How Many Horses?

[cwsqbm]

Originally Posted by stuhly

Gees people, we used to drag 80,000 lbs with 220 ponies.

We also used to walk to school, uphill both ways either in deep snow or 100+F heat. Thank God for progress.

Looking at DP motorhome, the weight of a 5,000 lb toad isn't going to be a major factor. I'd say that most modern (say 2000+) DP motorhomes have enough power to pull a Jeep. My goal is to slightly faster than the loaded trucks up the really steep hills. I don't like to hold up guys that are paid by the mile, but I don't mind if I have to slow down behind them.

Of course, a 300 hp motor pushing 30,000 lbs combined will be roughly as fast uphills as a 450 hp motor pushing 45,000 lbs.

[SteveLevin]

To add some specific data points, my coach weighs in at 28,000 pounds going down the road, and we don't tow. Engine is a 300hp/950tq ISC, and on 6% grades I easily hold the top of 4th gear -- 50mph. If I had a touch more power, I might be able to get into 5th and go quicker, but generally I am caught by my power and gearing. On a 6% grade, if I get hung up behind traffic, though, I can fairly easily accelerate back up to that 50mph.

On an 8% grade (which might be more akin to 6% towing 5,000 pounds) I hold about 43mph. On a 10% grade I find that my comfort leads me to gearing down to 3rd and holding 2,000 rpm to make sure I've got lots of cooling action, and that works out to 37mph.

On those numbers I am generally horsepower and not torque limited, so (in theory) if you had 300hp and 660tq (a common ISB setup) you could hit the same numbers, although you'd struggle to regain speed if you got balked (that's where torque is king...getting BACK to speed).

Steve

[DMTTRANSPORT]

[QUOTE=cwsqbm;2777154]We also used to walk to school, uphill both ways either in deep snow or 100+F heat. Thank God for progress.

Looking at DP motorhome, the weight of a 5,000 lb toad isn't going to be a major factor. I'd say that most modern (say 2000+) DP motorhomes have enough power to pull a Jeep. My goal is to slightly faster than the loaded trucks up the really steep hills. I don't like to hold up guys that are paid by the mile, but I don't mind if I have to slow down behind them.

Of course, a 300 hp motor pushing 30,000 lbs combined will be roughly as fast uphills as a 450 hp motor pushing 45,000 lbs.[/QUO

Going "slightly faster" go ahead and stay behind the Truck, you will be creating what is call "turtle races"...the ones that think they have the Power to go around but end up taking 5 miles to pass while backing up traffic...besides, I thought none of us were in a hurry