Gas or Diesel

[C_B_]

My Son is looking to get a 2015 Ford F-350 CC SB.

He's trying to decide between the 6.2 gas or pay extra for the 6.7 diesel.


He currently has a 6.0 diesel so he knows how the diesel pulls.

Question is how good will the 6.2 gasser do pulling his Cedar Creek 362BBS with a GVWR of 14,000 lbs.


Thanks in advance for your input.

C.B.

[Dog_Trainer]

Why don't we settle it all by hooking up frame to frame V-10 vs powerstroke same body and cab each truck.we will put the powerstroke going up hill and the v-10 pointed down hill. Wait lets pop some popcorn this is gonna be a good show.
I do realize all the hot shots and big trucks use a gasser because it is cheaper and pulls just as well 🙂

[Turtle_n_Peeps]

Sport45 wrote:

pnichols wrote:
Now ... if Ford would offer a turbo charged V10 ... then we'd begin to see the switch from diesels by the towing crowd back to smooth running cheap to maintain easy to find gas for gasser engines. The V10 gasser is already engineered to have a broad relatively flat torque curve for truck use. All it needs to complete the picture is a turbo for mountain use.

So true. And it wouldn't really need "boost", just enough turbo to maintain sea level manifold pressure at elevation.

On the other hand, 15psi of boost would have a 6.8 liter engine acting like a 13.6 liter (830 cubic inch) NA. That'd certainly be fun... 🙂

And would gobble fuel like a drunken sailor. :R At around 475 HP my engine eats about 1 gallon/ 1/4 mile run at WOT.

[Sport45]

pnichols wrote:
Now ... if Ford would offer a turbo charged V10 ... then we'd begin to see the switch from diesels by the towing crowd back to smooth running cheap to maintain easy to find gas for gasser engines. The V10 gasser is already engineered to have a broad relatively flat torque curve for truck use. All it needs to complete the picture is a turbo for mountain use.

So true. And it wouldn't really need "boost", just enough turbo to maintain sea level manifold pressure at elevation.

On the other hand, 15psi of boost would have a 6.8 liter engine acting like a 13.6 liter (830 cubic inch) NA. That'd certainly be fun... 🙂

[pnichols]

Vulcaneer wrote:
Having previously owned a 2006 V10 6.8 30V F350, I know where you're coming from. But I cannot agree with your preference. Spent too much time at 4000 RPMs pulling long hills in 3rd, or even second gear. Try pulling 13,000 pounds up over Donner pass sometime. You won't be able to hear your radio. Or much of anything else after you get over the top. Been there, done that, got the T shirt and the hat. My diesel does it so much better.

Well .... our ton-and-a-half E450 V10 with a 4:56 differential pulls our 11,800 lb. motorhome and our boat just fine over Donner ... not getting passed by diesels, either. I don't mind 4000 RPM if I know the engine is desinged for it and we don't care to listen to the radio when traveling. The V10 makes no noise when cruising along at 2100 RPM. What I do not care for is the thumping/grunting tailpipe sounds and tappet-dancing underhood sounds of a diesel on the highway or late at night in a campground. FWIW, I can also idle my V10 for hours in a campground or out in the middle of nowhere without needing to set a high-idle knob - for emergency battery charging, emergency motorhome A/C, and emergency motorhome heating - with nary a sound outside or inside and with no vibration in the floors ... smooth as silk.

As for ultra low end power (crankshaft torque) from a gasser: My 1965 Ford 3/4 ton heavy duty pickup (15 leaf springs in each rear stack and 3 gas tanks) with it's long-throw-crank 390 V8 had and needed only 4 gears. The first gear was what they called in the old days a Granny Gear, so it could climb a mountain idling. The engine probably wouldn't spin faster than 2500 RPM on a good day going downhill. We have a 500 foot long driveway with a very steep first 150 feet - probably a 15% grade or more - and that good old Ford gasser would pull it in 3rd gear. So I'm convinced ... the old Detroit crowd could build a gasser that acted like a diesel if they wanted to ... probably the EPA is preventing it nowadays.

