PDA

View Full Version : Turbo/Supercharge a Lawn Mower Engine


jtkplc
01-12-2006, 07:04 PM
Can someone explain if you can put a turbocharger or supercharger on gas lawn mower eninges? There are a few turbo diesel engines for lawn mowers. I'm wondering, because I would like to increase my HP on my 25 HP Kawasaki. Thanks...

lawnmaniac883
01-12-2006, 07:42 PM
Ok first and foremost let me say that it will NOT be possible. Now to explain why, bare with me on this one.
A) You would need a fuel injected engine I believe that your 25kaw isnt.
B) The plumbing would be damn near impossible to make with the limited space that the engine compartment area has on a mower engine.
C) You would need, in a turbo application, to fabricate a set of headers, put the turbo inline, then put a muffler somewhere downstream of the turbo. This complex plumbing would kill the efficiency of a turbo by quite a bit.
D) A supercharger would NOT be realistic mainly because you would need a belt running to it somewhere...but where? You cant possibly make the belt for the hydros run to a supercharger.
E) THERE IS NO PLACE TO STRAP A SUPERCHARGER TO THE ENGINE...

I could come up with more reasons why NOT but this will entertain most for now. Plus, you wouldnt really gain much hp from having a turbo, small gasoline engines dont have a high enough displacement to efficiently turn a compressor wheel and make a decent amount of boost without high drive pressures, these drive pressures would infact reduce the engines performance even more.

jtkplc
01-12-2006, 09:14 PM
ok, explain why a turbo on a few lawn mower diesel engines work? because they have a bigger displacement?

General Landscaping
01-12-2006, 09:48 PM
It can be done, but not worth the time and expense.

There is more to a "turbo" engine than what you see on the outside; larger bearing surfaces, more structural webbing in the block, forged crank, larger/more cooling capacity, altered ignition timing, etc.

In a "play" situation, you could have fun and boost it.
In an industrial application, engine life will be too short for a few extra HP to pay off.

If you really want more power, take off the 25 and trade up to something bigger.

jtkplc
01-12-2006, 09:56 PM
yeah, this wasn't something i was about ready to do. it was more a curiosity thing, something i hadn't read anything about and wanted to see what i could find out about it.

General Landscaping
01-12-2006, 10:01 PM
ok, explain why a turbo on a few lawn mower diesel engines work? because they have a bigger displacement?
They work because it is a matched unit, the turbo is sized to the engine.

on a side note:
Diesels are well suited to turbocharging because they are already built strong to handle the crazy compression ratio and torque produced.

kc2006
01-12-2006, 10:48 PM
send me the mower, I'll hook you up.

http://img.photobucket.com/albums/v643/mean83sc/100_5596.jpg

We've put nitrous on a small engine last year, never got to use it though.

jtkplc
01-12-2006, 10:55 PM
send me the mower, I'll hook you up.

http://img.photobucket.com/albums/v643/mean83sc/100_5596.jpg

We've put nitrous on a small engine last year, never got to use it though.

I heard Pepsi delivers more HP and than Coke...just a rumor though...

Dirty Water
01-12-2006, 10:56 PM
A) You would need a fuel injected engine I believe that your 25kaw isnt.

Nonsense, people have been turbocharging carberuated engines since turbochargers were invented...Both draw through and blow through designs.How many turbo's have you installed??? I've installed a handfull.


B) The plumbing would be damn near impossible to make with the limited space that the engine compartment area has on a mower engine.

Not really, You would have a airfilter on the inlet side of the turbocharger, and then a short length of tubing to the carbereratutor, since he won't be running much boost he could even get away with using something like 1" Flexible tubing.


C) You would need, in a turbo application, to fabricate a set of headers, put the turbo inline, then put a muffler somewhere downstream of the turbo. This complex plumbing would kill the efficiency of a turbo by quite a bit.

Thats no more complex that a car/truck setup, again Do you know anything about turbos?

Turbos work off thermodynamics, the hotter the exhaust is, the more pressure it will have, the more effiecent it will work.


D) A supercharger would NOT be realistic mainly because you would need a belt running to it somewhere...but where? You cant possibly make the belt for the hydros run to a supercharger.
E) THERE IS NO PLACE TO STRAP A SUPERCHARGER TO THE ENGINE...


I think it would be pretty easier to mount a supercharger to lawnmower if they made one small enough. Guys having been strapping chevy Smog Pumps to gocart engines for years to add a boost of power, essentially the same thing.

Plus, you wouldnt really gain much hp from having a turbo, small gasoline engines dont have a high enough displacement to efficiently turn a compressor wheel and make a decent amount of boost

Motorcycles with 150cc engines have turbos, why not a lawnmower, you just need to get one that matches the engine and your fine.

This guy twin turbocharged his :laugh:

kc2006
01-12-2006, 10:57 PM
haha. It was for measuring comparison. Someone was using a beer bottle commenting how big their turbo was, so I took a pic of mine with a 2 liter in it just to show off. its a junk turbo I have laying around. :D

kc2006
01-12-2006, 11:03 PM
Jon, the only problem with putting a turbo on a carb'd small engine is theres no way to supplement fuel. The way we do it with cars is by using a very powerful fuel pump and a boost referenced regulator. No way to do that with a small engine set up since they dont run a fuel pump. Now then you could always put a single injector in the intake duct and supplement it that way.

