L2501 Modifications

Dieseldonato

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B7510 hydro, yanmar ym146, cub cadet 1450, 582,782
Mar 15, 2022
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Amy time you lugg a diesel down its adding fuel to tey and compensate for the heavy load, thus the black smoke. Black smoke is partially burnt fuel. Adding the turbo increases the airflow allowing more available air during the same time the govenor is adding extra fuel to try and maintain rpm at a given load. Therefore just adding the turbo will increase power. Adjusting the full fuel screw will gain more power to the point the turbo can't flow enough air to compensate. Advancing the timing will also help lower egt, but increase peak combustion pressure. It's always a give and take.
 
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tractorX

Member

Equipment
KUBOTA L2501 DT 5' BOX BLADE 42" FORKS PIRANHA TB 5' BUSH HOG 6' GRADER
Sep 27, 2013
74
69
18
Rock Spring GA.
Amy time you lugg a diesel down its adding fuel to tey and compensate for the heavy load, thus the black smoke. Black smoke is partially burnt fuel. Adding the turbo increases the airflow allowing more available air during the same time the govenor is adding extra fuel to try and maintain rpm at a given load. Therefore just adding the turbo will increase power. Adjusting the full fuel screw will gain more power to the point the turbo can't flow enough air to compensate. Advancing the timing will also help lower egt, but increase peak combustion pressure. It's always a give and take.
welcome to the l2501 mod thread!
we like gearheads and mechanics hang'n out and talk'n shop.
if you have any "MORE HORSEPOWER" ideas please share!
i did the advance timing and fuel mod. 😁 luv'n it!
got any suggestions that would "complement" performance on this type of mod?

BTW, i am not a diesel mechanic, just a shadetree that likes learning new things.
 
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Rdrcr

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L2501 Turbo (Current), B2601 (Sold)
May 7, 2021
302
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WA
Hey Mike, what is the part # ? I tried looking those up but fell short. Thank you!
TC820-57510-620 (RH, HST)

TC820-47450-620 (LH, HST)

You’re very welcome!

Mike
 
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Rdrcr

Well-known member

Equipment
L2501 Turbo (Current), B2601 (Sold)
May 7, 2021
302
260
63
WA
Amy time you lugg a diesel down its adding fuel to tey and compensate for the heavy load, thus the black smoke. Black smoke is partially burnt fuel. Adding the turbo increases the airflow allowing more available air during the same time the govenor is adding extra fuel to try and maintain rpm at a given load. Therefore just adding the turbo will increase power. Adjusting the full fuel screw will gain more power to the point the turbo can't flow enough air to compensate. Advancing the timing will also help lower egt, but increase peak combustion pressure. It's always a give and take.
Great info! Thanks for sharing!

I've just turned up the fuel 1/2 turn and I've gone from 4PSI to 6PSI and I'm still not seeing any black smoke. I'm going to continue to turn up the fuel this week and monitor performance. I'll be going up 1/4 turns at a time, until I see smoke.

I don't have any plans to combine the Turbo system with the Timing advancement. I believe I'll be able to get all the performance I need from the Turbo.

Mike
 
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Rdrcr

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L2501 Turbo (Current), B2601 (Sold)
May 7, 2021
302
260
63
WA
How much fuel?

I’m currently at 1 1/2 turns of fuel. I’m seeing smoke on startup but, very little, a puff or two while running the tractor. The tractor is currently running 7 psi peak but, tappers to a sustained 5 psi under load. The tractor was making 7 psi with 1 full turn but was maintaining 4 psi under load. The 1/2 turn picked up 1 psi under load.

So, I’m still seeing incremental improvements but, at the cost of smoke at startup. I’m thinking I’ll keep going but, I’m wondering where the balance might be.

Mike
 
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tractorX

Member

Equipment
KUBOTA L2501 DT 5' BOX BLADE 42" FORKS PIRANHA TB 5' BUSH HOG 6' GRADER
Sep 27, 2013
74
69
18
Rock Spring GA.
How much fuel?

