Does HP matter?

[MARKMILES77]

Max horsepower is really important if you are going to use it.

It's more often used as a marketing point to say the Big Green tractor has more HP thean the Big Blue tractor so the owners can brag over morning coffee.

Guys that use their machines for primary tillage in tough ground, lots of acres, big implements, and a narrow planting window use that rated horsepower. Having said that most, compact tractor owners don't operate under those conditions.

Another issue, just to complicate matters, is that newbies often undersize their tractors and then find out they could do more if they had more power and weight so they start looking for a bigger machine.

I'll repeat my first statement. Max horsepower is really important if you are going to use it.

Where are you at with your tractor?

This is not a case of me trying to choose between buying a 3032E or a 3038E. They were just examples.
It is me trying to understand in a theoretical sense how torque and HP relate to each other and which is more important for tractors.

Mark

 

[MARKMILES77]

According to tractordata the torque for the 3032E is 80ftlbs @ 1680 rpms', the 3038E is 88ftlbs @ 1680 rpms'. That is a difference of 8 ftlbs or 10% increase further the 3038E will turn 2500 rpms' which is 100 more than the 3032E. All of that said I wouldn't consider them to be the same.

The Australian John Deere website lists these two models as follows:
Torque at rated engine speed (2500 RPM) ft/lb (N/m)
JD 3032E 62.7 (85.0)
JD 3038E 62.7 (85.0)

So the question of whether the 3038E's extra HP is useful depends upon what the engine PTO speed is right?
If you run the engine of both tractors at close to 2500 RPM to get 540 PTO speed then the 3032E has exactly the same torque as the 3038E. If on the other hand the engine's run at closer to 1680 RPM to get 540 PTO speed then the 3038E has more torque and therefore an advantage.

I think that makes sense?

Mark

 

[whistlepig]

danielmiessler.com | study | horsepower

 

[LD1]

This is not a case of me trying to choose between buying a 3032E or a 3038E. They were just examples.
It is me trying to understand in a theoretical sense how torque and HP relate to each other and which is more important for tractors.

Mark

Okay, that makes sense. And in that case, I'd say the HP is the more important number to watch. As you can never (easily) make more of it. But torque on the other had can be gained by gearing. I think it is safe to assume that the tractor has the right gearing to do the work it was designed to. IE: Every tractor I have owned had pleanty of gearing (torque) to spin the wheels in about all conditions. Just maybe not in high range all the time.

The tractor with the most HP will do the work quicker.

The Australian John Deere website lists these two models as follows:
Torque at rated engine speed (2500 RPM) ft/lb (N/m)
JD 3032E 62.7 (85.0)
JD 3038E 62.7 (85.0)

So the question of whether the 3038E's extra HP is useful depends upon what the engine PTO speed is right?
If you run the engine of both tractors at close to 2500 RPM to get 540 PTO speed then the 3032E has exactly the same torque as the 3038E. If on the other hand the engine's run at closer to 1680 RPM to get 540 PTO speed then the 3038E has more torque and therefore an advantage.

I think that makes sense?

Mark

I am not sure that the 1680 is actually the PTO RPM. (I am not sure). The only listing I see is that the 1680 is the peak torque RPM. In which for the 3038 is 88.5ft-lbs and for the 3032 it is 80. There fore the 3038 IS capable of doing MORE work @ 1680 rpm.

We can also do a little reverse figuring here also:

The 3038 is rated at 36.3HP @2500rpm That would make the torque @ 2500rpm 76.25

The 3032 is rated at 31.0HP @2400rpm That would make the torque @ 2400rpm 67.8

To add even more to this puzzle, the 36hp 3038 is 6ci SMALLER in displacement:confused3: Why the difference? How are they getting that much less HP out of the bigger 3032 engine?? Same comp ratio of 19:1, and they even share the same stroke length with the 3032 bore being bigger? And I dont see the extra 100 rpm's causing that much difference in HP, cause after all, at 1680rpm, the smaller motor makes more torque????? Could it be just de-tuned that much? I see a big potential in the 3032 for upping the HP

 

[Jerry/MT]

This is not a case of me trying to choose between buying a 3032E or a 3038E. They were just examples.
It is me trying to understand in a theoretical sense how torque and HP relate to each other and which is more important for tractors.

