Makenzie71

I have two motors that are going into gocarts...one is a 18 HP brigs vtwin and the other is a honda 6.5hp. Would the air pump from an FC rigged to either of these push enough air to get any power gains from the motor?

The 18=3600rpm max
the 6.5=8200rpm max


I'm only putting this here because FC owners know the most about the air pumps. I've never tested mine to see how much umph it has so maybe you guys can help me. If this thread HAS to be moved I'm ok with it.

Rotory

iTrader: (1)

wow thats a spectacular idea...what will you use to drive it?? mount a gear on the front i guess?

HKSTurboII

Try finding an electric leave blower and hook that in. We did that on a friend of mine's cart and it gaver it quite a boost.

sonic7

iTrader: (1)

I highly doubt that the stock air pump would actually spin fast enough to produce boost... Maybe if the pulley was smaller and the drive wheel was bigger, it might do something for the low end of the motor, but i would not expect a tower of power from it!

Jimmy325i

And here I'm trying to find a snowmobile rotary for my mini chopper project....

With a smaller drive pulley you might be onto something. It could work. You should be able to bench test it easy enough.

Rig the thing up on a piece of bar stock and bolt both motor and pump to it and make an inlet tube for the combo. Either the motor will choke, the motor will hum and wind up faster, or the air pump will blow up from over reving.

Keep us posted!

SureShot

I doubt if anyone has actually measured the actual displacement.
My SWAG (scientific wild *** guess) maybe 2ci/rev.

Back in the 60's I worked with a guy that built a 3 engine cart.
Two engines on the axle with the 3rd running a judson blower to the other two.
He claimed he clocked 90MPH on a 3/8 mile oval.
The guy was one hell of a mechanic, so I kinda believed him.

Makenzie71

Okay...I gonna try and test it tomorrow by doing this:

I have a motor that maxes out at 10000rpm@115volts. I'm going to clamp this motor down and wire a potentiometer into it and a volt meter so that I can regulate how fast the motor is turning. That's approx 87rpm per volt.

My vertical briggs maxes out at 4000rpm~46v (governed there for the mower but I don't know how fast it could turn) and my Honda motor turns at 8000rpm~92v.

I've got a pully that is within 1/16th of an inch of being the same size as the air pump so I'm going to mount that pully on the motor and clamp the pump down for testing.

Then I'll place a cap over the exhaust of the pump and screw in a low pressure air guage (measures to 40psi) to see how much consistant pressure it'll hold per RPM before stalling.

Of course this won't tell me how much boost it'll hold while an engine is also pulling air but it'll give me something to guess with.

Jimmy325i

should rig up some form of half assed flow bench for it as well. golf ball inside a clear plastic tube connected to the output. Not sure how you could corrilate any achieved data from the device but might give you an idea of flow. max pressure doesn't really mean much if it'll build 5psi but takes 30K revolutions to do it.

Makenzie71

I should...friend on another foum has a rigged up flow bench, gonna see how he did his to get real results

rotary>piston

I've actually been thinking about buying a nearly blown turbo from a junkyard and having a muffler shop weld it on to my 15.5 hp Kohler. It wouldn't have oil or anything, but if it just gave the sound of a turbo I'd be satisfied.

Actually I've been very curious about this: the "rev limiter" on a lawnmower, is it spark limited, or carb limited? How is it normally done on a kohler?

Oh yeah, you could also try to make a supercharger out of a hairdryer . That'd probably work better than an air pump.

Jimmy325i

get a blown t25 and remove the exhaust side. Attach a pulley and you have yourself a cetrifugal supercharger.

See you can actually find uses for shitty turbos afterall.

Makenzie71

lawnmowers are governed through the carb...I fixed mine by making my own manifold an using Mikuni carbs



oops double post

Makenzie71

lawnmowers are governed through the carb...I fixed mine by making my own manifolds an using Mikuni carbs

Makenzie71

what kinna turbos come on the busa?

rotary>piston

so if you boosted it, it would go to higher rpm?

Is it possible to put a motorcycle carb onto a lawnmower engine and make it run correctly? I'd love to be able to take my kohler to 6k rpm rather than getting stuck at 3600. If the valve springs held on I could probably get well over 20 hp out of it like that.

Makenzie71

No they don't work quite that way...I'm guessing it's a vert shaft rding lawn mower engine, right?

This is what I did with my last Vtwin vert shaft motor:

Pull the head caps off and remove the gasket...I took the gasket and traced it onto a 1/32" sheet of copper and then cut out the new copper gasket and installed it. That will give about 3hp on a vert 15hp motor=18hp.