I’m currently at 1 1/2 turns of fuel. I’m seeing smoke on startup but, very little, a puff or two while running the tractor. The tractor is currently running 7 psi peak but, tappers to a sustained 5 psi under load. The tractor was making 7 psi with 1 full turn but was maintaining 4 psi under load. The 1/2 turn picked up 1 psi under load.

So, I’m still seeing incremental improvements but, at the cost of smoke at startup. I’m thinking I’ll keep going but, I’m wondering where the balance might be.

Mike
WOW... more fuel + more air = more HP!
sounds like you just about got this bull dialed in.
cant offer any help other than maybe try to contact the OP @Mikemoto17 at 4Nmotorsport.com. to compare fuel settings. looks like he has FB and IG accounts too.
 
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Rdrcr

Well-known member

Equipment
L2501 Turbo (Current), B2601 (Sold)
May 7, 2021
302
260
63
WA
WOW... more fuel + more air = more HP!
sounds like you just about got this bull dialed in.
cant offer any help other than maybe try to contact the OP @Mikemoto17 at 4Nmotorsport.com. to compare fuel settings. looks like he has FB and IG accounts too.
Last I checked, he was at 2+ turns. But, he’s increased the RPM limit and advanced the timing.

I’m assuming that his setup ‘should’ be consuming more fuel than mine.

But, I’m starting to get close to his fuel setting which has me a bit perplexed.

Mike
 
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drewzee87t

Active member

Equipment
B2910 HST, Modern RC, Gannon Earthcavator, Frontier 1150 Tiller, Woods RM306
May 20, 2016
135
46
28
misery
Assuming you are actually adjusting the fuel rack and not the idle, you just adjust it until it makes boost and smokes when you outrun the turbine capacity. I turned mine up until it started to get egts in 1200 and then turned it back down so it doesn't really go over 1100 in normal use. That's pretty conservative you could probably push 1300s without issue.

It was probably 2 full turns or even a bit more but I don't have your pump. Depending on your pump you may also have an additional screw inside the rack that you want to adjust. I forget what it does but basically I tightened it and it seems to make the rack more responsive/faster to add fuel. Its like a buffer with a soft spring.

Your work looks great! Should be fun when you get it tuned where you like it.
 
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Rdrcr

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L2501 Turbo (Current), B2601 (Sold)
May 7, 2021
302
260
63
WA
^^^^
To my knowledge, from what I’ve seen and read, there is just the one adjustment screw. I’ll need to do some investigation and follow up regarding the injection pump fuel adjustment.

Perhaps NetMagi or TractorX can join that discussion.

In addition, it’s worth mentioning, I’m nowhere near 1,000* EGT. I’m still hovering in the 600-700*. So it’s definitely possible there’s another fuel adjustment that’s needed. Also, whats your boost response like? Does your tractor peak and then sustain a particular PSI? Just curious.

Mike
 

Dieseldonato

Well-known member

Equipment
B7510 hydro, yanmar ym146, cub cadet 1450, 582,782
Mar 15, 2022
695
397
63
Pa
Assuming you are actually adjusting the fuel rack and not the idle, you just adjust it until it makes boost and smokes when you outrun the turbine capacity. I turned mine up until it started to get egts in 1200 and then turned it back down so it doesn't really go over 1100 in normal use. That's pretty conservative you could probably push 1300s without issue.

It was probably 2 full turns or even a bit more but I don't have your pump. Depending on your pump you may also have an additional screw inside the rack that you want to adjust. I forget what it does but basically I tightened it and it seems to make the rack more responsive/faster to add fuel. Its like a buffer with a soft spring.

