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

Rdrcr

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Here’s a true teaser video. This is the tractor warming up on the PTO Dyno;


Mike
 

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Just found this thread today. Thank you, Mike. Better than Johnny X from Tractor Tim! (-;
 
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Runs With Scissors

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Waiting with anticipation!!!!
 
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Rdrcr

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^^^^
I'll have it up in about an hour! :D

Mike
 

Rdrcr

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Part 4: L2501 Turbo vs. PTO Dyno (The Results and Conclusion)

I’m sure for many readers, the following information is precisely what you’ve been waiting for. The results, period. No estimates. No blather. No guessing. No subjective observations. No excuses. You have been waiting for a culmination of factual, verifiable, objective and real measured results. Results obtained from proven testing equipment operated by professionals with years of experience. Plain and simple. Well, I’m back to deliver those results. Are you ready?

Here we go!

I had been searching for a facility to test my tractor’s performance for quite sometime. I was utterly bewildered upon discovering that very few tractor service facilities in my area have a PTO dynamometer. A PTO dynamometer measures a tractor’s performance by applying a calibrated and controlled braking force on the tractor PTO (Power Take Off) while measuring the speed of the rotation. Measuring the speed and power under a specific load allows the amount of torque produced by the engine at different speeds to be calculated. It’s a fairly complex piece of equipment. Shockingly, even my local Kubota dealer did not have a PTO dynamometer available. Not even for diagnostic purposes? Crazy. Originally I thought, since I live in what could be considered ‘tractor country’ with tons of agricultural businesses in my surrounding area that this type of equipment would be commonplace. Nope! That wasn’t the case at all.

I had to contact countless tractor service facilities outside of my local area for a PTO dynamometer, unfortunately, I wasn’t having any luck. Heck, at one point, I even contacted a PTO dynamometer manufacturer and inquired about the cost to buy my own PTO dynamometer. But, after learning that they cost upwards of $30,000, that idea was quickly squashed. Refusing to give up I continued to contact and collect clues from potential service facilities about a PTO dynamometer to test my tractor until I finally heard the words I needed to hear….”Yes, we have a PTO dyno. Yes, it is available for customer testing”. Woohoo!

The super friendly and helpful folks at Jennings Equipment, Inc. in Chehalis Washington, a Kubota dealership, were the ones that finally answered my call and were able to fulfill my request. They in fact had the elusive PTO dynamometer that I needed to evaluate my tractor’s revolutionary performance modifications and put them to the test.

Not only did they have a PTO dyno, but they have an AW AG.2X series Dynamometer featuring the latest high tech 2100SXT DynoPro computer system. This particular PTO dynamometer is arguably the best and most accurate PTO dyno in the industry today. Bonus!

Dyno.jpg


Hold on a second! Before I disclose the final results, perhaps I should share my original performance goal with this Turbo system. Simply stated, my goal was to surpass the performance output of the L3901 / L3902. These tractors produce 37.5 HP and 30.6 PTO HP respectively.

You said no blather? Common man! Let’s get on with it! How’d it do?

The tractor was hooked up to the AW AG.2X dynamometer and ran for a short time to make sure everything was securely attached to the tractor, functioning properly and recording the essential data.

Tractor1.jpg


After the initial setup, we warmed up the tractor to operating temperature and ran it for two merciless hours of testing. The percentage of load was increased incrementally as we continued to monitor engine diagnostics, boost pressure, EGT temperatures and the subsequent performance data. The tractor was ran under full boost and a heavy load for a solid hour. There were no surprises. The engine coolant temperature remained cool and consistent throughout the testing and Turbo system performed beautifully with zero issues whatsoever.

Tractor2.jpg


Once again, the Turbo setup;
L2501 HST 4WD (LA525 Loader w/ 66” QA Bucket, Liquid Tire Ballast) - MHI TD025 TURBO SYSTEM - 9 PSI - Fuel Setting, 2 1/4 Full Turns (42* ambient temperature).

Folks, meet the Kubota Standard L series L2501 Turbo or, perhaps more accurately described as the Standard L series L4401 Tractor powered by a Turbocharged D1703-M-DI-E4B engine!

The AW AG.2X dynamometer recorded:
PTO = 35 PTO HP
PTO Torque = 339 LB-FT
Engine Horsepower = 44.1 HP
Engine Torque = 109.8 LB-FT
Peak EGT = 1,185*

Results.jpg


That’s right! 35 PTO HP!!!
The Turbo kit produced a 45% increase in power! We’ve gone from a measly 19 PTO HP to a gargantuan 35 PTO HP! Yep, that’s Huge!

