torque output of a 730d

wondering if anyone has every heard of the torque output of a 730D when someone has dynoed one? Based on the amount of work most people claim the tractor will do, torque must makeup for only having 59-60 hp. Not anything important, just a curious question?
 
If you do a google search for Nebraska test data, you'll find a lot of information. The 730 wasn't tested, but the 720 data is considered accurate because there were few engine differences between the two
tractors.

720 diesel shows 116% of rated speed torque at about 60-65% of rated speed.
720 gas shows about 110-111% max.
An IH 450 diesel shows 103% of rated speed torque as a max. The IH 560 test does not show torque data that I have found.
 
Torque and horsepower are tied together mathmatically. The formula is HP= torque X RPMs divided by 5252, or torque = HP X 5252 divided by
RPM's. Doing the math gives you 280 ft lbs of torque using 60 hp at 1125 rpms.
 
Torque is what is measured by a dyno. It is mathematically turned into a hp value ( HP= torque x rpm x 5252 ). What you are referring to about the 60 hp JD is, since it makes that hp at 1100-1200 rpm instead of 1800-2000 like it's competition , it still has a higher % of it's torque/hp even when lugged down to 700 rpm. Drop the rpm almost 50% on any of the competition and see what % of their power they still have. Torque curve. When working , these things hardly ever seen anymore than 1000 rpm and probably a lot of time at 800 rpm. Unfortunately for the 2 lungers , there's a limit to the cubic inches that can be efficiently filled through 2 ports and two valves and rpm limited by looong stroke/rod angles. More cylinders , more valves/ports to fill them , higher rpm (ie HP ) and then you just add an over-under power shift/torque amp. to get it to stay in the rpm/hp sweet spot to get it through the tough spots. Pullers have proven what you can get out of a stroked 2 cyl. Put in field it won't last long. What else in the '50,s had 60-70 hp (720/30-820/30) and is still living and healthy in the numbers that are out there?
 
Also those models just seem good at putting the power to the ground ! A lot of it has to do with the weight of the machine and most of it on the rear end. I once heard 2 cyl. were 70% rear and 30% front ? not sure how it divides up in the real world ?
 
You are right there... depending upon how weighted, they may have been even over 70% on the back axle, much different than most or all competitors. 730s were also heavy, weighing nearly as much as a 4010, and more than a 3010.

Back in the early 90's we used our 720 to pull tandem axle silage boxes. We had a 3020 equipped with the same tires. One fall (93) was very wet, and the 3020 got stuck repeatedly in places. No matter, unhook, the 3020, back the 720 in its place, and she'd pull the boxes right out! That weight and its placement made all the difference.
 
COONIE - You need to go back about 2-3 more years on the Nebraska tests to get real #/ft at specific rpm torque numbers. About '53 to '55. And sorry to burst everybody's dream but the BIG TORQUE of the 2-cylinders is a MYTH. The IH gasoline 4-cylinders made peak torque at half full load rpm. And a Super H made torque numbers close to a 60 gasoline JD, Super M/400 made peak torque comparable to a 70. The 4-cyl IH start on gas diesels were down on HP and torque compared to the gasoline IH engines.

Thing I always noticed was an IH engine would run at governed speed until over loaded and pulled down, WAY down, in the case of Super M-TA's & 450's, around 1000 rpm to pull the T/A, then once back up to 1450, let the T/A fly back ahead. With varying load the engine speed would not vary more than 10 rpm. With a 2-cyl. JD the engine speed varied constantly, like the R we had for a couple months, historically weak crankshaft, no center main bearing, pull the engine down below the 975-1000 rpm full load rpm and you risk a broken crankshaft. The gasoline Super M-TA and R were less than one HP apart on the dyno, but the SM-TA would out work the R by a large percentage, the R burned less fuel, but gasoline was about $0.20-0.25/gallon, getting the work done on time was more important.
 
If we pretend there are no losses in the drive train and assume all of the engine HP is getting to the PTO, the 730 engine running at 60 HP & 1125 RPM has to be producing a torque of 280 Ft Lbs.

If we make the same magical assumptions of or for a Super M's drive train when he's sitting there pulling a 60 horse load and the engine is running 1650 RPM, the Super M engine has to have a torque of 191 Ft Lbs.

Do the same with a 3020 running 2400 RPM and it's engine has 131 Ft Lbs of torque.

An 830 pulling 60 HP with this same magical lossless drive train but only running at 1000 RPM will have a 315 Ft Lb torque.

A Minne U might pull the same 60 horse load at 1470 RPM and a torque of 214 Ft Lbs.


Remember the torque is the actual FORCE applied to the loads no matter what they are. The numbers I've picked and listed here are not 100% accurate but they're ball park numbers suitably close enough to illustrate the scenario. As you operate the machines listed, which in this line up would feel to have the most brute force guts and lugging power when pulling a 60 horse load? Probably not hard to tell.

The real magic comes from which has the fewest losses in the drive train and as one other guy said how well that power is put to the ground by weight distribution. Toss in the fuel economies and operating costs along with operator comfort, the work the machine is asked to complete, dealerships and their personalities and that's when things really get interesting and cause brand allegiances to emerge.

