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-   -   tow vehicle - rated torque vs load (gas or diesel?) (https://www.corvetteforum.com/forums/autocrossing-and-roadracing/3679146-tow-vehicle-rated-torque-vs-load-gas-or-diesel.html)

steve J06 07-08-2015 04:11 PM

tow vehicle - rated torque vs load (gas or diesel?)
 
Will be updating my tow vehicle later this year and would like input on the decision of gasser vs diesel. I've read lots of old threads and searched the interwebs and often seen posts like "get the diesel, you won't regret it", but I don't have unlimited funds so the extra $8500 for diesel is a significant consideration, plus lack experience working on a diesel. Specifically looking at F350 4x4 and either 6.2 gasser or 6.7 diesel, leaning to gas. The truck will be used for race trailer hauling (est. 8K lbs. max), hauling a slide in truck camper (est 4.5K lbs.), or snow plowing; obviously each will be done separately but want to consider the total intended use specification. I don't foresee trips longer than 1K miles at a time and probably more short trips around town than a strictly dedicated tow vehicle. Have already done the mileage/fuel/break even calculations but would like to have input on torque ratings and what it means on the road with a load. More specifically, under what conditions did you find a gasser to be inadequate? Is there a general rule of thumb like xx ft-lbs. torque moves xx lbs of load?

Bill Dearborn 07-08-2015 04:47 PM

You aren't going to get the low rpm torque with a gas engine that you get with a diesel. To compensate you will be using higher gear ratios which tend to eat gas all of the time. My 03 Tahoe does a great job of towing my 5.5K lb open trailer but it has 3:73 gears not the standard 3:42 that came with most Tahoes. That makes a big difference in towing capability and gas mileage with the gas mileage being affected all of the time whether or not I am towing or carrying a load.

For towing a load as large as you are thinking about it sounds like you have an enclosed trailer which not only adds weight but a large amount of wind drag. A gas engine geared to handle that will eat you up in fuel costs Vs a diesel even though diesel fuel is more expensive than gasoline.

You make a 1K mile trip with a gas engine in a rig the size you are considering and you will be lucky you average 10 mpg pulling an 8K enclosed trailer.

Look at the torque specs for wide open throttle operation. The gas engine will give you 405 lbs at 4500 rpm while the diesel will give you 850 at 1600 rpm. Which one will do a better job pulling your load away from a stop sign? Which one will be better able to tow your load down the road at highway speeds? The gas engine will come standard with a 3:73 ratio but to feel proper towing your load it may work better with the 4:30. You could get by with the 3:55 with the diesel.

Now the big question for you. Where in the hell are you going to find snow to plow when you live in San Diego?

Bill

steve J06 07-08-2015 05:23 PM


Originally Posted by Bill Dearborn (Post 1590007586)
You aren't going to get the low rpm torque with a gas engine that you get with a diesel. To compensate you will be using higher gear ratios which tend to eat gas all of the time. My 03 Tahoe does a great job of towing my 5.5K lb open trailer but it has 3:73 gears not the standard 3:42 that came with most Tahoes. That makes a big difference in towing capability and gas mileage with the gas mileage being affected all of the time whether or not I am towing or carrying a load.

For towing a load as large as you are thinking about it sounds like you have an enclosed trailer which not only adds weight but a large amount of wind drag. A gas engine geared to handle that will eat you up in fuel costs Vs a diesel even though diesel fuel is more expensive than gasoline.

You make a 1K mile trip with a gas engine in a rig the size you are considering and you will be lucky you average 10 mpg pulling an 8K enclosed trailer.

Look at the torque specs for wide open throttle operation. The gas engine will give you 405 lbs at 4500 rpm while the diesel will give you 850 at 1600 rpm. Which one will do a better job pulling your load away from a stop sign? Which one will be better able to tow your load down the road at highway speeds? The gas engine will come standard with a 3:73 ratio but to feel proper towing your load it may work better with the 4:30. You could get by with the 3:55 with the diesel.

Now the big question for you. Where in the hell are you going to find snow to plow when you live in San Diego?

