Horse Power boosters!

Discussion in 'Lawn Mowing' started by Vibe Ray, Feb 20, 2001.

  1. Vibe Ray

    Vibe Ray LawnSite Senior Member
    Messages: 785

    Hey guys! What ways do you know of to boost the Horse Power of a mower? The engine in question is a 19 HP Kawisaki. I have no problems with it at all, just wanna know if it's possible to give it even more power(you can never have too much). What about a turbo charger? Anyone know any tricks or upgrades? What about life extenders for the 19 HP Kawi? Such as coolers or better filters or whatever else.....What can you guys conjure up?!
  2. John DiMartino

    John DiMartino LawnSite Silver Member
    Messages: 2,555

    Check mounting plate pattern and clearances,crank size,if everything checks out ok,order 23hp-pull 19hp-replace with 23-sell 19 hp or keep for backup,easiest way i know of to increas hp reliably.I did this to my steiner 5 yrs ago,best thing i ever did,it had a 20hp onan,it was underpowered and bogged easily.When it popped a valve seat,i put in 24hp,huge increase in torque and hp,felt like a bigger increase than 4hp.
  3. Forever Green Lawn

    Forever Green Lawn LawnSite Senior Member
    Messages: 282

    John's option is the best. As far as modifying the Kawisaki engine, I wouldn't try it unless you really know what your doing. It is possible to increase the power slightly by increasing the compression ratio(milling the cylinder head), porting the intake and exhaust ports, and puting on a free flowing air cleaner. This type of work is really for go-cart racing and not for mowers and best left to pros, but it is possible! There is just no quick fix!

  4. motor86

    motor86 LawnSite Member
    Messages: 21

    Actually, there are a lot of things to do to it. I know of a person who took a standard 24hp Kawasaki and removed the govenor. He reved it all the way and got about 47hp out of it. He used if for pulling. He talked to Kawasaki about doing this and they said that they have tested it and it cuts their service life in half.

    Mods you could do in the order I would do them:

    Bore it over: Best mod you can do, will give big boost
    Larger Carb: More power at upper rpm's
    Remove muffler: less resistance
    Higher flow air cleaner: less resistance
    Mill head: increased compression, more power at lower rpms, have to run high octane(100 or more) if milled really far.
    Install heavier valve springs: this is one of the final mods. Doing this allows the engine to rev higher. At about 8,000 rpm the valves "float"(they don't come down) and do nothing. It is like a self govenor.

    Making this engine rev, and gearing down the drive would provide more power at the mower deck. If you have gearing now of 1:1 and rpm's of 3,000 and increase rpm's to 6000 and gear it down, then you would be increasing the power to the deck by 4 times (figuring doubling rpm's would double power). If this does not make sense, gearing it down 1:2 would double the power at the blades, while cutting the rpm's in half. Doubling hp of an engine and the gearing down would increase the power at the deck by 4 times.

    The most I would actually do to a lawn mower that I would use commercially would be bore it over. The rest of the mods are not worth the money, or service life, or reliability problems, not to mention noise.

    good luck
  5. Be carefull, we try it on one 21" Toro 2 stroke five years ago. The impressive performance had lasted only 2 month. Then one morning, without warning, the motor died. need a new engine, so it goes on the spare part. remind me a expensive learning.
  6. Jason Pallas

    Jason Pallas LawnSite Bronze Member
    Messages: 1,335

    I used to race karts and we did a lot of those mods - they cut the engine life dramatically. These engines are built to run at relatively low RPM forever. When you start to do these types of mods, it'll decrease your engine life exponentially. Those govenors are there for a reason. Take one off and you'll get killer RPMs and killer HP - for about a week, then bye, bye - it'll grenade on you. The best thing you can do is mill and bore it and lap and grind the valves/seats. Other than that, leave it alone.
  7. Randy Scott

    Randy Scott LawnSite Bronze Member
    Messages: 1,915

    Vibe,just leave the engine alone. If you think you have more Research and Development time into it than Kawasaki and know better than they do of what performance, or life you'll get out of the motor then go for it. But I strongly doubt you or anyone else has. The manufacturers try to put combinations together that are affordable and work well together. So if you need more horsepower, or think you might, you should have bought a bigger mower. I believe you have the 44" eXmark with this Kawi motor, that should work just fine. You start screwin' with it and you are asking for trouble in all forms from eqiupment failure, voiding the warranty, and mostly, somebody getting hurt. Like the guys said, performance enhancements are short term goals with one thing in mind, go fast and then rebuild.;)
  8. thefarmer4

    thefarmer4 LawnSite Member
    Messages: 71

    If you want more HP buy a bigger motor
    Making modifications Not a good idea especially if you don't uderstand what you are doing.
  9. AB Lawn Care

    AB Lawn Care LawnSite Senior Member
    from Ontario
    Messages: 585

    Also keep in mind most residential cleints do not like to hear a mower with no muffler.
  10. Vibe Ray

    Vibe Ray LawnSite Senior Member
    Messages: 785

    I completely understand guys! I don't have any problems with it, I just wanted to know of all the ways to boost power and also which of those mods are safe or ones that are worth the consequences. What do you guys say about turbochargers? They seem safe. Would it decrease engine life? Is it possible on the Kawi 19 HP? Is it worth it? What are your thooughts. All comments are welcome!

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