What is realistic diesel daily driver MPG?

[joelsplace]

I didn't read all 8 pages so sorry if this is a repeat.
The 80s 460 was seriously detuned from the factory. You might be happy with just a proper advance curve in the distributor lots of power and mileage to be had correcting it and no loss of reliability. They also had retarded cam timing but you have to replace the timing chain set to fix that. Doing both should help enough to make your happy with it. I doubt it will ever get 20mpg but I could see 15. You can buy a lot of fuel with the money you save not buying a diesel truck.
Google will help with the changes to the engine.

[dix39]

Originally Posted by OlJB

How much will you be towing your TT? If you are looking at towing in on weekends during the summer, maybe a 2 week vacation, then buy a 3/4 gasser. It will cost you less in fuel and maintenance. If you are comparing vehicles of the same model year, most gassers get better mileage than comparable diesels when not towing. Diesels get better mileage when towing. So, it really depends on how much you will be towing.
A half ton truck will either be overloaded or very near maximum payload, if your TT is 7000 lb loaded. That's why you should buy a 3/4 ton.

Very good points, IMHO.

There is also the consideration that diesel fuel is now generally more expensive than gasoline, and that the newer diesels require DEF which should be added to the fuel cost.

That being said, we had diesel pickups for hauling our 11.5' camper while towing our 23'cabin boat, all sorts of trailers, etc. The first I built in '81 and drove until we bought a '89 Dodge Cummins in '93 that we used until just a few years ago. I also used both trucks as daily drivers to work, about a 15 mile round trip.

Both trucks worked out to a 5 speed manual with 20% OD in 5th and 3.54 diff gearing, and were 4wd with manual hubs. Gearing is very important in achieving the best mileage possible at projected sustained top speeds. For us that was about 70 mph.

Over more than 300k miles and 35 years both trucks got 21-23 mpg empty, 15-16 with just the camper, and generally 1-2 mpg less when towing. One really heavy trailer took mileage down to 10.

After having MH,s for the last few years I'm currently looking for a single cab '94-98 Dodge Cummins with 4wd, manual trans, 3.54 diffs, and another 11.5' camper.

Steve

[Danj2001]

I don't think you are very knowledgeable about the engine or the issues regarding it. Do some research and see what the issues were and why they occurred. Virtually all of the issues resulted from owner neglect. Your input is 'interesting' but not credible.

[Jshopes81]

Originally Posted by Danj2001

I don't think you are very knowledgeable about the engine or the issues regarding it. Do some research and see what the issues were and why they occurred. Virtually all of the issues resulted from owner neglect. Your input is 'interesting' but not credible.

Whats that? I guess sarcasm doesnt always come across well in writing. Some jokers on here will tell you what a huge pile of crap the 6.0 is regardless of if theyve ever experienced one or not.

[Zoomschwortz]

Originally Posted by joelsplace

I didn't read all 8 pages so sorry if this is a repeat.
The 80s 460 was seriously detuned from the factory. You might be happy with just a proper advance curve in the distributor lots of power and mileage to be had correcting it and no loss of reliability. They also had retarded cam timing but you have to replace the timing chain set to fix that. Doing both should help enough to make your happy with it. I doubt it will ever get 20mpg but I could see 15. You can buy a lot of fuel with the money you save not buying a diesel truck.
Google will help with the changes to the engine.

Thank you for your input.

There is a person that specializes in high performance big block Fords within 30 minutes of where I live. On high performance Ford websites he is known a Scotty the Mad Porter and he can definitely make a bunch more hp/tq for my engine, but it comes at a cost,

My 88 was the first year of efi 460ci which has some 1st year issues that stand in the way of performance. The pistons sit lower in the block, killing quench, the heads have the smallest ports and valves that efi 460 came with, exhaust is restrictive, the computer doesn’t allow much in the way of performance changes.

I forget the exact hp/tq numbers to be gained (somewhere around 100hp 80tq) with new heads, ported intake, new cam and lifters, new Banks exhaust and the cost would be around $5k.

I’m pretty sure that after modifying the engine in this way, I would be happy with the power, but, unfortunately the engine is still connected to the very strong, but due to non lockup tq converter, very slippery C6 transmission that will not allow the mpg that newer transmissions give.

No doubt that trimming the air horn and bumping the timing will give some power gains and both are free.

I have done the 429ci timing chain swap on a carbureted 1976 460ci and it made a difference. Interesting item, my former 1976 F250 Camper Special w/460ci, C6, some kind of Milage Master intake and Carter 625 carb made more power than my 88 and with a heavy 70’s 11.5 foot camper, pulling a car trailer, 4 seater sand rail, spare engine, spare transaxle, full roll away tool box, around 50 gallons of av gas. I was 2500 lbs overweight on my rear axle and got 12.5 mpg.

I would be thrilled if my 88 could match the power and mpg of my 76, but sadly my 88 has never made the mpg running empty that my 76 did carrying a large heavy camper, car trailer while being 2500lbs overweight (loved my Hellwig overload springs), I cracked a wheel at the valve stem on that trip.

