Diesel Tow Rig Fuel Economy

[Travis Waldher]

ok.. mines a DD too. with the cost of gas going where it is and my truck requiring Super to even run. (yes.. I've tried less with bad results) I'm even considering going 1 ton diesel. Preferably Dodge, but Ford would be considered as well.

Can you list your empty highway driving mpg? engine type and any mods that helped improve it?

My truck (Gas 5.9L) is getting 18mpg, hopefully 19mpg soon. Need to know if Diesel fuel economy is that much better.

(#2 reason for upgrading would be increased towing capacity)

[DRM]

I feel sorry you even asked... You are about to get a list of "about" and "close to" mpg numbers that will be all over the place from 8mpg to 26 mpg.

Fact is - *most* people are just guessing about their mpg numbers.

Some have kept logs though - and THOSE are the people you should listen to


Here is one - these are logs running loaded AND unloaded, and some pretty impresive numbers based on the loads he told me he was pulling the majority of the time used:
http://www.4x4spot.com/dodge.htm


Good luck

[Oxjockey]

I get about 17 on summer fuel.

And I have a log of every drop of fuel I've put in the vehicle, including every receipt.

Keep in mind, 4x4 adds quite a bit of weight. My truck tips the scales at 6800lb. Edit: 3.73 gears, Cummins HO, got the EZ upgrade.

When I had the 5.9L gas, I had the same problem with using premium. Makes the diesel even cheaper.

Bryan

[DRM]

Originally posted by Travis Waldher
My truck (Gas 5.9L) is getting 18mpg, hopefully 19mpg soon. Need to know if Diesel fuel economy is that much better.

That is pretty good mpg for a gasser... and you will be hard pressed to beat that by more than 1 mpg. on a Cummins if you are LUCKY.

So assume 20 mpg on a cummins unloaded (many are between 18-20 unloaded from what I have seen).

Calculate how many miles you drive per year, figure in the cost of the premium gas and diesel in your area, and come up with a comparison figure.

Don't forget to figure in any loss in selling your current vehicle, as well as additional costs for the diesel vehicle if you want a more accurate comparison

[thump93yj]

DRM nailed it... most are full of it on their MPG claims... especially when folks compare xbrand diesel to ybrand diesel... everyone likes to brag.

I downloaded a simplified verstion of my spreadsheet down to a text file HERE . I'm a bit anal on my mileage records... oh well.

My truck is an '01 CTD 2500 4x4 LB Qcab, automatic, K&N filter is the only engine mod. Don't travel much on the highway without a trailer in tow so... I can't really give you accurate Hwy mpg... mine's mostly in town (Fort Worth/Dallas). Has gone from 15(new) to 17+(92K miles)

[CSP]

Like Ox, I've kept track of mileage on every fill up. I consistently get 17-18 with a '97 Powerstroke. This is about 50-50 stoplight and highway driving.

I was shocked to see you're getting 18 with a gasser. My last gasser (89 Bronco w/351) got 11 on a good day.

[Camp]

I have an '02 Duramax long bed regular cab 4x4. I have upped the tire size to a 25585R16 to bring the RPM down a little at hwy speed. I drive my truck 94 miles a day back and forth to work. Sorry DRM, I don't have a log, just calculate milage at every fill-up and don't write it down. On stock tires unloaded, I was getting 20 mpg on average. With the new tires and a 4" exhaust, I am getting as good as 24 mpg and as bad as 19 mpg, depending on how hard I am on the skinny pedal and how bad Denver traffic is that week. Pulling about 8000 lbs. over hwy 70 to Moab on stock tires, I got 16 mpg. On the new tires, I have not run to Moab but, pulled to an area outside of Colorado Springs and got 17 with about the same load.

Like I said, sorry, I don't catalog my milage so, no pretty spread sheets to give you. These are the numbers that my calculator tell me at each fill-up.

[Oxjockey]

Originally posted by Camp
With the new tires and a 4" exhaust, I am getting as good as 24 mpg and as bad as 19 mpg, depending

Did you change your speedo gear after you changed tire sizes?

Bryan

[Camp]

Originally posted by Oxjockey


Did you change your speedo gear after you changed tire sizes?

Bryan

No, I didn't for other reasons but, I did calculate the correction factor so that I can figure out proper fuel economy. I like the idea of the GM dealer not paying full attention to my slightly larger tire and my warranty lasting just a little longer

[Camp]

Oh yea, I guess I could mention that this year pulling to Moab I was on stock tires and we ran hard. Most of the pull I was above 90mph (campaign for a darwin award) and only got 11 mpg. We were running late so, we were hammer down. Not so good for fuel economy Also, I think I get better milage than most Duramax owners because my truck is the ever elusive 6-speed manual. There are very few of them out there

[Travis Waldher]

Originally posted by CSP
Like Ox, I've kept track of mileage on every fill up. I consistently get 17-18 with a '97 Powerstroke. This is about 50-50 stoplight and highway driving.

I was shocked to see you're getting 18 with a gasser. My last gasser (89 Bronco w/351) got 11 on a good day.

Starting to sound like, going Diesel would just be a gamble. Specially considering my truck will be payed off early 2005. I don't particularly like the idea of being stuck in payments for another 5 years.

Should note my truck has OD, 3.92 gears and 265/75R16 tires. 70mph is just under 2,000rpms.

Up until a few weeks ago, the truck consistently pulled 16mpg(+/- .4)@60mph driving 120 miles a day. No.. don't track it in a spreadsheet, but I do the math at every fillup. Every fillup is at the same gas station.

Couple weeks ago the catalytic converter fell apart (again), so I put in an aftermarket high-flow cat with a 3" pipe coming out the back. (my truck has a dual inlet on the cat from each head, about a 1.5"? pipe on each side going in).

That pushed me up to 17.8mpg (+/- .3 so far), my muffler is coming apart inside, probably partically plugged and that (after the radiator) is getting replaced. So far I've driven 1,000 or so miles and the number is pretty consistant.

Muffler shop advertises a highflow 3" exhaust that supposedly can get me another 9% or up to 19.4mpg. If there is any truth to their claims, I'm thinking I might realistically get close to 19mpg.

Beyond that.. my truck is running really warm mostly at freeway speeds, due to dead radiator. I'm hoping.. there's a small gain after I replace that. (hotter engine, less power, more gas to do same work)

If going diesel doesn't make sense, squeezing every once of fuel economy out of my truck within reason certainly seems to. (and yes.. I've already adjusted my driving style.)

[DRM]

BTW Travis - what IS your DD anyway? Specs?


Those gasser mpg numbers sure make me jealous

[Travis Waldher]

Originally posted by DRM
BTW Travis - what IS your DD anyway? Specs?


Those gasser mpg numbers sure make me jealous

1996 Dodge Ram 1500 4x4 extended cab short bed
5.9L 360 V8
Auto w/ OD
3.92 Gears, limited slip rear
265/75R15 tires (typically at 40-45psi)
125,500 miles on odometer

Mods:
Drop in K&N Air filter (oh yeah.. I should prolly clean that out)
high flow catalytic Converter. (3" exhaust, but factory muffler)
#2,500 overload springs
RS9000 shocks

Peak fuel economy on the truck seems to be at about 70mph. (figures speed limits here are 60 LOL), it slowly drops off from about 75-85, then really drops off from 90mph up. I'm guessing aerodynamics become more of an issue.

Plus.. anymore, I don't accelerate fast anymore. Most of that I got was from modifying my driving style.

In town, the fuel economy still kinda sucks, between 11-13mpg.

[DRM]

I am confident that a modification in driving style could get my Ford V10 up to around 14 mpg without much trouble. I drive 75-80, and that puts me well over 2k rpm, and that kills mpg on these V10's in a hurry. I also accelerate and pass a lot - not helping there either.

[tators]

[i]Originally posted by Camp [ I like the idea of the GM dealer not paying full attention to my slightly larger tire and my warranty lasting just a little longer [/B]

We call that the

"Super Swamper Extended Warranty Program"

[TEX]

My father-in-law has a '97 F250 4x4, reg-cab, Powerstroke, Auto trans, 235/85R16 tires, and ??? on the axle ratio. He drives ~40 miles each way to work, mostly Interstate. Runs it pretty hard, but empty most of the time. Says he gets ~18 like that. It's pretty much been that way since new, no better, no worse.

