Have a m4900 rated at 54 hp at 2600rpm. M5700 has same motor and injector pump and is rated at 61 hp at 2800rpm. Any way to upgrade my m4900 to increase hp, i.e., re-calibrate injector pump?
kubota m4900 hp increase
- Thread starter pjyork
- Start date
Billdog350
Member
Equipment
Kubota L3710 HST,L2230A QT,forks,Takeuchi TB125, 60" Luck Now pto Snowblower
They make factory turbos on similar motors if I recall. Rather than jump 7hp, why not jump 25+? You might be able to bolt on a turbo setup from a factory Kubota even.
Yes, you can recalibrate the fuel delivery and top rpm setting of the injection pump. However, first thing to do is to spend some time in the parts manual.
I seriously doubt that it is the same engine, it is probably the same engine class (such a V2500), but I could almost bet that the two engines carry a different specific (such as V2500A2 and V2500A3) engine number. And there in lies the rub, has the factory done anything else to deal with the higher horsepower and heat generated? You cannot get around that more fuel = more BTU's to deal with.
The V2500A2 could have slightly different internal components as well as the injection pump settings than the V2500A3, but then it may not. Without checking internal components you have no way of knowing that to get that to get that slightly higher rpm the camshaft profile is changed slightly, or the crankshaft has the additional step of nitridization. Or the compression ratio is slightly changed. All in the name of durability in dealing with the higher operating rpm, and heat generated by the increased fuel injected.
I am only using the generic number of "V2500" as a example.
Same thing with installing a turbo. Many non turbo engines do not have piston cooling jets, turbo engines normally do. You can't just slap a turbo on with out doing other changes and expect the same life span. Is the oil pump of higher capacity to deal with the piston jets? Yes in many times even the oil pump is changed between a turbo and non turbo engine. As well as the static compression ration and many other internal engine changes. Even the engine block sometimes changes between a turbo engine and non turbo engine.
So back to the parts manual, check pistons, camshaft, crankshaft, head, radiator, etc part numbers.
David
I seriously doubt that it is the same engine, it is probably the same engine class (such a V2500), but I could almost bet that the two engines carry a different specific (such as V2500A2 and V2500A3) engine number. And there in lies the rub, has the factory done anything else to deal with the higher horsepower and heat generated? You cannot get around that more fuel = more BTU's to deal with.
The V2500A2 could have slightly different internal components as well as the injection pump settings than the V2500A3, but then it may not. Without checking internal components you have no way of knowing that to get that to get that slightly higher rpm the camshaft profile is changed slightly, or the crankshaft has the additional step of nitridization. Or the compression ratio is slightly changed. All in the name of durability in dealing with the higher operating rpm, and heat generated by the increased fuel injected.
I am only using the generic number of "V2500" as a example.
Same thing with installing a turbo. Many non turbo engines do not have piston cooling jets, turbo engines normally do. You can't just slap a turbo on with out doing other changes and expect the same life span. Is the oil pump of higher capacity to deal with the piston jets? Yes in many times even the oil pump is changed between a turbo and non turbo engine. As well as the static compression ration and many other internal engine changes. Even the engine block sometimes changes between a turbo engine and non turbo engine.
So back to the parts manual, check pistons, camshaft, crankshaft, head, radiator, etc part numbers.
David
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I owned a M4900 for several yrs. It pulled a 9' disc cutter. It could have used a larger radiator so I agree when turning up the smoke screw engine temp will be a problem.
It’s no mystery how they get “more” hp... look again at the RPM limiter! I’ve got the M4700 with the same engine and it appears to be almost the same situation with a M5400 having a “bit” more HP. It’s a curiosity .... but I’m not going to take a chance on hurting a great machine in some ad hoc “soup it up” amateur fiddling which might end up causing expensive damage.
Yes, you can crank up the RPM on the 4900... but as already mentioned...only at the risk of overheating.
WHY do you think 7 more horses is going to be meaningful? WHAT are you trying to accomplish that the 4900 won’t do? How often doing the chores you presently do..... are you finding yourself operating a Max throttle and your M4900 not keeping up ... that a lower gear wouldn’t accomplish without risking damage?
