L2501 Turbo: A Journey Defined - The tractor, The comparison, The modification, The results...

Rdrcr

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L2501 Turbo (Current), B2601 (Sold)
May 7, 2021
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The 2501 has the same hydrostat unit as the 3301/3901 and the same 28:27 input ratio. The 2501 relief pressure is only 100 psi less than the 3301/3901, but yours may be at the lower end of the spec.

I wonder what the HP/torque curves look like.
Good to know. Thank you!

I'm hoping that I'll be able to see the HP/TQ curves when the tractor is placed on the PTO dyno.

Mike
 

drewzee87t

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B2910 HST, Modern RC, Gannon Earthcavator, Frontier 1150 Tiller, Woods RM306
May 20, 2016
139
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28
misery
The ability to push would be the effect of modding the relief in the hydrostat. Your wheels would have a lot more power up to the pressure you set. I don't know of anybody that has tested the ability of the hydro or axles and gear on the 2501 or whatever little kubota to get more pressure. I would assume you will find the limit when you break something. I bet you could do wheelies with it and not hurt anything
 
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mdhughes

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L3901DT
Dec 10, 2014
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Not surprising, with the fuel turned up, the tractor is consuming more fuel. Noticeably more than when stock. However, it still seems pretty good. It's looking like a gallon per hour of use.

I'll continue to monitor and report back.

Mike
This seems like a lot of fuel per hour, how did you come up with that number? My L3901DT has averaged 2.2 hours per gallon, this is over 29 tanks of fuel. I try to fill the tank as close as I can each time I fill it and have a meter on my storage tank to get the number of gallons I add to the tractor.
 
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Rdrcr

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L2501 Turbo (Current), B2601 (Sold)
May 7, 2021
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This seems like a lot of fuel per hour, how did you come up with that number? My L3901DT has averaged 2.2 hours per gallon, this is over 29 tanks of fuel. I try to fill the tank as close as I can each time I fill it and have a meter on my storage tank to get the number of gallons I add to the tractor.
Rough estimate based on the time I’ve spent on the tractor after filling the tank. I have a couple projects coming up and I’ll continue to monitor the fuel consumption and report back.

I do believe that this particular setup (simple mechanical diesel with Turbo and manually adjusted fuel settings) will consume more fuel than a comparable L3901.
I’m making this assumption on the basis that the L3901 fuel setup is computer controlled and much more precise.

Mike
 
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Rdrcr

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L2501 Turbo (Current), B2601 (Sold)
May 7, 2021
351
337
63
WA
The ability to push would be the effect of modding the relief in the hydrostat. Your wheels would have a lot more power up to the pressure you set. I don't know of anybody that has tested the ability of the hydro or axles and gear on the 2501 or whatever little kubota to get more pressure. I would assume you will find the limit when you break something. I bet you could do wheelies with it and not hurt anything
This would be awesome.

Although, I haven’t heard or read about anyone performing a similar modification. It’s tempting! But, well above my capabilities.

I may just have to be content with the amazing Turbo PTO performance, increased traveling speed in (H) gear and more power for the hills and rear attachments and implements.

Mike
 

ken erickson

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B7100 hst, 2650 front mount snowblower, L2501 hst qa loader
Nov 21, 2010
494
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Waupaca Wisconsin
while I have not kept accurate records of operating time/fuel consumption with my HST L2501 I feel like I am burning 1/2 to 3/4 gallon per hour with brush hogging at the high end. I tend to not push the tractor hard and would not be surprised if I did I would be burning closer to 1 gallon per hour.
 
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Oil pan 4

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L185 turbo
Sep 21, 2017
237
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NM
My tractor burns more fuel but it does a lot more work too. I used to Rev the engine up to 3,000rpm mow through a bunch of tall weeds then it would bog down, roll coal the whole time. Now it maintains speed, the turbo spools up with very little smoke and the rain flapper stands straight up and it mows through tall weeds no problem.
 
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drewzee87t

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B2910 HST, Modern RC, Gannon Earthcavator, Frontier 1150 Tiller, Woods RM306
May 20, 2016
139
53
28
misery
It is more efficient and way more powerful. The turbo increases performance when it's needed and scavenges the rest of the time making efficient.

But if you are a non hp tuner gearhead type you should probably just buy your tractor and not mess with it, which is most people. That's fine for you.

If you gave me almost anything i would try to make it work better, whether or not it was really needed.
 
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Rdrcr

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L2501 Turbo (Current), B2601 (Sold)
May 7, 2021
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CCV/PCV

I ran across some info on another Kubota engine while doing some reading regarding the CCV/PCV and turbocharging. These particular folks were suggesting to remove a steel retainer and spring from the CCV/PCV and then vent to the intake.

1459446A-412A-4615-AAAD-400E764E8FC9.jpeg

9BF271CD-064B-48C6-8794-2CB7DB4E3FE0.jpeg

Now, I’m not sure the D1703 has this assembly (I haven’t checked yet) but, I assume it does.

Assuming that the L2501 has the steel retainer and spring, I would imagine that as crankcase pressure builds, that retainer/spring opens and the gasses are released through the CCV/PCV hose and into the intake manifold (or inlet pipe w/ Turbo). On my Turbo System, I’m re-routing the CCV/PCV gasses to the Turbo inlet pipe. A re-route, which I have done, should be all that’s needed, correct?

Why would these folks suggest removing it? What’s the purpose?

Thinking out loud...
Do they simply want ALL excess crankcase gasses to flow through immediately? Or, do they believe the retainer/spring is an obstruction that is allowing more pressure than they wish?
I don't know.

Mike
 
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Oil pan 4

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L185 turbo
Sep 21, 2017
237
30
28
NM
I have heard that Kubota PCVs like to fail and blow out crank seals, then you lose all your oil and the engine seizes.
On mine the PCV hose just hangs down a little lower than the engine.
 
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Rdrcr

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Equipment
L2501 Turbo (Current), B2601 (Sold)
May 7, 2021
351
337
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WA
I have heard that Kubota PCVs like to fail and blow out crank seals, then you lose all your oil and the engine seizes.
On mine the PCV hose just hangs down a little lower than the engine.
Hmmm, interesting. So, do you believe they are being proactive recommending the removal of the retainer/spring in the event of a circumstance as you describe?

Mike