A Question for the "Horsepower" Folks

Hello, all...and thanks for your time and consideration. 

I'm hoping to get some feedback regarding horsepower, as pertains to my TT towing situation. 

I'm currently towing a 3,000 lb light travel trailer (single axle, so the max loaded weight is 3,800 lbs) with an XTerra that is rated to tow 5,000 lbs and has a V6 with 261 horsepower. 

It's doing OK, but the tow vehicle really has to "work" going up the mountains around here, which is in the foothills of the appalachians...3,000 ft summit max.  My "red line" RPM is 6,000 on that vehicle, and there are sustained periods when I'm between 4,000-4,500 RPM in that vehicle just to generally keep moving with traffic. 

We're looking at full-sized vans at the moment...they would generally work for our family and our needs. 

I'm considering a 5.6L V8 at 317 HP and a 6.0L V8 at 342 HP, and I'm wondering...how much of a difference would it make? 

Would either of these vans (rated to pull 9,500 lbs+) muscle my little TT around and be a big upgrade?  Given the weight of the vans themselves, would the 317 HP van feel "dumpy" and lack power? 

We don't have any major "Rocky Mountain" plans forthcoming, but we do want to spend some time in the Great Smoky Mountains, the White Mountains of the northeast, etc...do you think I'd be "safe" with either of these, or do I really need to look closely at the horsepower situation? 

(2 adults, 2 kids, 2 dogs, and a reasonable amount of gear.  Generally staying places that have water available, so not hauling on-board water, and not having to transport gray/black water over the road.) 

Thanks! 

If you are towing then the best idea is to get a diesel.

Running the rpms in the range you stated is somewhat normal. That's where the peak horsepower and torque are. Gas motorhomes run there all the time climbing hills, as do larger gas pick-ups pulling heavier campers.
That said, there's no such thing as too much truck. Pay attention to the payload of the van just in case you want to up-size trailers later.

A V6 is designed to rev up high to produce its horsepower, so don't be concerned about it working hard. It may be a bit noisy, though.

Yes, a bigger engine will produce the desired Hp at a lower rpm and give the appearance of an effortless tow. Would either be an "upgrade"? From a performance point of view, I'm sure both would be.

You can evaluate power by comparing weight/hp, i.e. how many lbs does each Hp have to move. If the combined weight of van & trailer is, say 10,000 lbs, and the engine max Hp is 300, the weight/Hp ratio is 10,000/300 = 33.3 lbs/Hp. However, rear axle gear ratio and transmission gearing also have a substantial effect. A van configured for maximum fuel economy will probably feel sluggish when towing anything on grades. It's a tradeoff between towing and non-towing use.

SeilerBird said:

If you are towing then the best idea is to get a diesel.

Click to expand...

I agree. ^^^

Diesels have much more torque and that makes a big difference.

I know a lot of people think if they don't travel as fast as the cars they will get run over.
When I towed my trailer with my SUV I had no problems driving behind a semi going up the mountain at 35-40 mph.
The faster you go up a mountain the more fuel you burn too.

I don't know about your TT but my cargo trailer states (in the owners manual) that the maximum speed is 55 mph.
But who reads owners manuals?

Running the rpms in the range you stated is somewhat normal. That's where the peak horsepower and torque are. Gas motorhomes run there all the time climbing hills, as do larger gas pick-ups pulling heavier campers.

Excellent insight...just the type of thing I was hoping for...thank you very much! 

A V6 is designed to rev up high to produce its horsepower, so don't be concerned about it working hard. It may be a bit noisy, though.

Yes, a bigger engine will produce the desired Hp at a lower rpm and give the appearance of an effortless tow. Would either be an "upgrade"? From a performance point of view, I'm sure both would be.


Form vs function...thanks very much, Gary...I appreciate the insight. 

HP does not move loads, TORQUE does. 

SeilerBird said:

If you are towing then the best idea is to get a diesel.

Click to expand...

For a 3000 lb TT?

A full sized van would probably do mighty fine by that TT.  But yeah, you'll typically need to wind (naturally aspirated) gassers up pretty good to get the rated power.  You *should* have more torque in the lower end of the V8 so you don't need to wind it up quite so often though.

donn said:

HP does not move loads, TORQUE does.

Click to expand...

Not true, you can move a load without torque, but you can't move anything without HP. How can you move an object without torque? Use linear actuators, mag lev devices, hydraulics, the original 1 horse open sleigh, etc. no twisting engines,  but the load still moves. On the other hand moving the smallest lightest Styrofoam bb a single mm in a petri dish requires some small finite HP.

MMW said:

For a 3000 lb TT?