(There are many reasons to rate an engine lower than it’s full capacity. There may be local or regional limitations for regulatory reasons, or for EPA reasons, etc., but these models pre-date most of those. Anyway, if you think you really NEED more HP... I suspect you probably need a different tractor entirely.)
Yes, you can crank up the RPM on the 4900... but as already mentioned...only at the risk of overheating.
WHY do you think 7 more horses is going to be meaningful? WHAT are you trying to accomplish that the 4900 won’t do? How often doing the chores you presently do..... are you finding yourself operating a Max throttle and your M4900 not keeping up ... that a lower gear wouldn’t accomplish without risking damage?
(There are many reasons to rate an engine lower than it’s full capacity. There may be local or regional limitations for regulatory reasons, or for EPA reasons, etc., but these models pre-date most of those. Anyway, if you think you really NEED more HP... I suspect you probably need a different tractor entirely.)
Why does it have to be a need? Some people don't NEED a tractor at all. Do you pick on them to for buying one? What is the big deal with modifying your gear if you want? IT IS YOUR GEAR. - SMH
To the OP, all the power to you (err, your tractor actually- lol).
If there was a known turbo kit I could slap on my B2650 I would do it in a heartbeat! Not because I need to, or because the B2650 needs more power. I would do it because I could, I like turbos, and I like messing with stuff. Many people ENJOY modifying things. You enjoy your private plane right?
Do we ask you why you ruin our environment with your private planes for personal pleasure? Living in a free country we just have to accept some things. A guy messing with his tractor is one of them.
Could be all wet but... Why is it that people fixate in horsepower? It's the torque rise that is important with a diesel engine, especially in a tractor. Horsepower is kind of inconsequential in my view.
Additionally, how do you know the ACTUAL horsepower without using a dyno anyway???
If you go by the advertised horsepower that Kubota specs, been my experience that Kubota rates their motors very conservatively. You may be supprosed what the output ACTUALLY is, but only way to determine that is a PTO dyno.
For example, had my open station M9 in the shop last winter for a tune up and other issues and they put it on their PTO dyno and it developed 91 pto horsepower. Kubota rates PTO power at 82. Quite a difference I'd say.
Additionally, how do you know the ACTUAL horsepower without using a dyno anyway???
If you go by the advertised horsepower that Kubota specs, been my experience that Kubota rates their motors very conservatively. You may be supprosed what the output ACTUALLY is, but only way to determine that is a PTO dyno.
For example, had my open station M9 in the shop last winter for a tune up and other issues and they put it on their PTO dyno and it developed 91 pto horsepower. Kubota rates PTO power at 82. Quite a difference I'd say.
According to Tractordata.com, they both have a 5 cyl 2.7L F2803 engine, and the M4700 coolant capacity = 6.2 L, M5700 = 8.0 L so looks like cooling may be in the frame somewhere.... 
If jbw111 you operate tractor in low ambient temps and keep the cooling system in top condition, and instead Kubota designs for high ambient temps and people not being too diligent about keeping radiator fins clean, etc .... it may be fine.
There's also fan size and fan speed... not to mention all the other potential changes in engine components that previous posters have mentioned. And torque rise or lack thereof (not covered by tractordata.com)...
I was on the fringes of an off-highway truck repower and someone forgot to check the heat rejection of the new engines... some of the retro fit to counter the overheating included bigger radiators, bigger diameter fans and higher fan speeds... it just wasn't worth the effort. But like NHSleddog says if you will get a kick out of getting the extra HP anyway, with or without extra changes, JFDI
If jbw111 you operate tractor in low ambient temps and keep the cooling system in top condition, and instead Kubota designs for high ambient temps and people not being too diligent about keeping radiator fins clean, etc .... it may be fine.
There's also fan size and fan speed... not to mention all the other potential changes in engine components that previous posters have mentioned. And torque rise or lack thereof (not covered by tractordata.com)...
