Mileage for gas trucks vs diesel trucks?

[2airishuman]

Originally Posted by Westfalia

...Also with an auto tranny, most will unlock the torque converter when you let off the throttle causing an increase in downhill speed with your trailer load. On steep mountain passes (especially of the two lane variety), without an exhaust brake or compression braking, you'll end up needing to ride the brakes most of the way and risk over heating them on TV and trailer alike...

you are buying a new truck right?

since 05 on the fords and around the same time on ge'em the automatics (98% of the trucks made are auto now)...

have tow/haul mode and tranny programing that changes this issue significantly.

on the fords an inclinometer? measures grade, IF it's 5-6% or more the tranny automatically shifts down.

touch the brakes while going down hill (regardless of grade) and the tranny will shift down again...

that gear (3rd or 4th) is held until the go pedal is pushed or the grade flattens.

i think the torque converter clutch stays closed/locked during this time.

the feature works very well, i've crossed dozens of passes with a 10klb+ trailer in tow and made many long decents...

with only touching the brakes occasionally. often these downhills stretches are done at 50 or 55 (or much slower) without braking 4 miles...

and while all the carsnsuvs are riding the pedal and big trucks are smoking pads...

these tow/haul set ups are really amazing, if you haven't driven a truck with it, please do!

i've never seen any climb in tranny temps and the truck/trailer are still both on original brake pads (50K+ miles towing)...

so does the dodge only have engine braking or is this in addition to a tow/haul tranny feature?

the integrated brake controller is also an amazing gadget, which again both ford and the other guy now have.

cheers
2air'

[2airishuman]

it looks like the torqshift will also down shift IF the truck is accelerating while 'coasting'...

according to the the intellidog.com website (http://intellidog.com/dieselmann/home.html)...


"Finally, to help maintain vehicle speed when desending a grade and help increase brake pad longevity, the transmission will downshift automatically. If the computer senses vehicle speed increase with the accelerator released, it will downshift to the next lowest gear. If vehicle speed continues to increase, the computer will command the transmission to downshift again. The grade braking downshift mode will be deactivated if the Tow/Haul mode is deactivated or the accelerator is depressed."

when the truck has slowed sufficiently to allow the shift, it can go as low as 2nd gear? i think.

cheers
2air'

[BillTex]

Mrmossy, you must have missed the earlier discussion on the actual cost most folks pay for the diesel upgrade (this was on another thread). No one in their right mind pays “sticker price” for anything. I paid a little more than $3k for the diesel/Alison upgrade on our Chevy.
One good trip with this combo convinced me it was worth every dime.
As noted, turbo charging, as far as I know only available on diesels as a factory option in the US, is indispensable at altitude (not really a concern for me living on the “best coast”). As outlined in my analysis, the cost advantage of diesel is minimal in day to day driving, much better on the highway and, when towing, the economy becomes significant.
With your Argy, clearly diesel is not needed. (But you sure would like it if you tried it!)

2air, you are right about T/H. The Alison is so intuitive it is scary. Just a dream to tow with. Inclines, quick stops, etc just put it in T/H and let it do its thing! (I am sure the new 6 spd Ford must be similar). Barely use brakes on declines…

Not everything in life can be cost justified. If so, we would not be pulling Airstream’s around. Sometimes we get things just for the fun of it…

Bill

[safari 28]

I think one of the big hang ups is proper use of gears in a gassser. I am a performance marine guy, think nothing of running a small block at 4 grand for hours. They love it. So, on these past 2 trips going nationwide, in heavy climbing and downhill runs I ran over 60 mph uphill in 2 nd gear at 3900 rpm. I passed semis, motorhomes you name it. Going down hill the same thing brakes for curves only. It never lost a beat, and as the altitude increased it needed more fuel. I think the problem is most feel they are hurting the drivetrain. I submit it does no harm and letting the engine rev is harmless. It ran sometimes in Colorado, Wyoming and NewMexico for 45 minutes and more at 3900 plus with no issues. Temp needle was steady. On the open road most times at 2300 going 65 in 3rd or 1900 in overdrive if real level.

The new series of half ton trucks set up for towing are just impressive, and come a long way even in the past 5 years. I understand Diesel for the 15klb and up fivers, and the comfort level they give to the owner who feels he tearing up his gasser over 3000 rpm. Each his own, but lease a new gasser as I have done for 2-3 years before shelling out the big bucks. You will experience a worry free tow, let it rev, work it hard and turn it in for a new one. You just might do what I am considering--buying the damn thing.

