How does horsepower affect performance?

[CT_Tree_Guy]

Lots of great points all around as usual, and a lot of common ground. I think everyone agrees that more torque can be good if you "need" it and have the weight and traction to put it to the ground. And that apart from things like raw lifting ability for picking up indivisible objects, and the weight and size of the attachments you can use, the smaller tractor can do very much the same tasks the larger one can do, given a good low gear and an adequate supply of squirrels, it will just take longer.

I just wanted to defend JCS *[jcmseven]* a bit re: <font color="blue"> If the two machines listed are equal in weight and have similar tires, they should seem to pull about the same, even though one has more engine power (both torque and horsepower). </font> It sounded to me as if you were just saying that if either engine is able to spin the tires, then the bigger-engine tractor won't have any more effective pulling power than the smaller-engine one, since the coefficient of friction, and amount of power being put to the ground, is exactly the same. I would be pretty much in 100% agreement. In the case of the 18-wheeler example, the VW engine would obviously not be able to spin the tires.

As I said, I think we're all pretty much on the same page. IF you NEED to get things done faster, or have more pull, or not be pushing your tractor as hard at a given pace of work, get more power and more weight.

Lastly, I would just reiterate what I've heard and said many times. When in doubt, get more power, and try to avoid the low end of the power range in a given frame size. And don't forget about lifting capacities, and attachments, for tasks that can't be broken down into smaller "bites". A 402 kg loader can take all the time it wants, but it will never, ever pick up an 853 kg rock or log. And a six-foot backhoe will never dig 9 or 11 feet deep.

 

[3RRL]

jcm...jmc...very cool /forums/images/graemlins/cool.gif

From CT
</font><font color="blue" class="small">( Lots of great points all around as usual, and a lot of common ground.)</font>

Everyone...all great points...
Best discussion I've participated in so far.
Thanks

 

[Mickey_Fx]

From an engineering standpoint, torque is the twisting force around a rotating shaft. It is real and can be measured. HP is a mathematical calc that defines a specific amount of work being accomplished in a specific amount of time.

If memory serves me right, 1HP = 33,000ft lbs/per min. or 550ft lbs/sec

You can always gear down a lower powered piece od equipmemt but it will take longer to get a specific amount of work done.

As has been stated previously, what the tractor is capable of doesn't mater if the power can't get coupled to the ground.

 

[CT_Tree_Guy]

<font color="blue"> I just wanted to defend JCS </font>, and while I'm at it, I'd like to give honorable mention to JFK, FDR, the FBI and the '69 GTO. /forums/images/graemlins/laugh.gif /forums/images/graemlins/tongue.gif

Grr, I was working on two posts at the same time, one to a guy called JCS who is having trouble with his 3,000 sq. ft. concrete floor because the guys who were leveling the pour fell asleep, and it hardened all uneven! Man, what a nightmare!

One more thought on what a smaller tractor might not be able to do: pick up 5' round bales, or pull the baler that makes them. Although it might be kinda cool if you could get a little 18" round baler for a BX to make bite-sized mini-wheats for cows. /forums/images/graemlins/laugh.gif /forums/images/graemlins/cool.gif

 

[JustGary]

<font color="blue"> "If you only need torque, you can get it by downshifting. You could pull stumps with a squirrel in a rotating cage if you have enough gear reduction, traction, and patience. Two squirrels would pull the stump twice as fast, if they were the of the same sex, straight, and cooperating. You would also need to halve the gear reduction.
" </font>

In theory, yes, but when you actually attempt this you find that the squirrels pee a poo on everything, which makes the grease behave differently and increases the friction in all of the gear works. At some point their little wheel quits moving because of all the loss they induced by not holding their bladders. They find that they need a bigger wheel and many more friends just to get going again.

I used to have a little Datsun 1200 that I could just shove and then get in and start it by letting out the clutch. I also had an '83 Ford F150 that I couldn't move at all by myself. And they both had only four wheels...

- Just Gary

P.S. Just for fun I used to drive that F150 without using the brakes. It had enough rolling friction that if you kept enough distance in front of you, you could usually slow down fast enough for most any situation by just letting off the gas. It would soon come to a complete stop.

 

[JustGary]

<font color="blue"> "I was working on two posts at the same time" </font>

Hmmmm. A two poster, huh? Just two more and you'll become a bed!

CT_Tree_Guy, I like the way you think. We both see the world from odd angles. Keep it up, some of us get the jokes.

By the way, I don't know about any honorable mention for the FBI.

- Just Gary

 

[CT_Tree_Guy]

<font color="blue">Keep it up, some of us get the jokes.
</font>

Gary, you don't know how reassuring that is. /forums/images/graemlins/smile.gif

As for the FBI - yeah, after I posted that I started thinking about Ruby Ridge, Waco, J. Edgar Hoover (LOVE the dress) and "intelligence failures" ... oh well - how about the NFL instead, or maybe the YMCA? /forums/images/graemlins/smile.gif

 

[flwiii]

I would like to inject a scenario for those who believe more HP is better.

We have 2 engines. One creates 50 foot pounds of torque at 2500 RPM and engine 2 creates 50 foot pounds of torque at 8000 RPM.

Calculating HP:
Engine #1 -- (50 * 2500) / 5252 = 23.80 HP

Engine #2 -- (50 * 8000) / 5252 = 76.16 HP

Which would you rather use to pull your Box Blade?

 

[CT_Tree_Guy]

<font color="blue"> a scenario for those who believe more HP is better. </font>

First, I think that anyone who would categorically say that "more HP is better" (leaving aside for the moment the issue of the relevance of HP vs. torque in a typical tractor application) has missed some of the finer points of this thread.

Second, I know of no few if any CUT engines that pull 8 grand, so I'm not sure of the relevance of this example.

Lastly, as to <font color="blue"> Which would you rather use to pull your Box Blade? </font> I would choose Engine #1, and put Engine #2 on EBay. /forums/images/graemlins/laugh.gif

 

[JustGary]

<font color="blue"> "Engine #2 -- (50 * 8000) / 5252 = 76.16 HP" </font>

Now that number is really close to that old Datsun 1200! As I recall, it was 69 HP at 6000 RPM. I had that car over 100 MPH once (on an old airstrip). I don't think I ever got the full 69 HP though. I feel cheated.

My answer is I'd rather have the engine that pulls the box blade best in its particular vehicle. We'd have to know more than just the engine to make a choice.

Why is it that my 28 HP tractor can probably pull my 350 HP pickup all over my yard (I'm not going to try)? Is it horsepower? Is it torque? Magic, perhaps. No, on second thought, just clean living.

- Just Gary