I was on the fringes of an off-highway truck repower and someone forgot to check the heat rejection of the new engines... some of the retro fit to counter the overheating included bigger radiators, bigger diameter fans and higher fan speeds... it just wasn't worth the effort. But like NHSleddog says if you will get a kick out of getting the extra HP anyway, with or without extra changes, JFDI
SledDog you get up on the wrong side of the bed today?
I wasn’t criticizing the OP.... I was offering sensible advice if he wants to enjoy reliability and longevity of his M4900.
I even offered him the REASON the M5700 makes more HP.... it’s a simple matter to increase the RPM limiter..... just be willing to accept the decreased reliability and overheating burden of that.
If you want to pump up your little toy.... go ahead...no skin off my nose. I’ll just sit here and await for the time you originate a thread crying about how your little B2650 has crapped out after you monkeyed with it and you want help fixing it.
ROFLMAO - Tractor Shaming? Are you saying the B2650 with 26hp is small, and your M4700 with 51hp is big? Actual big tractor owners would laugh at your toy but that is neither here nor there. It is just a toy right? No big deal, I would just buy another one.
This forum is full of people having problems with their bone stock OEM machines? How can that be if they didn't modify it? At the same time Kubota puts turbos on all kinds of engines. Why does Kubota put turbos in and change tunes on tractors if there is nothing there to do? Think about that.
If you don't want to change anything on your big tractor (lol) don't. You don't need to project fictitious prolems on others for wanting to though. In other words don't be so scared of someone else's modifications.
Some people like living inside the condom, some don't.
Dog,..I don’t know why you think you have an axe to grind with me... or someone... I’m not picking on you... My WIFE refers to my stuff as my “little toys”... even my 16,000 lb compactor-roller. It’s just a diminutive reference in an attempt to de-fuse the chip you’re carrying around. Forget it. Find someone someplace else to try to start something.... It ain’t gonna work here.
A good example of this sort of thing is a Continental engine I worked on in the early 80’s in a piece of construction equipment. When it failed we ordered a replacment from the mfr’r and found the only replacement we could obtain was a short-block we could transplant the heads on.
The data-sheet stated a 24 hp difference.
It turned out the heads were identical... but the real difference was high-compression 4-ring pistons instead of 3-ring low-compression pistons and a totally different cam.
I stay out of these discussions
if one needs more HP get a bigger tractor instead of turning it up, that's asking for all sorts of problems
if one needs more HP get a bigger tractor instead of turning it up, that's asking for all sorts of problems
Someone suggested to look at the internal parts between the two models, so out of curiosity did just that. Comparing your experience with anything but the two models above adds zero value to the question the OP asked.
Block: Same
Pistons: Same
Rings: Same
Crankshaft: Same
Head: Same
Camshaft: Same
Oil Pump: Same
Water Pump: Same
WP Pulley: Same
Radiator: Same
Injection Pump: Same
Fuel camshaft: Same
Exhaust manifold: Same
Intake model: Same
Governor components: Same
Speed control components: Same
Valves, rocker arms and springs: Same
Fuel Injectors: Same
Label, Model: Different
*Used Kubota's illustrated parts list for above comparison between M4900DT and M5700DT. Illustrated Parts
If going to turbo, be aware that many turbo models use different pistons (ring lands are steel) vs their normally aspirated counterpart.
Good luck to the OP and let us know how your mods turn out.
Block: Same
Pistons: Same
Rings: Same
Crankshaft: Same
Head: Same
Camshaft: Same
Oil Pump: Same
Water Pump: Same
WP Pulley: Same
Radiator: Same
Injection Pump: Same
Fuel camshaft: Same
Exhaust manifold: Same
Intake model: Same
Governor components: Same
Speed control components: Same
Valves, rocker arms and springs: Same
Fuel Injectors: Same
Label, Model: Different
*Used Kubota's illustrated parts list for above comparison between M4900DT and M5700DT. Illustrated Parts
If going to turbo, be aware that many turbo models use different pistons (ring lands are steel) vs their normally aspirated counterpart.
Good luck to the OP and let us know how your mods turn out.
It is fun to read along, especially when things don't go as planned....
I like to watch them end successfully and use all the knowledge learned along the way. Like they say, it takes all types.