A full sized van would probably do mighty fine by that TT.  But yeah, you'll typically need to wind (naturally aspirated) gassers up pretty good to get the rated power.  You *should* have more torque in the lower end of the V8 so you don't need to wind it up quite so often though.

Click to expand...

Thanks for the feedback...this vehicle will be pulling the 3,000 lb TT a few weeks each summer and for 6-8 other outings between the spring and the fall...besides that, it'll get me to work each day, pick up the kids from school, etc...one of our two "regular" vehicles.  I can't get too carried away with what we're purchasing and running each day.  Thanks! 

donn said:

HP does not move loads, TORQUE does.

Click to expand...

I just wish this silly idea would just go away.  Horsepower is the measure of the work an engine can do.  A slow turning diesel with twice the torque has enormous internal stresses but folks think that somehow they are loafing.

Horsepower is nothing more than torque x RPM.  Whether you're running a low torque engine at high RPMs or a high torque engine at lower RPMs, they're both making the same amount of power.

Another way of looking at it is a gas engine has the option tp slow down and gaining efficiency when lightly loaded while a high torque diesel can't rev up and produce more power when it's needed.

That's just as valid as the other saying.

When towing the torque makes a bigger difference. Then hp.  I tow with a 1995 Chevy g20 conversation van.  6500 tow capacity. 350 or 5.7 v8.  Only 200hp but 330ft torque.

Next time your on the highway. Notice  all the Chevy work vans loaded down tools and ladders blowing by. Most of them have the 4.8 275 hp

Redline is 6K?      4K to 4.5K is 2/3rds to 3/4 of 6K. Plenty of safety margin. Your vehicle is doing just fine. Keep an eye on the oil, and drive on.

HP does not move loads, TORQUE does. 

Click to expand...

The guy who originally said that ought to be shot, or at least gagged. He obviously wasn't an engineer or a physicist! Horsepower is the only thing that moves loads, and Hp and torque are fixed in an intrinsic relationship anyway. If you have more torque, you also have more Hp. RPMs is the difference, with the diesel engine producing its torque much lower in the Rpm range than most gas engines. That makes the horsepower of a diesel more readily available because the engine doesn't have to rev up high to get it. But once the engine is producing the horsepower, a diesel horse and a gas horse pull the same. And a high torque motor that cannot achieve many Rpms still won't move things effectively. For example, an electric motor with its rotor locked has an incredible amount of torque but produces no power at all because the rpms are zero.

Ahh, forgive me for going off on this subject. It's one of my pet peeves... 


Addendum: Note the word "originally", referring to whomever coined this phrase many years ago. It has been repeated so often that it has become gospel among motorheads, but it just ain't so.

Gary RV Roamer said:

The guy who originally said that ought to be shot, or at least gagged.

Ahh, forgive me for going off on this subject. It's one of my pet peeves... 

Click to expand...

OK Gary, I sure j
Hope your joking,  if not then you need to understand statements like this can get you into a lot of trouble.  Making threats may not be against the law, but could get this site shut down.
As it is I have lost all respect for you as a person, a moderator and the site for allowing you to post such a horrible comment.

Just to clarify
"For decades, man has debated over which of these measurements of a car engine's power output is more important, has more of an impact on everyday driving, and is more worthwhile when buying a vehicle. What's the difference, anyway? Horsepower provides highway passing power when your engine is revving hard, allowing you to accelerate at high speeds, while torque gives you low-end power and the ability to move quickly after stopping. In other words, torque lets you do the work, but horsepower lets you do the work quickly."

Gary RV Roamer said:

Horsepower is the only thing that moves loads, and Hp and torque are fixed in an intrinsic relationship anyway. If you have more torque, you also have more Hp. RPMs is the difference, with the diesel engine producing its torque much lower in the Rpm range than most gas engines.

Click to expand...

Of course this is correct, but folks will only believe what they want to believe.

I have a diesel for the better fuel mileage, longer range and no need to contribute to the ethanol lobby.

For one, I fully support Gary!! There was absolutely no threat made to anyone!!  Gary was referring to some unknown person who started this idea 100 years ago, not the person who brought it up on this thread, who was simply repeating this old idea.

Furthermore, he is correct.  NOTHING moves without a force being applied, which is commonly measured as horsepower.  Horsepower comes in many forms not involving torque.  If I remember correctly, 1 horsepower = 55 ft-lbs/sec.  No turning motion required.  In an automotive application,  RPM X Torque = HP.  The power of a turning tire to move a camper CAN be measured as torque, but there is horsepower and RPM creating that torque.

Gary has provided so much very good advise on so many varied topics for so long, he has earned all of our respect, and earned a pass on any potential error, and this is not one!