Diesel vs Gas

[Barry Parkof]

I have made the decision to buy a new 2012 GMC tow vehicle for my 2011 Classic 30. Presently, I am towing with my 2009 1/2 ton GMC, that's rated at 9500lbs towing with the 5.3, and it does an amazing job. The power is adequate, but I would like to get a bit more stability. Gas mileage is about 8.5 to 9 mpg. We recently completed a 5000 mile trip, mostly on flat ground and all was fine.

I have test driven both the 3/4 ton Gas and Diesel, but am not really convinced that I need to spend the extra money for the Diesel. Does anyone have any experience towing with a 3/4 ton GMC with the 6 liter gas engine? What kind of fuel mileage are you getting and are you satisfied with the vehicle?
I also notice that the diesel truck drives just a bit smoother than the gas, and I attribute this to the extra weight of the heavier engine.

Thanks,

[Zigidachs]

Hot topic with opinions reaching across the spectrum! We have a '11 30' Classic and pull with a dually Ram which we had purchased to pull a fiver. Absolutely no problems with power, security, and stability. Economy is very reasonable. (11.5-12.5) (Could be better without the DRW)

Diesels were made to tow as I was advised by many wise folks. The diesel engine lasts longer than a gas engine, has more torque, and is much more reliable over the long haul....pun intended. An inline Cumins (6 cylinder) is supposed to be more fuel efficient than a V-8.

If I could use my past experience for a future purchase, I would buy a one ton SRW, long bed ( for storage), & a diesel. Always go for more power and torque than you think you might need....eventually you will need the power

One of the most critical features on a diesel is the exhaust brake ( don't buy a TV without this asset). We easily coast down 7% grades, exit freeway ramps, or slow in traffic, and rarely have to touch the brakes because of the exhaust brake.

We climb at freeway speeds.

There is more than ample storage in the long bed.... generators, tools, mats, air pump, hoses, washing supplies, BBQ, and sporting equipment.

Good luck....


Zigi

[Ridgerunner3]

I have a 2010 Chevy 2500 4X4 Crew Cab 6.0 with 3.73 rear end. I have driven 25000 miles with about 1/2 of that pulling the trailer. I get 16 - 17 mpg on the highway empty. I get 11 - 11.5 mpg pulling a AS 25 with a 6300# gross weight. I had a 2008 Chevy 1500 4X4 Extended Cab with 5.3 and 3.73 rear end and 4 speed transmission.

The 2500 actually gets better mpg than my 2008 1500 while pulling the trailer but that is partially because of the 6 speed transmission in the 2500.

The difference in the two trucks is huge when pulling a trailer. It is a great truck. There where some major improvements in the 2500 design starting in 2011.

I struggled with the decision of the Duramax vs. the Vortec when I bought my truck. I could not bring myself to spend the money to buy and maintain the diesel if I did not really need the diesel. I was also concerned about the ready availability of diesel fuel when traveling in some of the remote areas in the west. Starting in 2011 Chevy increased fuel tank size to somewhere around 35 gals. Prior to that the tanks where 26 gal. There have been times that I almost ran out of gas when traveling out west because of the lack of gas stations let alone a gas station with diesel in some of the remote areas. I now carry a 5 gallon safety can of gas when traveling out west.

I am sure you will be happy with the 2500 no matter which engine you choose.

Good luck.

[Denis4x4]

I have an '06 GMC 2500 crew cab 4x4 with 4:11 gears and the 6.0 engine. Just drove 850 miles and got 15 MPG driving faster than I really should. With a 25' Safari, I get 11 -12 MPG. A 6.0 gas engine with a 6 speed auto and 3:73 gears and 2WD should be an excellent combo.

[Streamside]

Parkof
If you are looking for milage figures here is a link to Duramax Diesel numbers http://www.airforums.com/forums/f463...lts-78016.html
Easy to calculate the savings (gas vs. diesel) but the payoff of the cost of diesel powertrains may not be for over a hundred thousand miles or so.

[moosetags]

We have a 2005 Safari 25FB, named Lucy, that weighs 7,400# ready to camp. Over the past 5 1/2 years, we have towed Lucy almost 90,000 miles, and have spent over 1,000 nights in her. Until about six months ago, we have towed Lucy with two 3/4 ton Suburbans with the 6.0 liter gasoline engines. The towing experience has been excellent in all towing situations.

Last May, we ordered an Outfitter truck camper. We planned to pull Lucy while carrying the truck camper. As the truck camper weighs about 3,000#, we felt that we would need a diesel to do the job. We were not thrilled about going diesel, but felt that our new camping rig was beyond the capabilities of a gasoline truck engine. In August, we took delivery of a 2011 Silverado 3500 Duramax. We took delivery of the Truck camper in September, and immediately started towing Lucy with the truck/truck camper combination. We set Lucy up as our base camp, and venture out into the back country in the truck camper for a couple of days at a time.

