Hydro power loss? 20%, not on it's worst day!

art · Jul 16, 2004

Hydro power loss? 20%, not on it\'s worst day!

I keep seeing that hydro's loose such numbers of 20 and 40% on this board and I thought do to the number of e-mails sent to me about it that I would put up a few facts. /forums/images/graemlins/shocked.gif I went to the Nebraska Tests which is required if a company wants to sell tractors in that state. The tests are quite expensive and some manufacturers have chosen not to sell there do to the limited market. They are at http://tractortestlab.nl.edu/ These are the two tests that I found that were the worst as some were even closer. I'm using two basically 100 PTO hosepower tractors using a IH hydro 100 test #1158 and a 966 gear drive test #1123. The gear drive weight was 13670lbs and the hydro was 12765lbs The gear on the economy run pulled 6606lbs at 4.84mph at 85.21 drawbar horsepower. The hydro pulled 5,287 at 5.55mph at 78.31 drawbar horsepower. At 75% of maximum pull the gear pulled at 70.99 drawbar horsepower and the hydro at 67.68 drawbar horsepower. Mind you these tests were done over thirty years ago! The newer three range transmissions will be even more efficient then these could test! /forums/images/graemlins/grin.gif Fuel being used will be the largest difference but when doing PTO work or loader work the hydro has long been a winner of efficiency. /forums/images/graemlins/grin.gif I appreciate Junkmans line and I hope this clears up some of the miss information given here. /forums/images/graemlins/smirk.gif

MikePA · Jul 16, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

IOW, the hydro tractor power loss is between 4.7% and 8.1%. /forums/images/graemlins/cool.gif

To20Chris · Jul 16, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

Could you double check that link? It did not work for me - Thanks!

Gary_in_Indiana · Jul 16, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

Mike,

According to my owner's manual, the PTO HP of my JD 4200 is between one and two less HP with the HST instead of the gear transmission. The PTO HP is right at nineteen plus with HST and over twenty with the gear transmissioin so your percentages are right on with my manual. /forums/images/graemlins/smile.gif

JerryG · Jul 16, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

There is a bit of a difference between drawbar hp and PTO hp. The hydro would have more hp loss when used for drawbar hp than for PTO hp.

RichNJKubota · Jul 16, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

Correct link:
http://tractortestlab.unl.edu/

timb · Jul 16, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

Not an ideal comparison, but of course there are limited choices to try to find a match in the Nebraska lists.

Those two tractors are not identical. Close, but not as close as you would have in hydro/gear versions of the same CUT. The IH 100 Hydro starts off with a slightly bigger engine rated for slightly more hp than the 966. The real loss on the IH 100 Hydro from PTO output to drawbar is somewhat higher than 8% - more on the lines of 25% where the 966 is seeing about 15% loss drawbar compared to PTO.

One thought - the quoted 20%-30% loss number may then not be referring to the difference between a hydro and a gear system but rather the absolute loss in the hydro system. But - a gear tranny has it's own parasitic losses - there are no frictionless devices or free lunches - and that loss may often be on the lines of 15% give or take looking at some gross-hp-to-drawbar-hp losses posted.

A guess- but that math would line up somewhere in the same ballpark as the IH comparison shows.

So does a hydro lose you 20%-30%? Yes, but a gear loses you 15%. Call it an actual 10% hydro disadvantage. Whether that matters is up to the individual situation.

MikePA · Jul 16, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

 So does a hydro lose you 20%-30%? Yes, but a gear loses you 15%. Call it an actual 10% hydro disadvantage. Whether that matters is up to the individual situation.
You are mixing percent differences and percentage point differences.

The percent difference between a 20% loss and a 15% loss is 25% not 10%. (5 divided by 20) That's why it's always best to work from the original numbers and not derived percentages.

((Drawbar hp gear - drawbar hp hydro) / Drawbar hp gear) x 100 = Percent Hydro Loss vs Gear

((85.21 - 78.31) / 85.21) x 100 = 8.1%
((70.99 - 67.68) / 70.99) x 100 = 4.7%

art · Jul 17, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

There are some other facts here that you fellows missed! Like the fact that the hydro actually pulled the weight faster but yet it was less weight. That the hydro actually weighed less by 900 lbs. Tried to change the link but to late! Sorry

gone · Jul 17, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

you are comparing 100hp tractors,i think yoll find if you compare 25 hp tractors the percentage will grow. the 544 ih hydo if i remember right lost 10 drawbar hp compared to the gear on a 50 hp tractor but my memory could be off that was in the 70's. i can state the fact the gear could out plow the hydro hands down from personal experence on the farm

art · Jul 17, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

Another set of tests that are interesting is the test #1151 IH 666 diesel and the hydro 70 test #1154 both using the 312 engine and rated simuliar horsepowers. The economy run produced 58.01 drawbar horsepower on the gear drive and 53.10 on the hydro. This again brings the difference below the 10% difference between the two in the amount pulled. On the 75% pull they gear pulled 46.8 drawbar horsepower and the hydro pulled 45.08 drawwbar horsepower! /forums/images/graemlins/shocked.gifThat is pretty close to equal but the amazing thing here is the fact the gear was only pulling 4,240lbs and the hydro 4935lbs!!!! /forums/images/graemlins/grin.gif There really is only a little difference at best and often unnoticed for the benifits of the rest of the operations the tractors might be used for.