[pnichols]

Sport45 wrote:
I think most diesel owners are more in love with the turbocharger than the fuel. They just don't realize it.

You hit the proverbial nail on it's proverbial head with that keen observation. I've stated in post after post that it's blatantly not right to compare TC diesels to non-TC gassers. The problem is ... there's no TC gasser truck engines available to speak of that are worth their salt. It probably isn't going to happen either - the opposite is happening - vehicle manufacturers are close to fully Europeanizing the U.S. market by inundating us with little tiny turbo charged diesels in everything. Lawn mowers and Harley motorcycles are next after the conversion to diesel delivery trucks, diesel small motorhomes, and diesel socker-mom-mobiles is complete.

My brother said a very honest thing about his older 4X4 NA diesel pickup - his words about the truck were something akin to "gutless wonder".

Now ... if Ford would offer a turbo charged V10 ... then we'd begin to see the switch from diesels by the towing crowd back to smooth running cheap to maintain easy to find gas for gasser engines. The V10 gasser is already engineered to have a broad relatively flat torque curve for truck use. All it needs to complete the picture is a turbo for mountain use.

[Sport45]

I think most diesel owners are more in love with the turbocharger than the fuel. They just don't realize it.

A NA diesel is a wheezing pig on mountain passes, same as gas. My late father in law pulled his TT with a 6.2l diesel Suburban and I can tell you from experience it was no powerhouse. The gas engines of the day would easily outrun it. They couldn't touch it for fuel mileage though. And diesel was much cheaper than gas back in the day.

[john_bet]

Find me a gaser that has 600# of torque at 1600rpm and still has it at 2500rpm the same year as mine. So far I have not found a hill, mountain that I can't pull at a speed I am comfortable with on any interstate. So far the current crop of trucks don't impress me for the price.

[Sport45]

rhagfo wrote:
If your motor-home is 11,800# loaded then you are missing that my 5er is 11,000#, total GCW that I am moving is 19,000# with the TV.

Please strike this from the record. rhagfo has already rested his case...
😉

[goducks10]

I think it's just more enjoyable to climb a 6% grade and see if the Cummins will hold 6th. I don't find any enjoyment in finding out how high of rpms a gasser will need to keep up with a diesel in the mtns. Seems like a lot of work to me.

[Vulcaneer]

pnichols wrote:
My "preference" is a high RPM engine - not a thumping/rumbling beast. I much preference the spirited whine of the V10 when pulling up grades and accelerating. Nowadays high RPM engines that are also reliable can be mass produced so as to last a long time ... Ford's truck V10 is an example. For several decades this was not the case - so low RPM diesels became popular all over the world for three reasons - reliably back then being one of them. The other two reasons probably being kick in the seat of the pants without gear changes and ease of production of diesel fuel all over the world as compared to the processes required for gasoline.

Having previously owned a 2006 V10 6.8 30V F350, I know where you're coming from. But I cannot agree with your preference. Spent too much time at 4000 RPMs pulling long hills in 3rd, or even second gear. Try pulling 13,000 pounds up over Donner pass sometime. You won't be able to hear your radio. Or much of anything else after you get over the top. Been there, done that, got the T shirt and the hat. My diesel does it so much better.

But I WILL agree there are times when I like the high whine of a gas engine. Like in an Indy or F1 race car, or a race boat, even a lower revving Nascar, a drag racer, and/or a hard accelerating 2 cycle motocross bike. These sound wonderful when each is up on their torque and Horsepower curve. Not so much when they are not.

But there are also times I like the lower rev'ing pull in low end high torque application. Like a 4 stroke enduro motorcycle clawing it's way through heavy trails, while maintaining tractability, a bulldozer pushing a very heavy load, and just digging in and going, and a diesel truck pulling a heavy load, without the noise and sweat of a gasser trying to accomplish the same amount of work in the same amount of time. And I can hear the radio, just fine.