The new diesel tow vehicle is, quite frankly, amazing. We have now towed Lucy about 5,000 miles with it. We can now accelerate up any grade. We can use the cruise control, and the truck rarely has to downshift on most upgrades. It just reaches down into its giant bag of torque, and keeps on chugging. We are also very impressed with the truck's engine braking feature. It gives us confidence on long steep downgrades.

All in all, we are quite satisfied with the diesel. It cost more to buy and to service. The fuel mileage is better than the gas, but not enough to offset the higher fuel cost. Our mileage increase with the diesel is less because we have added a 3,000# truck camper to the mix.

Brian

[mefly2]

Our 1/2 ton Triton got up to 19mpg highway unloaded and 10-12 around town ... not too bad until we hooked up the AS and wanted to cruise up the mountain passes around here. Then it became obvious that we needed a lot more torque to just hold a steady 50-55mph... and not max out the transmission, too.

So, we took a bath on our low miles trade in and bought a diesel * singularly for the torque* ... but the other huge advantages are better standard brakes, second transmission cooler, exhaust brake, stronger receiver hitch, huge tow mirrors, and tow haul mode. We get a bit less hwy mpg at 16, and only about 10 around town, but the mountains / hills disappear and we feel that the safety margin with a slightly heavier TV is well worth the investment (~ $10k for just the diesel / auto trans option) in our personal safety when pulling the rather light AS we have.

WE decided upon the Ram brand because they were the only diesel TV that we found not requiring DEF / urea to be added at suggested oil change intervals. The mpg seems to be about the same for all of the brands offering 6.7 displacement. There is no shortage of diesel availablilty in this part of the country; over the course of the last 10 years, it has become a standard offering even for the quickie convenience stores. Suggest that you check gas buddy.com under the diesel tab to see for yourself. PS: wife loves the interior creature comforts on the Ram... all this from a formerly dedicated Ford / Chevy man since 1965!

[JFScheck]

2011 Ford SRW crew cab short bed 6.7 diesel towing a 2011 30' classic with ProPride hitch & Titan 50 gallon tank replacing OEM 26 gallon tank.

Life get's no better!!!

[slowmover]

The "easy" way to decide between diesel & gas has more to do with how long one will keep the TV, and how many miles it cover in that time frame. The diesel favors the higher percentage of towing miles against solo, and total miles on the TV.

5,000-miles towing annually is not high.

Spec'ng a vehicle for its minor role (if that is as TV) is the backwards way of doing things (in dollars & cents), but it's hardly unusual in the RV world.

Similarly, todays diesels are so overpowered -- and emissions-laden -- that the truck is well past TT need, and the fuel economy of the early 2000's is gone. The purchase price isn't justified for low annual use, low trailer weight and overall truck economy, IOW.

In straight money terms:

The best gas motor truck with ProPride or Pullrite hitch and TT disc brakes would be a better match and easier to live with if set against diesel truck, second or third tier hitch and trailer drum brakes if one is going to compare on-the-road performance and cost.

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[techiej]

2 additional items that favor the diesel (and why we went that way) are the exhaust brake and the lower engine noise owing to the much lower rpm's

[Mike Leary]

Since we full-time, I talk with a lot of diesel owners. The news is the Chevs seem to have injector problems and the Fords have some sort of problem that causes them to run rough and smoke badly upon start-up. (turbo?)These would be questions I'd ask from a dealer were I contemplating a purchase. I've heard these comments quite a few times, including one Chev having to be towed a long way for warranty work.

[r carl]

Being gas engines can be expected beyond 200k and now are around 400hp with 6
speed transmissions, and more reliable than a diesel, diesels are not the best tow truck for a camper unless you need 800 foot pounds of torque.
IMHO

[Wayward]

I replaced our old Chevy 3/4 ton diesel with the 6.2l Ford gas 3/4 ton and the 6spd TorqShift. More than enough power and a minor difference in fuel mileage.

I posted a report on this truck a while back but my bottom line is that with the new model trucks, the new transmissions and the integrated electronic engine/tranny controllers are a far bigger factor in driveability, mileage and power on demand than gas vs diesel.

The 6.2l has plenty power, but it is its high tech tranny and well designed controller software that make it a far far better towing machine than the old diesel. I do not miss the diesel at all, especially the frequent high cost of maintenance.

[JimGolden]

I think you have to look at the mission. If the primary requirement is towing, then ask the question "How many Kenworths, Peterbilts, Volvos, and Freightliners do I see on the highway with gasoline engines?" Answer: Zero.

I have a truck similar to Rednax's; 2004 1/2 Dodge Ram 4-door long bed. Mine is 4x4 (don't remember if his is) and I have the heavy duty 4-speed automatic whereas he has the 6-speed manual. I get 21mpg running empty at 65mph, and I get 12mpg pulling a 34' triple axle that is maxed out to the gills on what we can put in it. I often haul a motorcycle and about 500lbs of other stuff in the bed. I could probably get 15mpg towing a 25 foot Airstream and not have the Hog and all the other stuff in the bed.

