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TL150 291ft/lbs trque, TL250 240 ft/lbs?

9K views 37 replies 10 participants last post by  AWJ Services 
#1 ·
Anyone have any thoughts on why TK would drop torque down so much on the new model? I know they have a new Kubota engine in this model but what aspect of the new Kubota warrants the big drop in torque? :confused:
 
#2 ·
I notice the 250 is tier 3 compliant. Emissions requirements often lead to engine changes in heavy equipment. The difference in engine operating torque is substantial in these two models--198 foot-lbs at 2600 rpm on the newer model, 232 foot-lbs at 2200 on the older one, both figures being gross torque before accessory power loss is substracted. I didn't calculate net torque since that number isn't supplied on the 150 brochure.
 
#4 ·
AWJ, my question wasn't why does a smaller engine have less torque, it was why would TK go with an engine that has less torque when usually you see new models trying to up all the specs slightly. Thanks Northmiss, it sounds like they made the change to get tier 3 compliance.
 
#5 ·
Unfortunatley engineers build skid steers and that was what they felt was the best match.
Bobcat uses the same engine in there 330 series as well.

Yanmar supplies all of the engines(Tier III) across the board so not sure why they did not step up on the big engine.
Maybe it was not ready for production?
On there website they no longer have that series engine listed.
 
#6 ·
Maybe the Torque rise is higher which sometimes makes up for a lower number. I know the torque rise is a rating that is never displayed in earthmoving equipment but is bragged about in the agriculture market.
 
#8 ·
Torque rise appears to be 25% in the old model, about 21% in the new so there would appear to be no advantage here for the new machine. Hard to know how important torque rise is for the machines these days. My dozer will only lug down about 100 - 120 rpm under a heavy load so it really doesn't back very far up the torque curve, and it never ever lugs down to peak torque rpm, so these peak numbers don't seem very meaningful to me. Since there appears to be no difference in these two loaders' fuel consumption, the only thing I can guess at is emissions difference warranting the engine change.
As far as AWJ's idea that torque is 100% related to engine size, that really isn't true. Many if not most manufacturers of heavy equipment will equip a given machine series with the same displacement engine and simply vary the turbo boost pressure (along with fuel delivery) to increase torque at a given rpm. The Deere 450J - 650J series dozers would be a good example of the idea. All have the same sized engines, but very different torque numbers.
 
#9 ·
As far as AWJ's idea that torque is 100% related to engine size, that really isn't true.
Well of course not when you are comparing a non turbo too a turbo engine.
Torque is 100% related too engine size.The larger the engine the more torque.
Engines will make a certain ft/lbs per cubic inch and there is a maximum that they will make.Thats why we have bigger engines and not just bigger turbos.
On the other hand Hp is a derivitive of torque and rpm so you can make the same torque but not the same hp or vice versa as in the case of the smaller Kubota engine.
 
#10 ·
Most engines will max out the torque in the 1500rpm range. The higher the rpm the more H.P. but not exactly more torque. But depending on the fuel ratio vs cubic inch the engine will spec better on the torque curve. The difference in torque specs per cubic inch is when one engine has ...example 80 hp @2500 rpm or another engine will have 80 hp @ 2000 rpm ......
 
#11 ·
AWJ,
I think you prove my point by saying that a given engine will have different torque characteristics based on whether it is turbocharged or not. Torque is therefore not just related to displacement, but also to fuel and air flow (a turbocharger increasing the oxygen density in the cylinder) and to compression ratio. Obviously there is a limit to the turbocharging process, so that past a certain point a larger displacement is needed. Torque is not 100% related to engine size or displacement. Komatsu's latest 22 class dozers have REDUCED engine size to produce more torque, at least in the D37-EX22. You may want to examine their specs as an interesting lesson in mechanical engineering.
 
