How any PTO horse power does an 8N have?

[Youare]

I have a 1951 Ford 8N and a 2001 Kubota L3000DT. The Kubota is rated a couple of horsepower more on both the engine and PTO.

I have a Farmi winch that I have used on both tractors. Two things are really noticable. PTO horsepower is developed at very different engine RPM's on each tractor. The 8N is a slower turning engine, the Kubota dosen't reach full PTO speed until you get to 2300 RPM.

I have found when using the winch pulling logs with the 8N it will out pull the Kubota even though it is rated a little higher in horsepower. The other big factor is tractor weight, the 8N is a little heavier than the Kubota.

The horsepower to weight ratio on the 8N is better than that of the Kubota. One is a utility tractor the other is a compact.
Power steering, 4WD, better loader, and more speed ranges make the Kubota shine. However, the 8N was one nice tractor.

Randy

 

[budman72]

Something often overlooked is that everyone talks about HP, but torque is what matters. I don't know the spec's on the 8N, but usually stroke is what puts out the torque.

I recall seeing an old car once, 500 CID, 150 HP, 0-60 in about 6 seconds(specs from memory, but close) It didn't have HP, but the torque talks! Try that in your 150 HP econobox.

 

[TresCrows]

I recall seeing an old car once, 500 CID, 150 HP, 0-60 in about 6 seconds

A 6 second zero to sixty really is not all that quick these days. Quite a few cars can do it under 5 and motorcycles in half that, even slow ones. Some people say torque, some say horsepower, some displacement, some like engines that rev, some not, it is a combination of factors that tailor an engine to a specific purpose. Tractor engines with lot's of torque really would not fare well in a sports car. The equation for horsepower takes into account torque, stroke and RPM and BMEP etc so you cannot seperate one from the other mathematically. J

 

[Anonymous Poster]

Lets not go there. I was intentionally avoiding ther HP vs torque thingy. Do a search on torque if interested. But.... it is interesting that the same owner of an 8n gas and a newer diesel with slightly more hp said that the gasser will outpull the diesel with a PTO driven winch . Sort of blows the diesel power myth out of the window doesn't it.

 

[Anonymous Poster]

A 6 second zero to sixty really is not all that quick these days. Quite a few cars can do it under 5 and motorcycles in half that, even slow ones.

Maybe so, but compare the weight of the vehicles then and now. They outweighed the new cars by 3:1. That makes your 5 second car a 15 second car...

 

[SteveBenson]

I had to think about the torque vs. HP issue a while back when buying a truck for towing. I was looking at a dodge 3500 with a turbo diesel in it. I was suprised when looking at the specs that the engine had only 225 HP. I mentioned to the sales guy (who was the truck sales guy) that I thought the HP was a little on the low size. He said it was the torque that matters not the HP. I had to go home and think about this and rationalized as follows:

HP = T x RPM, so HP is proportional to the torque. But how an engine performs over a range of RPMs is an important factor in overall performance. That's why diesels tout their wide power bands.

HP = The rate at which work is done. Towing a load up a hill is a specific amount of work, no matter how fast it is done. Your speed going up the hill dictates the rate at which this work is done. Therefore, your speed up the hill is directly proportional to the HP required. Therefore, HP is the determining factor in this scenerio (which is probably the most important scenerio in heavy towing). So HP does matter.

So the guy was trying to pull the wool over my eyes a little, or maybe he just didn't know what he was talking about. But I think the real selling point of this engine was that it has a very wide flat power band and delivers the same power (about 225 HP) over nearly it's entire operating range. Therefore it's much more effective at transferring that power to the ground , all the time. This is unlike some little sports car engine that develops 225 HP at 5500 RPM, but probably only half that at 3000 RPM. This means you are only able to achieve top HP at certain fixed speeds. And nobody going to drive around all the time at 5500 RPM.

Thinking about it further I've come to think about it in the following way: Torque relates to the question; Can I do it? HP relates to the question; How fast can I do it?

Of course you need to look at the torque (and thus HP) over the operating RPM range of the motor to evaluate the true overall performance of the engine /forums/images/graemlins/grin.gif

 

[Anonymous Poster]

Yep Steve you pretty much have it. Hp does matter but low rpm torque is very important in tractors and pulling vehicles.

 

[TresCrows]

Maybe so, but compare the weight of the vehicles then and now. They outweighed the new cars by 3:1. That makes your 5 second car a 15 second car...

Please don't think I am picking on you. I am just not agreeing with this statement. It is popular to believe cars today are lighter built and yes many are but many are not. Modern automobiles can be as heavy or heavier and yet many have increadible acceleration. My Tundra 4X4 is pretty chunky but it will embarrass many cars old and new when it comes to acceleration, 0-60 in under 8 seconds, curb weight 4,700 lbs. Most personal vehicles weigh between 3,000 and 6,000 lbs depending on what exactly it is, then and now. The Viper is an example of torque and horsepower combined with a fairly light chassis. Some of the big Chevy and Ford PU trucks are examples of 6,000 lb vehilces (or close) that have huge power and darn impressive acceleration. The Kawasaki Z1000, 0-60 in 3.15 seconds, 493 lbs wet. Dodge Viper, Corvette, Porche and several fairly mundane cars can easily go under 6 and even 5 seconds. My 3,500 lb Mustang SVO, 1986, would do about 5.5 seconds, it was not stock but not wild either. It was also a 4 cylinder. On a dyno it pulled 275 horses at 19 psi boost. I put 65,000 miles on that car trouble free--mostly--- and sold it to a guy down the street (back home) who collected cars. He still has it.
Anyway, I just like talking about vehicles--sorry---in a way horsepower relates to torque like voltage relates to amperage. One without the other is useless. The good old 8N was wisely designed with it's large displacement engine which makes plenty of torque avaialbe. I bet it has a very broad power range also. J

 

[SteveBenson]

Yep, it's the low RPM torque that gives you the wide power band. And, of course, the "can do".