Rated HP vs Net

[Hilbilly]

I've been doing some comparison shopping, looking at Massey 1758 / 1759 and the Kubota L6060 / M7060. Mostly I've been comparing the "rated" hp of each. The Kubota owners manuals don't list rated hp but do list the net estimated engine hp and factory observed PTO hp. The Massey owners manuals repeat the same information given in the brochure but exchange the hp descriptions from rated to estimated.

L6060 Brochure
engine rated = 62hp ....... engine net = 60hp
pto = 53hp (doesn't state rated or net)

L6060 Owners Manual
engine net = 60hp manufactures estimate
pto = 53hp factory observed

M7060 Brochure
engine rated = 74.3hp......engine net = 71hp
pto = 64hp (doesn't state rated or net)

M7060 Owners Manual
engine net = 71hp manufactures estimate
pto = 64 factory observed

Massey 1758 & 1759 Brochure
engine rated = 59hp
pto rated = 44.4hp for 1758 and 45.6hp for the 1759

Massey 1758 & 1759 Owners Manual
engine estimated gross = 59hp
pto estimate = 44.5 cab and 45.6 platform

So what I have discovered is that I am not comparing apples to apples.

The things that stand out for me is;
1) Massey presents their information with the biggest numbers, ie rated or gross. They provide no net information.
2) Kubota lists the net estimated engine hp in the brochure and factory observed PTO hp. Curious as to what the estimated gross or net PTO hp would be.

I don't intend this to be a bashing thread of either Brand. Obviously I am considering both because I like them both.

EDIT: revised numbers to reflect the error of kw vs hp as noted in the 2nd post. Thanks for that.

 

[Seven Gables]

On your kubota owners manual specs I think those are kW numbers, pretty sure their cant be that big of difference in hp between the two, brochure and owners manual. B

 

[Hilbilly]

You are right!!!! In the Brochure the hp is listed first and the KW follow in brackets. In the manual it is reversed. I need to fix the numbers or delete the thread.

 

[Hozzie]

Typically net HP is simply a calculation of how much of the engine HP makes it to the ground vs what HP the engine produces. PTO HP Estimated is based on a percentage calculation similar to net HP that takes into account mechanical loss. For whatever reason, Kubota's system seems to have less % loss in PTO that a lot of other brands. I don't believe they are making it up, I have seen tests that confirm the HP numbers for the PTO.

The 7060 numbers of 71 and 64 are the correct values. I can't say if the MF numbers are net or estimated, but it is a big difference either way. The MF's would be closer in spec the the MX5800 from Kubota. It is 61 Gross/58 Net/50 PTO. I have one and really like it.

A Kubota will typically weight less in a similar size which is important (more weight is better). I have filled tires, etc to make some of that up. Unless you have a size issue for getting into and out of places and cost is not your main concern, I think the M7060 is certainly more tractor that the MF's.

 

[aczlan]

Gross engine horsepower is how much is put out by the force of the cylinders pushing on the crankshaft through the connecting rods.

Net engine horsepower is how much is left over after running accessories such as the water pump, alternator, etc.

PTO horsepower it is how much horsepower makes it through the transmission and out to the PTO.

PTO horsepower will be less on hydrostatic tractor then on the same model gear driven tractor as the hydrostatic transmission is always pumping some fluid in the low pressure circuit to keep the high pressure pump for the hydrostatic transmission from starving.

Calculated PTO horsepower is likely using an estimate of how much horsepower the transmission loses for parasitic losses.

Observed PTO horsepower is likely from putting the tractor on a PTO dynamometer and seeing how much horsepower it puts out through the PTO.

Aaron Z

 

[TheMadOne]

I feel Kubota is more transparent than most when it comes to net vs gross vs observed hp.

Kuboata put a dyno on a L6060 and it produced 53 PTO HP. PTO HP is what matters. I don't care if I have a 37HP or 35HP tractor. I have 28 PTO HP. Massey using calculated PTO HP isn't really bad, per say. Most companies are so paranoid about overselling the PTO HP on their units that actual testing will reveal an extra HP or two. I wouldn't be surprised to see the 1758 hit 45.5 PTO HP in actual testing.

