L3902 vs L3302 horsepower difference

[Tractor Jacques]

Comparing the Kubota L3302 and L3902, they're nearly identical except for a bit more horsepower on the L3902.
But what I don't understand is where those extra horses come from. Looking at the published specs (comparing HST models):

                           L3302    L3902
Engine Gross Power (HP)     33.0     37.5    +4.5hp (+13%)
Engine Net Power (HP)       31.8     36.3    +4.5hp (+14%)
PTO Power (HP)              26.1     30.3    +4.2hp (+16%)
Number Cylinders               3        3
Bore (in)                    3.4      3.4
Stroke (in)                  4.0      4.0
Displacement (in³)         111.4    111.4
Rated Speed (rpm)           2700     2700

I understand how the L2502 gets less power with shorter stroke (3.6") and 2200 rpm.
I understand how the L4802 gets more power with 4 cylinders.
But I don't understand how the L3302 and L3900 have different power output with apparently-identical specs?

 

[mikester]

HP = torque x RPM

It's a paper exercise for sales persons to sell stuff. Want to buy some left handed hammers?

 

[hodge]

increased fuel.

 

[BAP]

Kubota sets up the injection pump differently to get the extra horsepower. It’s a common practice among all engine manufacturers, that by tweaking the fuel delivery, they can make engines have different horsepower ratings.

 

[SDT]

Kubota sets up the injection pump differently to get the extra horsepower. It’s a common practice among all engine manufacturers, that by tweaking the fuel delivery, they can make engines have different horsepower ratings.

Bingo.

 

[Rdrcr]

ECM tuning....they add more fuel to the L3902.

My Turbocharged L2501 makes 44.1 HP, 109.8 lb-ft, and 35 PTO HP

Mike

 

[NorthwoodsLife]

As others mentioned. Injection, tuning, or a different PSI on the turbo if it's turbo charged.
It's pretty common actually. One of my past motorcycles was an 800, my wife's is a 650. Same brand. Same engine. The engines are identical 800cc engine. One made about 45 HP, the other 65HP. Tuning and injection was the only difference.

So, you may ask why not buy the smaller HP unit and convert it. The reason is it'll cost you more to do that than just buying the bigger rated tractor. And it would void your warranty.

 

[Rdrcr]

So, you may ask why not buy the smaller HP unit and convert it. The reason is it'll cost you more to do that than just buying the bigger rated tractor. And it would void your warranty.

Actually, my L2501 with the Turbo kit installed (at retail price), is $2K less expensive than the L3901, $4K cheaper than an L3902 all while making more power and delivering additional performance. But, yes, you loose your warranty (if applicable).

Mike

 

[NorthwoodsLife]

Actually, my L2501 with the Turbo kit installed (at retail price), is $2K less expensive than the L3901, $4K cheaper than an L3902 all while making more power and delivering additional performance. But, yes, you loose your warranty (if applicable).

Mike

That's interesting.

What it this turbo kit you speak of?

Is a Kubota kit?

 

[rc51stierhoff]

I think it’s a Binford…

 

[Rdrcr]

That's interesting.

What it this turbo kit you speak of?

Is a Kubota kit?

Definitely not a Kubota kit. But, it uses an OEM Kubota Turbocharger.

L2501-Turbo-Details

Professional Service

www.s2tpp.com

Mike

 

[PaulL]

Definitely not a Kubota kit. But, it uses an OEM Kubota Turbocharger.

L2501-Turbo-Details

Professional Service

www.s2tpp.com

Mike

The L3302 makes rated HP at 2700 RPM. The L2502 at 2200 RPM. When you mount the turbo, are you changing the RPM range as well, or does it now make 40+HP at 2200RPM?

I presume the L3302 and L3902 have different PTO gearing than the L2502, despite being substantially similar.

 

[Rdrcr]

The L3302 makes rated HP at 2700 RPM. The L2502 at 2200 RPM. When you mount the turbo, are you changing the RPM range as well, or does it now make 40+HP at 2200RPM?

I presume the L3302 and L3902 have different PTO gearing than the L2502, despite being substantially similar.

The RPM limit remains unchanged and the Turbocharged L2501 makes peak power (44HP) at 2,200 RPM, same as factory.


The L2501, L2502, L3301, L3302, L3901 and L3902 all share the same Hydrostat unit and the same 28:27 input ratio. All components in PTO are the same with the exception of two gears. You can match PTO speeds in the L2501 by replacing those two gears.

The L2501 HST relief pressure is only 100psi lower than the L3301 / L3302 and L3901 / L3902.

Mike

 

[PaulL]

The RPM limit remains unchanged and the Turbocharged L2501 makes peak power (44HP) at 2,200 RPM, same as factory.

Nice!! Makes me wish I had an L2501. Of course, in my part of the world we don't have emissions rules, so we get L3200, L3800 and L4600. I'm presuming that genuinely means we're two generations behind - we still have the machines from before the 01 series.