Yes the diesel cost more to acquire. But after owning one (this is my first), it'd be hard to go back. For towing, I think it whips it all over a gasser. Diesels make torque; lots of it, and that is what you need for towing. But the newer ones are pretty good on horsepower too. I get "Diesel Power" magazine and they have all kinds of trucks in there that just make insane power. Just this month they have a Cummins powered Dodge making 1200 horsepower. Of course at that level you'll need to beef up the entire drive train, but the potential is there.

As far as remote availability of fuel goes, consider this: My one good friend is a mechanic for JAARS (Jungle Aviation and Radio Service). JAARS flies missionary flights of supplies and stuff into remote locations to help people. They are replacing all of their piston engined airplanes with turbine powered aircraft. The reason: You can just about always find diesel fuel, kerosene, or jet fuel anywhere in the world (all three are essentially the same basic fuel....just the additives differ....so you simply carry a jug of additive conditioner with you and you can run the engine off any of the three) but gasoline you cannot. If you travel to super remote Alaska, chances are you will find diesel fuel, kerosene, or Jet A before you'll find gasoline. I wouldn't worry about finding diesel fuel as an issue at all.


All this being said, if you're going to only tow once in awhile and your primary mission is to run empty, the gasser will be $6K cheaper to buy, fuel will be cheaper (I still haven't figured this out....except it's basic gouging because diesel fuel is cheaper to make than gasoline is....but you can't electively reduce the amount of driving delivery trucks do (diesel) as compared to passenger cars "If gas is $6 a gallon I'll make 3 trips to town a week instead of 5...." vs. "the groceries must be delivered to the store on time so I have to drive the same schedule no matter the cost of diesel fuel...."

So in summary: Diesels are great. But if you're not going to take advantage of their advantages a lot, the gasser is a lot cheaper

[r carl]

Originally Posted by JimGolden

So in summary: Diesels are great.

You mean the older diesels are great, like yours and rednax's.

[slowmover]

CTD's rule for mpg and longevity. The triple nickle motor is the one to have with the man trans behind it. I'm planning on changing the 3.73 gears to 3.42 for increased economy by getting the 1,300-1,500 rpm sweet spot (per Cummins info) closer to my Fourth and Direct best cruise range for town and country driving. 22-mpg average all miles past 37k. Or, 15-cpm fuel cost solo, and 25-cpm fuel cost towing (at $4/gl).

These trucks are already overpowered for trailers of under 16k. So the even higher power numbers of 2012 make even less sense given higher adjusted purchase price and complex exhaust treatment (one could buy a crate Hemi engine and auto trans for the cost of the emissions package on a diesel, literally) and potential reliability concerns.

And six speed autos plus the most modern V8's (or DI V6's) are beyond powerful compared to 20 or 30 years ago with much better mpg.

Still, no A/S actually needs a pickup truck. Maybe for a full-timer. If fuel goes to $5/gl, what then? Etc.

We all pulled these trailers, not just A/S, of up to 8-9k gross with cars into the 1980's. Got used to 7-mpg (and convert the fuel price of 1980 to today, whooee!).


.

[SSquared]

Do any non-diesel vehicles have engine brakes?

I've taken my current trailer (all 1,560 pounds of it) on US36 between Estes Park and Grand Lake CO, a route which climbs over 12,000 feet. On the steep downhills, that small trailer was enough to push my 3.0 liter minivan past the safe speed, even with the car in first gear. The brakes got mighty hot.

I suppose a 6 liter truck would have double the engine braking power, but that wouldn't be enough if we get the 6,000 pound AS we're dreaming of.

So are the only choices get a diesel / stay off that road?

[tpi]

Gas engines don't have exhaust brake, but they do have a couple of features which enhance engine braking:
1. They tend to have high redlines.
2, They have throttle which increases pumping loss, generally an undesirable feature. But for engine braking it is good.

Diesel good: Effortless torque and power, efficiency.
Diesel bad: Complexity, transitional technology, very high fuel pressures in some instances (expensive injection system sensitive to fuel quality).

[Phoenix]

FYI,

Link to explanation of difference between diesel and jet fuel:

What is the Difference Between Jet Fuel & Diesel Fuel? | eHow.com

Link to explanation of "Jake Brake" (compression release diesel engine brake):

Compression release engine brake - Wikipedia, the free encyclopedia

[slowmover]

Originally Posted by SSquared

Do any non-diesel vehicles have engine brakes?

I've taken my current trailer (all 1,560 pounds of it) on US36 between Estes Park and Grand Lake CO, a route which climbs over 12,000 feet. On the steep downhills, that small trailer was enough to push my 3.0 liter minivan past the safe speed, even with the car in first gear. The brakes got mighty hot.

I suppose a 6 liter truck would have double the engine braking power, but that wouldn't be enough if we get the 6,000 pound AS we're dreaming of.

So are the only choices get a diesel / stay off that road?

Years ago there was an aftermarket gasoline engine exhaust brake called The Mountain Tamer by an outfit in Arizona. I always wished I'd had the opportunity to get one and the optional accessory parts as it would have been useful for fuel economy, not just grade descents.

As to how to descend your experience is more one of better utilizing vehicle gearing against road speed plus braking technique (and the subject of other, specific threads; search).

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