[TinLoaf]

I've seen a lot of talk about diesel vs. gas from a cost perspective but to some folks the cost isn't the biggest issue. In today's world we need to start becoming concerned about our reliance on foreign oil. Towing Airstreams vs. 14 foot tall 5th wheels is a heck of a good start.

I got a diesel because I would be burning less fuel - plain and simple.

I towed with a 4.6 liter F-150 and got no higher than 7 mpg. I'm getting between 13 and 14 mpg with the diesel Excursion. That's a savings of 65 gallons of fuel every 1000 miles.

[BillTex]

Originally Posted by safari 28

I think one of the big hang ups is proper use of gears in a gassser. I am a performance marine guy, think nothing of running a small block at 4 grand for hours. They love it. So, on these past 2 trips going nationwide, in heavy climbing and downhill runs I ran over 60 mph uphill in 2 nd gear at 3900 rpm. I passed semis, motorhomes you name it. Going down hill the same thing brakes for curves only. It never lost a beat, and as the altitude increased it needed more fuel. I think the problem is most feel they are hurting the drivetrain. I submit it does no harm and letting the engine rev is harmless. It ran sometimes in Colorado, Wyoming and NewMexico for 45 minutes and more at 3900 plus with no issues. Temp needle was steady. On the open road most times at 2300 going 65 in 3rd or 1900 in overdrive if real level.

The new series of half ton trucks set up for towing are just impressive, and come a long way even in the past 5 years. I understand Diesel for the 15klb and up fivers, and the comfort level they give to the owner who feels he tearing up his gasser over 3000 rpm. Each his own, but lease a new gasser as I have done for 2-3 years before shelling out the big bucks. You will experience a worry free tow, let it rev, work it hard and turn it in for a new one. You just might do what I am considering--buying the damn thing.

Safari28…another country heard from!

That is certainly another point of view, although many would consider it not financially astute. As this is (was) a gas mileage post; can you let us know what you are getting for mpg driving like this?
Turning in a leased vehicle with undue wear and tear can lead to significant costs (My Buddy just lost thousands on a returned mini-van-ouch! And they were not “hard” on this family/commuter car.). I am not so sure you are not already “shelling out the big bucks” in the long term. But, if you’ve got deep enough pockets, leasing may work.


I hope you are also monitoring the tranny temps with that kind of driving. Last I checked GM ½ ton trucks did not have a tranny temp gauge available (not even as an option) and not sure what adding one would do to your lease agreement. Not sure about Ford ½ tons.

Many of us buy trucks to last a long time (we keep our vehicles for 10 years for example) so I tend to more careful in selecting my vehicles and in how I treat them.

Anywho…thanks for another perspective. Goes to show; there is more than one way to skin a …

Bill

p.s. Please let us know where you turn in your vehicles.

[safari 28]

Ford would never consider towing a 6400lb trailer excessive in any way. The only thing to worry about is the frontal surface area. Not even a issue with any Airstream. Ford dealer told me if it breaks they will tow the a/s in as well/ he was the commercial lease manager and knew the lease down to the fine print. I was upfront on the use of this vehicle and wanted no surprises. The only real turn in issues at the end of a lease are dents and excessive mileage/ or a filthy interior. Never worried about trans temps as the needle never moves. Mileage was 12.1 on 15k miles of towing. Immediate checks vary from 18.5 to 6.3 on the computer. E85 about 2 mpg less but usually 50 cents / gallon less than unleaded.Usually a buck less than diesel!! I have changed the oil 3 times at 15k miles total. Trans fluid perfect. Ford dealer does the 29.95 oil change to keep thing on the up and up. Damn thing works and no problems. SIMPLE.

[mrchinup1]

'I hope you are also monitoring the tranny temps with that kind of driving. Last I checked GM ½ ton trucks did not have a tranny temp gauge available (not even as an option) and not sure what adding one would do to your lease agreement. Not sure about Ford ½ tons.'

Bill, i have a digital read out on my 07 silverado.

[azflycaster]

Originally Posted by TinLoaf

I've seen a lot of talk about diesel vs. gas from a cost perspective but to some folks the cost isn't the biggest issue. In today's world we need to start becoming concerned about our reliance on foreign oil. Towing Airstreams vs. 14 foot tall 5th wheels is a heck of a good start.

I got a diesel because I would be burning less fuel - plain and simple.

I towed with a 4.6 liter F-150 and got no higher than 7 mpg. I'm getting between 13 and 14 mpg with the diesel Excursion. That's a savings of 65 gallons of fuel every 1000 miles.

