Really Kubota! rated speed 395 RPM faster than PTO speed??

[kuboman]

Modern tractor engines will increase the power as the rpm drops off from rated rpm. On any of ours there is at least a 10% increase in hp down to about 1700 rpm then it starts to drop off. Nothing new about that, the larger diesels have been doing that going on 20 years.

 

[Ken45101]

I know I'm on the conservative side, but I do not want to be running an engine at max rpm for mowing or other PTO work. I definitely want an engine that gives me the 540 PTO speed below max rpms. That's one thing I don't like about the MX series (e.g. MX5100) is that you have to be running it flat out to get 540 rpm PTO speed. I was always taught not to run an engine at max although I'm sure the Kubota engines are engineered to do their job well.

BTW, I have both the M9540 and the M5040. Good tractors.

Ken

 

[RickB]

I hate to shock all of you, but the reported differences in rated and maximum horsepower are typical throughout the industry, and have been for decades. Google Nebraska Tractor Test Results and read a bunch of official test data. Nothing new, different, or out of the ordinary.

 

[RickB]

Modern tractor engines will increase the power as the rpm drops off from rated rpm. On any of ours there is at least a 10% increase in hp down to about 1700 rpm then it starts to drop off. Nothing new about that, the larger diesels have been doing that going on 20 years.

There's a difference between peak HP and peak torque.

 

[kuboman]

There's a difference between peak HP and peak torque.

Yep I know, I am talking HP right now. As mentioned above go to Nebraska tractor tests and have a read.

 

[RickB]

Yep I know, I am talking HP right now. As mentioned above go to Nebraska tractor tests and have a read.

Yeah, that was my idea.

 

[art]

Engine manufacturers have been doing this for years. The old IH 1086 was one of the first, at factory rated horsepower it was 130.6 and at 80 percent it was 135 horsepower.

I relate to this as being more of a constant torque engine and simular to the old PT 250 cummins which had a huge pwoer bulge.

Many of the newer computer operated diesels are running a forty plus horsepower power bulge!

 

[art]

Engine manufacturers have been doing this for years. The old IH 1086 was one of the first, at factory rated horsepower it was 130.6 and at 80 percent it was 135 horsepower.

I relate to this as being more of a constant torque engine and simular to the old PT 250 cummins which had a huge pwoer bulge.

Many of the newer computer operated diesels are running a forty plus horsepower power bulge!

 

[slowzuki]

I don't think the Nebraska tests were your idea, how old are you?

(I know what you meant, but the tests were mentioned earlier in the thread)

BTW folks, you want your torque to rise as rpm falls off or the tractor will feel flat and quickly lose rpm under heavy loads.

Yeah, that was my idea.

 

[Jay4200]

huh?? Your engine produces MORE horsepower the the slower it runs? I learn something everyday. I know torque will rise but are you sure your horsepower goes up 20 hp when you turn it down 200 RPMs?

Of course. All engines do that, eventually.

JayC