Hello Everyone.

Im thinking of using one of the tuned pipes I use to have with some OS MAX 61 engines for my converted Mitsubishi 33cc

Would this work in terms of increasing performance.

Any experience will be appreciated.

Thank you very much.

Victor.

A tuned pipe will work if the exhaust open degrees is more than 150° crank angle. Less, and it will be a nice muffler, more angle, and it will give you better power PROVIDED you tune the pipe well.
Hmm.. transfer porting angle should not be too large as well. You'll need at least 20° blowdown. (angle between exhaust open and transfer open)
If the above is acadabra for you, don't bother. Follow your heart, and don't expect miracles.

I'm thinking the size, and in particular the inlet and outlet, on a 10cc pipe are going to be too small for a 33cc. I have a pipe for a 30cc engine and it is the size of a junior league baseball bat!! If the outlet on a tuned pipe is too small for an engine, bad things happen...

AV8TOR

I used a tuned pipe on a 45 cc Kawasaki engine, which I converted to aircraft use.

Calculated power increase was in the region 60%.

As stated ... size of a baseball bat.

Have a read of this site and compare what you have with what you need depending on the design parameters outlined.

http://www.mh-aerotools.de/airfoils/javapipe_en.htm

Tuned pipes will work fine on the engine. The noise levels are reduced quite nicely, but then the propeller noise becomes more noticeable, so you'll likely need a better less noisy prop then too. But the gas engines behave more like four stroke glow engines, as they turn lower RPMs, so a 10cc tuned pipe may or may not work if you can't get it long enough for the lower RPM engine. But it won't hurt to try it out though. It may work really well even without trying to tune it up for more performance.

I was playing with a tuned pipe with this engine a while back too. I forget which pipe it was, it could be a 10cc but I think it was a 15cc pipe though. I was using it on a 26cc gas engine. It did help quiet the engine down quite a bit as compared to the little lawn mower mufflers many people use on the gas engines.

As an afterthought, I did not read the original post too well.
A 10cc pipe on a 33cc engine could well be opening a can of worms, and cause very bad running, throttle setup and engine overheating due to the pipe being too small. The shockwave that should push back the fresh charge into the cylinder, will probably arrive when the scavenge ports are still wide open, causing severe loss of power and overheating, possibly backfiring.

I can agree with you Pe, but it wouldn't hurt to try and see what happens. It may work Ok or may not. Only one way to find out for sure. But if the OP is wanting a tuned pipe boost in performance, he needs to get a tuned pipe rated for the engine's size.

Oddy,
If you go to the site I showed in post #5, you can get a free download of a tuned pipe designer. There you can put in your relevent information based on your engine and then compare the outcome with the pipe you have there.

Not rocket science. Sometimes I wonder if some who put comments in here actually read others input.

The Hepperle tuned pipe designer is a very rudimentary tool. It gives you a starting point, but not more.
Affordable tuned pipe design is available here:
http://www.buildandclick.com/