The B2650 Project: Turbo Edition

Hahnsolo

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B2650 Tractor, B2782B Snow Blower
Mar 13, 2023
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DISCLAIMER:

The information contained in the following pages is intended for general information purposes only.

Original poster assumes no responsibility for errors or omissions in the content of these posts, and in no event will be held responsible for any direct, indirect, consequential, or incidental damages to physical or mental health of the reader or any devices or machinery owned by said reader. OP reserves the right to make additions, deletions, or modifications to the contents on these posts at any time without prior notice. Reader assumes full responsibility for any damages to referred equipment and relieves poster from all risk. Thanks, and have a pleasant tomorrow.


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Hello and welcome to the thread. Like a number of people on here, I am a fairly recent tractor owner. I have been learning lots of new things (good and bad) about tractor ownership, operation, modification, and maintenance. It's been an interesting ride so far and it looks like it's going to get even more interesting in the next few months. . .

A little history: I'll keep this short, but it provides information for the motive to jump into the abyss of adding a turbocharger to my B2650 tractor.

Several years ago, I built a retirement home up in the Rocky Mountains on the western side of the range. Knowing that I was going to be clearing A LOT of snow in the winters, I found and purchased a low-hour Kubota B2650 with a cab on it. Perfect. Had the dealer put on a B2782 snow blower and had it making white rooster tails in the winter of 2021/2022.

That winter was relatively mild for the area, and the machine worked Okay for the task, but I new immediately that it was struggling to make power. As many of you probably already know, you loose ~3% of your horse power for every 1000 feet of elevation. Here's the kicker: I'm at just under 8000 feet! Yup, 24% of my horse power was GONE before I even turned the key. My 25 horse engine was now making about 19 horse power. Ouch.

This past winter was completely different. We had one of the heaviest, longest winters on record. We were constantly out blowing my 150' driveway and parking area. The machine would do it, but you had to back off forward speed and let it work much slower. All the while, there was almost always some amount of black smoke coming out of the exhaust. For the diesel gurus out there, you already know that black smoke is an indicator of partially burned fuel. The insidious part of this condition is the undesirable rise in exhaust gas temperatures that come along with it. Late in the winter I purchased and installed an EGT sensor and gauge to monitor the exhaust gas temps. When idling or just driving around, temps stayed relatively low, around 350 to 500 degrees (F). But when I dropped the blower and started getting serious, temps would start going up dramatically. Depending on the load, I would see an average of around 600 to 800 degrees, with spikes up to 900 and even 1000 degrees. Researching maximum allowable temps on the internet did not reveal an exact safety zone, however, a general consensus of users agree that transient temperatures between 1200 and 1300(F) in a diesel engine is acceptable, however, a maximum "sustained" temperature should never exceed 1200 degrees (F). This is obviously an arguable point, but at least gave me a starting point for safe operation.

I spent a lot of hours trying to find any information I could on installing an aftermarket turbo on ANY Kubota tractor, let alone the specifics on a B2650. I had all but resigned myself to being one of the first to actually undertake this project alone. Then, just before giving up, I must have entered just the right keywords in my browser and landed on a thread in this forum by "Mike" aka "Rdrcr", detailing the design and installation of a turbo in his Kubota tractor! HALELUYA! I felt like I had just won the lottery. If you haven't already, go read the thread: "L2501 Turbo: A Journey Defined - The tractor, The comparison, The modification, The results. . .". It is an amazing read with incredible details on his own journey on undertaking the arduous task of adding a turbo to his tractor. He is building pieces of art and spared no cost in the process. Those who purchase a kit from him will have the best of the best. I have to give credit to him for giving me the confidence to start my own thread on the subject, and he is still very generous with his help and knowledge to this day. Thanks Mike!

With that being said, my approach will be more like "garage rat". I want to challenge myself to see how inexpensively (?! LOL) I can make this mod and still use good materials and techniques. I won't cut corners, but it might not look as cool. As long as I can at least recover the six horse power I'm loosing from altitude sickness, I'll be happy. Anything above that and I'll be ecstatic.

Whew! Okay kids, now that we got that out of the way, buckle up, rev up the throttle, and let's start this journey. . .

Solo
 
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85Hokie

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Hope there a lots of pictures!
 