Bill

Hi Bill,
Ha Ha, we have ice shavers, I buy 1,000 lbs of ice and fill the driveway. :rofl: Seriously though, we are planning a move in 2016 and there will be snow, so planning ahead for the vehicle and want something to do in the off season.

Trailer will be enclosed, don't have one yet but anticipate later this year, truck w/3.73 gears for sure, and if it got 10mpg loaded that would be fine as most tracks are within a 1/2 day drive. Will change my diesel engine/cost break even point so I'll give that some thought. I currently get 11 mpg unloaded in my '05 F250 so not unexpected on the cost of gas. Good point about the wind drag but to my understanding, that is more of a hp consideration at highway speed. yes? Agree, the low rpm torque being the big differentiator but still am thinking that is more of a start and hill concern. yes? Thus wanting to have an idea of wheel tq vs load for hills and/or hp vs wind drag for mpg on the flats. Please let me know if this type of thinking is misplaced. thanks.

c4cruiser 07-08-2015 05:44 PM

I tow my 20' enclosed trailer that holds my '87 Vette autocross/track day car using my '08 Silverado 1/2 ton with the 6.0 gas motor. The truck is an extended cab Z71 and has 3.73 gears in a G80 locker diff (not posi). The trailer and car weigh just about 6800 lbs.

My truck is rated to tow up to 8500 lbs and has a GCWR of 14K lbs. If the truck had 4.10's, it could tow 10,500 and a GCWR or 16K lbs but it would also have to have the "Enhanced Trailering Performance Package". Whatever that is...

Your current F250 should be able to do the job; what motor is in it? 5.4 Triton? The current line of Chevy/GMC trucks have an available 6.2L motor and a 6-speed trans. Some people are saying that the new (Dodge) Ram trucks are pretty impressive with the Hemi engine. I'm not a red Dodge fan, but their trucks are supposed to be much better than they were some 3-4 years ago.

steve J06 07-08-2015 07:14 PM


Originally Posted by c4cruiser (Post 1590007988)
I tow my 20' enclosed trailer that holds my '87 Vette autocross/track day car using my '08 Silverado 1/2 ton with the 6.0 gas motor. The truck is an extended cab Z71 and has 3.73 gears in a G80 locker diff (not posi). The trailer and car weigh just about 6800 lbs.

^ thanks!
My current F250 has 5.4L triton w/4speed auto. I figured the newer ones with more TQ and a 6 speed auto would be a bit stronger but how much? Enough for 8K? Your post is similar to many I've found here and elsewhere, wherein the user describes what they "can" haul and from those it seems my proposed use is a non-issue. However, I also see lots of "diesel hauls awesome and I forgot the trailer was there" type posts which certainly lends to the diesel side on the long haul but then what about in-town use? The common lore is that diesel motors don't do well with short commuter type trips and will require more maintenance because of this.

I see very few comments from someone who had a gas and decided it was not up to the task so moved to a diesel and the reasons why. Anyone change from gas to diesel without another change like larger trailer?

JeremyGSU 07-08-2015 07:48 PM

Get a diesel. Hands down. The difference isn't just in the power, it's the chassis, braking, etc.

I used to have an '06 F-150 4-door with the 5.4L and 3.55 gears. My friend had a 20 ft enclosed car hauler with around a 2,200 lbs car, gear, etc. My truck could pull it but at 70mph I had to turn over-drive off to hold the speed. It would also sag the truck quite a bit without the weight bars. My friend had an '07 2500 with the Duramax. It was literally night and day towing the same trailer with his truck. His truck towed it so much easier it wasn't even funny. His truck only had 660 tq versus the newer ones with 800 tq plus. It sagged less, braked better, etc. It's just that much heavier. You could cruise at 70mph no problem and accelerate well if you wanted to. Mine just kept it going. My same friend later bought a '14 F-250 and it towed even better. You almost can't tell the trailer is back there.

I now have a '11 Tundra with the 5.7L. It's a hoss for a gas motor. I pull my Vette on an open 20' car hauler and it does well. But I recently towed an enclosed 18' trailer with just a grill in it and some other stuff, probably several thousand pounds less than the car hauler and it kept kicking the torque converter on/off cruising at 70mph. It's not really the weight, it's mostly wind drag. It towed worse than the car hauler.

