jmtandem wrote:
Just because it's a diesel doesn't mean it's more powerful.
Just because it's a gas engine does not mean it can’t be faster up a hill than a diesel with a lois more torque.
As I indicated when you posted this same material on another thread earlier this week; pass this on to Ford, GM and Dodge Ram because they are not enlightened like you on this subject and they think that torque values are far better for towing larger loads. Their towing guides always seem to favor higher torque for heavier towing. And industry says the same thing with ships, construction equipment, train locomotives, over the road trucks, etc. Lower HP and higher torque wins the heavy towing industry sales. Most over the road trucks have about 500-600 HP diesels; and put out 1600-1800 foot pounds of torque. And they are moving 80,000 pounds up and over the Rockies and Sierras. There is certainly more to it than just HP.
Next time cite a video towing gas vs diesel up to the Eisenhower tunnel in Colorado on the interstate and watch what a turbo charged diesel can do to a normally aspired gas engine at higher altitudes. The diesel loses virtually none of it's sea level power; the gasser loses about two percent per 1000 feet according to Ford. At 10,000 feet elevation that is one fifth of the gas engines power lost just to altitude.
All that matters is seat of the pants experiences of RVers, not textbook stuff. Real world trumps textbook material every day for RVers. Without HP and Torque combined nothing moves, except perhaps sailboats.
This is a towing forum not a motorcycle or car racing forum where HP is more important, vehicles are light, speeds are high, fast accelleration important. They are not towing fifth wheels up the mountains. A 60 HP motorcycle with 40 foot pounds of torque can easily out accellerate and beat any over the road truck with 1800 foot pounds of diesel torque every time, but what is the point? The motorcycle is not doing much work moving itself and a rider; the truck is hauling 80,000 pounds. Torque equals work. Not everything is about how fast you can race your RV to the top of the mountain.
Weeell Not exactly there Tandem...
First of all this is physics and that doesnt change. No matter how much you want it to.
Second the auto mfgs know this well...but there is big money in convincing you you need all that torque and HP...their biggest profit margin vehicles are the Expensive pick ups. Most of it is marketing BS. This is more about whose got the Biggest One, or playing to the male ego.
And yes Class 8 trucks do run some 500+ Hp vehicles. But you dont need that to haul 80K LBS. In Europe and other places loads exceed 100,000 lbs and they have been doing it with much less HP In the 380-420 range for many years ...even up and over the Alps.
Whats more important on hills than raw HP is the RPM Range that you can deliver that HP in. IE how far down the rpm scale can you lug the engine before changing gears. Also if you look carefully most Class 8 over the road trucks (except construction) use axle ratios in the 3:00's, 3:42 etc.
Sorry but from an engineering perspective and Physics the OP is correct. (at least in the main. I may have worded some things a bit differently but as I read it is a pretty good explanation)
In my opinion we have all been sold a bill of goods by the auto industry that has more to do with their profits than it does with any real world NEED for all of this ever bigger and bigger numbers game for HP and Torque.