We achieved the 35 PTO HP at the factory 2,105 RPM PTO setting, our target RPM. Absolutely fantastic! We recorded a maximum of 1,185* EGT, a safe temperature for sustained usage. Excellent! We recorded a maximum boost pressure of 9PSI under full load. Perfect!

In addition, at just a 10% load, the tractor is producing a whopping 26 PTO HP at 2,105 RPM’s. That’s worth repeating. At just a 10% load, the tractor is producing 26 PTO HP. What does that mean? The Turbo system is making so much power and torque that the tractor doesn’t even have to work hard to run most PTO implements. Simply remarkable!

The knowledgeable Jennings staff and technicians had a couple suggestions regarding the tractor and Turbo system. They said to make sure to use the clutch and engage the PTO at idle. I’m pretty sure that’s standard procedure but, they wanted to be clear since any deviation from this routine could cause excessive wear on these components due to the colossal power improvement. No surprise there.

To put the gains into perspective, here are the power outputs of a standard L2501, an L2501 with the ‘FREE’ Injection Pump Timing Modification, an L3901 / L3902 and the L2501 Turbo (all equipped with HST);

L2501 Stock = 24.8 HP / 70.2 LB-FT
19 PTO HP at 2,105 RPM

L2501 w/ ‘FREE’ Injection Pump Timing = 31.2 HP / 77.3 LB-FT
25 PTO HP at 2,200 RPM

L3901 / L3902 = 37.5 HP / 83.6 LB-FT
30.6 PTO HP at 2,700 RPM

L2501 Turbo = 44.1 HP / 109.8 LB-FT
35 PTO HP at 2,105 RPM

I’m sure you can draw your own conclusions. I know I have.

On a side note, unbeknownst to me, apparently there was some sort of side betting going on by the Jennings staff regarding the numbers my tractor was going to make. And, had I known about the bets, the tractor would have made some serious money! Based on their prior experiences testing other tractors, nobody there thought this tractor would produce anything north of 30 PTO HP. Heck, I honestly didn’t know either! But, that’s why the testing had to be done!

Altogether we’re obviously very happy with the results. This Turbo system surpassed my goals and performed exceptionally well during the testing. Everyone involved in the testing process was extremely impressed with the Turbo system, the components, the quality, the packaging, the performance and the final outcome.

That’s great Bro! Congratulations….But, you’re probably rolling coal and murdering the earth! Sorry to rain on your parade dude!

Nope! We’re running super clean! During the testing there wasn’t any visible smoke at any RPM, or at any load. The tractor is burning clean and efficiently in all operating conditions. The only visible smoke I have experienced with this Turbo setup is during startup, which is the same behavior with stock fuel settings. Albeit, there is a bit more smoke with the modified settings when compared to the original fuel setting. But, that’s only common sense and should be expected.

Okay. Fine! You got my attention. I want a L2501 Turbo kit. But, what if I’m not as awe inspired with the results as you are? I want this Turbo kit to produce even more power!!!

Fair enough. Fair question. Yes, we could have made more PTO HP. We left plenty of additional power on the table (or dyno). We could have easily pushed the power output well beyond 35 PTO HP. How? We could have continued to increase the load on the tractor and as the RPM’s naturally drop with the additional load, we could have then increased the throttle and RPM’s or even surpass the rated PTO RPM’s we were testing at. The increase in throttle input and RPM’s would have made more power. We weren’t anywhere close to stalling the tractor. Moreover, considering how clean the engine is running, we could have easily added more fuel, thereby producing even more power. I estimate this Turbo system can easily produce 40 PTO HP on the L2501, if one so desired. Anyone wanna bet?

Continued below...
 
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Rdrcr

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However, maximum power wasn’t our goal. My limiting factor during the testing was EGT temperature. I didn’t want to see the EGT’s climb over 1,200 degrees during sustained operation on or off the PTO Dyno. Instead of seeking maximum power, we took a conservative approach. We didn’t want to maximize the potential of the turbo system. We wanted to meet our goals safely, without compromising any components, or placing any undue stress on the engine, or tractor. We want this Turbo system to deliver exceptional performance and trouble free operation for the life expectancy of the powertrain.

Speaking about reliability, durability and longevity. I’m aware of the skeptics out there. What will it take to convince those individuals that adding a Turbocharger system to an originally N/A (naturally aspirated) diesel engine can be done safely, reliably and durably, for years to come? Good question. What will it take to silence the skeptics? 200 hours of trouble free operation? 500 hours? 1,000 hours? 3,000 hours? A full 5,000 hours? I don’t know.
I can say that every precaution with regards to the engineering and design of the Turbo system to ensure reliability and preserve longevity of the engine, Turbocharger system and the tractor has been made. None of us want to harm our tractors, or be burdened with expensive repairs, or downtime.