Gas engines can tow enclosed trailers, sure but if you ever got the opportunity to tow with a diesel there is just no comparison. For an enclosed trailer that size and weight I would recommend diesel. No amount of gears, etc. will make it even close.

BEZ06 07-08-2015 08:00 PM

I have a 2013 F150 with the 3.7L Twin Turbo EcoBoost. I've towed my 6500 lb enclosed trailer around 6000 miles to events and it does a great job.

I could pull up to a max of about an 8000 lb trailer. An F150 with Max Tow and Heavy Duty could easily pull 10,000 lbs - the stock hitch will probably limit the tongue weight.

The EcoBoost has 420 lb-ft of torque at 2500 rpm - very "diesel like". And MORE torque than the 6.2L gasser in the F250!!!

For 2015 you can get the Heavy Duty Payload package that will make the truck a true 1 Ton truck. Depending on cab, drive line, wheelbase/bed length, you can get up to 2200 to 2500 lbs of payload capacity (the "sales" brochure lists up near 3000 lbs, but by the time you get a nice load of comfort/convenience options it will drop it down from that "sales" number!).

The Max Tow package has hitch limit of something like a max of 1220 lb tongue weight, but if you're pulling an 8000 lb trailer that shouldn't be a problem at all. The "sales" specs say you can pull up to 12,000 lbs, but the payload capacity and hitch rating will keep that down to less than 10,000 lbs. The GCWR for most configurations will be 16,000 to 17,000 lbs.

My King Ranch F150 is a great daily driver. It's small enough to park easily most places, it has great comfort features, and gets fairly good gas mileage - around 17-18 mpg on the highway at 70 mph (up to 20+ at less than 70), 15 mpg around town, and 10 mpg towing.

Check it out: http://www.ford.com/trucks/f150/specifications/towing/

.

lrobe22 07-08-2015 09:22 PM

The hd payload package sounds nice, but it's no 1 ton nor even 3/4 ton. If you want to drive this often unloaded, you will get very good mpg unloaded and you will survive in a 150 loaded.
The f150 is a nice truck, but it's still lacking lug nuts, full floating hubs, and transmission beef not to mention a few other things to be remotely compared to a heavier truck. Fwiw, imo it is clearly superior to the gm/dodge offerings.
I have a 2014 f250 king ranch 6.7 and love it. 15/19mpg unloaded. I don't think you(op) need a diesel, so it's a judgement call for you. I'd recommend the 250 or 350 especially considering dealer pricing flexibility versus the 150. Here, you can easily get $11k off superduties.... 150's maybe $1k so far.

BEZ06 07-08-2015 09:39 PM


Originally Posted by steve J06 (Post 1590007337)
... looking at F350 4x4 and either 6.2 gasser or 6.7 diesel, leaning to gas. The truck will be used for....hauling a slide in truck camper (est 4.5K lbs.)...

I just read your requirements again, and looked in the Ford SuperDuty specs: http://www.ford.com/trucks/superduty...tions/payload/

I had mentioned a properly equipped F150 could easily pull your trailer, but looking at your requirement to haul that 4500 lb slide in camper.....

Wow!!! In the specs in that link above, there are a couple of regular cab F350 4x4 SRW models that will BARELY work!!

What you're really going to need is an F350 Dually - especially if you want something other than a regular cab!!! You're gonna need a big-a$$ and big-$$$$$$ truck to carry 4500 lbs in the bed!!!!!

And you're definitely going to want the diesel to haul that much weight around in the bed of your truck!!

Edited: Dayum! I just looked online at my local dealer's inventory, and they have a bunch of F350 DRW 4x4 Crew cab diesels available for $48K - and, if you want a tricked out Lariat they have one for $65K!!

So....You can get a nice F350 DRW 4x4 diesel for a lot less than I thought!
.

