Gross verses Net HP - what the heck?

[MChalkley]

JimBinMI - This gets confusinger and confusinger (as a teacher, I'm sure you appreciate my command of the English language). I shouldn't have made such a broad, sweeping statement, since I'm only familiar with the L Series Kubotas (but, to make up for it, I'm very familiar with them /w3tcompact/icons/wink.gif). Anyway, to quote you, "I have before me" two brochures, both Kubota, both dated 2000, one for the Grand L series in general, the other for the L4610 in particular. Both brochures list Gross, Net, and PTO HP's, but all model numbers correspond to Net HP. So, apparently, even Kubota isn't consistent between different series of tractors. Go figure. I guess this once again underscores the need to do your homework, so you know what you're buying.

BTW, obviously the NH marketing folks aren't mathematicians; otherwise your TC18 would be a TC19! /w3tcompact/icons/laugh.gif

MarkC

 

[huckflynn]

Based on everything I was reading in various forums on the web, the one thing you could not trust when shopping for a tractor was hp. I had a 20hp Kohler engine in a Yardman that was underpowered for my needs and people were telling me to move "up" to an 18hp Kubota. I ended up getting a BX2200 but the information gathering and decision making process was unnecessarily complicated by a lack of standards for comparison. For the epitome of confusion try this link from Carver Equipment: http://www.carverequipment.com/comparing_the_bx_sub.htm


Huck

 

[MChalkley]

Interesting link. Of course, it depends on what you're trying to compare and what you want to do with the tractor. Generally speaking, HP ratings (of the same type, of course, since that's what this thread is all about) can be compared one to another just fine, as long as you're also comparing engines with similar characteristics. Remember that HP is a function of the engine's torque and RPM, so directly comparing the HP of a diesel engine with a maximum RPM of 2800 to a gas engine with the same rated HP at 4000 RPM is bound to lead to a misinformed decision. It's a very complicated topic, but generally speaking, for the uses a tractor is put to, a 20 HP diesel will work a 20 HP gas engine into the ground without breaking a sweat, and I'm talking about before the gas engine is worn out and the diesel still has 2/3 of its useful life expectancy left.

On another branch of the topic entirely, you also have to consider what you're trying to accomplish. Not too long ago, I pulled a friend's 68 HP Deutz-Allis tractor out of the mud where he'd gotten stuck in his field. So that means my L4310HST is more "powerful" than his, right? Again, it depends on what you want to do with it. The fact that mine is 4wd and his is 2wd has a bearing on it. I'd rather have mine, that's for sure. But he uses his for farming, and he runs some implements on his PTO that I sure wouldn't run with mine. Know why? Because he's got 68 HP and I've only got 43. It makes a big difference.

If it's pulling power you want, then the fact of the matter is that very few tractors weigh even close to enough to use the available HP for traction. So, again, comparison's are fine as long as you're using the same units and understand the units involved, but just as importantly, you have to make sure that what you're comparing is really what's important to do the job you need to get done. My friend can verify that 43 HP will outpull 68 HP any day of the week, if you stack deck so everything else is in the favor of the tractor with 43. But I don't tease him too much because I know what he'll say - he'll just ask me if I want to try taking his 2,000 lb 8' bushhog that'll cut 4" trees for a spin. Uh, no thanks... /w3tcompact/icons/smile.gif

MarkC

 

[huckflynn]

Thank you for clarifying that horsepower is not a good standard for the average consumer. I came from the Mr. Ed School of Horsepower -- a horse is a horse of course of course - unless of course a diesel horse flogs a gas powered horse that's dead./w3tcompact/icons/wink.gif

Huck

 

[W5FL]

Hmmmmm...

My M6800SD shows 68 net HP and 62 pto hp. I can't find any mention of gross HP.

 

[hayden]

FYI - her'e the response I got from Kubota on this question. Definitions are good, but doesn't help the fact that they do not publish all the numbers, and the numbers that they do publish are inconsistent..

Dear Mr. Hayden:

Thank you for your inquiry to Kubota. Here is the response from the Sales
Department:

Your question is a good one and one that is often asked. Due to standards
that are set either by our Industry, or by competitors this is the way we
present our products to Market
We present three (3) Horsepower ratings
1. Gross Horsepower = This is the Manufacturers rated Horsepower for the
engine ONLY, meaning less water pump, alternator, etc. This is the maximum
rating for the engine only or stated differently the Starting Available
Horsepower.
2. Net Horsepower = This is the rating that provides available Horsepower
that will power a tractor, or operating Horsepower
3. PTO Horsepower = The available Horsepower available to power the Power
Take Off unit, this is again lower than Net Horsepower due to the drive
train consuming power
I believe this should help separate the purpose of stating multiple
horsepower rating as we do in our literature.
Thank-you for your question, and when it is time to buy a tractor, Please
consider Kubota.