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Turning a 25 HP tractor into a 35 HP tractor?

17K views 6 replies 7 participants last post by  forphase1  
#1 ·

I was wandering around on YouTube a while back and stumbled across this guy and his Kubota L2501 which is now an L3501. I’ll try to make this short and y’all can go watch his videos for the mechanical details and such.

Guy bought an L2501DT, and was disappointed at the lack of power, so he messed with the injection pump and timing to get ~35 hp out of the engine. Apparently this same engine was used in some of the older pre-emissions L series machines that were 35 hp, and Kubota detuned the engine down to 25 hp for the L2501.

Here’s my idea. Obviously a lot of us are not as mechanically inclined as this fellow, and personally, I wouldn’t want anyone tearing apart the engine of my brand new $20k+ tractor. Would it be possible (legally) for tractor manufacturers to produce a 25 hp tractor (L2501, 3025E, Workmaster 25) that could easily be turned up to 30-35 hp, by someone with average mechanical experience, like changing their oil and other simple maintenance? Then you would be able to have a brand new 35 hp tractor with zero emissions equipment. In my mind, technically the manufacturer IS selling a 25 hp tractor. I know it it much more complicated than that, but it’s just an idea I got after watching this fellow’s video.
 
#2 ·
Would it be possible (legally) for tractor manufacturers to produce a 25 hp tractor (L2501, 3025E, Workmaster 25) that could easily be turned up to 30-35 hp, by someone with average mechanical experience, like changing their oil and other simple maintenance?
I'm not a lawyer but the answer is most likely "only if the manufacturer wants to fight the government in court" which they likely don't. The thing is the legal environment is very favorable to the government in these cases thanks to the Chevron doctrine which states that courts should defer to agencies that Congress has delegated power to when it comes to the interpretation of the law the agency is operating under. The EPA, and government, was recently dealt a blow on this by the Supreme Court but it's still very much in the air how that doctrine will change. In any case, the Tier IV emissions standards for tractors fall under an EPA rule so the only argument is if the rule violates the powers delegated to Congress. If it doesn't and the EPA says that tuning a tractor to a higher HP violates their rules then the manufacturers could be forced to put in anti-tuning measures.

Let's not even get started on CARB though that's another hairball.

Regardless, it's going to take a ton of money to overcome the EPA's authority in court and the manufacturers likely don't want to.
 
#3 ·
As an example Harley has performance engine kits that if used with the proper computer programming are emissions legal. Some can even be covered by the factory warranty. However they must been certified by the government and only used on designated models. So money must be invested into certifying a package to be legal vs how many packages can be sold afterwards
 
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#5 · (Edited)
I own the tractor featured in this article. It is possible on a Kubota l2501 only through a rather unique set of circumstances specific to this tractor and its engine. It’s a long video and I’ve watched it twice. This is a completely mechanical engine whose horsepower was reduced by a mechanical governor and a detuned mechanical injection pump. There is no electronic engine management whatsoever. For the most part it was accomplished by shimming the injection pump drive and raising the RPMs back to the level the engine was really designed to operate at…. the l2501 it is governed about 2200 RPM. It was originally designed to operate several hundred RPMs higher. Essentially Kubota detuned a 35 hp motor in very simple manner to make it EPA horsepower compliant, much the same as the original 6bt Cummins 5.9 was detuned to accommodate the early Dodge trucks. The L series tractor chassis is nearly identical throughout its varied horsepower range. All these factors make this modification much more doable. FWIW, the l2501 already has 70 lb. ft. of torque, which is a ton for a 25hp tractor, so I don’t think this is a necessary modification and don’t intend to modify mine. I would guess Kubota will probably try to make this tractor more tamperproof in the future also.
Probably should also add that this is an excellent video and is a great example of how YouTube videos pertaining to mechanical interests should be done.
 
#7 ·
Yes, it can be done. I just installed a module on my 3025E and I'm getting more horsepower. I still have additional testing to do, but there is a clear improvement. See this thread for details. 3025e HP increase
 
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