Mark

HP=(Torque x RPM)/5252 so torque and horsepower are inseparable. Peak torque and peak horspower occur at differnent rpm's and both are important for tractors. Peak torque occurs at lower rpm mainly due a higher pressure delivered to the cylinder at low engine airflows. Delivered cylinder pressure decreases with increasing airflow(increasing rpm) because of increased velocities in the induction system (aircleaner, manifold,valves). Valve timing also comes in to play. Max horsepower is limited by max temperature in the cylinder and air flow being limited by losses and occurs at a higher rpm.

 

[SPYDERLK]

If torque is the same, work that CAN be done is the same.

You can ALWAYS gain torque by gearing. Thats no secret. But HP remains constant (minus a little frictional losses).

If you can gear the the higher HP machine to do more work, you can ALSO gear the lower HP machine to do just as much work. (IF the engine starts off with the same torque)

And the RPM's have nothing to do with the time element of HP. All the RPM's mean is THAT is the point that they measured the HP. Two totally different things. RPM is just the point at which the measurment is taken.

You can take a 100hp engine with 100ft lbs of torque, and then you can take a 20hp engine with the SAME 100ft-lbs, and the work they are ABLE to do is exactally the same. The 100hp engine will just be quicker is all.

HP=(Torque x RPM)/5252 so torque and horsepower are inseparable. Peak torque and peak horspower occur at differnent rpm's and both are important for tractors.

Easy enuf to confuse people with truth when you separate key issues too much. Time is key to power. ... ForcexDistance, Work [Energy] is key to Dynamic torque. -- Me and my torquewrench can beat either of those engines. ... Who says that ant - cant - move that rubber tree plant.
larry

 

[DarkBlack]

If torque is the same, work that CAN be done is the same.

You can ALWAYS gain torque by gearing. Thats no secret. But HP remains constant (minus a little frictional losses).

If you can gear the the higher HP machine to do more work, you can ALSO gear the lower HP machine to do just as much work. (IF the engine starts off with the same torque)

And the RPM's have nothing to do with the time element of HP. All the RPM's mean is THAT is the point that they measured the HP. Two totally different things. RPM is just the point at which the measurment is taken.

You can take a 100hp engine with 100ft lbs of torque, and then you can take a 20hp engine with the SAME 100ft-lbs, and the work they are ABLE to do is exactally the same. The 100hp engine will just be quicker is all.

????????

 

[ATP]

Okay, that makes sense. And in that case, I'd say the HP is the more important number to watch. As you can never (easily) make more of it. But torque on the other had can be gained by gearing. I think it is safe to assume that the tractor has the right gearing to do the work it was designed to. IE: Every tractor I have owned had pleanty of gearing (torque) to spin the wheels in about all conditions. Just maybe not in high range all the time.

The tractor with the most HP will do the work quicker.


I am not sure that the 1680 is actually the PTO RPM. (I am not sure). The only listing I see is that the 1680 is the peak torque RPM. In which for the 3038 is 88.5ft-lbs and for the 3032 it is 80. There fore the 3038 IS capable of doing MORE work @ 1680 rpm.

We can also do a little reverse figuring here also:

The 3038 is rated at 36.3HP @2500rpm That would make the torque @ 2500rpm 76.25

The 3032 is rated at 31.0HP @2400rpm That would make the torque @ 2400rpm 67.8

To add even more to this puzzle, the 36hp 3038 is 6ci SMALLER in displacement:confused3: Why the difference? How are they getting that much less HP out of the bigger 3032 engine?? Same comp ratio of 19:1, and they even share the same stroke length with the 3032 bore being bigger? And I dont see the extra 100 rpm's causing that much difference in HP, cause after all, at 1680rpm, the smaller motor makes more torque????? Could it be just de-tuned that much? I see a big potential in the 3032 for upping the HP

Good answer above....!
The answer specifically to the 3032 jd and 3038e is that the 32 is more cubes natural aspiration
The 3038 is less cubes and turbo charged....
But to answer the op question... If more horse is available
Get it.. If all things else are equal..... But as we see here.... All other things are never equal...

 

[LD1]

????????

What part do you not understand:confused3:

 

[gmj]

Size always matters

 

[Monster5601]

This is not a case of me trying to choose between buying a 3032E or a 3038E. They were just examples.
It is me trying to understand in a theoretical sense how torque and HP relate to each other and which is more important for tractors.