Incidentally, thinking of my old 2 cylinder gas bulldozer. It had only 45 HP and a few hundred foot pounds of torque. But it also had a 120 pound flywheel. You could count the rpm's, when it really got it's back into it. But it just kept going. You could rarely stall it. In fact when the starter broke, I would kick start it by putting a pipe wrench on the PTO shaft and standing on it. Once you got that fly wheel to move, she was going to start. Even when it stopped on the compression stroke, all you have to do is stand on the wrench a little longer. It only had 6:1 compression.

[dougsee3]

Here is my take on the difference and why people like there diesels.
I only have GM specs readily available.
Four motors crusing down the road at a approxamate 2000 rpm that most would or could cruise at and only needing, I do not know exactly but about 75 to 100 HP to Cruise along.
Now by just pushing the pedal down with no down shift the approxamate maximum HP available is.

2005 Duramax LLY about 225Hp @ 2000rpm

2005 8.1 L18 about 165hp @2000rpm

20?? 6.0 LQ4 about 125hp @ 2000rpm (similar HP on a 2010 L96)

2010 6.2 L9H about 140hp @ 2000rpm


Now as soon as the HP required to maintain that speed is exceeded a down shift would be required to maintain that speed. Now if the next lower gear is or has the required Hp to maintain that speed then there no loss but if the load continues and you have to drop down another gear there will and could be be a greater loss of speed especially with the gas engine.

Do to the higher torque of the diesel and with higher Hp levels availble from just throttle input they are going to pull and feel better doing it.
The gas engine because of its very wide operating RPM range will have or be in more areas were the gearing will not be as optimal, in all high load and speed situations. With that being said with proper gearing and not selecting or towing at the max tow rating the gas can manage very well.

For example the 6.0 dropping down to third on a four speed 4L80E/4.10 gear would be making about 190 HP and to second gear a possible 275 hp. Although these are good they are not near as much HP that the diesel can manage at highway speed limits.

But in the end as the load increases and both the gas and diesel start to slow the diesel has an advantage as the torque starts to climb at a faster longer rate than a gas as the RPM's slow down keeping more HP available.

I do think that part of the love of towing with diesel's is that most but not all are not towing at, or even near the max towing. People with gas seem to want or are stuck to, pushing up to, or tow lot closer to the max ratings.


(The other part is these HP levels they are at sea level, start at 3000 ft and go up to 5000 or 6000 ft and the difference in hp margins between the gas and diesel grow by quite a bit.)

[pnichols]

Horsepower without torque with gears is still equal to horsepower with torque without gears.

As you probably know, many Class A motorhomes weigh what your total weight is and yet are powered by the higher horsepower (three valves per cylinder) 365 HP version of the V10 gasser.

By the way, when I said earlier above what our RV setup (lighter than your total RV setup) with only the 305 V10 version would do - I didn't mean to imply that I was pushing it anywhere near the limit during those times. It has plenty of pulling performance headroom left in any situation I've ever had it in.

(See .... I told you perceived diesel pulling advantage was purely preference based. 😉 )

[rhagfo]

pnichols wrote:

rhagfo wrote:
I move an 11,000# 5er without difficulty at highway speed on both interstates and two lane roads. I do this with about 270 hp and 530# of torque, and 3.55 gears. I can pull 6% and 7% grades at speed in 4th with my 5 speed manual.

You can do the math all you want, but not likely a 270hp gas engine with less torque could do that even with 4.10's or lower.

My V10 will easily do the same on the same grades at the same speeds and at 9000 foot altitudes pulling our 11,800 lb. motorhome's weight - I just have put up with (enjoy!) the gear changes and it's 4800 RPM so as to tap more of it's horsepower (305 HP maximum). It's crankshaft torque is probably only around 420 lbs. when doing this -> but proper overall vehicle gearing leverages-up this crankshaft torque to the drive axle torque needed to do this.