TEX

[jp junkie]

98 CTD, 12v, 4x4, 3500, 5 speed, average 16.2mpg combined.

[injectedEB]

'02 F250 7.3L Crewcab, short bed, 4x4, 6 speed, 3.73 gears, no mods (for now) - daily commute at 75-80mph for ~40miles each way I have an average of 17.4mpg over 6250 miles. (bought it used with ~44k on the engine.)
Ran a trip to NM and back keeping it below 2k rpm and had an average of 21mpg.
A friend with an identical F250, plus some engine/performance mods did the same trip with me and averaged 24.3mpg. His mods are a custom chip from ATS, 4" exhaust, ATS turbo shroud, HX cross over, 203 thermostat, and pre-fuel pump mods and regulator. His in town average is 21.5mpg.

I know of at least one 4x2 F350 supercab short bed that is averaging 26mpg unloaded - but he drives with a string on his toe and never goes over 2krpms.

both of us fully track our fuel and mileage and also have excel spreadsheets tracking it...

I haven't done enough towing with mine yet to make a call of mpg when loaded.

BTW - a 1500/150 should get quite a bit better mileage than a 2500/250-3500/350 as they are quite a bit lighter. The frames alone on the 3/4 and 1 tons are about twice as heavy, not to mention the different running gear.

[DRM]

InjectedEB - could I get a copy of that spreadsheet for both vehicles, along with some basic vehicle info and pics? I would LOVE to add that kind of info to my little page on mpg logs to get real world info out there for people to compare

[Travis Waldher]

Originally posted by DRM
InjectedEB - could I get a copy of that spreadsheet for both vehicles, along with some basic vehicle info and pics? I would LOVE to add that kind of info to my little page on mpg logs to get real world info out there for people to compare

same here... I'de like to see it if yuo dont' mind. twaldher@comcast.net

[Haole]

I get consistantly (No DRM, I stopped keeping a log.) 15 mpg if I drive 65 mph, and 13 mpg if I drive 75 mph.

I have a 2003 7.3L PSD CC Dually.

Alot of people tell me my mileage should go up once it's broke in. I'm just wondering when it's going to happen. (Just under 15k on the odometer.)

[Haole]

Originally posted by tators



We call that the

"Super Swamper Extended Warranty Program"

My heep is dealer installed. Bought with 33's and went to 35's.

Thinking about doing the same on the SD. Only with 19.5" rims and appropriate tires. Load range G instead of E.

[Travis Waldher]

Originally posted by eurobob
I get consistantly (No DRM, I stopped keeping a log.) 15 mpg if I drive 65 mph, and 13 mpg if I drive 75 mph.

I have a 2003 7.3L PSD CC Dually.

Alot of people tell me my mileage should go up once it's broke in. I'm just wondering when it's going to happen. (Just under 15k on the odometer.)

on the cummins at least, I hear around 50k.

[gunracer1]

i get 16 to 18 running empty mostly highway driving. i have hit 20 once but that was a tank that i never went over 65mph. i have big injectors, #10 fuel plate huge airfilter [hate k&n's] 5" exhaust and i have bumped the timing. the #s you are getting with your truck are great, you should be pleased. i have right at 400 hp and 1k torque right now and if i could quite playing with it i would get better miliage. but i just bought a new turbo so with some fuel plate mods, i should be in the 500hp range. o yea my truck has 219k on it right now. mike

[Coreyperez13]

I've got a 2002 Dodge long bed, xtd cab 4x4 3/4 ton with the 5.9ltr in-line 6, 6sp (HO). I get 16.?? in town, usually flogging it. My neighbor gets around 21 running 75mph with a nearly identical truck, but his is the 03 short bed SRW 1 ton. His is nearly all highway miles. Both of our trucks are stock, but mine will get a chip someday soon (I hope), and fuel economy seems to increase a few miles per gallon with a mild chip. I can send you my fuel log if your really interested, and it should prove that I'm not "Blowing smoke".

Corey