Robert_in_NY · Jul 17, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

Since everyone here is talking about the International Hydros I wonder if we should bring up the fact that those hydros did not hold up under the power. The International Hydros resale value is junk compared to the gear counterpart. So while the hydro may only lose around 5-10% they didn't hold up to constant heavy strain. In the end that would make the gear tractor a winner any day.

What it boils down to is this. Who cares if the hydro robs some power from your machine? You bought a tractor to do the job you wanted it to do. If "YOUR" machine will do the job then why be so worried if it doesn't have as much hp as the gear version. Not all tractors are used the same and I will say the majority of hydro tractors find themselves mowing a lawn from time to time while you will not find very many gear tractors mowing lawns. The trannys are designed for different tasks and each buyer has to know what he wants to do. So in the end I still do not know why the big fuss over the hydro power loss. If anyone can explain that to me then I will be thankful. Take care.

art · Jul 17, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

Robert ten years ago I would agree with the price difference. We never had to much trouble with them not working when they were used for what they were designed for and operators keep the oil in them so we might have more working yet then in other areas. The resale value has more then doubled in the last ten years as many farmers are finding that on mixer wagons they work the best. Even older gas models have gone up quite a bit. Many of the larger ones bring all that the gear models do and more at this time. /forums/images/graemlins/blush.gif

Robert_in_NY · Jul 17, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

I agree that they were nice machines if used for what they were designed for. I know a lot of guys who swear by them for haying tractors but then it comes down to you have to have two tractors again as plowing and other heavy tillage did not sit well with these tractors. Just like the 2+2's from International, the owners did not use them like they were intended and they got a bad reputation. The problem now is unless you know the entire history of these machines you would be hesitant to pay any amount because you don't know if these machines were taken care of or mistreated and repairs are not cheap on them.

Poppa · Jul 17, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

( What it boils down to is this. Who cares if the hydro robs some power from your machine? You bought a tractor to do the job you wanted it to do. If "YOUR" machine will do the job then why be so worried if it doesn't have as much hp as the gear version. Not all tractors are used the same and I will say the majority of hydro tractors find themselves mowing a lawn from time to time while you will not find very many gear tractors mowing lawns. The trannys are designed for different tasks and each buyer has to know what he wants to do. So in the end I still do not know why the big fuss over the hydro power loss. If anyone can explain that to me then I will be thankful . Take care. )

Honest to God that paragraph right there should suffice as the last word on all these Hydro-Gear discussions. I took the liberty of italicizing and bold facing various pertinent parts of that quote.

Figure out what works best for you. Figure out what you feel the most comfortable with. Figure this all out and then buy the HP you need to do the job regardless of what transmission you have chosen.

I think the reason these discussions upset me so much is that I get caught up in the reasoning and then realize at the end that I am right back where I started except that I am older and as PoleCat might say ??????????!!!!!!I CAN"T AFFORD THAT /forums/images/graemlins/shocked.gif /forums/images/graemlins/shocked.gif /forums/images/graemlins/shocked.gif /forums/images/graemlins/shocked.gif /forums/images/graemlins/shocked.gif /forums/images/graemlins/shocked.gif /forums/images/graemlins/shocked.gif!!!!!!

Mike

timb · Jul 17, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

( That's why it's always best to work from the original numbers and not derived percentages.
)

Right, except you didn't.

The real numbers on several spec sheets I looked up are 104 PTO hp on the Hydro 100, 100 even on the 966. 4% starting advantage to the Hydro 100 with it's slightly bigger engine. Given that the PTO number must include the parasitic loss of the tranny pump even running at idle - as we see with the CUTs, the ENGINE hp has to be somewhere around 5% or 6% higher than the 966.

Now - despite that starting advantage the 966 puts 85.21 % of it's PTO numbers on the drawbar, (85.21/100) yet the Hydro 100 gets 75.31% (78.31/104) of it's PTO numbers to the drawbar.

I'd say that's represents close enough to a 25% drawbar loss (from the PTO rating) and also probably 30% overall loss from engine rating hp to drawbar hp.

The 966 therefore has a tick under 15% drawbar hp loss from the PTO hp and probably comes in roughly 20% overall drawbar hp loss from the engine hp.

That's 10% difference of overall system efficiency in rough numbers.

KNotMe · Jul 18, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

Much ado about nothing. HST machines were manufactured as is with HST, there is no subsequent power loss. If you desire a machine with a certain specification, by all means get it.

MikePA · Jul 18, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

 Right, except you didn't. 
Sigh, I did. I worked from Art's original numbers.

KiotiJohn · Jul 18, 2004

Re: Hydro power loss? 20%, not on it\'s worst day!

( Honest to God that paragraph right there should suffice as the last word on all these Hydro-Gear discussions. )
But, Poppa, you know it won't be. There always has to be someone who will keep it going, no matter what. One guy says X and the other says Y and then everybody takes sides. It's human nature at it's worst, and won't change in our lifetimes. Usually you will find that the ones who continue to argue are people who have not really had experience with at least one part of the discussion, just arguing their side with no practical knowledge of the other. The HST wars are pretty lame really, but have gone on for more years than many people are old on this board. It's certainly isn't a new thing. John