Your work looks great! Should be fun when you get it tuned where you like it.
This depends where your pyrometer is mounted. Pre or post turbo, and depending on the engine some cylinders have a tendency to run hotter then others. 1200*f pre turbo is typically considered "safe" although it will start to do damage if left there for long periods of time. Aluminum melts somewhere around 1400*f, and even being close to thr exhaust port were still a couple hundred degrees off of actual combustion temps. Additionally you have to worry about heat soaking the turbo and exhaust when running long durations of high egt's. Hence why the oem's tends to be conservative with boost numbers to keep the egt's down around 1000* (ish). Anything I tune for reliability, I try to stay at or under 1200* pre turbo. full load would be towing heavy and going up a steep sustained grade in my case. I would want to be extra cautious with a tractor.
 
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drewzee87t

Active member

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B2910 HST, Modern RC, Gannon Earthcavator, Frontier 1150 Tiller, Woods RM306
May 20, 2016
135
46
28
misery
This depends where your pyrometer is mounted. Pre or post turbo, and depending on the engine some cylinders have a tendency to run hotter then others. 1200*f pre turbo is typically considered "safe" although it will start to do damage if left there for long periods of time. Aluminum melts somewhere around 1400*f, and even being close to thr exhaust port were still a couple hundred degrees off of actual combustion temps. Additionally you have to worry about heat soaking the turbo and exhaust when running long durations of high egt's. Hence why the oem's tends to be conservative with boost numbers to keep the egt's down around 1000* (ish). Anything I tune for reliability, I try to stay at or under 1200* pre turbo. full load would be towing heavy and going up a steep sustained grade in my case. I would want to be extra cautious with a tractor.
My sensor is in the exhaust manifold collector right before the turbo, but I think we are saying the same thing as far as keeping the temps reasonable. I have a guage with boost and egt right in front of me when I am boosting I look at it.

Heavy load for me is running a 6 foot finish mower in heavy hay pasture. That will usually boost around 3-5 consistent with heavy grass boosting to 7-10psi. I don't ever really run full boost for any longer than 20 seconds. I did drive this thing to about 13 psi once when I was first tuning it. It was neat, but it got hot super fast. I have boost limited only by fuel, my wastegate is wired shut.
 
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Dieseldonato

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B7510 hydro, yanmar ym146, cub cadet 1450, 582,782
Mar 15, 2022
695
397
63
Pa
My sensor is in the exhaust manifold collector right before the turbo, but I think we are saying the same thing as far as keeping the temps reasonable. I have a guage with boost and egt right in front of me when I am boosting I look at it.
Sorry if I came across poorly. I wasn't being specific to your set up, but trying to expand on sensor placement and the difference between ok for a short time and sustained egt's.
 
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Rdrcr

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L2501 Turbo (Current), B2601 (Sold)
May 7, 2021
302
260
63
WA
My sensor is in the exhaust manifold collector right before the turbo, but I think we are saying the same thing as far as keeping the temps reasonable. I have a guage with boost and egt right in front of me when I am boosting I look at it
That’s exactly how I have my probe setup and I’m constantly watching both my EGT and boost gauge as I’m running the tractor.

Thanks for posting your boost characteristics. Although, I’m not boosting as high as you are currently (I may be soon with more fuel), the behavior from my turbo is strikingly similar.

What size turbo are you running?

Mike
 

drewzee87t

Active member

Equipment
B2910 HST, Modern RC, Gannon Earthcavator, Frontier 1150 Tiller, Woods RM306
May 20, 2016
135
46
28
misery
^^^^
To my knowledge, from what I’ve seen and read, there is just the one adjustment screw. I’ll need to do some investigation and follow up regarding the injection pump fuel adjustment.

Perhaps NetMagi or TractorX can join that discussion.

In addition, it’s worth mentioning, I’m nowhere near 1,000* EGT. I’m still hovering in the 600-700*. So it’s definitely possible there’s another fuel adjustment that’s needed. Also, whats your boost response like? Does your tractor peak and then sustain a particular PSI? Just curious.