All these things are why I give people the blank stare poker face look when they ask me what brand of old tractor is best? I always say that depends and ask, best for what!

Hope that makes sense.
 
Often the torque rise such as that of a 730 will make the tractor feel more powerful than you might expect, and perhaps more powerful than it really is. Or another way of thinking of this is that a tractor engine
where peak torque is around max revs will rapidly stall once loading starts to pull the revs down, whereas a 730 will just go on fighting harder without having to change down a gear.
 
Holly Diesel Smoke, did I get more than I had planned on. I understand the relationship to torque and horsepower and the math to get there. Had physics in college to. However, we all know that some tractors horsepowers seem to stand taller than others and part of that I believe must have something to do with the long stroke of the 2 cylinder, and how low the torque is produced.
I do need an additional education on the terminology used by connie minne on % of speed and torque. I've pondering that over and can't come up with an understanding.
I was pretty impressed with the depth of knowledge some of you guy have on the subject.
Thanks
 
Who cares what the numbers are. I go by in the field experience and the 2 cylinder diesels were awesome on the torque and lugging.
 
I think what Coonie Minnie was saying might be easier understood with numbers put in it.

Let's say the engine was rated 60 HP at 1125 RPM. That RATING requires a torque of 280 FT Lb because that's the torque it put out at its "rated HP" this is the "rated" torque.

The 116% of RATED torque (which some call torque rise) at 60 to 65% of rated SPEED means it was putting out a torque of 324 Ft Lbs (the rated torque of 280 times 1.16) to the drive train when it was being lugged down to about 700 RPM which is 62.5% of the RATED speed.

Because of the decreased speed however it was only putting out 43 HP instead of 60. It is this raw guts torque being available (116% of rated torque) that lets it "brute force" its way through an overload condition schlogging the plow over a clay knob or through a patch of real sticky gumbo.

As another fellow said correctly, the dyno measures torque and at certain speeds it pointers are calibrated to point to numbers representing the HP it's consuming.

I've had guys watch me run a tractor on the dyno at shows & see that HP needle jump up to a reading of maybe 10 HP over the RATED HP and insist they saw a bone stock all fuel long hood A put out 35 HP! Been accused of not being truthful with them saying I know it has more than that.... I saw it!

Because HP is speed related and it's only running 700 RPM even though that "torque needle" is pointing at 35, it's really working at about 20 HP.

Maybe that helps... maybe not?

I hope it did.

Later.
 
(quoted from post at 16:21:02 10/19/15) I think what Coonie Minnie was saying might be easier understood with numbers put in it.

Let's say the engine was rated 60 HP at 1125 RPM. That RATING requires a torque of 280 FT Lb because that's the torque it put out at its "rated HP" this is the "rated" torque.

The 116% of RATED torque (which some call torque rise) at 60 to 65% of rated SPEED means it was putting out a torque of 324 Ft Lbs (the rated torque of 280 times 1.16) to the drive train when it was being lugged down to about 700 RPM which is 62.5% of the RATED speed.

Because of the decreased speed however it was only putting out 43 HP instead of 60. It is this raw guts torque being available (116% of rated torque) that lets it "brute force" its way through an overload condition schlogging the plow over a clay knob or through a patch of real sticky gumbo.

As another fellow said correctly, the dyno measures torque and at certain speeds it pointers are calibrated to point to numbers representing the HP it's consuming.

I've had guys watch me run a tractor on the dyno at shows & see that HP needle jump up to a reading of maybe 10 HP over the RATED HP and insist they saw a bone stock all fuel long hood A put out 35 HP! Been accused of not being truthful with them saying I know it has more than that.... I saw it!

Because HP is speed related and it's only running 700 RPM even though that "torque needle" is pointing at 35, it's really working at about 20 HP.

Maybe that helps... maybe not?

I hope it did.

Later.

Yes that does help me to understand the whole concept. I appreciate the education. Learn something new every day
Thanks
 
You're very welcome.

I recall decades ago when our big tractor was a Farmall H with a power kit in it. When fitting ground back then we wanted to throttle back in the turns to prevent throwing up ridges with our old drag disc & spike tooth. The Farmall H was a fine machine but he simply would not turn the ends at reduced throttle without clutching & dropping down a gear.

Dad never like having the foot clutched Farmall H and the hand clutched JD H at the same time. Believed it too much like an accident waiting to happen by not clutching the right way at the right time so he got another Deere replacing the H with a '46 longhood A. The A had less HP than the H but it pulled that same tain all day long throttling up & down through the turns never clutching or shifting. Just pull back on the speed control lever until about straight out & 'round the ends he went nice & slow without tossing up ridges. Once straightened out, all the way forward with the speed control & crack crack crack back up to speed it went.

That's the field experience Greenenvy was talking about.
 
Broken R cranks are an absolute wives tale- not worth my breath- but here's a visual on the 830's Torque Rise- as you can see, max torque is at 600 RPM.
a203884.jpg
 

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