BX24 Engine Has "BX23" Label!

[Volfandt]

great post lp333, this may open some otherwise closed doors to us.
I much more enjoy the "nut's & bolts" much better than the "spec's" anyday

In a past life I worked directly with sales and marketing and one of the main goals of a particular marketing division is to gain an edge (or advantage) over it's competition. Most times the resulting edge isn't an out and out misrepresentation, it's merely taking a different avenue to arrive at the same conclusion. The conclusion is probably not false, it's just measured or determined by a different formula at a different place. I used to call it imaginative fabrication
This is why I snicker at those that take the "spec's" as gospel and not use the "real world" application of a product as a better measureing stick.

Whats likely to be more accurate, the spec indicateing a 460lb lifting limit on the FEL or actually seeing and/or working said FEL easily with nearly 600lbs of material?

Theres just NO WAY a particular product in a specific class is going to be "that much" better than comparable competing models, the competition is just too tight to allow one model to "run away" with it all, with the loan exception like Kubota did when it "invented" the subcut line. Course it wasn't long for it's competiton to catchup.

Anyways, I do have a WSM on the D905 but not the D902 and it would be interesting for those of us to post various specs between 'em to see if we can figure out where that additional 1 hp comes from. Could be we could easily squeeze out alittle mo-power out of both with sacrifying durability
I'd really like to increase the GPM more in my BX23 but not at the cost of prematurely wearing out various hydraulic assemblies.

This would fall in line with Kubota's ongoing efforts to cut the production costs for the popular BX units.

Sometimes this is not a bad thing. Kubota seems to have stepped up to correct the 1st release issues that plagued the new BX series and when I visit the various different dealers to check out all the brands out there, plastic (or composite) materials are integrated into even the premium large tractors as well as the CUTS & SCUTs. In some cases the engines have been scaled back from 4 to 3 cylinder and alot of users have commented on the 3 cylinder diesels being smoother and even more powerful, over a comparable 4 cylinder. Some say the composite "skins" of these new tractors take more abuse without showing the results better than metal, i.e. no pot marks and/or dents.
Course time will tell and in a tractor's time frame, it can take decades to get that "great" reputation.

 

[x703jko]

...I invite TBN members who who are more knowledgeable than me to shed light on this puzzling HP claim.

Power (HP) is equal to torque x engine speed. The two engines have the same output at 3600 RPM but one has lower power at 3000 RPM versus the other at 3200 RPM. Assuming the torque is the same (good assumption of engine displacement is the same), then the engine that is spec'd at 3200 RPM must have a greater output (HP) than the one spec'd at 3000 RPM.

Note also that it's really hard to compare the performance of two engines with data from only two speeds - usually, it helps greatly to have an output curve - HP versus RPM and Torque (ft-lb) versus engine speed. This is what most engine design engineers rely on to compare two engines.

Now, that being said, just because the two engines have the same displacement doesn't mean that they have the same performance. A number of other factors can impact output - piston stroke, piston weight, heat management, fuel injection method (direct or port), valve timing, valve diameter, ignition timing, air induction (naturally aspirated, or forced induction) etc.

Hence, just because the 905 and 902 have the same displacement doesn't mean that they'll have the same output.

 

[Volfandt]

Good points.
We already know that both are approx the same displacement and have indirect fuel injection. We also know that they have different fuel injection pumps and that the D902 weighs in less than the D905.
It would be interesting to see if the internals (pistons, rod's, crank etc), have the same part #'s between 'em.

The D905 has a bore & stroke of: 2.83" X 2.90", 54.8 cu in.
Maximum torque is rated @ 40.5 ft lbs between 2200 & 2600 rpm.
Engine gross power is rated at 22hp but the WSM doesn't indicate at what rpm gross hp is achieved.
The WSM indicate's that the Rated Revolution is 3200 rpm but it is unclear if this is where the rated hp is measured.

Going on lp333's posted numbers on the rated outputs at 3000, 3200 & 3600 rpm of both engines, it would almost seem to point to the D905 as being close to or even having the same power output as the D902. We would either need to see a full power curve chart per x703jko's suggestion or see what the D905 is rated at @3200 rpm. (or what the D902 is rated @ 3000 rpm).