Fuel Mileage Question

[BowtieWrangler]

i have a 99 Dodge Ram 4x4 extend cab towing package fully loaded with the 5.9, fiberglass toneau, 33x12.5 mickey thompson baja claw radials, i tow my jeep on a trailor with my gear and altogether probally about 4000pds of weight...i got through a tank and 7/8ths going to silver lake from the detroit area, which is 242 miles so 48.75 gallons of gas which puts me at about 5miles a gallon....without the jeep/trailor its only about a half a tank difference what is the problem here ........ i kno this thing is a gas guzzler but that dont even seem logically right

i have done a complete tune up i run full synthetic oil, the thing is maintained regularly, i bought the truck from brother who only put highway miles on it for the most part it has 75k on it, he said that he had the fuel filter change which means that hole unit was swapped out, what do you guys think the deal is with it

[Toivo]

perhaps putting stock sized tires on it? I hope you are not running OD either.

[user name]

what gears do you have? i would think it sounds like you need to go to a lower gear so the engine isnt working so hard. or swap to stock tires for towing.

[Cooter]

Sounds about right for a lifted V8 towing a trailer with a heavy right foot...

[Mclovin]

Originally Posted by Cooter

Sounds about right for a lifted V8 towing a trailer with a heavy right foot...

BINGO !!!!!!

[PavementPounder]

Originally Posted by Cooter

Sounds about right for a lifted V8 towing a trailer with a heavy right foot...

My lifted V10 regeared to 5.13 with 37's does better than that when towing. I've went from Highland to Shift's and back with an XJ on an 1800ib trailer on one tank (35gal).

His stock tires are probably 265's and he's really only at 285's (33) right now. It sounds like the motor doesn't have it where you want it in the power curve. Go with some bolt-on mods and make sure you don't have any codes stored that may suggest sensor issues.

[Cooter]

He is pulling a lot more (I would have to guess the Jeep/trailer combo is more that 4K unless it is an early '5 or a flatfender) with quite a bit less torque, and I would imagine he is trying to keep up with traffic from a stop and on hills.

I can have better than a 7 MpG difference pulling a loaded trailer depending on how I drive- even the van got 12 MpG pulling the CJ6 back from St Louis, but I knew that there was no point to push it hard.

[Haggar]

My last tow rig was a 2000 Ram 2500HD, 5.9 liter, automatic, extended cab, long bed, 4x4 camper special. 4.10 gears, stock 32" tires.

My normal driving was 10 city / 12.5 highway, driving somewhat aggresive, averaging 80 mph on the highway.

Towing a 5000lb - 6000lb trailer (Jeep, tractor, or someone elses truck on a 1600-2000lb trailer), I generally got 8-9 mpg, as low at 7 in a windy rainstorm. I usually towed at 75-80 mph, because 65-70 was a bit too high rpm for 3rd and not high enough for 4th. I got rid of it at 55000 miles, it didn't really vary that much over the 4 years I had it.

My bone stock 1996 truck (same setup as the first, except 120k mile V10 and 3.55 gears) gets roughly the same mileage in all conditions.

So, I'd expect a bit of a drop with the tires, but not quite 5mpg that you seem to be getting. But I suppose its possible. Did you lift it? If so, I could see that. Esepcially if you were towing on a windy day..

[Monkeyevil]

Are you burning any oil? When the plenum gasket goes it will start to get horrid mileage.

I ususally get 12 towing in my 5.9 with a 5-speed, 3.55's and 265's. I did a test one time and ran down to the badlands in 4th gear at around 75 pulling about 6,000lbs... I got 9 mpg.

[BowtieWrangler]

no oil burning, the thing is pretty much perfect condition my brother never even took it off the road, my rpms were riding at about 3k for majority of the trip and i kno the higher rpms eat more gas but it didnt wanna really drop lower then 2800
the jeep was a yj, i did keep the pedal all the way down before the second kick on the pedal wear it would be wide open, it just seems odd that id go through that much gas, it was bad when i had the stock tires on too, the trucks not lifted still stock height, i mean im only seeing a half a tank difference between towing and not towing, i cant remember what gear it has in it right now im not gonna lie its what ever one came with the towing package im so caught up in the jeep i cant remember the stuff on the truck, as far as bolt on i have the cold air intake on it but that didnt really seem to do much for it, what other bolt ons would actually help this if nething, or would it be more worth while to hold off save some money and get me a new Ram with a MultiDisplacemnt Hemi

[PavementPounder]

Originally Posted by BowtieWrangler

or would it be more worth while to hold off save some money and get me a new Ram with a MultiDisplacemnt Hemi

Is your Ram mostly a tow vehicle? If so, I would go with the diesel.


