HP Rating: Gross or PTO???

[BillG_in_TX]

Neophyte,

I think the Garys missed the point of your question. You were asking about the drop from Gross to Net, not from Gross to PTO. I think your rule of thumb is fairly accurate. For example, in the Kubota Grand L30 series, comparing Gross to Net to PTO(gear) to PTO(hydro), the numbers are:
L3130 - 32.1 / 31.0 / 25.5 / 24.0
L4330 - 43.2 / 41.0 / 36.0 / 34.5

So the drop from gross to net hp is 1.1 for the 3130 and 2.2 for the 4330. The drop to PTO hp is much more pronounced, especially for the HST.

 

[Golfgar4]

Uh, Bill???

/forums/images/graemlins/blush.gif /forums/images/graemlins/crazy.gif /forums/images/graemlins/blush.gif /forums/images/graemlins/crazy.gif /forums/images/graemlins/blush.gif /forums/images/graemlins/crazy.gif /forums/images/graemlins/blush.gif

On behalf of the other 2 Gary's (even though their names only have 1 R in them), you got us! /forums/images/graemlins/frown.gif

I went back and re-read Neophytes reply and that is exactly what he was asking!

What can I say? /forums/images/graemlins/confused.gif Must be time for me to retire!! /forums/images/graemlins/smirk.gif

 

[fivestring]

DOH!

You got that 40 acre golf course ready for the Gar(r)ys???????

 

[fivestring]

I was still thinking of the original question -- "Are these Gross HP ratings for the tractor overall or PTO HP ratings?" /forums/images/graemlins/confused.gif

 

[Golfgar4]

</font><font color="blue" class="small">( You got that 40 acre golf course ready for the Gar(r)ys??????? )</font>

Working on it! Better work faster, huh? /forums/images/graemlins/crazy.gif

 

[Neophyte]

"Hi, I'm Garry, this is my brother Gary and this is my other brother Gary." /forums/images/graemlins/grin.gif

Don't sweat it guys, everyone is allowed a brain cramp now and then ... especially when you are trying to help someone out. /forums/images/graemlins/wink.gif

 

[Slamfire]

Somebody posted a formula for taking pto hp and converting it to net hp. I ran it on my 18 pto hp and came up with someting like 22 hp at the rear wheel. That would be 122%, although I'm sure that wasn't the exact number. From there you could compare to the gross hp, although I don't know why you'd want to know that number. /forums/images/graemlins/wink.gif

 

[rozett]

I agree with the others... when talking about attachments, it's PTO HP that matters.

Actually, gross HP is a pretty useless number anyway. The manufacturers hide behind gross HP so that you and I can't compare models for what really matters.... torque delivered to the rear axle!

 

[5030]

Neophyte:

Hi, I'm Daryl and this is my other brother Daryl....Boy, I wish my mother had named me "SUE" /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

On the thread side of this, Cummins Engine Company figures a 20% decrease in flywheel (which would be Net horsepower) versus rear wheel horsepower. That could be applied to a tractor. Frictional looses in the transmission and final drive will account for about 20% reduction in useable horsepower with a gear type transmission. I'd imagine that it would be more like 25% with a hydrostatic transmission. The Cummins standard is what all engine manufacturers use as a benchmark. Remember, that's horsepower to the drive wheels, not the pto shaft. That's an animal of a different color.

 

[Neophyte]

This question is probably a thread by itself but here it goes ...

Why don't manufacturers publish torque values and where can I find these values for the tractors I'm currently looking at?

FYI, I have been looking at the JD 4310 or 4410, NH TC33D or TC35D and Kubota L3130 or L3430. Anyone happen to know the torque values on any of these tractors?

I found it odd as well that car & truck manufacturers publish torque values but you don't see it on any of the tractor spec sheets. I think I would rather know the generated torque of a work tractor before, lets say, a family sedan ... if you know what I'm mean. /forums/images/graemlins/confused.gif