Seriously, if you’re not adverse to modifying your tractor and you want more power, you may want to consider a L2501 Turbo kit.

To sum up, I think it’s safe to say the Turbocharged L2501 is in a class of its own! You simply cannot beat the cost, or the performance this tractor is delivering.
When we consider the total tractor investment and want to compare PTO productivity for your money, if you recall, the standard L2501 costs you $963 per PTO HP. The L3901 / L3902 delivers a much more reasonable $754 / $860 per PTO HP. An L2501 with the ‘FREE’ injection pump timing modification emerges with a delightful $733 per PTO HP, besting the L3901 / L3902 but, unfortunately, without matching the power output.
The L2501 equipped with this Turbo kit, easily trounces the performance output of the L3901 / L3902 while also delivering an outstanding $595 per PTO HP! It’s the obvious PTO HP per dollar champion! All the while saving you $2,234 on a L3901 and $4,487 on the L3902 tractor purchase. That’s money that could be used towards purchasing much needed implements!

Frankly, adding this Turbo kit to the L2501 makes all the other comparable Kubota Standard L Series tractors pretty much irrelevant. The L2501 tractor appropriately modified, can meet, or exceed the performance of all the other equivalent Kubota Standard L Series tractors. The L2501 can literally do it all.

Lastly, if you own an L2501 (or you are considering an L2501 tractor in the future) and think you might need more power sometime down the road, or additional power now, for high altitude operation, additional power for running and driving larger PTO driven implements like rotary cutters, snowblowers, flail mowers, finish mowers and rotary tillers in demanding conditions and/or challenging terrain, powering larger wood chippers, PTO generators, or post hole diggers, need additional operating speed and pulling power for larger, heavier dirt working ground engagement implements, more power for traversing steep terrain, and/or higher ground speeds in (H) gear on hills, and a cost savings over factory options, this is your ticket! Whew, that was a mouthful!

The L2501 Turbo is unquestionably, the definitive answer to an expensive tractor upgrade and it is without a doubt, the ‘Hot Rod’ solution to a hobby farmer’s quandary.

Thanks again for reading and let the discussion begin.

Mike
 
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Rdrcr

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Here's a short video of the L2501 Turbo running on the PTO Dyno (testing shown at the 1:03 mark);

Mike
 
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Nicfin36

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Wow, simply amazing! I read your updates this morning and did not have the time to respond. I am surprised you have not have a bunch of replies to your write-up and results since then.

As someone who is mediocre in doing most things, I am truly impressed with what you have achieved. My L2501 is a nice little tractor as/is, but I don't think I have heard anyone complain about too much power from the L2501, especially at the PTO. I have no doubt that if you fabricated kits for it, they would sell like crazy.
 
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nbking

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That's pretty awesome. Will make people really think about a modded L2501 over a more factory hp tractor. And no DPF. Yay!!
 
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Runs With Scissors

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I feel like I need a cigarette now!

Best write up ever!!! So good and thorough in fact, I am having a hard time coming up with any questions.

Was the water running on to the floor for cooling the dyno?

Paul
 
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Runs With Scissors

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For some reason the quote of Isaac Newton just popped into my head and it seems appropriate to post it here.

"If I have seen further, it is by standing on the shoulders of giants." Isaac Newton
 
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ken erickson

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I have really enjoyed your write-up on your turbo journey especially considering I also own a L2501 hst.
The dyno results are impressive! My only wish is that it would have been possible to have your tractor do a few dyno runs before you made the modifications. It would be interesting to me to know what numbers your tractor produced compared to Kubota's printed specifications. The reason I say this is I am old enough to have lived through the muscle car era when certain manufacturers and engines notoriously produced more HP and torque than the published specs! :)

Job well done and I hope you follow up with any other mods or issues that might pop up.
 
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Rdrcr

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I feel like I need a cigarette now!

Best write up ever!!! So good and thorough in fact, I am having a hard time coming up with any questions.

Was the water running on to the floor for cooling the dyno?

Paul
Thank you. Lots of work and research went in to both the Turbo Kit and the review. I’m glad you and others have enjoyed it!

I’m happy to answer any questions that come up!

The water is from the reservoir in the PTO dyno. I can’t remember if the water purpose is simply for cooling or, if it provides both cooling and the load resistance. I did inquire about the water, but I can’t recall specifically. Most PTO dyno operators will attach a hose to the spout and place the hose directly in a drain. Jennings had a drain right next to the tractor so they just let it spray water during the testing.