Mike
If you aren't making egt you aren't making boost. You need fuel still. Mine is a 4 cyl but there is the fuel rack on mine, which is under the furthest injector to the right, the shiny brass looking screw and nut facing right at you. That's my rack adjustment. The one that is still capped that is sticking out the front of the pump housing forward, with a grey cap still on it, is the idle speed adjust. I tried to adjust my fuel rack with this at first :)

You probably just need more turns to get fuel. You also have to be loading the hell out of the tractor to get boost. I push up against an immovable force (big tree) and that will boost it. Just running up a hill or something only will boost until the hydro catches up. You need to spin that against a tree with your egt and your screwdriver.
 

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Rdrcr

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L2501 Turbo (Current), B2601 (Sold)
May 7, 2021
302
260
63
WA
If you aren't making egt you aren't making boost. You need fuel still. Mine is a 4 cyl but there is the fuel rack on mine, which is under the furthest injector to the right, the shiny brass looking screw and nut facing right at you. That's my rack adjustment. The one that is still capped that is sticking out the front of the pump housing forward, with a grey cap still on it, is the idle speed adjust. I tried to adjust my fuel rack with this at first :)

You probably just need more turns to get fuel. You also have to be loading the hell out of the tractor to get boost. I push up against an immovable force (big tree) and that will boost it. Just running up a hill or something only will boost until the hydro catches up. You need to spin that against a tree with your egt and your screwdriver.
It doesn’t look like the L2501’s injection pump has a screw to adjust the rack. I’ve studied my injection pump and looked through the service manual a couldn’t find any information on an additional screw. It appears just to have the one screw for all fuel settings. If I’m wrong, somebody let me know.

That said, thank you for the suggestion of running the tractor up against an immovable object. That did the trick! Once again, thank you!

My fuel is set at a full 2 turns. I’m getting 9 PSI of boost, 6-7 PSI sustained and no smoke during operation.

D95CFA8F-DE1C-4936-9D94-EA058DC6FFD1.jpeg


49C8B898-124D-4FF1-B5CE-FE9B93FAD84C.jpeg

The tractor feels great! I believe it wants even more fuel, perhaps 2 1/2 turns but, I think I’m currently right where I want to be. I’m gonna run it for a while and see how it goes.

Mike
 
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Dieseldonato

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B7510 hydro, yanmar ym146, cub cadet 1450, 582,782
Mar 15, 2022
695
397
63
Pa
Could be wrong, but looking at the parts break down, looks like you have your full fuel screw out the front of the case, then your idle and full speed screws are on the top of the speed control housing on either side of the throttle lever. If I'm understanding what I'm seeing the full fuel screw limits rack travel.
 
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tractorX

Member

Equipment
KUBOTA L2501 DT 5' BOX BLADE 42" FORKS PIRANHA TB 5' BUSH HOG 6' GRADER
Sep 27, 2013
74
69
18
Rock Spring GA.
It doesn’t look like the L2501’s injection pump has a screw to adjust the rack. I’ve studied my injection pump and looked through the service manual a couldn’t find any information on an additional screw. It appears just to have the one screw for all fuel settings. If I’m wrong, somebody let me know.

That said, thank you for the suggestion of running the tractor up against an immovable object. That did the trick! Once again, thank you!

My fuel is set at a full 2 turns. I’m getting 9 PSI of boost, 6-7 PSI sustained and no smoke during operation

View attachment 85117

View attachment 85120
The tractor feels great! I believe it wants even more fuel, perhaps 2 1/2 turns but, I think I’m currently right where I want to be. I’m gonna run it for a while and see how it goes.

Mike
i did some digging around too. looks like there is only 1 fuel adjustment screw as pointed out by you and others.
i have a question about part # 140. can you change out spacers for more or less fuel pressure... or is the spacer sized by manufacture for that model injector solely?
kubota V2203 diagram
1660180456954.png
 
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Rdrcr

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Equipment
L2501 Turbo (Current), B2601 (Sold)
May 7, 2021
302
260
63
WA
^^^^
Good question.
Even if that is an option, I'm not sure that's something I'd want to mess with.

Mike