A lot of dealers have PTO dynos. Anybody with a 1758 want to do a pull for science?

 

[finn1]

Dealership pto dynamometer are notoriously inaccurate. SAE power ratings are run / corrected to standard temperature and barometric pressure. Dealership dynamometer systems typically don’t have the sofisticated controls or software todo this, so power recorded is simply a snapshot at whatever conditions exist at that particular dealership, at that specific atmospheric condition, on that specific day.

A fully equipped and calibrated laboratory dynamometer system, with proper controls, costs several million dollars.

Also, consider that engine to engine and tractor to tractor variability for a given model will be several percent of the advertised numbers.

The tractors sent to the Nebraska tractor tests were always factory / laboratory tuned to the top of the spec.

Bottom line: don’t get too wound up over a couple of horsepower fifference between tractors from different manufacturers when making a decision. Spend some time making sure the features and ergonomics are suitable for you.

 

[Sawyer Rob]

For ME, it's the pto that does the work, so I don't care what the other hp ratings are!

I always compare pto hp...

SR

 

[Hilbilly]

Dealership pto dynamometer are notoriously inaccurate. SAE power ratings are run / corrected to standard temperature and barometric pressure. Dealership dynamometer systems typically don’t have the sofisticated controls or software todo this, so power recorded is simply a snapshot at whatever conditions exist at that particular dealership, at that specific atmospheric condition, on that specific day.

A fully equipped and calibrated laboratory dynamometer system, with proper controls, costs several million dollars.

Also, consider that engine to engine and tractor to tractor variability for a given model will be several percent of the advertised numbers.

The tractors sent to the Nebraska tractor tests were always factory / laboratory tuned to the top of the spec.

Bottom line: don’t get too wound up over a couple of horsepower fifference between tractors from different manufacturers when making a decision. Spend some time making sure the features and ergonomics are suitable for you.

I love the tractor I have other than some issues that need to be worked out but I would like to try either the Massey 1758 of the Kubota L6060 just to get a feel for the difference in power from the one I have. The problem is that none of the Massey dealers anywhere within 200 miles has a 1758 for me to try and I'm told the only way to get one is to have a stock one shipped up from a US dealer or to order one from the factory. You bet they're not doing that without a knowing there will be a sale. The Kubota dealers have just got their new shipments in but the tractors have not yet been assembled. I guess I could sit in the cab but it would feel weird being in a tractor with no wheels. The Kubota dealer I talked to today said these things move fast this time of year, so I'm thinking I won't get to test drive one and there is no way I would spend $65,000 for a tractor without getting a long test drive. There aren't any of these tractors in BC for me to try right now, used or new. Doesn't bode well for being able to negotiate on the prices.

 

[Hilbilly]

For ME, it's the pto that does the work, so I don't care what the other hp ratings are!

I always compare pto hp...

SR

I guess it really depends on the individual owners needs. I rarely use the PTO and when I do, it's usually for something that doesn't need a lot of HP. The only thing I need PTO hp for is the snow blower and I didn't even need to use it this winter. For me the biggest need for power is when pulling the boxblade or pushing the snow plow uphill. Even just traveling up my driveway it would be nice to have a little more HP so I could travel a bit faster.

 

[CobyRupert]

Gross engine horsepower is how much is put out by the force of the cylinders pushing on the crankshaft through the connecting rods.
Net engine horsepower is how much is left over after running accessories such as the water pump, alternator, etc.
PTO horsepower it is how much horsepower makes it through the transmission and out to the PTO.
PTO horsepower will be less on hydrostatic tractor then on the same model gear driven tractor as the hydrostatic transmission is always pumping some fluid in the low pressure circuit to keep the high pressure pump for the hydrostatic transmission from starving.
Calculated PTO horsepower is likely using an estimate of how much horsepower the transmission loses for parasitic losses.
Observed PTO horsepower is likely from putting the tractor on a PTO dynamometer and seeing how much horsepower it puts out through the PTO.
Aaron Z

Thanks for the explanation. I've always heard that some engine ratings are the engine "bench test" without the additional "load sucker" accessories, factory exhaust, etc...
PTO horsepower is a good indication on what you'll actually get.

