Confused about power

[Ewang207]

Can anyone explain why there seems to be so much concern about the power to weight ratio (32.1 hp / 3305 lbs.) with the L3130? The Kioti CK30 has a nearly identical ratio (30 hp / 3055 lbs.) and people seem to rave about its power. I'm getting ready to buy a new 3130 but this is a bit confusing.

 

[kcook]

I agree, I have looked at it differenty. Each make of tractor will do the job I need, so it comes down to price, service after the sale and dealers in the area.

KC

 

[RayMunising]

I'd say because power and weight are the 2 most important factors in determining what a tractor is capable of doing. Too little weight and you're wasting HP spinning your wheels. Too little HP and you won't have the power to operate the implement you need to. Those 2 single factors more than anything else determine which tractor is the right tractor for you. A B7800/B3030 is half the weight of the L3130. It'll make a world of difference in the work each tractor will do. There's only 3 HP difference between a L3130 and a L3430. If 3 HP doesn't make a difference then why would Kubota make a 3430? Weight and HP go hand in hand to get the task done.

What criteria did you use to determine a 3130 would fill your needs rather than a B3030 or a 3430?

 

[Ewang207]

I've been laboring over the decision between a B7800 or the L3130 for some time. I had decided on the 7800 and went to buy one when my dealer suggested that the 3130 was much more tractor for just a little more money (see my recent post in the buying/pricing forum). The 3130 has two more PTO hp than the 7800 and should effectively run any implement it could, and still have plenty of weight for other jobs that the B7800 may not be as suitable for. Didn't want to spend even more to go up to the 3430.

 

[RayMunising]

Looks like you got lots of good advice in your other thread.

I'm struggling with the B7800/L3130 issue myself but mine is a very specfic need (snowblowing) which requires high pto power but little traction (compared to say pulling a plow) and I'm questioning just how much power it takes away from the PTO to move the heavier L3130 compared to the lighter B7800. Also the particular snowblower that Kubota makes for the B7800 looks like it'd take a lot less power to run then the snowblower designed for the L3130. That makes me wonder if the L3130 isn't underpowered compared to the B7800 for snowblowing. So I hope my thread about L3130 vs B7800 PTO power isn't making you have second thoughts about your situation. I'm sure either machine would satisfy your needs. I'd choose whichever one you're most comfortable with.

 

[MessickFarmEqu]

Don't over analyze this guys. People say the 3130 is underpowered because its a large frame for the amount of power that it has. Its weight ratio's are well above the acceptable margins for a compact tractor. I'd say either tractor will power the PTO so closely you would never know the difference. Now getting those implements around with the 3130 will be a bit nicer. It is a cadillac.

 

[have_blue]

</font><font color="blue" class="small">( Can anyone explain why there seems to be so much concern about the power to weight ratio (32.1 hp / 3305 lbs.) with the L3130? )</font>

With cars, motorcycles, and aircraft, power to weight ratio is crucial for good performance. Performance is measured in speed, acceleration, and agility.

Tractors are a lot different. Since they run so slowly, power-to-weight ratio is a pretty useless statistic.

Instead of "power-to-weight", use power *and* weight. That makes the Kubota better than the Kioti on both stats.

 

[RayMunising]

I don't want to steal this thread but since you're a dealer you undoubtedly have lots of knowledge that I'd like to tap into. Here's my quick question ...

The front mount snow blower for the B7800 is 17.25" in dia with 3 blades
The front mount blower for the l3130 is 24.00" in dia with 4 blades.

I have no doubt that the l3130 blower is a far superior blower but also will require far more power to run. There's a hugh difference turning a 24" fan vs a 17" one. My question is which is the more effective setup, the big blower attached to a heavy L3130 with a 24HP pto (which some consider to be a small engine for the tractor) or the smaller blower attached to a lightweight b7800 with a 22HP pto (which is the most powerful engine in its class)?

When I need to blow out a 2 foot snowfall out of a 1100 foot long driveway with a 6% incline @ 20 below zero with 30mph winds I want a machine that's going to get the job done. The last thing I want after spending 25K on an outfit is the feeling that its underpowered! I don't think I'd have that underpowered feeling with the B7800. Owners of the B7800/B2910/B3030 says it's a great snow machine. I haven't heard from anyone using a 3130/snowblower but there have been some who thought the 3130 was a little underpowered.

So, the bottom line is which is the better machine for snowblowing serious snow on a regular basis? As a dealer I'd really appreciate your recommendation and why you feel it's the best choice. Thanks!

 

[chevyorange]

Hello, Isn't the 17" fan being run off the mid PTO which is turning at 2600 rpm and the 24 running off the back at 540 rpm?Just a thought,I don"t know the blower rpm's but i would think they are different.

 

[RayMunising]

Hi,
Nope, both are running off the mid pto.

Model B2782
Application B7800 B2710 B2910

mount Front
Overall Length w/3 Pt. Hitch 149.7" (3802 mm)
Overall Width 63" (1600 mm)
Overall Height / Chute 46.0" (1168 mm)
Cutting Width 60.0" (1524 mm)
Lift Height Above Ground
Operating 7.25" (184 mm)
Transport 10.5" (267 mm)
Cutting Depth 6.75" (171 mm)
Impeller Fan Diamete 17.5" (445 mm)
Impeller Fan Speed 903 rpm
Impellers Fan Blades 3
Auger Diameter 14.0" (356 mm)
Chute Rotation 220°
Weight 375 lbs


Model L2471A
Tractor Application L3130/L3430/L3830/L4340/L4630/L5030
Mounting Front Quick Hitch
Overall Length 32" (813 mm)
Overall Width 62" (1575 mm)
Overall Height 59.25" (1505 mm)
Cutting Width 61.9" (1572 mm)
Lift Height Above Ground 13" (330 mm)
Cutting Depth 6.5" (165 mm)
Blower Diameter 23.75" (603 mm)
No. of Impellers 4
Auger Diameter 14.75" (375 mm)
Chute Rotation 220 Degrees

The L2471A is one heck of a blower but I fear in reality it'd be too much for the L3130 even though it's the blower Kubota recommends for it.


<font color="red">
NEWS FLASH. The answer my friend is in my other thread. The anwser is blowing ...

Geez that was terrible. But it's 2:13AM. Can't expect much /forums/images/graemlins/tongue.gif

Please return to your regularly scheduled original poster question. Sorry to have diverted attention from your original post. </font>

 

[chadincolo]

</font><font color="blue" class="small">( Tractors are a lot different. Since they run so slowly, power-to-weight ratio is a pretty useless statistic. )</font>

Actually, power to weight ratio is one of the most important specifications for some applications. If you are planning on pulling anything, digging with the loader, you NEED weight. My main tractor is around 50 hp, and weighs somewhere in the 10,000 pound neighborhood (don't know exactly since I dumped the fluid out of the rear tires, was right about 12,000). The thing is, pulling a ripper or pushing with the front blade, it needs more weight if I give it full throttle. The little B7100 here at work on the other hand, just needs enough weight on the front to keep it on the ground with the bush hog on the back.

As a chore tractor, power to weight doesn't mean much, as a work tractor, pay close attention to power to weight.

 

[have_blue]

Chad,

Using power-to-weight ratio (P:W) for a tractor is a catch 22.

If you add weight to a tractor, the P:W goes down! If you lighten a tractor, the P:W goes up, but pulling power goes way down.

What I am saying is, instead of judging by P:W ratio, we should judge by power AND weight. Both should be appropriate for the implements a given tractor is expected to pull.

 

[Bob_Skurka]

Bob, I've been sitting back here watching, and I have to say that I think you and Chad are BOTH right but are probably splitting hairs on the defintions and really probably agree, but your agreement depends on the application.

Generally for the small tractors that we play with (a typical CUT) here on TBN, I would side with your points. For larger AG tractors, I would suggest that Chad probably hits the nail on the head. But you are talking about general useages and Chad is talking about ground engaging use, and that is probably were the basis of division is.

The only thing with what Chad wrote that I would disagree with, and this ONLY applies to CUTs is that heavy weight is needed for FEL work. To that point I would say PROPER BALLAST and BALANCE is far more important than absolute machine weight. I can site examples of lighter tractors that have greater FEL capacities than heavier machines to prove that point. But again, I am referring to CUT size machines that are really jacks of all trades, the machines that are used for mowing the lawn, tilling a garden, blowing snow, digging post holes and moving dirt and mulch around our 5, 10 or even 40 acre mini-estates.

My preference for an "all around" tractor for homeowner general use is typically a light to medium weight tractor with removable ballast. I'm willing to give up a bit of traction since I don't "pull a plow" and especially since my tiller doesn't seem to even need me to be in 4wd. I'd rather not rut the yard and have the lovely Mrs_Bob scream at me if I run a heavy piece of equipment across the lawn. I've found that most people who maintain their property really don't gain any advantage from owning a heavy tractor, that probably explains much of the popularity of the Kubota B series light weight tractors. Now if you want to log the woods (pulling really big trees, not dragging 8" to 12" trees) then weight is good. If you actually use a plow, then weight is your friend. If box blade work is a major task, then weight is good.

Define your uses, use that to figure out what weight tractor is best. Most people are probably BEST served by going to the light or middle weight range machines (assuming they are not type who NEED weight).

 

[Spiffy]

I didn't remember posting to this thread!? /forums/images/graemlins/confused.gif /forums/images/graemlins/grin.gif

Kidding, I see "chadincolo". /forums/images/graemlins/smile.gif

Anyway, just to add something productive, I think Bob nailed it with defining the uses.

I'm more familiar with ag than the 20-30HP CUTs I think are in question here, but if FEL is the main thing in question, again balance would be the answer. Barring that, pure weight can make up some difference, however, dont forget tires can be filled or weights can be added where ever needed.

On the same note [probably mentioned earlier and I missed it], weight plays in with tire design on pulling power vs. turf damage.