Supercharged111 07-08-2015 09:52 PM

We have a 6.2 4x4 4 door dually at work and we have the same in 6.7. With the gasser loaded with 6 3k Honda generators and 2 people, it'd barely climb the hills out here. With no trailer, it was hitting 3rd gear to climb hills in the wind. In a truck that big, it's garbage. The 6.7 was loaded with far more equipment and never left 6th gear. Every time we'd convoy out of a gas station to an on ramp the 6.4 and 6.7 diesels would walk us with ease. If you were to pull an open trailer, I'd say OK, but to pull enclosed AND a slide in you're going to be very disappointed. Oh, and we get 10mpg without a trailer in that thing, so forget about 10mpg loaded. Why do you need a new truck? Get one a few years old so you don't hate your life every time you load that pig down.

seamus2154 07-08-2015 10:16 PM

Diesel all the way. I own a new 2015 1500 GMC crew w/a gas 5.3, 3.42's. Can it pull my trailer?…yes. Does it?…yes. Around Florida short trips no problem. But recently I was going pretty far up to VIR. I rented a new 2014 F250 diesel crew cab. WOW. What a breeze towing up there! Also got 13.5 mpg the whole way at 80 mph! When I got to the event my friend and I noticed that the truck of choice amongst most was the diesel F250. I am a GM guy but if I were buy a tow vehicle it would be the F250 all the way and I own a new GMC 1500. I used to own a duramax and the maintenance is easy. Fuel filter, and oil need to be stayed on top of, but not a big deal.

steve J06 07-08-2015 11:12 PM


Originally Posted by BEZ06 (Post 1590009635)
....... but looking at your requirement to haul that 4500 lb slide in camper.....there are a couple of regular cab F350 4x4 SRW models that will BARELY work!!

Based on some web browsing, that seems to be the upper limit for nicer units, but I am not interested in going DRW so likely will compromise a bit for slightly less load

Edited: Dayum! I just looked online at my local dealer's inventory, and they have a bunch of F350 DRW 4x4 Crew cab diesels available for $48K - and, if you want a tricked out Lariat they have one for $65K!!

So....You can get a nice F350 DRW 4x4 diesel for a lot less than I thought!
.




Originally Posted by Supercharged111 (Post 1590009748)
We have a 6.2 4x4 4 door dually at work and we have the same in 6.7. With the gasser loaded with 6 3k Honda generators and 2 people, it'd barely climb the hills out here. With no trailer, it was hitting 3rd gear to climb hills in the wind. In a truck that big, it's garbage. The 6.7 was loaded with far more equipment and never left 6th gear. Every time we'd convoy out of a gas station to an on ramp the 6.4 and 6.7 diesels would walk us with ease. If you were to pull an open trailer, I'd say OK, but to pull enclosed AND a slide in you're going to be very disappointed. Oh, and we get 10mpg without a trailer in that thing, so forget about 10mpg loaded. Why do you need a new truck? Get one a few years old so you don't hate your life every time you load that pig down.

^Perfect answer! BTW would not haul trailer and camper together, that would be a bit much.

JeremyGSU 07-09-2015 08:22 AM


Originally Posted by seamus2154 (Post 1590009958)
I used to own a duramax and the maintenance is easy. Fuel filter, and oil need to be stayed on top of, but not a big deal.

True. Just keep in mind that the newest diesels now require DPF's and use Urea. Not a huge issue but they do require some more maintenance than the trucks of the past and with stricter emissions I'm not sure they really get any better fuel mileage than the older trucks.

My recommendation if you are serious about diesel is get a year or two old truck. My friend bought a '14 F-250 Lariat for $60,000 a few years ago. One year later and 20k he traded it back to Ford and they resold it for $42 I believe. Big time depreciation on something that expensive. 20,000 miles is NOTHING anymore on any vehicle. No reason to buy new IMO.

steve J06 07-09-2015 11:07 AM


Originally Posted by JeremyGSU (Post 1590011550)
My recommendation if you are serious about diesel is get a year or two old truck. My friend bought a '14 F-250 Lariat for $60,000 a few years ago. One year later and 20k he traded it back to Ford and they resold it for $42 I believe. Big time depreciation on something that expensive. 20,000 miles is NOTHING anymore on any vehicle. No reason to buy new IMO.