Mike
 

barts

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... The reason I say this is I am old enough to have lived through the muscle car era when certain manufacturers and engines notoriously produced more HP and torque than the published specs! :)
That of course was done to try and avoid both regulatory intervention and insurance companies charging more for customers with 300+ hp vehicles. Today, the only advantages of claiming less power might be to try and escape additional emissions requirements from the EPA... but those guys test things and fine companies for cheating.

There might be minor variations on power output due to various manufacturing variances... but nothing like the power jump from the this turbo. Impressive work!
 
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Rdrcr

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I have really enjoyed your write-up on your turbo journey especially considering I also own a L2501 hst.
The dyno results are impressive! My only wish is that it would have been possible to have your tractor do a few dyno runs before you made the modifications. It would be interesting to me to know what numbers your tractor produced compared to Kubota's printed specifications. The reason I say this is I am old enough to have lived through the muscle car era when certain manufacturers and engines notoriously produced more HP and torque than the published specs! :)

Job well done and I hope you follow up with any other mods or issues that might pop up.
Amen. I fully agree.
I ALWAYS performed before and after dyno tests on ALL modifications I install on my vehicles.

My original plan was to have a before and after dyno on the tractor, so we can compare the exact gains head-to-head. Unfortunately, I had such a difficult time finding a PTO dyno, it just wasn’t possible before the fabrication work began on the tractor.

That said, yes, I could have removed the Turbo Kit, tested the tractor, then reinstall the Turbo Kit and retest. I didn’t for a couple reasons. Time and Money. But, really just money because the time…just costs more money, lol. I was on their clock, paying by the hour. I didn’t have anybody at the time to help the removal and installation, and I didn’t want to have to pay one of their technicians to help. It would have been really, really expensive.

However, I’m pretty sure you’ll get your wish. They have several customers that want this Turbo Kit for their L2501 HST tractors. So, when that happens, I’ll make sure we test one or more of those tractors for back-to-back results.

That said, regardless of the output of my L2501 stock, be it 19 PTO, 20 PTO, 21 PTO, there is no way it was originally making 35 PTO HP. The Turbo works and works really really well. I’m just glad I had the opportunity to confirm what I already knew, from the L2501 Turbo’s performance on my property.

Mike
 
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Rdrcr

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^^^^
I'll add to the above.

Here is a PTO dyno for an L2501 with the 'Free' Injection Pump Timing and Fuel Increase (1 full turn) Modification (Testing begins at 1:07);

This was on a 'Gear-Drive' L2501. The Gear-Drive Transmission typically produces 7% more PTO power than an HST Transmission.

Here is my L2501 Turbo PTO dyno for comparison;

If a 'modded', gear-drive L2501 makes 25 PTO HP, what would a stock L2501 HST produce?

Mike
 

Rdrcr

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Wow, simply amazing! I read your updates this morning and did not have the time to respond. I am surprised you have not have a bunch of replies to your write-up and results since then.

As someone who is mediocre in doing most things, I am truly impressed with what you have achieved. My L2501 is a nice little tractor as/is, but I don't think I have heard anyone complain about too much power from the L2501, especially at the PTO. I have no doubt that if you fabricated kits for it, they would sell like crazy.
Thank you! Much appreciated.

I'm trying to get my good friend to bring over his L3301 HST 4WD so we can drag race in (H) gear! :LOL:

The additional power is nice to have, especially if you have any PTO driven implements. The tractor just doesn't work hard anymore when powering the equipment. When I mentioned the L2501 Turbo powers my Wood Chipper in 'heroic' fashion, trust me, I meant it!

We've got several interested parties in Turbo kits. Right now, I'm just focusing on upgrading/improving the Turbo oil feed/drain lines/fittings and getting the Turbo charge pipe re-designed so the hood prop rod/absorber can be used. For those that are interested something should be available soon.

Mike
 
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Rdrcr

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That's pretty awesome. Will make people really think about a modded L2501 over a more factory hp tractor. And no DPF. Yay!!
Thank you!

Agreed. All the power (and more) of the L3901 / L3902 but, without the DPF, Regen, ECU and high engine RPM's. The L2501 Turbo is just a simple mechanical diesel.

I keep reading about the pre-emission tractor prices. It's said that they're on the rise and there are lots of folks that refuse to purchase new tractors because of the emission systems.

Mike
 

Nicfin36

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I keep reading about the pre-emission tractor prices. It's said that they're on the rise and there are lots of folks that refuse to purchase new tractors because of the emission systems.
100% true. That's why many find this mod so appealing.
 
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