The numbers you use need to be adjusted. It takes about 20% more oil to produce diesel then it does gasoline. Also what abouit MPG when not towing? Since I only tow one weekend a month on average and my non towing MPG is very good (18+), I use less oil with my gasser then I would with a diesel. If I was full timing, it would be different.

[Sky]

Originally Posted by azflycaster

The numbers you use need to be adjusted. It takes about 20% more oil to produce diesel then it does gasoline. Also what abouit MPG when not towing? Since I only tow one weekend a month on average and my non towing MPG is very good (18+), I use less oil with my gasser then I would with a diesel. If I was full timing, it would be different.

Very good point AZ. Here is how a 42 gallon barrel of crude breaks down.

[TinLoaf]

Originally Posted by azflycaster

The numbers you use need to be adjusted. It takes about 20% more oil to produce diesel then it does gasoline. Also what abouit MPG when not towing? Since I only tow one weekend a month on average and my non towing MPG is very good (18+), I use less oil with my gasser then I would with a diesel. If I was full timing, it would be different.

Even if I bump my numbers for diesel up by 20% I'm still burning 50 gallons less diesel than I would be gasoline every 1000 miles. That's my situation, which is a little more extreme with my 7 mpg figure. In my case diesel is a much more efficient use of fuel.

I use the Excursion for 90% towing. I commute in a more fuel efficient sedan or I'd be broke. However, I get between 21 and 22 mpg highway when not towing with the Excursion. That's pretty awesome for an 8,000 pound pig.

The only thing that graph shows is that 10 gallons of that 42 gallon drum goes toward making diesel and 19.6 gallons goes toward making gasoline. It does NOT mean that it takes 42 gallons of crude to make 10 gallons of diesel like sky might be implying.

[Sky]

Originally Posted by TinLoaf

blah blah blah

The only thing that graph shows is that 10 gallons of that 42 gallon drum goes toward making diesel and 19.6 gallons goes toward making gasoline. It does NOT mean that it takes 42 gallons of crude to make 10 gallons of diesel like sky might be implying.

The problem with crude oil is that it contains hundreds of different types of hydrocarbons all mixed together. You have to separate the different types of hydrocarbons to have anything useful. Fortunately there is an easy way to separate things, and this is what oil refining is all about.

From what I am reading, 10 gallons of a 42 gallon barrel contain the type of hydrocarbons used to make diesel. So, yes I am implying that you can only get 10 gallons of diesel out of 42 gallon of crude. But, the other 32 gallons obviously don't go to waste.

But, I have been wrong before

Anyway TinLoaf, I agree with you also. I wouldn't trade my diesel truck for the world!

[Larry C]

For whatever it's worth, we towed over 5,000 miles from lower Alabama to Maine, and returned last summer. We have a 2,000 30' Excella, and a 2003 Donge/Cummins - 6 speed manual, 3:73 rear end....2 wheel drive - of course.
I averages 15.0 mpg at speeds of 55 to 60 mph.
I carry an extra fuel tank (115 gallons) to give me a total capacity of 155 gallons..(145 usable). It gives me the option to shop price for fuel, as we all know, it can vary as much as 0.25/gallon..
Larry C

[slowmover]

Originally Posted by Larry C

For whatever it's worth, we towed over 5,000 miles from lower Alabama to Maine, and returned last summer. We have a 2,000 30' Excella, and a 2003 Donge/Cummins - 6 speed manual, 3:73 rear end....2 wheel drive - of course.
I averages 15.0 mpg at speeds of 55 to 60 mph.
I carry an extra fuel tank (115 gallons) to give me a total capacity of 155 gallons..(145 usable). It gives me the option to shop price for fuel, as we all know, it can vary as much as 0.25/gallon..
Larry C

Pretty much the same rig as mine. What does your combination weigh? Our numbers are otherwise similar:

Tow at 63 mph
15+ mpg on Interstate
13+ mpg on secondary highways

[MrAgent007]

My 2006 Hummer H1 Alpha with the Duramax engine and Allison transmission combo with 19,000 miles gets me approximately 20 MPG highway and 17 MPG in city. Towing my 2006 22-0 CCD gets me approximately 15 to 16 MPG highway. Highway speed defined as 55 to 60 with rpm at no greater than 2000. So far, the Duramax/Allison combo in the H1 has resulted in reasonable fuel milage. Hopefully it will improve as the engine gets completely broken in.

[BillTex]

Originally Posted by MrAgent007

My 2006 Hummer H1 Alpha with the Duramax engine and Allison transmission combo with 19,000 miles gets me approximately 20 MPG highway and 17 MPG in city. Towing my 2006 22-0 CCD gets me approximately 15 to 16 MPG highway. Highway speed defined as 55 to 60 with rpm at no greater than 2000. So far, the Duramax/Allison combo in the H1 has resulted in reasonable fuel milage. Hopefully it will improve as the engine gets completely broken in.