Nobody uses bHP (brake horsepower) measured at the wheels anymore? Not even the Nebraska tests? This would be a good indication too, especially on hydros.
Which begs the question: Is the loss to the PTO the same as loss to wheels on a hydro? On a gear? More or less?

 

[ericm979]

The PTO is not driven through the HST so there's no loss there. But there is a small extra loss as explained above because the HST is still pumping some fluid. You see that in specs of gear vs hst versions of the same tractor where the gear model has a few more PTO HP. For example a Kubota L4060 gear has 34 pto hp while the HST has 32.5. Both have 42 gross hp and 40 net.

Brake HP is just dyno HP- a brake is a type of dyno. So it could be measured at the engine or PTO. The old car SAE standard used back in the mucle car days allowed removing accessories, mufflers and air cleaners and was at the engine, so it resulted in artificially high numbers.

 

[CobyRupert]

The PTO is not driven through the HST so there's no loss there. But there is a small extra loss as explained above because the HST is still pumping some fluid. You see that in specs of gear vs hst versions of the same tractor where the gear model has a few more PTO HP. For example a Kubota L4060 gear has 34 pto hp while the HST has 32.5. Both have 42 gross hp and 40 net.

Brake HP is just dyno HP- a brake is a type of dyno. So it could be measured at the engine or PTO. The old car SAE standard used back in the mucle car days allowed removing accessories, mufflers and air cleaners and was at the engine, so it resulted in artificially high numbers.

Good info.
So.....is there no info on the horsepower the gear tractor can put on the ground (wheels) versus the hydro?

 

[jeff9366]

Doesn't bode well for being able to negotiate on prices.

Most years Kubota factory incentives are most generous, and fall on a wider assortment of equipment in the Spring.

For the last two years we have been in a period of fairly rapidly rising machinery prices due to tariffs, steel price increases and a strong market for new tractors <80 horsepower. I speculate net machinery prices escalated 5% per year in 2017 and 2018.

The marketing tactic of increasing prices during periods of strong demand, then discounting back a portion of the price increase as a limited time incentive, is as old as marketing itself.

Ponder the cost of waiting.

British Columbia is on the coast. There should be numerous dealers for you to negotiate with within 100 miles once you finalize options.

 

[Sawyer Rob]

I guess it really depends on the individual owners needs. I rarely use the PTO and when I do, it's usually for something that doesn't need a lot of HP. The only thing I need PTO hp for is the snow blower and I didn't even need to use it this winter. For me the biggest need for power is when pulling the boxblade or pushing the snow plow uphill. Even just traveling up my driveway it would be nice to have a little more HP so I could travel a bit faster.

Well, MY experience is, if it's got more to the pto, it's got more to the ground.

So, for me, pto hp is the most important...

SR

 

[Hilbilly]

Well, MY experience is, if it's got more to the pto, it's got more to the ground.

So, for me, pto hp is the most important...

SR

Good point!

 

[finn1]

No way are you going to get an accurate assessment of power by driving an unladen tractor around the dealers lot. You will need to hook up ground engaging equipment at the very least.

Driving an unloaded tractor will, at best, give you an idea of the gain calibrated into the throttle, ie governor response, but not actual usable horsepower.

One of the tricks calibrates use, particularly in cars and trucks is to front load the throttle progression curves to increase perceived power in the first few degrees of throttle progression. It makes the vehicle feel peppy because a little throttle really makes the vehicle jump as perceived in a typical around the block test drive. Problems arise when that same pedal calibration makes the vehicle all but undriveable off road.

Pull a load up a hill and that peppy calibration is no better than a standard calibration.