The only reason I can see is to get the exact setup wanted. I'd have to buy used anyways for the diesel as new rig is just a bit much at this point. Thanks for the input.

fatbillybob 07-10-2015 11:13 AM

It is more than diesel HP and torque. Diesels are set up to tow with tow haul modes that work, integrated trailer brake contollers, and diesel exhaust brakes. These kinds of features make for very pleasent long tows and much safer towing by someone not familiar with towing like a girlfrield helping you drive when you are tired. Diesels don't get driven by their trailers a much as lighter gas vehicles. Tow comfort is so important. Towing you deal with so much more effects of wind and weather. I have towed with many. Warning once you tow diesel you are never going back.
In cali diesel is less than gas. Mileage with new diesel smog stuff makes mileage better than gas but not like in pre 2007 diesels.
Plowing with diesel is also better. I like my ram diesel megacab so much it is my daily driver for short drives too parking in a medium sized city. I don't worry about maintenence. I have 30k miles so far and have done nothing but oil changes. Rebuild reccomendation comes at 300k miles per dodge. The cummins motor is a bullet proof beast.

ratt_finkel 07-10-2015 12:51 PM

Diesel for enclosed.
Gas for open.

Tow vehicles are always a compromise. I've got friends that tow with Buick Roadmasters and Honda Ridgelines. Others that insist on having the biggest and best.

I tow with a diesel and I wouldn't go back to anything but. 2015 Cummins 4WD Mega cab currently.

Anthony @ LGMotorsports 07-10-2015 02:00 PM

After all of the trucks I have driven here, towing the race cars, towing customer cars....

Nothing in the world beats a good diesel truck when towing. The last 3 1 ton dually Chevy DMax trucks we have had could pull a 50 foot goose neck with two cars, and spares in it without even thinking about it.

Depending on the trailer and how tall it is, weight...what you can see with fuel mileage. We typically see 14-18 unloaded, and 9-10mpg with the big trailer and two cars. Smaller one car trailers and one car on it, it doesn't change much at all.

Tuned the DMax can see over 20 mpg unloaded.

Bill Dearborn 07-10-2015 07:31 PM

That is the other thing. Don't limit yourself to looking at Ford. Take a look at Chevy/GMC and RAM. They are all pretty much equivalent so look for the best deal. If you know where you are going to be moving to next year you might want to check out what the most popular truck is in that area. Service may be better for it than the others.

Oh, I think low rpm torque is great at highway speeds. If you are at 800+ ft lbs of torque at 1600 rpm it won't be much lower at 2200 where the engine may be turning when doing highway speeds.

Whenever I think of towing with a powerful truck I always remember a trip returning to upstate NY from Spring Carlisle in PA. I was driving about 70 mph in cruise going up a several mile long steep hill on I81 north of Harrisburg and this Chevy Pickup with an open trailer loaded with a shiny 70 Chevelle drove by me like I was standing still. My 4.3 L 160 HP V6 Olds Bravada couldn't catch it when I tried to catch up and see what speed he was going. That was a demonstration of pure power.

Bill

steve J06 07-10-2015 08:19 PM

All of the info is appreciated.

I'm mostly convinced about diesel but still reading up on service and reliability. How have people found the newer diesels with DEF and DPFs? I'm finding lots of posts on truck forums about what a pain in the rear they are, but getting the impression it is mostly due to operator mis-understanding of the new systems.

JSTAN 07-11-2015 07:10 AM


Originally Posted by steve J06 (Post 1590023603)
All of the info is appreciated.

I'm mostly convinced about diesel but still reading up on service and reliability. How have people found the newer diesels with DEF and DPFs? I'm finding lots of posts on truck forums about what a pain in the rear they are, but getting the impression it is mostly due to operator mis-understanding of the new systems.

Where are you moving to? Find out what the inspection requirements are for diesels.

If you are moving to a state where you can delete the emissions systems (DPF/EGR) and pass the yearly inspections then you dont have to worry about the above. Plus with those system deleted and given a proper tune, you will get better fuel mileage and performance.

I live in MA and they will fail you if you touch the emissions systems where as other states wont.


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