Mark

Look at torque and horsepower from this facet, torque is the amount of twist that can be applied to a shaft. Horsepower is how fast the torque can be applied.

 

[MF1433V]

Look at torque and horsepower from this facet, torque is the amount of twist that can be applied to a shaft. Horsepower is how fast the torque can be applied.

I agree and would add another non-technical comment, torque will get you there, HP keeps you there. What I mean is torque is the power to accelerate, etc...but HP allows you to maintain the work / speed etc...

That is why in the automotive world Torque is all important for 0-60 times but HP is critical for Top Speed numbers.

So yes it does matter, (but only if you actually will use those extra horses).

 

[jejeosborne]

HP=(Torque x RPM)/5252 so torque and horsepower are inseparable.

This is all that anyone needs to look at. HP and Torque are always equal at 5252 rpms. I would choose the tractor that creates the most torque up to and at pto speed. End of story. Who cares if your engine makes more HP at higher rpms, these are tow and work machines not race cars.

 

[RaydaKub]

This is all that anyone needs to look at. HP and Torque are always equal at 5252 rpms. I would choose the tractor that creates the most torque up to and at pto speed. End of story. Who cares if your engine makes more HP at higher rpms, these are tow and work machines not race cars.

Yikes! No thanks! Me thinks the torque at 5252 rpms isn't gonna be so good.

 

[jejeosborne]

Yikes! No thanks! Me thinks the torque at 5252 rpms isn't gonna be so good.

No thanks!? You disagree?

 

[SPYDERLK]

Yikes! No thanks! Me thinks the torque at 5252 rpms isn't gonna be so good.

No thanks!? You disagree?

... How about HP will always be half the Torque at 2626. He'll be more comfortable with that.

 

[DarkBlack]

If torque is the same, work that CAN be done is the same.
incorrect

You can ALWAYS gain torque by gearing. Thats no secret. But HP remains constant (minus a little frictional losses).
correct

If you can gear the the higher HP machine to do more work, you can ALSO gear the lower HP machine to do just as much work. (IF the engine starts off with the same torque)
incorrect

And the RPM's have nothing to do with the time element of HP. All the RPM's mean is THAT is the point that they measured the HP. Two totally different things. RPM is just the point at which the measurment is taken.
incorrect

You can take a 100hp engine with 100ft lbs of torque, and then you can take a 20hp engine with the SAME 100ft-lbs, and the work they are ABLE to do is exactally the same. The 100hp engine will just be quicker is all.

incorrect

If you are actually interested in physics, Your local community college would probably offer classes. It's probably the best start to truely understanding such a complicated subject.

 

[LD1]

If you are actually interested in physics, Your local community college would probably offer classes. It's probably the best start to truely understanding such a complicated subject.

Wow, I dont even know where to begin.

For starters, I think you are just trolling for an argument. Simply trying to tell me I am wrong (when I know I am right) without anything to back up your statement.

If you are going to tell me I am wrong, please explain to the crowd why YOU "think" I am wrong??

And the comment about taking a class at a community college...:laughing:....are you just that big of a prick on the internet, or are you that way in person too:laughing:

Now....unless you want to join in on the discussion, in an adult and grown up manner, and share your points of view with why you feel I am wrong, I suggest you go find another forum to troll.

 

[DarkBlack]

If you didn't try to cover up your insecurity, and lack of true knowlege on the subject while resorting to small minded name calling, I'd actually convince myself to take the time to explain to you why your postings on this subject are wrong. I think you must be re-writing physics books here.
The very fact that you take my recomondation to study the subject for real if you want to tell others about... it as an insult... says it all:laughing:
Why invest the time/money in a specialized areaof knowlege when you can just pop up a wiki-pedia screen and post on your favorite site as an expert?
Oh, by the way, I hope if you every need serious help from a profession, like surgery, You might want to start hoping now, that the doctor did real studying at a college, not just reading your internet education on a tractor forum. You might be mistakenly calling the person with real in-depth knowlege needed a troll.:thumbdown:

 

[RaydaKub]

No thanks!? You disagree?

First off, I'm not an authority on the subject. But I recall another thread talking about the burn rate for diesel in the cylinder and that because of that rate, an ideal rpm for max torque was down around 1800-2000, maybe up to 2400, I don't recall.

But aside from that, I don't want a diesel that I want to keep running at that rpm. The clatter at start up would be horrendous.