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Hahnsolo

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B2650 Tractor, B2782B Snow Blower
Mar 13, 2023
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Rocky Mountains
Oh yeah, there will be lots of pictures. I firmly believe that is one of the best ways to convey information.
Here's a little teaser:
 

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Rdrcr

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Oh yeah, there will be lots of pictures. I firmly believe that is one of the best ways to convey information.
Here's a little teaser:
I love it!
That’s a great start!

I look forward to your progress!
And, let me know if you need any additional assistance along the way.

Mike
 

cthomas

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Can you also make a parts number list so I can copy you with my kinda similar tractor?
 
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Hahnsolo

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B2650 Tractor, B2782B Snow Blower
Mar 13, 2023
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Rocky Mountains
Actually, no, that manifold is available from dealers. I will post a more detailed answer tomorrow.
Solo
 
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North Idaho Wolfman

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Maybe this will be a buzz kill, but your just adding the parts from a B3350 without the emissions equipment.
It should be fine and dandy.
Good luck to you in your adventure!
 
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Hahnsolo

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B2650 Tractor, B2782B Snow Blower
Mar 13, 2023
102
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Rocky Mountains
Maybe this will be a buzz kill, but your just adding the parts from a B3350 without the emissions equipment.
It should be fine and dandy.
Good luck to you in your adventure!
Exactly! The benefits of a turbocharger without all the emissions BS!

Solo
 
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Hahnsolo

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B2650 Tractor, B2782B Snow Blower
Mar 13, 2023
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Rocky Mountains
Good Afternoon everybody, are you ready to get started? Let's take a look at the main players and their stats:

Turbocharger:
Mitsubishi P/N: TD025M-05T

Available through numerous sites online. Be careful; there are a plethora of cheap Chinese knock-offs available for under $200. Don't do it. Purchase a genuine Mitsubishi turbo. I paid about $650 for mine from a reputable parts house. You don't need to pay more.

Exhaust Manifold:
Kubota P/N: 1E038-12312

Ironically, this is one of the few major pieces you can still get from online retailers or Kubota themselves. The standard exhaust manifold on a B2650 has a square, 4-bolt plate that attaches to the mating exhaust plate and tubing on a naturally asperated engine. The B2650 utilizes a D1305 engine that has a larger bore and longer stroke, but is otherwise identical to the D1105 on which it is based. Hence, this 3-bolt manifold will bolt right up to the engine AND bolt right up to the turbo's 3-bolt exhaust input. This will make your life much easier, but expect to pay between $150 and $200 for it. Otherwise, your gonna have to kluge up some kind of 4 to 3 bolt adapter plate.

Exhaust flange:
Custom Machined Part

If you look at the Kubota drawings for a turbo assembly, you will see a rather large tail piece that attaches to the exhaust output of the turbo and connects into the exhaust tubing. This is called an exhaust flange. During my research, I found one that was the correct size to fit the turbo with the exhaust outlet point upward, but when I actually tried to find one to purchase, the only one I could find had the exhaust outlet pointing off to the side, which would not allow any room for routing the exhaust tubing out of the engine compartment. Therefore, this is one part that has to be fabricated on a CNC mill. It is really quite simple and can be made from 1/4" steel and allows the exhaust tubing to exit from the back and curve up and over the turbo to exit the engine compartment. I can provide the Solid Works drawing and file to those interested.

Edit 8/29/23: During continual research I came across a company that sells these custom exhaust flanges for the TD025 turbo. The company is called Kinugawa and they specialize in all things turbo, including parts for Mitsubishi TD series. They also sell custom modified TD025 turbos but I cannot vouch for their performance or quality. The exhaust flange they sell is actually a kit of four pieces: The exhaust flange and gasket, and a second flange and gasket that mates up to the three-hole mounting flange on the turbo. This second flange allows you to weld up an adapter to go from the 4-hole mount found on the B2650 exhaust manifold, to the 3-hole mounting plate on the turbo, sparing you the cost of purchasing a new 3-hole exhaust manifold as shown in this list of parts. Note of caution: If you decide to use these parts, they are mild steel and can be welded to stainless steel exhaust pipe, however, the possibility of the weld cracking over time due to different coefficients of expansion is increased. Here is the link:


Exhaust Flange Gasket:
Kubota P/N: 16292-17110

This is simply the gasket that goes between the turbo and the exhaust flange. Unfortunately, at the time I didn't have it available to include in this pic, but you still need it. It's available online through several retailers for about $16. See Edit 8/29/23 above.