So ... it seems that it is unfortunately impossible to discuss diesel versus gasser performance comparisons without throwing away logic/physics/engineering and eventually reverting back to good old preference. This is assuming that one leaves turbo charging out of the discussion - because it's "completely unfair" to compare a turbo charged diesel engine of X horsepower to a non-turbo charged gas engine of the same X horsepower. Engine manufacturers of course nowadays seem to always include turbo charging to their modern diesel engine designs, thus giving diesel owners another explanation as to why, in at least mountain driving, they feel that their diesels pull better - as their engines should do when the air thins out. A turbo charged gas engine continues to put out better horsepower as the altitude increases, too ... but just try to get turbo charging in a truck gasser engine.

If your motor-home is 11,800# loaded then you are missing that my 5er is 11,000#, total GCW that I am moving is 19,000# with the TV.

[pnichols]

rhagfo wrote:
I move an 11,000# 5er without difficulty at highway speed on both interstates and two lane roads. I do this with about 270 hp and 530# of torque, and 3.55 gears. I can pull 6% and 7% grades at speed in 4th with my 5 speed manual.

You can do the math all you want, but not likely a 270hp gas engine with less torque could do that even with 4.10's or lower.

My V10 will easily do the same on the same grades at the same speeds and at 9000 foot altitudes pulling our 11,800 lb. motorhome's weight - I just have put up with (enjoy!) the gear changes and it's 4800 RPM so as to tap more of it's horsepower (305 HP maximum). It's crankshaft torque is probably only around 420 lbs. when doing this -> but proper overall vehicle gearing leverages-up this crankshaft torque to the drive axle torque needed to do this.

So ... it seems that it is unfortunately impossible to discuss diesel versus gasser performance comparisons without throwing away logic/physics/engineering and eventually reverting back to good old preference. This is assuming that one leaves turbo charging out of the discussion - because it's "completely unfair" to compare a turbo charged diesel engine of X horsepower to a non-turbo charged gas engine of the same X horsepower. Engine manufacturers of course nowadays seem to always include turbo charging to their modern diesel engine designs, thus giving diesel owners another explanation as to why, in at least mountain driving, they feel that their diesels pull better - as their engines should do when the air thins out. A turbo charged gas engine continues to put out better horsepower as the altitude increases, too ... but just try to get turbo charging in a truck gasser engine.

[rhagfo]

Vulcaneer wrote:

pnichols wrote:

tdeal823 wrote:
Once you have the torque of a diesel at your foot anything else will be like pulling with a KIA.

That's purely a matter of preference and not based on the physics of horsepower conversion.

The only torque that matters is the torque actually being applied to the drive axle(s) ... and what it takes to make that is horsepower conversion by the proper overall vehicle gearing so as to transform that horsepower into drive axle torque.

Diesels pull different than gassers, not intrinsically better than gassers. Thoroughly read and absorb this discussion thread to understand what's really going on with the two different ways of pulling a load:

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27698336/srt/pa/pging/1/page/1

Well....that is NOT the only thing that matters. Nor is the HP conversion. Another important thing is...at what RPM. If it makes the Torque (and HP) at a much lower RPM, then the comfort of towing is much better. And your seat of the pants feeling is much better. That is the biggest difference between diesel and gas towing capability and comfort.

Diesel produces the torque and HP at lower RPM. And the curves are much flatter...from bottom to top of the rpm range.

Vulcaneer, You are wasting your time and effort trying to explain the difference between towing with a lot of HP vs. a lot of Torque.
I move an 11,000# 5er without difficulty at highway speed on both interstates and two lane roads. I do this with about 270 hp and 530# of torque, and 3.55 gears. I can pull 6% and 7% grades at speed in 4th with my 5 speed manual.

You can do the math all you want, but not likely a 270hp gas engine with less torque could do that even with 4.10's or lower.

I rest my case.