Still too much work for a mower :D

General Landscaping
01-12-2006, 11:12 PM
haha. It was for measuring comparison. Someone was using a beer bottle commenting how big their turbo was, so I took a pic of mine with a 2 liter in it just to show off. its a junk turbo I have laying around. :D
Did that fall off a Cummins?


Dirty Water: Thanks, I didn't have the patience to do that

kc2006
01-12-2006, 11:19 PM
I'm not sure, either a cummins or a cat. its a ht3b the guy I got it from told me it was from a 900 inch motor, biggest semi engine I've ever stood on.

Dirty Water
01-12-2006, 11:52 PM
http://i8.ebayimg.com/02/i/04/91/5e/64_12_sb.JPG

Thats a grown mans hand.

Of course, theres always these too.

http://www.out-of-hand.com/zippy/scroll1.jpg

lawnmaniac883
01-13-2006, 03:58 PM
Dirty Water, jeez guy calm down now, have not installed any turbos, I am man enough to admit that. I dont know how to rebuild one but am not ******ed on the subject. Was JMO what I said, instead of bashing my post, give the guy your own insight on the subject. Not trying to start something here.

General Landscaping
01-13-2006, 09:24 PM
Guys having been strapping chevy Smog Pumps to gocart engines for years to add a boost of power, essentially the same thing.


Do you have any firsthand knowledge of this... sounds interesting.

Approximate boost PSI on a 5HP @ WOT?

UNISCAPER
01-13-2006, 10:02 PM
Back in the day, we took a smog pump from a 1973 350 cubic inch Chevy and ran a 1-1 pulley set up off the flywheel. On top of the pump, we mounted a 22mm Del Orto slide butterfly carb. We shaved the head .060 and cced the chambers, then recessed the spot on the head for the valves to open into. We welded the camshaft and had it reground. We ported, polished, shined and installed larger valves in a 4HP Techumseh on my Bonanza mini bike. We then used a 1.25" diameter stainless steel tube that was 23" long for an exhaust header.

What we did....Kept breaking rods at 5300 RPM, so, machined a titanium rod and made a steel forged crank, then balanced the engine. At 7600 RPM, we noticed throttle flutter and had to add a second carb, so we had a progressive system that added more fuel as RPM's went up. We redlined at 9350 RPM. After developing heat spots, we added a water cooled cylinder head, modeled after the 930 Porsche Turbo Carrera and used a Fiat heater core as a radiator.
What it did...Smoked 7 Mercury clutches while doing bleach burn outs. At Oswego drag raceway, I got a motorcycle racer to ride it for a time, (I was only 12 and was not allowed to qualify the bike) and at the 1/8th mile he got scared and backed off. It clocked an 8.3 second 1/8, not good by motorcycle standards, but for a 4HP Techumseh lawn mower motor, not bad.

It was a pretty crazy ride, and, the supercharger was improvized, and the hours we had in that engine were insane.

hosejockey2002
01-14-2006, 12:37 AM
I think the gist of this thread that I'm getting is:

Can you add a turbo or supercharger to a lawn mower engine to get more power? Yes, absolutely.

Can you do it easily and cheaply enough to effectively increase the performance of your mower without sacrificing reliabilty and cost-effectiveness? Probably not.

You gotta admit, though, it would be pretty friggin' cool to have a flathead Briggs or Tecumseh that turned 9350 rpm.:eek:

General Landscaping
01-14-2006, 12:45 AM
You gotta admit, though, it would be pretty friggin' cool to have a flathead Briggs or Tecumseh that turned 9350 rpm.:eek:

So what's the blade tip speed?:dizzy:
It has to be approaching Plaid... or at least Ludicrous speed.

Restrorob
01-14-2006, 05:46 AM
So what's the blade tip speed?:dizzy:
It has to be approaching Plaid... or at least Ludicrous speed.

Your right, Imagine heading across a customer's yard and sucking the grass right up by the roots leaving bare dirt.

lawnmaniac883
01-14-2006, 02:46 PM
Better yet, imagine seeing the red hot glowing spindles and the having the burnt rubber smell...

pi man
06-15-2008, 04:56 AM
Originally Posted by lawnmaniac883
A) You would need a fuel injected engine I believe that your 25kaw isnt.

Then added to by Dirty Water
Nonsense, people have been turbocharging carberuated engines since turbochargers were invented...Both draw through and blow through designs.How many turbo's have you installed??? I've installed a handfull.