#13 ·
AWJ,
I think you prove my point by saying that a given engine will have different torque characteristics based on whether it is turbocharged or not. Torque is therefore not just related to displacement, but also to fuel and air flow (a turbocharger increasing the oxygen density in the cylinder) and to compression ratio. Obviously there is a limit to the turbocharging process, so that past a certain point a larger displacement is needed. Torque is not 100% related to engine size or displacement. Komatsu's latest 22 class dozers have REDUCED engine size to produce more torque, at least in the D37-EX22. You may want to examine their specs as an interesting lesson in mechanical engineering.
I agree... torque is not necesarily related to engine size when you have a turbo. I had a dodge cummins w/ factory 500ft tq... added another turbo... and 1400ft tq on the dyno.
 
#14 ·
Lawnworks, you provide an excellent example of the concept. Here is another interesting twist. Around about 2003 Cat added a turbocharger to the D3G 6 cylinder 5 liter diesel to aid with emissions compliance. It appeared there was no change to the engine specs at first glance: 70 net HP before and after. Yet the naturally aspirated engine produced the power at 2400 rpm, and the lightly turbocharged version at 2200 rpm for 153 ft-lbs and 167 ft-lbs operating torque respectively, almost a 10% jump in torque with turbocharging. Now here's the interesting part: the newly-released D3K produces 74 net HP at only 1900 rpm and a whopping 204.5 ft-lbs of operating torque, almost a 22% jump over the prior year's model, but yet with a 4 cylinder diesel with 12% less displacement (4.4L) than its 6 cylinder predecessor. This is about the clearest example I can cite of why the notion that "Torque is 100% related to engine size" is wrong. It is interesting that we use these machines every day but sometimes do not appreciate the mystery going on under the hood.
 
#16 ·
You guys read sales literature and drive heavy equipment.
I actually build race engines and have a engine dyno, a cylinder head flow bench and a fully equipped shop.

Don't patronize me.
I don't have any literature to back up what I am saying just a dyno. I had a stock cummins 5.9 that put MAYBE 500 ft tq stock... then added injectors, fuel pump, other goodies, and compound turbos. Torque went from 500 to 1400 to the wheels.

Don't you think the amount of air you can cram into a cylinder via turbo(s) has something to w/ output? With your thinking a turbo is waste of metal.

Turbos are gooooood!!!

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#19 ·
So you are suggesting that you can use a smaller engine and just add a bigger turbo?
Do you not think that if you done the same thing with a larger engine then there would not be an increase in torque?
Yeah I see your point. Might the smaller one be more efficient... (just a question not being a smartazz). Also, I can see the advantage of having a smaller turboed engine in a skid.

But back to the original point when you throw turbos into the mix... cubic inches and torque don't always correlate.
 
#20 ·
Plus I will add that if you stuck that engine in a steady state application it would burn up pretty darn quick.
There is way more too this than you think.
I am in no way trying too be argumentative just that I really understand this stuff.
Well I think there is a balance... don't you think turbos create an efficiency factor? I guess the larger engines won't have to work as hard as the smaller one and the life span will be more. They say there is no replacement for displacement. I guess it also really depends on how well the bottom end is built... some motors can expect more of a lifespan than others.
 
#21 ·
But back to the original point when you throw turbos into the mix... cubic inches and torque don't always correlate
If you compare apples too apples they do.
But if you compare apples too oranges they do not.:)

If you pull up the engine specs from the engine manufacturer you will find a term called"BSFC".Brake specific fuel consumption.Basically it is the amount of power that an engine makes per quanity of fuel.The lower the better.
It determines the engines efficiency.
Remember that a turbo has too be turned by the exhaust flow which in turn is dictated by piston speed.
What that means is if 2 engines of different sizes are at the same rpm the one with the larger ci will have more piston speed so in a sense it will move more air which in turn will actually allow the turbo too spin faster which results in a higher volumetric efficiency hence my statement that torque is directly related too engine size.
Now some manufacturers will do a better job of getting more power out of a similar engine.Also dyno's are not an industry standard so no 2 may not read alike.
 
