dyno results. Explain those numbers

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Not real sure where you got that but I would say someone had a dyno contest of putting pulling tractors on one and the charts shows what the particular tractor was rated at and what the tractor is actually pulling.

Some do that at pulls so the HP difference in a class doesnt happen.

Looks like the rated HP of tractors and what they actually put out. Maybe it could used like a handicap system? Dave

I'm too lazy to look them all up but the rated figures don't make sence. Deere coulden't have sold a single 320 with a 16hp rating & if they were wrote in backward's someone ought to have plugged up the other plug wire before putting it on a dyno.

Same tractor on the same dyno pull. Rated is taken at 540 pto rpm. Then lugged to max torque.
Max is what the torque peaked at when the engine was lugged down. Not an actual HP number.
Example. If the max reading was taken at 75% of rated speed when lugged down. Then the HP reading on the dyno dial needs to be multiplied by .75 to actually show HP.
The two stroke had flat torque output. Didn't matter if it was 1200 or 2400rpm. The torque on the dyno was identical.
The difference on the 830's indicated one with slow and limited governor response.
Peak HP was different but once the rack finally moved to full open. The torque readings were similar.

The "rated" numbers at at "Rated Pto Speed". Not manufactures rated HP measured at Nebraska.
"Max" actually isn't a HP reading but an indication of torque rise when lugged.
It's somebody else's chart and writing. Sorry it's somewhat vague at first glance.

But why would it not indicate max HP? Why do you say that it is max torque. So when I put my JD 60 on my dyno and it has 43 hp at 540 RPM, then I lug it down to 65 hp, is that not max HP instead of max torque?

Stuart, horse power is torque x speed. When You lug a tractor down then the torque goes up BUT the speed goes down. Therefore the horse power goes down as well.
Most of the common Dynometers are just a hydraulic pump hooked up to a pressure gauge that is marked in Horse power. The big hand wheel is hooked up to a pressure regulator. So you are adjusting the pumps out put pressure therefore changing the load on the tractor. Most have a separate RPM gauge. So they are only showing the correct horse power when the RPMs are at the speed the gauge is calibrated for.
I used to have trouble, when I was selling equipment, with a neighboring dealer. He sold the same John Deere tractor we did but he told all of his farmers that he had "his" set special at the factory to have more horse power. He then would have one of his techs show the customer that on his dynometer. He had many of his customers convinced that their 4455 where putting out 200 hp. I got the last laugh many times when those same farmers came in to buy tillage equipment using that "200 hp" figure to buy their tillage equipment. Then they could not pull it. I then had them bring in their tractor and showed them the true horse power on a certified dynometer.

I think that they where meaning rated= at rated pto speed and max at maximum horse power reading on the dynometers gauge. If you read on down I explain to Stuart on how a dynometer really workes. So this "max" was just a number not a true horse power.
As for that 320 only putting out 16 hp. I have seen many tractors that would only put out half of what they where rated at. Many reasons for that. A example would be a worn out engine that is low on compression. A diesel with bad injestiors.

If 'Max' is not an actual HP number... then it's not really 'MAX' is it?
If you want to know HP at maximum torque why not just calculate what that figure is?

On a lot of modern high torque rise engines I'd take some of those numbers to be reasonably close to maximum power over rated. It's not uncommon to see 50% torque rise on some engines today which often gets produced very quickly below rated speed, thus a large power bulge. 10-20% power bulge is not uncommon... although the likelyhood of those tractors having the cam profile and turbo to produce it is low.

Rod

Amybody know where you can buy a M&W Dynometer? I burned my old one up in a shop fire.

Sounds like they got the same guy to run the dyno as the guy who dreams up the "horsepower" ratings for Sears table saws.

Mark, your reply made me chuckle. BTDT with the Sears saw! Switched it to 220V and it made a big difference but still underrated. Jim

OVERRATED! Sheesh, where's my head this morning? Jim