CC vs. HP

[JFoy]

I'm trying to understand the relationship between displacement and HP. Using a couple models from the Kubota line, both the L4701 and the L6060 have a displacement of 148cc. The L4701 has 47hp and the L6060 has 62hp. So, does that imply that the 148cc displacement on the L4701 is under utilized?

Thanks,
John

 

[Steve1300]

Tractor data indicates that there are dimensional differences (slight) between the two engines and that one is turbo charged but not the other. Also, one is common rail injection while the other is direct injection. While the displacement is stated to be the same, between fuel injection method, a difference in emissions control (while both advertise being Tier IV), and turbo charging; it is more than just an under-utilized displacement. If you make these modifications to the 4701, you may get similar HP?

 

[LD1]

IF you are tractor shopping, I'd forget the CC spec.

HP is what to look at. HP is your power, and how fast you can get work done. Implements are typically rated by the horsepower they need to run, as are hydraulic things.

As far as being "under-utilized"........ could be a good thing....or not. Dont look at it that way though.

All tractor MFG's for along time have been using the same core block (same CC's) across a broad range of HP ratings. There is alot more to HP than the CC's. Injector pump setting and turbo both come to mind. So instead of casting a whole different series of blocks for each HP tractor, they use the same ones, and tune/tweak them differently.

Pay more money for a higher tuned/tweaked tractor to get more power. Or pay less for one that isnt. You may say the lower HP one is under-utilized, but some may say it will last longer not trying to over-utilize the block.

In either case, these tractors are rated for constant use. IF you compare CC's of tractors to other engines, like in cars and trucks......HP per CC.....tractors dont even come close.

 

[motownbrowne]

LD1 said it very well, as usual. :thumbsup:

I just wanted to add another example or two. There are some engines that have both automotive and industrial applications. The two closest to the top of mind are the 5.9l Cummins diesel, and the Ford 300 gas motors. Put them in a truck and you can turn the HP up because the power demand is intermittent. Put them in a generator or a tractor and you gotta turn the power down, otherwise, you're gonna overheat them.

That's another thing that a block putting out more power needs, is a larger cooling system. If the 6060 makes more power, it may very well have more coolant capacity.

So, no the displacement isn't "under-utilized", the engine is de-tuned to make less power than it's capable of. Like LD1 said, this is common in the tractor world dating back several decades. Personally, I'd rather have a larger block putting out less HP than the other way around, but in reality, it probably makes no difference. These motors are all designed for continuous use and should have a very long service life.