The carb is what is governed, this it prevents enough fuel and air from entering the engine to rev over a certain point. I fixed this by removing the intake manifold and carb...I then traced each flange to some 1/8" mild steel and made new flanges. I then acquired two 40mm Mikuni carbs. These were from dirtbikes. these carbs will have bolt holes on one side where they mounted to the bike, I trimed the bolt holes and such off to make that end as round as possible (watch out cuz there are jets on that end on the bottom that you don't want to foul). From here take and weld a 3" long piece of 1.5" ID tubing to your flanges connect it to the carb using a pice of rubber hose...radiator hose and hose clamps work great. The increased flow, slightly high RPM, and more fuel will give you another 5hp easy...if not more.

But...

You will suffer poor fuel economy...by lawnmmower standards. And there's a chance that if the timing and what not are not in decent shape on your setup you'll burn a hole in a piston...always run premium gas.

rotary>piston

yeah, but boost basically is like getting a bigger carb.
If you allow twice as much air to pass, then the engine will rev higher (assuming everything else, like valves and such, could keep up). The same would happen if you forced twice as much air past. In the end, either way the engine is getting twice as much air/fuel in the cylinder, so it would rev higher.
Yes the engine is on an old assed ride a mower frame. The only problem (well, not the ONLY problem), is that it has no brakes. Is there any way to set up a braking system on something like that? There is no front axle, and the rear one has belts everywhere so there's no room to mount a stationary piece (like a caliper), so I don't know what to do. I was actually thinking about attaching something like a bar with rubber on the end to the old mow deck adjuster and letting that hit the street to stop, either that or putting a wheel on that bar that would hit the street and slow it down. I don't know, what do you think?

Makenzie71

#1...you get boost through carb that's on the mower because it's oporated through the vacume generated by the suction within the engine.

#2...you couldn't set the carb as a pull through because the fuel delivery setup they usually have is operated by the pulsing vacume...a turboed or blown carb would have a constant pull on it...which may prevent the fuel system from operating propperly...I think, I dunno for certain.

#3...the carb on the mower would not be able to supply enough fuel to feed a boosted mower (it would lean out WAY too much causing damage).

This is all why I changed my carbs over to mikunis, they can supply enough air and fuel for a mower engine to operate better and they have a few more applications...but if you want to really turbo a 15.5 vert engine (I assume it's a Vtwin) you'll want two 40mm Mikunis or similar or one big 80-90mm...or maybe even a small 2 barrel. I'm fairly certain the Mikunis could keep up with a slight boost but this is all something I've just started thinking about.

As far as brakes...look at your trans axle...there should be a lever sticking out of it attached to a bar going ner where your peddle is at...check that and make sure it's attached and there's no slack in it. If the brake assemble is busted inside then look at the pully that drives the transaxle. It should be a big flat pully...I've put the caliper assembly from a Virago around one of these pullies, but it was a bitch.

Makenzie71

oh yeah...and there's a difference between more power and a higher redline.

The engine you got prolly maxes out at 3500ish rpm with the stock carb...well, with an un-governed carb you could get into the high 4000's....but it's like revving your S5 to 11000rpm...sounds cool but no. With an un-governed setup keep in mind that it will rev until it starts breaking things...you're power band will still be in the same vacinity, so there's no need to push too hard.

rotary>piston

actually it's a flat single cylinder engine.
There's a brake on the transmission, but it's so small that it won't even stop the thing, that's why I'm looking for another system.
In case you haven't figured it out, this "go-kart" I have is junk me and my friend turned into a vehicle. It's basically the equivalent of a muscle car. Low redline, terrible handling, terrible brakes, but lots of torque. Before I screwed up an got oil on the belt (how was I supposed to know the tranny wouldn't hold oil ) it went 40 easy with the three speed tranny we have (yes, it is a manual!).

MrBob 86

The smog pump on a go kart engine has been done before. I dont remember the address but there is a webpage. You might want to try looking here -> http://www.4cycle.com

Makenzie71

How did you get it to go so fast? Reverse the pullies?

Liquid Anarchy

iTrader: (2)

...why isn't this somewhere else?

Makenzie71

Because initally it was related directly to the emmisions pump that the FC uses. And I'm still wanting to know exactly how much the FC emmisions pump flows, it's general stats. Beings that only FC's came with the FC emmisions pump I thought it would be best to ask those who would have FC emmisions pumps...that happens to be FC owners...and FC owners typically hang out in the FC section.