Cool, that is pretty much in-line with what other D/A drivers (and for that matter pretty much all the diesel Folks) are getting for mpg.
I didn't know they were putting the D/A in the Hummer now?! Very cool setup.

It would seem, on average, that most Folks towing with small block ½ tons are getting 11-12 mpg (believable) or worse if overburdened, while most diesel Folk’s are getting 14-15 mpg (also believable) towing. Occasionally someone claims something way outside these averages, but there are bound to be anomalies and fliers in any statistical sampling. (It is kind of funny some of the outrageous responses people post that are way outside the bell curve. I guess that's why reading these forum is so much fun. Don't believe everything you read...)
Bill

[Larry C]

Originally Posted by REDNAX

Pretty much the same rig as mine. What does your combination weigh? Our numbers are otherwise similar:

Tow at 63 mph
15+ mpg on Interstate
13+ mpg on secondary highways

Our weights are a bit different, because of the 115 gallons of extra fuel in the aux tank...mine will be around
Truck weighs around 8,000.
AS (depending on how it's loaded) around 8,000.
This is the second Dodge/Cummins, and we love it! Especially when in mountains, I equipped this one with the exhaust brake, and I've never felt safer when goiing downhill.
Take care
Larry

[BillTex]

Some observations from a 700 mile ski trip this past weekend. Not really scientific, but real world data anyway;
Performed a little experiment on Rt 89 through mountains of Vermont and NH (at least we call them mountains here in New England!). This is a rolling highway, usually light traffic up North which allows you to set the cruise, kick back, and let it roll. Total payload (5 passengers, ski/snowboard gear) estimated at 1300-1400 lbs plus full tank of diesel. Each leg of the test was done for ½ hour, truck has the 6spd Allison, cruise control was on, tranny in “D,” mpg as reported by DIC.
On open road when not towing, I typically set the cruise at either 69 mph or 73 mph if there is not traffic. After paying ~4.00/gallon for diesel I was very determined to find out the point of peak economy for my truck.

65 mph
1600 RPM. Average fuel economy 17.6 mpg. This was very surprising and disappointing.

69 mph
1750 RPM. Average fuel economy 22.2 mpg. Wow, this was great!

73 mph
1900 RPM. Average fuel economy 22.4 mpg. This also was very surprising and better still.

I did not try any other speeds as these are typical for my driving style and we were starting to get into more traffic by this time.
The remainder of the trip yielded 20.0 mpg through Boston traffic. Traffic was flowing at about 70 mph (not bumper2bumper) but had normal brake tapping and slow downs.
Overall mpg for the trip; highway, back roads in the mountains, and Boston traffic yielded 20.2 mpg. I do not have the power curves for this engine/tranny but will look them up when I get a chance. If anyone else has them available please post, this might help explain the poor mpg at 65 mph.
This was for me, one of the most in-depth studies of mpg for a typical non-towing weekend. The recent spikes in fuel costs are what motivated me to take a close look at how we are doing with fuel. In summary, I was pleased with the efficiency of the ¾ ton diesel. I never got these kinds of returns driving any gasser (I have owned 3 ½ ton small block gas pickups and 2 ½ ton small block gas Suburbans). For those that drive ½ tons, let’s hope the diesels start hitting the market soon. It has been my experience, that diesel engine fuel efficiency is for real. Imagine what the diesel hybrids will do?

Bill

[BillTex]

OK-found one. It would appear that fuel consumption was greater at peak torque. This would make sense.

Interesting.

Bill

[myoung]

Don't know what a diesel engine might show, but for what it's worth, our longest sustained test of gas mileage produced a 13.4 mpg average covering nearly 9,000 miles from California, across the Sierras and Rockies, thru the plains, across part of Canada, over the very steep grades of upstate New York and Massachusetts, back down thru the steep grades of Pennsylvania and Maryland, back thru the midwest and south to Texas, across the high deserts, and eventually to the new home in Arizona. A lot of meandering around along the way, too.

All this with a 5.7 liter gasser pulling the heaviest load we have ever hauled because we had sold our home and expected to live in the trailer for 6-8 months. I wouldn't be surprised to learn that we were carrying over 7,000 pounds for much of the trip.

In all, we are very happy with this gas mileage and the fact that the Durango burns regular, unleaded gasoline...the cheapest grade except in Nebraska and Iowa where we burned the mid-grade with more ethanol and a cheaper price.