digits, up to low teens. I had heard that 600 is the best EGT for fuel economy. I hope 15 mpg is not as good as it will get. Anyone have suggestions?



Will a bigger turbo bring in more air at cruising RPMs so that fuel economy will increase? I had figured taller tires would lower RPMs at speed and burn less fuel but it looks like those who are getting better highway economy run shorter tires and slightly higher RPMs. What is the most efficient RPM for the Cummins? If i add a GSK could my fuel economy increase?

Getting good fuel economy is a challenge between running the right rpms and keeping rolling resistance and wind resistance down. Some people run taller tires to change their effective final gearing to improve their rpms. The problem with this is that the tires have a much larger rotational inertia and tend to have more rolling resistance so you don't get much benefit and can even make your economy worse if you go to really big tires.



RPM's are important to fuel economy so they are something worth thinking about. If you turn more rpms then necessary, you are not being efficient but also, lugging your engine is not efficient and a lot of people do this. Cummins published a graph for our engines of power output per unit of fuel versus rpm and the most efficient rpm was at torque peak(1800). This is for wide open throttle though so 1800 is not always the best speed to turn your engine. When you don't need any power, idle is the most efficient rpm and basically all other amounts of power call for an rpm somewhere in between.



As for fueling, a gsk and a fuel plate will not affect economy as long as you don't actually take advantage of the extra rpms and fuel that you can use.



Here are my recommendations for getting good economy: Don't drive fast since wind resistance is proportional to the square of velocity(not to mention, your rpms will be lower). Don't accelerate hard(F=ma). Try to anticipate lights and downhills so that you don't have to use the brakes. Don't lift your truck or run huge tires. Make sure that your brakes aren't dragging, your tires are aired up, and that your bearings are good. Run synthetics.



Sorry for the long post. My recommendations are based on competing for efficiency in a ford ranger that I converted to be electric. If you ever drive an electric vehicle, they really teach you how to drive efficiently.

 

[MMcCallie]

EKlem,
Thanks for the stats. Sounds like the less the engine has to work, the better the fuel economy should be. How many mpg does your Cummins get? What do you think a 10,000 lb SUV with no lift, 35" tires, 3. 73 gears, 15. 5 degrees of timing, a 215 pump and DDP3 injectors should get on the highway?
Thanks,
Matt

 

[EKlem]

I have seen as high as 24 mpg on my truck in highway driving. I generally use 20% biodiesel in my fuel which probably has some effect on mileage but I have not measured it. Unfortunately the mileage numbers on my dodge are hard to interpret due to having a trailer or a lot of kayaks on the roof almost every single tank of fuel.



MMcCallie, with your setup, I see no reason why you shouldn't be getting 18 mpg on the highway instead of 15. Mileage is a hard thing to compare though because it is so terrain dependant, weather dependant and driver dependant. I also don't know how efficient a 4R100 is, all of my experience is with manuals.

 

[Ahopper]

What gives?

i got back from my trip today. got 19. 5 mpg on the way home? the only things that were different were the mexican non ulsd and i had the k&n in the whole trip home insted of on the way there i switched it out to the paper one 60 miles into it (206 total one way). it makes no sence to me? while i was ther i took off my rf tire and took off the caliper and greased the pins because it seemed to drag a bit. but on the way home it still got hot enogh for it to be over boiling point(sprayed water on it). the terain was compleatly flat going from sea level to 1000 feet. i fueled up on ulsd and we will see if that is the culprit.



also does anyone know how to fix a draging caliper? is there anyway you can clean them to fix them? i bled the line and got alot on junk at first to come out? any sugestions would be great thanks alot for all the input so far.

 

[MMcCallie]

On my 15 mpg trip i drove through very heavy rains and strong winds the entire tank. I use a switch to lockup the torque converter solid so there is no slippage. The truck was loaded inside with a few hundred pounds worth of parts but i didn't think that would make much difference. I'll soon be starting another tank and will have mostly city stop and go mileage to report, possibly next weekend.

 

[DonTX]

Say EKlem, my brother also drives an electric Ford Ranger, email me if you would like contact.

 

[Dr.Bob]

eklem, is yours 2 wheel?

 

[Dr.Bob]

I'm begining to think it's all fuel related. I get between 15 and 20, should not very that much. I asked a local fuel hauler what the cetane of his fuel was and he said 40. Every spring I seem to get better mileage fore a few weeks I think it's because they are putting better grade fuel in the tanks to get rid of winter blend, then it goes back down.

 

[Grizzly]

All my highway miles have been with the Lance camper in my signature and the average mileage was 14. 5 mpg.

 

[EKlem]

I'm begining to think it's all fuel related. I get between 15 and 20, should not very that much. I asked a local fuel hauler what the cetane of his fuel was and he said 40. Every spring I seem to get better mileage fore a few weeks I think it's because they are putting better grade fuel in the tanks to get rid of winter blend, then it goes back down.

I have often wondered the same thing as you. As I said earlier I have seen as high as 24 but I have also seen as low as 19 in what I would think should be identical conditions(wind, terrain, temp, speed, etc). I don't get as much variability in the electrics which really makes me wonder what is going on. It is really nice though on those tanks when that fuel gauge just seems to be taking forever to drop.



Dr. Bob, my truck is a four wheel drive. I took the 4 wheel drive out of the ranger and it did make a difference.

 

[McLaughlin]

I typically get 17 - 19 highway in the summer and 15-16 in town. The last two winters though I only got 12 - 13 in town and I don't idle for long (a minute or so at most).



I saw a report by Cummins that basically said there will be a fuel mileage loss in the winter. I don't remember the figures but the number 10% comes to mind.



I think I have a problem other then just the fuel changing between summer and winter but haven't been able to get a handle on it yet; however, I think it is related to excess fuel when the engine and outside air temps are cold.





It may be that my truck really doesn't like winter weather.

 

[arthr31]

True, there is about 10% fuel efficiency loss with winter blend diesel. I typically see 2-3 MPG less during the winter months. Winter seems I get 18-19 MPG no matter the driving or how I drive. In Summer I get 20-22 MPG.



Now... two weeks ago I got my first tank of ULSD. It seems to be performing the same as winter blend, 18MPG, but I'm concerned if it will be the same in the Summer. I really like the 4-5 months that I get around 22MPG!