Turbo charging a two stroke generally should work as explained but the reson why a turbo works and not a supercharger like was originally asked about is cos a turbo maintainsa lot more pressure in the exhaust whereas a supercharger running off a simple drive belt wont. This means that when the fuel/air enters the upper half of the cylinder on the down stroke it has abnormally high pressure and a much larger amount of fuel/air will be forced out of the exhaust pipe before the compression stoke without being burnt. This wont happen with a turbo as there will be high pressure in the exhaust pipe as well so a larger amount of fuel/air will stay in the cylinder to be ignited. Any positive effects of adding a supercharger as opposed to a turbocharger will be very small and will require large amounts of fuel severly reducing efficiency and probably causing chronic back firing.

jkason
06-17-2008, 10:36 AM
Yeah.
You NEED forged internals for a blower/turbo setup. And head STUDS.
Otherwise they will just melt. Air-cooleds run hotter than liquid-cooled anyways.
Also, think about where the debris will go when these things let loose.
I see shrapnel penetrating the backs of LCOs everywhere, messing up the advertising on their t-shirts.

pugs
06-17-2008, 12:34 PM
Jon, the only problem with putting a turbo on a carb'd small engine is theres no way to supplement fuel. The way we do it with cars is by using a very powerful fuel pump and a boost referenced regulator. No way to do that with a small engine set up since they dont run a fuel pump. Now then you could always put a single injector in the intake duct and supplement it that way.

Still too much work for a mower :D

Actually it would not be very hard. You would probably need to put a different fuel pump on it to overcome the pressure in the bowl. On the kawasaki's it would be easy to get the vent hooked up so you dont need a carb box or what not. The external vented ones just run a tube...the internal vented will be good as long as long as your intake is sealed up. What this does is pressurize the bowl to the same level as the air flowing through the carb.

Grab a book by Corky Bell. That should get you started if you wanna learn more about turbos.

racer11x2008
01-17-2009, 07:11 PM
Just take a 900cfm weed blower connected to your carb/airbox. The are now using them on karts. Add a bigger jet, bigger header and pipe (make it yourself) go to a K&N type/shaped filter maybe a little timming chang and slightly hotter plug to handle the fuel, remove the governer.
Polish everything inside it and open up the ports and polish everything.
Completely go through the carb (polish it) and make sure everything is correct (float height, Gaskets cut to openings correctly, jet seat, spring tension depending on carb and application? Go to bigger carb?

Off the subject,
We are running a Clone Kart class here and the stock 6.5 (Blue Motor) with an adult setup turns well over 9.5hp These seem to be real good little engines. Dual Bearing cranks and all. Engine purchased at the track would be @$150
Similar Briggs and Honda OHV Engines can produce well over 38HP without a turbo! But the cost is to the moon. Same could be done with the Jangdong at a fraction of the price.

This is the same engine sold at harbor freight. Jangdong I think its called?
It also has the same mounting pattern as the Briggs engines.


Racer11x

randy448
01-18-2009, 02:03 PM
:weightlifter:somebody got big enough brakets and pipes for this one?

nosparkplugs
01-18-2009, 02:16 PM
Can someone explain if you can put a turbocharger or supercharger on gas lawn mower eninges? There are a few turbo diesel engines for lawn mowers. I'm wondering, because I would like to increase my HP on my 25 HP Kawasaki. Thanks...


I'm sure if you can think of it , and have the engineering skills, money, parts, tools you can turbo charge just about anything.


Over the years their have been several failed attempts to offer turbo diesels in midmount commercial ZTR's. Diesel engines have the thermal heat advantage, respond to turbo charging much better than gasoline engines. We only need to look at the few manufactures whom have years of experience, and have failed to offer a truly cost effective turbo diesel ZTR, so why would they even mess with a gasoline engine:hammerhead:

A turbocharger would add more cost to the already expensive gasoline or diesel engines

GravelyNut
01-18-2009, 02:39 PM
:weightlifter:somebody got big enough brakets and pipes for this one?






That looks like one off of a loco. Like a GE or an EMD.

GravelyNut
01-18-2009, 02:54 PM
Your right, Imagine heading across a customer's yard and sucking the grass right up by the roots leaving bare dirt.

Funny you should mention something like that. While at the Mow In back in Oct in WV, I was showing a member how fast a Power Brush/Broom normally turned. And then ran it up to full power on the 35-G. Now imagine a sweeper nearly 6 inches above the ground pulling up debris, grass, and dirt. And it ( brush ) was only turning 1.5 times normal. You don't want to be near the front of it when it's down. :usflag:

ricky86
01-18-2009, 11:54 PM
:weightlifter:somebody got big enough brakets and pipes for this one?

OK What is that for?

GravelyNut
01-19-2009, 04:12 AM
OK What is that for?Having just gone to the GE loco website, I'd say a 7FDL engine.

topsites
01-19-2009, 03:05 PM
Yes, but in terms of expense...

The first things I would consider are less expensive upgrades that also result
in more power and better fuel efficiency, things such as:

A 10.2 mm spark plug wire, die-electric grease all the nipples and fittings.
A double platinum spark plug.
A high performance coil.
A high performance air intake.
Synthetic oil.
Super unleaded fuel (for non-diesels).

The problem is...
With the exception of the plug, the die-electric, the oil and the fuel,
nobody seems to make these parts, either.

They just don't make high performance parts for mowers, the few places that do make them are for racing applications,
these racing parts aren't made to withstand daily or long-term use, the few parts I have found took a lot of time cross-
referencing and studying up, and I'm not much for major modifications.

As a rule if I want more power I turn it up, thou it eats fuel and it's not good for the engine.