wnjj wrote:



Not really. The engine torque does not directly turn the wheels. It is fed through a transmission. This means the higher torque engine will deliver more HP to the wheels only if the 2 setups have same rear axle gearing and are operating in the same tranny gear. Practically, this gives the higher torque motor an advantage off the line. But once moving, the high torque (low rpm) engine will need to shift sooner. Shifting up proportionally decreases the torque applied to the rear wheels and you're soon back to the same wheel torque that the low torque engine is providing.

The torque at the wheels applied at a certain speed (wheel rpm) is the horsepower being delivered. The engine that can maximize the HP delivered to the wheels throughout various gears and conditions will pull harder. If both engines produce the same HP within the rpm band they operate in between shifts, they will perform the same. Gas engines don't pull hard at low rpm when first taking off or if run in too high of a gear. This was the issue with 3 and 4 speed transmissions. Too often the gas engine was shifting from a rev limiter to below its HP producing rpm range. With 5 and 6 speeds these days the problem is all but gone.

The reason earlier generation diesels "worked better" is because people didn't want to have the gasser cranking out the high rpm needed to produce its peak power or the transmission didn't provide the proper gearing. Gassers also don't have the benefit of a turbo so they lose HP at high elevations.

The newest diesels pull harder simply because they are producing more HP than the gas engines.

rhagfo wrote:

It isn't HP that moves the load it is torque! HP gives you speed, I currently have 610 FT lbs. of torque produces by my 01 Cummins, adding RV 274 injectors to the mix too see if I can do better on winter fuel.

rhagfo wrote:

JUST and FYI a gallon of Diesel has more power than a Gallon of Gass!

transamz9 wrote:

The gearing works the same on a diesel as it does on a gas.

Hannibal wrote:



Except that the gas engine can rev and use more gearing to multiply torque.

It's horsepower that determines how fast we can tow.

http://www.catrvclub.org/PDF_Docs/Understanding_Perf.pdf

rhagfo wrote:



True, but is is torque that determines how much you can tow. This is why I can pull 12K at speed with 3.55 gears up hill.

wnjj wrote:

Its torque determines the gearing you need to keep the engine in its sweet spot at speed. Its HP determines how much of a load you can move at that speed.

azwildcat99 wrote:



I have been reading the posts for a while, but finally decided to chime in after everyone's reluctance to acknowledge the fact that...

Horsepower and Torque are related!

http://www.1728.org/mtrtrq.htm

HP = Torque * RPM/5252 So unless you are revving your engine up above 5200RPMS or racing F1 at 19k RPMS, HP is largely irrelevant. It's the torque that matters. Diesel or Gas your TV makes more torque than HP at the engine speeds we are pulling at, any of us. Given that, a diesel usually has superior figures (500+ vs 300-400).

As to the Diesel vs Gas, if you can afford it go Diesel, but there is nothing wrong with Gas. Cheaper fuel, less smelly, lower maintenance costs, easier to work on, and the list goes on. But Diesel has it's share of pros as well. I don't think there would be much of a debate if the up-front costs were identical.

I used to tow our 3k pop-up for years with my 5.3L 4sp 1500 with 3.73. It towed great, but downshifted to 2nd on the 6% grades. I then moved up to a 7000lb 31ft TT and it was having to downshift to 2nd on the freeway (just the 101 not I-17 here in AZ). I recently upgraded to a 07 Classic 2500 D/A. What a difference! It stays in 4th gear up the grades to Flag and can accelerate if I choose, but I say around 60 for sanity :-)

Good Discussions!

azwildcat99 wrote:



I have been reading the posts for a while, but finally decided to chime in after everyone's reluctance to acknowledge the fact that...

Horsepower and Torque are related!

http://www.1728.org/mtrtrq.htm

HP = Torque * RPM/5252 So unless you are revving your engine up above 5200RPMS or racing F1 at 19k RPMS, HP is largely irrelevant. It's the torque that matters. Diesel or Gas your TV makes more torque than HP at the engine speeds we are pulling at, any of us. Given that, a diesel usually has superior figures (500+ vs 300-400).

As to the Diesel vs Gas, if you can afford it go Diesel, but there is nothing wrong with Gas. Cheaper fuel, less smelly, lower maintenance costs, easier to work on, and the list goes on. But Diesel has it's share of pros as well. I don't think there would be much of a debate if the up-front costs were identical.

I used to tow our 3k pop-up for years with my 5.3L 4sp 1500 with 3.73. It towed great, but downshifted to 2nd on the 6% grades. I then moved up to a 7000lb 31ft TT and it was having to downshift to 2nd on the freeway (just the 101 not I-17 here in AZ). I recently upgraded to a 07 Classic 2500 D/A. What a difference! It stays in 4th gear up the grades to Flag and can accelerate if I choose, but I say around 60 for sanity :-)

Good Discussions!