Turbo Flange Gasket:
Kubota P/N: 16292-17100

Metal gasket that fits between the mounting flange on the turbo and the exhaust output flange on the exhaust manifold. Available online for about $14. See Edit 8/29/23 above.

Exhaust Manifold Gasket:
Kubota P/N: 16261-12350

Gasket that fits between the exhaust manifold and engine block. Online for about $10. See Edit 8/29/23 above.

Turbo Mounting Hardware:
Stud - Kubota P/N: 01513-70820 (qty.3)
Split Washer - Kubota P/N: 04512-70080 (qty.3)
Hex Nut - Kubota P/N: 02156-50080 (qty.3)

These are the hardware pieces required to attach the turbocharger to the exhaust manifold. You can try to source them on your own, but it's probably just easier to get them from a Kubota dealer for a few bucks online. MAKE SURE YOU ORDER THREE OF EACH PART!

Exhaust Flange Mounting Hardware:
M8-1.25x25 (qty.4)
M8 Split Washer (qty.4)

These are the bolts and washers that attach the exhaust flange to the outlet of the turbocharger. You will need 4-each to complete the assembly. Available just about anywhere for a few bucks.

Oil Flange Mounting Hardware:
M6-1.00x12 (qty.2) Edit: M6-1.00x20 (qty.2)
M6 Split Washer (qty.2)
Edit: Add M6 Flat Washer (qty.2)

These hold the oil drain flange to the center section of the turbocharger to provide an oil return line to the engine block. I wasn't sure if I should include these or not, but since you're buying other parts you might as well get these too. Also available just about anywhere for a few bucks.



Well, that just about does it for now. I won't be posting every day of course, but will post when I've made some progress. I need to stop yappin' and actually try to get these parts mounted and see what happens. Stay tuned, more to come. . .


Turbo Parts.png
 
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Hahnsolo

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B2650 Tractor, B2782B Snow Blower
Mar 13, 2023
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Rocky Mountains
Well HALALUYA! It fits! This was the most nerve wracking part of the build; wondering if I had gotten all the right parts to attach the turbo to the engine and have it all work. It fits beautifully, and there is ample room around it to route tubes and fittings. It was also dead-nuts easy. I simply took apart the muffler and exhaust connections, removed the old exhaust manifold, installed the new manifold, and bolted the turbo right to it! This was less than an hour work.

Now I need to figure out how to route the exhaust and fresh air tubing and the oil supply line and I think I'll be there. This was a huge first step in the process and I am quite pleased with the results. Once I get a few more things figured out, I will post a step-by-step procedure detailing everything needed to complete the project.
Stay tuned!

Solo

IMG_9601.jpg
 
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Rdrcr

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^^^^
Looks great!!!

Mike
 
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Hahnsolo

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B2650 Tractor, B2782B Snow Blower
Mar 13, 2023
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Rocky Mountains
Thanks Mike. As you found out, it's an incredible amount of work just to get to this point. Once you're here, you know you can make it the rest of the way.

Solo
 
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GrizBota

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Great start. I liked the thread on the turbo L2501. I’ll be following this one as well.

I’d really like more than 30 PTO Hp on my L3830. Outside of that, I love the tractor.
 
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Hahnsolo

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B2650 Tractor, B2782B Snow Blower
Mar 13, 2023
102
168
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Rocky Mountains
Hi Grizbota:

It would be great if we could more threads on different tractors for owners to refer to. Knowledge is power. The more people post on their own upgrades makes it easier for others to follow, without the fear of damaging the tractors.

Solo
 
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Hahnsolo

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B2650 Tractor, B2782B Snow Blower
Mar 13, 2023
102
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Rocky Mountains
Sorry for the tardiness of this post. After checking the fitment of the basic turbo and exhaust manifold, the turbo was removed from the manifold to be prepared and permanently installed later. Then the real work began.

