Horse Power boosters!

[Vibe Ray]

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?!

[John DiMartino]

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.

[Forever Green Lawn]

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!

Scott

[motor86]

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

[4 Saisons]

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.

[Jason Pallas]

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.

[Randy Scott]

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.;)

[thefarmer4]

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.

[AB Lawn Care]

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

[Vibe Ray]

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!

[Keith]

One word.......NitroMethane!

[Eric ELM]

If you are worried about hp, just buy one with a bigger motor since you haven't even gotten a mower yet. ;)

[motor86]

Turbochargers basically increase compression, but it requires no mod's to the head to accomplish it. If you turbocharge it, then you will have to run higher octane fuel. You see a lot of turbocharged diesels. That is because they do not have gas in the cylinder on the compression stoke, so it will not detonate. A turbocharger increases the hp on all engines, but it is not worth the expense of high octane fuel.

[plow kid]

Sometimes you need a 5000 rpm burst to get the job done

Alba Inc. makes a turbo-charger[hypermax] kit for kawasaki, honda, and yamaha quad engines, I have heard of people that have modified the turbo and assorted parts to fit a v-twin but i would rather spend my $5200.00:eek: for the turbo on a new mower then have 10 more ponies on a clunker mower that will throw a rod if you get the boost up too high.
ps, 107+ octane boost will work just fine for you.

[you could try avation fuel, lol]

[Chopper Lover]

I love high performance! I really wish I had not sold my old Dodge Dart Sport (Duster body style) with the 360!!

Back to mowers...

This is your bread and butter we are talking about and a standard theory comes into play.

"IF IT AIN'T BROKE, DON'T FIX IT!"

Before making any changes I think you should consider this:

Can you replace the motor with no damage to your finances???

Can you afford to buy a new motor AFTER you spent all the money to modify the one you already have?

If you can afford to replace it with the 23 you want by all means play away. Then again, if you can afford to buy the newer, more powerful motor, why not do what John DiMartino suggested? Get a new one and sell or keep the 19 as a reserve.

Just a thought... Let us know how it goes!
Mark

[Eric ELM]

I think it would help if he would of told you this is something he wants to do to a mower he is buying in a few weeks. As I told him, just get one with a bigger motor. This would be the best thing for him to do.

[Andyinchville2]

I think a free flowing exhaust would help alot....I believe Dixie Chopper has a +1 HP muffler....I don't know if it is noisier tho....I though about using a car muffler in place of the stock muffler.....Should be quieter AND offer less flow resistance.....If it's big enough for a 350 V8, I dont think a 2 cylinder engine would even challenge it.

[Forest]

One word.......NitroMethane!




Three more words.......Nitrous Oxide Systems! :blob3: :blob3: :D

[a a green]

in all seriousness. I drag race cars and I know this, superchargers, turbos nitrous, all speed up the rotating mass. think about it it speeds it up, but it also speeds up wear on the engine...just a thought....

[Vibe Ray]

What exactly is "boring it over" anyway?

[cgaengineer]

in all seriousness. I drag race cars and I know this, superchargers, turbos nitrous, all speed up the rotating mass. think about it it speeds it up, but it also speeds up wear on the engine...just a thought....

More than wear, stress...those little aluminum rods were not designed for 2 times the power.

[IMAGE]

What exactly is "boring it over" anyway?

The piston moves up and down in the cylinder, right? Well as it does it wears. After it wears enough to get sloppy, it needs a rebuild. Rebuilding it would be to bore it over. Specifically boring it over is boring the cylinder out a little bit. .010" and .020" are common. Then a new larger piston is used. All this is made to do is rebuild it and gain compression back/eliminate the slop. The increase in hp would be so little it would not be worth the effort of tearing the motor apart to do it.

[joesimoes2]

Hey guys what you think the engineers are doing.
Now you want info from gardeners how to boost your engine power. if you want your motor to last don’t do a thing to your engine keep it original but what do I know.

[GravelyNut]

The piston moves up and down in the cylinder, right? Well as it does it wears. After it wears enough to get sloppy, it needs a rebuild. Rebuilding it would be to bore it over. Specifically boring it over is boring the cylinder out a little bit. .010" and .020" are common. Then a new larger piston is used. All this is made to do is rebuild it and gain compression back/eliminate the slop. The increase in hp would be so little it would not be worth the effort of tearing the motor apart to do it.
On the older single cylinder Kohlers, going to the max oversize piston would get you at most 2 HP. So spending $200 for parts gets you 2 HP, plus your time in doing the work. Not really a good tradeoff in a new engine. And then your engine won't last as long as it would if stock.

[mag360]

Wow. It's pretty cool to come across some of Eric Elm's old posts. Kind of like seeing a ghost because I wasn't expecting it (thread is over 6 years old).

[Optimum Lawn]

I think a free flowing exhaust would help alot....I believe Dixie Chopper has a +1 HP muffler....I don't know if it is noisier tho....I though about using a car muffler in place of the stock muffler.....Should be quieter AND offer less flow resistance.....If it's big enough for a 350 V8, I dont think a 2 cylinder engine would even challenge it.

