HP & RPM's on Sub-CUT's and CUT's?

[BluRidgDav]

HP & RPM\'s on Sub-CUT\'s and CUT\'s?

I've noticed that the same engines are sometimes used on two different sized tractors,
and that they're rated with different HP and RPM. Examples:

2210 = 23hp @ 3000rpm / 17.7hp PTO
4110 = 20hp @ 2600rpm / 17hp PTO

2305 = 24hp @ 3000rpm / 18hp PTO
2320 = 22hp @ 2600rpm / ??hp PTO (guestimated?)

Are the Sub-CUT engines being pushed too hard?
Or are the CUT engines being pushed too little?

Seems like the CUT transmissions are a little more efficient at getting their reduced HP's
back/down to the PTO's though?

Thanx, Dave.

 

[RoyJackson]

Re: HP & RPM\'s on Sub-CUT\'s and CUT\'s?

You're somewhat simplifying things...
The power at a given RPM is just one part of the equation. One must also look into gearing, tire sizes and intended uses. In all likelihood, the primary use of the sub-CUT's will be lawn mowing. The bigger tractor (such as the 4110) is probably expected to be more intended for golf course or larger estates.

Of course, there's always the marketing issues in the sub-UT market.

 

[BluRidgDav]

Re: HP & RPM\'s on Sub-CUT\'s and CUT\'s?

Thanx, Roy.

I understand your point about other factors affecting the overall performance of a tractor.

But, I don't fully understand all the "marketing" comments that I keep reading about sub-CUT's.
They always seem to imply that the HP numbers are somewhat phony if they're generated
@ 3000rpm, and that "real" tractors should be measured @ 2600.

My question is this;
If an engine is capable of being run @ 3000rpm for years and years in a 2210.
Wouldn't the 4110 benefit by running the same engine at @ 3000rpm also?
It's marketing and performance surely wouldn't be harmed by generating 23hp?
And with it's more efficient transmission, sending maybe 19hp to it's PTO?
All the while imploying it's other advantages of larger wheels, etc?

Dave.

 

[RoyJackson]

Re: HP & RPM\'s on Sub-CUT\'s and CUT\'s?

Again, I think you're looking at the specs without considering the usage.

The 4110 and the 2210 do use the same engine (Yanmar 3TNE74) but for different applications. Although Deere (and the other brands) don't provide torque information (especially the torque curves), I would expect to find the 4110 has maximum torque and a broader torque band at a lower RPM. As I'd mentioned earlier, intended usage of the two tractors you mentioned is different.

The 3TNE74 is an industrial/marine engine. I am sure one would find many different power ratings depending upon the intended use.

As the 2210 is (probably) intended for mowing, it would be expected to run at PTO speed more often. The 4110 may be intended for a bigger variety of tasks.

Again, the gearing and tires are different (gearing, since both are hydro's, is a guess on my part).

There's a lot involved in determining HP/Torque ratings. I'm not a Deere Engineer, so I can only make semi-educated guesses.

 

[RogerH]

Re: HP & RPM\'s on Sub-CUT\'s and CUT\'s?

I wonder how much noise and vibration may have to do with the the different engine speeds. The engine on the 2210 is mounted on rubber mounts while the 4110 engine is not. The older 955 also ran at over 3000 rpm and had its engine on rubber mounts. Wonder how the 2320 engine is mounted?

 

[jd110]

Re: HP & RPM\'s on Sub-CUT\'s and CUT\'s?

There are many variables in determining HP and rpm ranges. If automotive comparisons are any clearer, think of a small block chevy 350. They were produced anywhere from around 120 HP at approx. 2500 rpm to say around 375 HP at 6500 RPM in a corvette. Even though they are essentially the same engine, differences in camshaft profile and timing, fuel system, valve sizes, intake and exhaust ports and manifolds make these engines very different. Just because one version has higher horsepower and higher rpm does NOT mean the lower horsepower version will produce the more horsepower simply by raising rpm's. In fact, it probably will produce less horsepower at higher rpm because the fuel and air systems are not designed to run at those speeds. Hopefully this makes some sense.

 

[grimmt]

Re: HP & RPM\'s on Sub-CUT\'s and CUT\'s?

It appears that the 4110 and 2110 engines are identical in every way.

The difference in horsepower is merely based on the RPM rating.

Here is yanmar's dyno chart for the engine:

http://www.yanmar.co.jp/english/products/industry/indusrial/tne/3tne74.htm

I can't profess to understand why they use 2 different RPM values to derive the ratings for the two tractors, I can only assume that some industry convention comes into play (as Roy implies).

 

[BluRidgDav]

Re: HP & RPM\'s on Sub-CUT\'s and CUT\'s?

I'm starting to wonder if maybe it's a result of using common transmissions/gearing from other tractors, etc?

Maybe the transmission that they needed to fit into the 2210's frame is a common part with some other piece of equipment, and requires a 3000rpm input from the engine, in order to turn the PTO's at 2100rpm and 540rpm respectively.

While the 4110 shares it's transmission with other tractors, that require only 2600rpm IN, to produce 2100/540rpm OUT?

Thanx for all the "input",
Dave.

 

[BluRidgDav]

Re: HP & RPM\'s on Sub-CUT\'s and CUT\'s?

Looks like the 3000 RPM trend has crept into the world of CUT tractors.

The new JD 2320 CUT will share the same engine as the smaller Sub-CUT 2305.
It boasts the same HP's at both the engine and PTO.
According to some of the technical graphs in the other 2320 posts,
this requires the same 3000 RPM engine speed.
It appears to be an "isolated" engine, mounted on rubber bushings.
And the new 2320 features a cutting height adjustment knob,
just like the "mowing" Sub-CUT's.

So, most of the theories proposed in this thread seem to right?

Thanx, Dave.