3000rpm sounds really high to me for a highway cruising speed - especially with larger than stock tires, even though they are not much larger. How fast are you actually travelling at 3000 rpms when the trans is done doing all its shifting? Is your torque converter perhaps not locking up in 4th gear?

[Renegade II]

Originally Posted by BowtieWrangler

........................ or would it be more worth while to hold off save some money and get me a new Ram with a MultiDisplacemnt Hemi

If it's going to be mostly for towing, Diesel is the way to fly. 14.2 MPG on my last trip to Silver Lake. With the Jeep on the trailer and both vehicles loaded full of gear. @55MPH

[Haggar]

Is it a 1/2 ton or a 3/4 ton truck?

It sounds like you are towing with overdrive off and a decent speed.

Hmm, did you happen to recalibrate the speedometer with the new tires?

If you go buy a hemi, you'll still be getting less than 10 mpg towing a 5500 lb trailer, which is more close to what your YJ/trailer really weigh.

[roll-bar Bob]

Originally Posted by Renegade II

If it's going to be mostly for towing, Diesel is the way to fly. 14.2 MPG on my last trip to Silver Lake. With the Jeep on the trailer and both vehicles loaded full of gear. @55MPH

SELL IT DIESEL IS THE WAY TO GO TOW RIGS ARE FOR THE ROAD LEAVE THEM STOCK THEY WILL LAST LONGER

[PavementPounder]

Originally Posted by roll-bar Bob

TOW RIGS ARE FOR THE ROAD LEAVE THEM STOCK THEY WILL LAST LONGER

I would have to disagree with that. Racinja has some footage of me driving the fenceline at the Mounds yesterday. After I was done, the wheel was closer to center than before (worn track bar bushing) and the speedo started working again (loose wheel speed sensor wire). To celebrate, I dragged my trailer all over Oakland county for no reason last night. :tonka:


But I guess its true 99% of the time.

[Haggar]

Originally Posted by roll-bar Bob

SELL IT DIESEL IS THE WAY TO GO TOW RIGS ARE FOR THE ROAD LEAVE THEM STOCK THEY WILL LAST LONGER

You want him to spend $40k on a new truck and yet you are too cheap to spend $200 on a front axle or 5 cents for a caps lock key?

[nixxerRsixxer]

Originally Posted by PavementPounder

My lifted V10 regeared to 5.13 with 37's does better than that when towing. I've went from Highland to Shift's and back with an XJ on an 1800ib trailer on one tank (35gal).

His stock tires are probably 265's and he's really only at 285's (33) right now. It sounds like the motor doesn't have it where you want it in the power curve. Go with some bolt-on mods and make sure you don't have any codes stored that may suggest sensor issues.

you do know that 265 and 285 is the width right? it is feasible to have a 265 and 285 the same height.. the aspect ratio and wheel diameter determine over all height.


and yeah 5mpg sounds like you are towing with 3.55s and going 80mph..

[nixxerRsixxer]

Originally Posted by Haggar

Is it a 1/2 ton or a 3/4 ton truck?

It sounds like you are towing with overdrive off and a decent speed.

Hmm, did you happen to recalibrate the speedometer with the new tires?

If you go buy a hemi, you'll still be getting less than 10 mpg towing a 5500 lb trailer, which is more close to what your YJ/trailer really weigh.

really because i got 14mpg on the way back with general lees jeep from detroit going 70ish

[roll-bar Bob]

Originally Posted by Haggar

You want him to spend $40k on a new truck and yet you are too cheap to spend $200 on a front axle or 5 cents for a caps lock key?

32K OUT THE DOOR WITH 6 MILES ON IT ( AS FOR THE CAPS ) AND AS FOR THE TOO CHEEP TO SPEND $2OO ON A FRONT AXLE THAT IS ONLY WORTH $100 YES I GUESS I AM

[PavementPounder]

Originally Posted by nyxis

you do know that 265 and 285 is the width right? it is feasible to have a 265 and 285 the same height.. the aspect ratio and wheel diameter determine over all height.

I know how to do tire math. Have you ever even seen a 285/70 tire? Go Google that size and see what you come up with. Probably a scattering across a couple manufacturers in the 17 or 18" diameter. We're talking BR's, which come with 16" rims. I've run many different sizes on my truck, to include 245, 265, 285, 315, 35's - all with 4.10's, and 37's with 5.13's. The OD's on the powertrains aren't much different and he's spinning way higher than I ever did when I was towing with 4.10s in his size range. 285/75's are the closest comparison to his 33's that I could speak to from experience. I can't even find a 285/70 in a 16" rim at first glance. BFG doesn't even make them.