[BlueRoad]

Originally Posted by Zoomschwortz

I am weighing the pros and cons of selling 3 of my vehicles and buying a diesel pickup that would be used as my daily driver and for pulling up to 7,000 lb travel trailer.

What mpg are you getting with your diesel pickup when used as a daily driver?

1) what truck do you have?
2j 4x4 or 4x2?
3) Stick or automatic?

Thank you for your time and information.
Ken

If it doesn't have to be NEW, we loved our 1998 5.9 Cummins 8 foot bed auto 4 x 4 (why not have a 4 x 4)

We averaged 20+ mpg in combined driving and usually hit 24+ on the freeway.

But it was not new with all the goodies and it definitely did NOT have DEF..

[n7mog]

1999 Dodge 2500 Cummins
5 Spd manual
3.54 rearend
4x4 drivetrain
20.7 MPG empty and with a smaller load.

[calinb]

2016 Ram 2500 Cummins Big Horn. 4WD/68RFE automatic

Max.: 22 mpg empty at very steady 50 mph highway.
Min: 9 mpg with truck camper and flat towing a Honda CRV at 80+ mph on Interstate. (Unlike the barn door truck camper, the CRV barely reduces the mileage when added behind the camper.)

Typical truck camper vacation travels (mostly US highway system with occasional towns): about 15 mpg avg.

Typical driver commuting: 17 mpg (Minimal city driving but 3 mi. of 10 to 20 mph up and down our steep, narrow, and unpaved grade really kills the gas mileage).

The Cummins diesel is like all the jet engines I flew behind as an airline pilot--idling costs ya' fuel, big-time!

[bamaboy473]

Originally Posted by calinb

The Cummins diesel is like all the jet engines I flew behind as an airline pilot--idling costs ya' fuel, big-time!

Kind of a bizarre statement, but welcome to the club.


Where did you get fuel burn figures for either of those engines?

Jets operate at what level of thrust compared to diesels when both are at idle, and at operational RPMs?

[calinb]

Originally Posted by bamaboy473

Kind of a bizarre statement, but welcome to the club.


Where did you get fuel burn figures for either of those engines?

<snip>

My point is putzing around (driving very slowly or idling) a lot in a Cummins Ram results in a very noticeable decrease in gas mileage that far exceeds what I've ever seen from gasoline powered vehicles (including gasoline pickup trucks) under similar usage conditions. At least it does in my Cummins Ram.

My post wasn't intended to be quantitative or technical. My comment (sort of an aviation analogy, really) was motivated by my memories of delays on ramps in turbojet aircraft with the engines turning (or even lengthy taxiing, which typically requires little more than idle thrust, if any more at all.) Low altitude flight is also inefficient and jet fuel costly.

[Zoomschwortz]

So, I took my trailer up to Bellingham Washington over the weekend and came back yesterday.

Driving on I-5 between Bellingham and Seattle, following semi trucks doing 60mph, there were places that I was nearly full throttle, in 2nd gear and the semi’s were pulling away. Not a pretty sound with the 460 winging 4500 rpm for a minute or two. Got my wife asking if everything was okay and now thinking that maybe a newer truck would be a good idea.

On the way home, we happened to stop in a small town and let the dogs take a pee. When we came back to the truck and trailer, there was a man looking at my trailer who started asking questions. We talked for a while and it turns out that he has a 2019 Chev 3500 Duramax pulling a 19,000 lb toy hauler. He cruises over Snoquallmie pass at 70mph and says he could go much faster.

He just finished a 2100 mile trip to Alaska with the toy hauler and said he had to add an additional 10 gallons of DEF for the trip, but said the truck was working hard.

I took a 2019 F350 XLT 6.2 4x4 Supercab for a test drive today. What a difference.

My test drives have just begun, so I’ll be checking out trucks from the big 3 in gas and diesel.

I asked the salesman if I could pull my trailer on a test drive. He just laughed, so I take that as a no.

Of course the truck today was empty making it harder to know how it will do pulling a trailer, but it sure felt like it wouldn’t have any trouble pulling mine.
I’m betting a diesel with twice the torque would hardly know the trailer is there.

I really want to thank everyone for taking the time to help me.

[jjackrash]

All the new HD trucks are ridiculously fantastic towing machines. And now is a great time to pick up a 2019 leftover while they are still left, unless you really just want a new 2020.

[theaaronbush]

A 3/4 or 1 ton diesel will walk away from any gas engine without a strain or downshift. They are pulling monsters.

[Zoomschwortz]

Originally Posted by theaaronbush

A 3/4 or 1 ton diesel will walk away from any gas engine without a strain or downshift. They are pulling monsters.

There is absolutely no doubt that a new diesel pickup would effortlessly fill my towing needs, but I wonder if a truck that can pull 25k-30k is used to pull 7k would be the equivalent of using a 10 pound maul to drive in a 2d nail.

In this world of apps, I wish someone had an app that would let me put in truck info, engine info, trailer info and then tell me how many mph I could go on different % grades.

If I can pull my loaded trailer over the Washington, Oregon, Idaho and Montana passes @ 5-10 mph over the speed limit and get 12+mpg while towing and 20mpg empty, I will be so, so happy.