#22 ·
AWJ,
Your original statement was "torque is 100% related to engine size." It is not. It may be proportional to engine size, but there are clearly other parameters. It is also untrue that one need have a larger cubic inch engine to have efficient spool through of air through the turbocharger, since one may modify parameters of the turbo to get efficient pressure delivery. This is critically important in an age of $5 diesel, since the end user will profit from having the smallest engine possible which will produce sufficient torque for the job at hand. This is why Komatsu has reduced its small dozer engine size to 3.3L from 3.9L, why Cat has reduced its 5 liter 6 cyl to a smaller 4 cylinder 4.4L in its finish dozers. The goal is producing fewer emissions, more power, less fuel consumption, and in dozers a smaller engine which sits lower in the machine frame to lessen center of gravity, hood obstruction of the blade etc. The benefits of optimized smaller engines here ought to be obvious. If you can't see this then just smile as you pay for all that red diesel.
 
#24 ·
AWJ, I have to hand it to you: if stubborness is a virtue, you're a saint. I have just shown you that other manufacturers are producing small, high-efficiency tier 3 diesels TODAY. Why Yanmar's is not as efficient I can't say. Perhaps it is a cost saving move. But the Yanmar technology isn't the best available. Just compare the numbers as to what's possible: a) Takeuchi TL250, 3.8 liter Yanmar, 2600 operating rpm, 92 net hp (24 hp/liter displacement), 186 ft-lbs operating torque (49 ft-lbs/ liter); b) Komatsu D37-EX22 dozer: 3.26 Liter Komatsu, 89 net hp at 2200 operating rpm (27 hp/liter), 212 ft-lbs op torque (65 ft-lbs/l). THere is little question as to which engine produces more horsepower and torque, and little question as to the efficiencies that are now possible. If I could order the TL250 with the Komatsu engine in it, I would! But you can get the Komatsu dozer for the very cheap price of $96,000 as of last month when I checked. Smaller engine, more torque. How many examples do I have to give you?
 
#25 ·
It is an interesting discussion if nothing else. I don't claim to know the how and why of torque as it relates to displacement. There are some interesting comparisons to be made however

CAT 201 cubic inches somewhere around 215 foot/pounds I think. Hard to find the data as CAT is not very proud of it I assume. It might actually be somewhat less than that.

Bobcat 202 cubic inches 217 foot/pounds as rated for S300

Deere 187 cubic inches out of a 5 cylinder and around 251 foot pounds. The Deere is interesting in that it is a very small motor that runs a 5 cylinder, but gets a very respectable torque rating.

CASE 274 cubic inches and 288 foot/pounds. It would seem to follow the big displacement big torque numbers theory.

CASE 195 cubic inches (445, 430) and 229 foot pounds. More torque from less cubes.

I could not get the torque for the S250 or the CAT equivilent but I would guess they would be less than 217 as they are smaller machines. The same Deere power plant that runs the 325 as the 332 makes only 195 foot pounds in the 325. I would guess it must be in the fuel metering.

Like I said I don't know enough to comment on why they are all over the map, but they are.
 
#26 ·
The TL250 Has a Kubota engine not a Yanmar.

I am not stubborn just comfortable in my knowledge.

You have too be careful as well when comparing different manufacturers specs due too difference in correction factors.
When they dyno the engine they correct it too a standard.
Gas engine stuff is usually done too an SAE 607 or SAE 1349
These are just 2 and some foreign manufacturers may not Follow SAE practices plus coupled with the Net and Gross ratings as well it can be confusing and deceiving.
No different than bucket breakout ratings.

Essentially an engine is just an air pump so the larger it is the more air it will move and without air fuel will not burn.There are ways too increase volumetric efficiency ,like turbos,more valves,better injectors etc but anytime you take the same engine and make it larger it will lower the torque curve in the rpm range and increase it.

This very same discussion was brought about a Truck I was looking at too buy with a 5.9L Cummings in it and I was instructed it was too small?
 
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