To say this endeavor is difficult at best is a gross understatement. Every step of the way there are traps, pitfalls, and errors that slow the process to a crawl. Such was the case with finding the proper parts to assemble a functional, reliable oil system for the turbocharger. There are umpteen different fitting sizes, thread types, lengths, diameters, interferences, and restrictions that make me wonder how I'll ever get through it.

Alas, I googled, measured, checked, double-checked, failed, and finally figured this part out.

It all starts with the oil pressure sender unit on the side of the engine. Well, to be more accurate, the type and thread size of the hole. In the world of hydraulic and plumbing fittings, there are two common types: 1/8"NPT (National Pipe Thread), which is an American standard, and 1/8" BSPT (British Standard Pipe Tapered). Both these fittings are a tapered thread design that tightens up the farther it's threaded into the hole. The problem is, the length, diameter, thread shape, and taper of these fittings is very close, but not necessarily interchangeable.

The first thing I did was order all the fittings I thought I was going to need to get oil to/from the turbocharger to keep it from blowing up. I was mostly successful in this endeavor, however, I made a mistake in assuming that the oil pressure sending unit I unscrewed from the engine block had 1/8"NPT threads. WRONG!

When I received my parts I unscrewed the oil sender unit from the block and tried to thread the first fitting into the engine block hole, and it simply would not start. I could not get it to thread into the hole. Looking at the the new 1/8" NPT fitting side-by-side with the oil sender unit, I could visually see a subtle but definite difference: The tip of the NPT fitting was slightly larger in diameter, which explains why it wouldn't thread into the hole. Here is a close up for reference (Left: sender unit, Right: NPT fitting):

IMG_9625.jpg


It's clear now to see the oil pressure sending unit is a 1/8" BSPT thread, and the fitting is a 1/8" NPT thread. GRRRRRR. . . . . . .

So, back to the store I went to get a 1/8" male BSPT by 1/8" female NPT fitting to screw into the block. Finally, a break-through! I gooped it up with some thread sealant. . .


image18 (1).jpeg


and easily threaded it into the engine block.

image17.jpeg


NOW I am finally making some progress. I seated it in place and tightened it with a metric wrench. From this point forward, all fittings are either 1/8" NPT or AN4 size. I screwed an elbow in place with thread sealant and oriented it to the right:

image16.jpeg


This next fitting is a critical piece. This 4-way female 1/8" NPT fitting distributes oil to the turbocharger and the original oil sender unit. I would have used a 3-way fitting but I am adding an extra pressure transducer on the right side. NOTE: YOU CAN'T INSERT AN NPT THREAD INTO A BSPT HOLE, BUT YOU CAN INSERT A BSPT FITTING INTO AN NPT HOLE! IT WILL JUST SEAT MUCH DEEPER AND REQUIRE A LITTLE MORE SEALANT. THIS IS WHY THE OIL SENDER UNIT FITS ALL THE WAY UP IN THE BOTTOM:

image12.jpeg


Finally, I added a 1/8" NPT by AN4 fitting to the top for the tubing that will supply oil directly to the turbocharger. Note that the original oil sender unit and the new oil pressure transducer are arranged in such a way to prevent the possibility of an air bubble affecting performance:

image11.jpeg


Also, when re-attaching the original oil sender unit to the new oil distribution manifold, you will need to mount it horizontally to prevent the possibility of air bubbles, then bend the electrical tab downward to attach the connector, due to short wire length:

IMG_9781.jpg


That's about it for now. I will address the oil supply and drain lines in the next couple of posts.

Solo
 

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GrizBota

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L3830HST/LA724, B2601/LA435/RCK54-32, RCR1872, CDI 66”grapple, pallet forks
Apr 26, 2023
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Good figuring on the oil fittings.

I think I ran into that on my older Toyota (when they were still made in Japan). The differential breathers were close to, but not quite, 1/8” NPT. IIRC, I used a tap (or maybe a brass fitting that could form to the steel housing) to resolve the situation to extend the breather tube to the engine bay.

Any thoughts about having that four way fitting and other fittings hanging off the adapter in terms of vibration and cyclic loading cause the BSPT to NPT adapter to crack at some point? I had that happen on the plumbing for an oil sending unit (mechanical) on a diesel engine once. 2 or 3 inch nipple with the sending unit on the end, eventually vibrated the nipple until it cracked. It pumped out a bit of oil before I was able to get it parked.