Old Thread this is

My muffler on my 20HP Kohler blew the innerds out so was noisey. So instead of buying a new factory job I wanted something better/quieter. So i went searching for a car muffler of about 1 1/4" dia inlet and found the pontiac Firefly muffler would be about right for inlet dia and overall size for fitting the space.
Cut the old muffler off from the head pipes fabbed up a collector into the muffler and ended up with more HP and a MUCH quieter running engine to the point the deck makes more noise than the engine. And it is still working the same after about 3 seasons. Now I wish the factory could make quieter running mufflers without squishing HP...not like we are trying to quell 10000 plus RPM of noise here.
Tis my pet peeve, the noise all these engines emit from the factory.
Thinking of doing it to the 12.5 Kawy...just to knock the noise level down.

[cgaengineer]

The piston moves up and down in the cylinder, right? Well as it does it wears. After it wears enough to get sloppy, it needs a rebuild. Rebuilding it would be to bore it over. Specifically boring it over is boring the cylinder out a little bit. .010" and .020" are common. Then a new larger piston is used. All this is made to do is rebuild it and gain compression back/eliminate the slop. The increase in hp would be so little it would not be worth the effort of tearing the motor apart to do it.


fianlly someone who understands boring a cylinder .020 yields nothing as far as performance except in the fact that the new .020 piston is riding in a new unscratched cylinder and compression is restored to new again.

I love it when people tell me they have bored it .050 over!

[edward hedrick]

Vibe: I have a Scag w 22 Koh. I installed a Enginaire precleaner and a larger muffler from Koh. A better intake

and larger exhaust will help get more performance from

your 19 Kawi. ed

[topsites]

Yeah first you need to do all the regular maintenance to it, otherwise there's no point.

Then run super unleaded, synthetic oil, and double platinum spark plugs.
That's what I do, also oil the pre-cleaner lightly and change often.

Any radical aftermarket modifications such as turbo boosters or open air cleaners will make the engine yours.
If you ever go to sell it I don't want this ricer looking thing, plus it may damage it.

So anything the basics you accept the risk you may have to replace the engine, things such as tweaking the rpm's.
Too bad the stupid coil and wire are integrated, it would be so cool to use like an aftermarket 8 or 10mm super wire.

[GravelyNut]

Older Gravely twin Onans had the best exhaust. 2 Nelson mufflers the size that 10 to 16 HP singles from Kohler and B&S had. Look like these from Stens.

[lawnman_scott]

What exactly is "boring it over" anyway?so did you do anything to it?

[cgaengineer]

Yeah first you need to do all the regular maintenance to it, otherwise there's no point.

Then run super unleaded, synthetic oil, and double platinum spark plugs.
That's what I do, also oil the pre-cleaner lightly and change often.

Any radical aftermarket modifications such as turbo boosters or open air cleaners will make the engine yours.
If you ever go to sell it I don't want this ricer looking thing, plus it may damage it.

So anything the basics you accept the risk you may have to replace the engine, things such as tweaking the rpm's.
Too bad the stupid coil and wire are integrated, it would be so cool to use like an aftermarket 8 or 10mm super wire.

Actually topsites, super unleaded will net you less horsepower on a normally aspirated, standard compression internal combustion engine. Super unleaded fuel has additives that make the fuel harder to burn so that the heat created during compression does not ignite the fuel.

[Valk]

Saying it another way, additional/added octane makes gasoline burn slower...so that one can take advantage of ******ing the timing (BTDC)...(which will maximize power output from a higher compression engine).

[GravelyNut]

Saying it another way, additional/added octane makes gasoline burn slower...so that one can take advantage of ******ing the timing (BTDC)...(which will maximize power output from a higher compression engine).

Small problem there. With higher octane fuel, you advance the timing to take advantage of it not causing pre-ignition. With lower octane fuels, you ****** the ignition.

[GravelyNut]

Actually topsites, super unleaded will net you less horsepower on a normally aspirated, standard compression internal combustion engine. Super unleaded fuel has additives that make the fuel harder to burn so that the heat created during compression does not ignite the fuel.

True only in an engine that does not have a spark advance controlled by a computer and only when you are switching back and forth between fuels. If you have an engine that runs only the super, you advance the timing and get more power out of it.

[Valk]

Small problem there. With higher octane fuel, you advance the timing to take advantage of it not causing pre-ignition. With lower octane fuels, you ****** the ignition.
I did state that incorrectly...thank you!

[Happy Frog]

High quality free flow air filter and exhaust is your answer. If you need more power, buy a bigger engine. If the engine doesn't fit the mower, buy a bigger mower...
If you want a dragster mower, put a motorcycle engine on it and I'll pray for your salvation... :laugh::laugh::laugh:

[tb8100]

you need exhaust like what Bad Boy uses on their big block Vanguards!

http://i5.photobucket.com/albums/y162/craq/exhaust001.jpg
http://i5.photobucket.com/albums/y162/craq/exhaust002.jpg
http://i5.photobucket.com/albums/y162/craq/exhaust003.jpg

:weightlifter: