B3200 Engine Torque?

[quarencia]

According to this document, max torque is 94.9 Nm
https://www.kubota.com.au/wp-content/uploads/2015/09/L3200-L3800.pdf

I found that in my google search. That is for the Australian L3200 with the D1503 engine. Its a 3 cylinder engine with almost the same displacement as the B3200 V1505 4 cylinder engine. Based on my research, I think the B3200 should be in the 90 to 95 Nm (66 to 70 ft-lb) range, which is only a few better than the B2650. The B3150 & B3300SU (both with V1505) are rated at 72.2 & 67 ft-lb respectively. Notice that the higher horse power B3300 has less torque with the same engine than the B3150! Go figure. Hence the reason I知 looking for the actual B3200 number and not anecdotal comparisons.

But I appreciate the effort to actually answer the question I asked.

I am not sure how much faith to put in Kubota ratings anyway. I have seen too many examples like the B3150 and B3300 above where the ratings do not make logical sense. Not only do the two tractors have the same engine with same bore, stroke, and displacement, they use the same injection pump. So, the only way you get different numbers is with different pressure set-up on the pump. I suppose they could have different cams or pistons, but that would surprise me.

I am going to call dealer on Monday and see if they have B3200 specs.

 

[ptsg]

Is this what you're looking for?

http://www.kubotaengine.com/assets/documents/15_v1505t_30.pdf

 

[quarencia]

Is this what you're looking for?

http://www.kubotaengine.com/assets/documents/15_v1505t_30.pdf

Wow, I did not find that document in my search. But it confuses me more. That is for a V1505-T-E3B engine with same bore, stroke & displacement as other V1505s, but that one is rated at a whopping 44.2 hp. Those specs do say that is an intermittent rating. I think the tractor specs Kubota puts out are continuous operation ratings and not intermittent. That engine shows torque in the range of 105 to 120 Nm (77.5 to 88.5 ft-lb). That is alarmingly higher than the other V1505 tractor ratings.

Will call dealer on Monday.

 

[ptsg]

Keep in mind that those are probably the highest spec for the engine. So depending on the application, the engine might get derated a bit, like for instance on the B3200.

 

[Jim Nelson]

In your original post you mentioned "secondary engine vibration" , I've owned B7100,B7200,B7510,B7800, and RTV900, The B7800 is easily the smoothest that I have owned and the RTV900 is the roughest by far. I still own both of these machines and it's not that big of a deal to me. I've always heard that the 4 cyl. engine was rough running and when Cat came out with their 950 loader with a 4 cyl. they ended up having to put in a dummy cam to smooth it out.

I ran equipment for a living most of my life and got to where I never really paid much attention but after retiring and getting into these small tractors I've paid more attention.I know for sure the RTV900,3 cyl. is the roughest running engine I can remember and the B7800 4cyl. is pretty darn smooth.

 

[Fallon]

HP = (RPM * Torque) / 5252

So if you measure power at the same RPM it's a straight up comparison with only 1 variable. Conveniently tractors all have PTO HP measured at 540 RPM. Ya there are transmission losses gearing things from peak torque on the engine. But those are generally similar enough to rule out.

 

[PaulL2]

Conveniently tractors all have PTO HP measured at 540 RPM

540 PTO RPM, not 540 tractor RPM.

I think Kubota's measurements may have come under question in recent times, as the BX tractors suddenly have different power ratings than before with absolutely no mechanical change or model change. I'm assuming that their measurement approach was found to be inadequate.

They also often measure HP at a specified RPM, but that isn't the peak power the engine produces in the application. So if you look at a car's power it will generally say "225HP @ 6200 RPM" and that's going to be the peak power it'll produce. With the BX it says "22 HP @ 3300 RPM", when it seems happy to run to nearly 4000 RPM, I'm pretty sure it's making more than 22 HP at those higher RPM. Even more so the L2501, which is rated at about 2200 RPM, which seems to not be far off idle. At WOT I'd guess it's making a lot more power.

 

[Fallon]

540 PTO RPM, not 540 tractor RPM.

I think Kubota's measurements may have come under question in recent times, as the BX tractors suddenly have different power ratings than before with absolutely no mechanical change or model change. I'm assuming that their measurement approach was found to be inadequate.

They also often measure HP at a specified RPM, but that isn't the peak power the engine produces in the application. So if you look at a car's power it will generally say "225HP @ 6200 RPM" and that's going to be the peak power it'll produce. With the BX it says "22 HP @ 3300 RPM", when it seems happy to run to nearly 4000 RPM, I'm pretty sure it's making more than 22 HP at those higher RPM. Even more so the L2501, which is rated at about 2200 RPM, which seems to not be far off idle. At WOT I'd guess it's making a lot more power.

Tractors in general are tuned to have peak torque at just under PTO RPM. That way if you encounter resistance working, you push the machine into peak torque to keep going rather than out of peak torque into a stall.

I get your concern that engine torque & PTO torque aren't the same. But all machines have transmission losses. Really we care about the power that makes it to the wheels or PTO shaft. That's the usable power out of the machine (ignoring A/C & hydraulics). As the engines & transmissions are optimized around PTO output & the consistency of the RPM part of the equation it makes for an ideal apples to apples comparison of torque or HP. It makes comparing of tractor engines a lot easier to compare than car engines.

As for the differences in rated power output, they can & do monkey with fuel & other settings for various reasons. Lots of machines got detuned to 25hp due to emissions reasons. You just need to monkey with injector pump settings to do that. They did a few more tweaks than that to turn the old L3200 into the new L2501, but not many. That was just to get below the 25hp line for extra emissions gear requirements.

 

[PaulL2]

This is true, but to make that comparison you need to know the PTO torque, not the engine torque. If you know that, then yes it'd be a very reliable comparison point as it's easily able to be replicated.