lutys chainsaw mods,How to build a short expansion chamber, 2.2 extra bhp.

this expansion chamber pushed an extra 2.2 hp on my highly modified zanoah clone chainsaw 58cc. overall 8hp.

[@IndianaDoug]

I like what you’re going for, and over a stock muffler I’m sure it’s better. However, you need a much larger volume for the sound waves to bounce back to help hold the charge in. People confuse “pressure” or “back pressure” with resonance I’ve noticed. Regardless, I too have a theory on how to create a smaller expansion chamber but doubt I will. Perhaps it will get your wheels spinning? Do you know about wavelengths in regard to antenna technology? They’re measured in wave length. Look up ¼ wave antenna, a much smaller antenna that works on the same frequency as its full length counterpart.

[@marklutwyche8578]

I understand we're you are coming from, but a few years ago I fitted a sonic cone into a standard muffler and it held back the rpms it was the only thing I did and torque was really great but it only reved to 6000 rpm, so yes the sonic wave held back flow a lot, think of it as a sound wave from a large firework and how the sound wave pulses your chest, yes a large volume will work great but it's not practical for a chainsaw, but thank you for your input.

[@IndianaDoug]

@@marklutwyche8578 sounds like your sonic cone is increasing the physical pressure coming from the exhaust port. Like if you were to place your hand by a car exhaust you can feel the pressure. This design may aid in scavenging, but at a cost…Heat. A muffler only “muffles” sound. Not until you start taking away the muffled effect, does performance increase. My buddy Joe has a video on various muffler and pipe shapes he tested on his Dynamometer, the results were wild. The best performing one looked like a horn that starts out small, then increases in size outwards. No matter what we do for a muffler mod, there will be restriction inside the can. More restriction, more heat. Less restriction, less heat. There’s a give and take and finding that perfect match is tricky. I hope you find it👍🏻

[@marklutwyche8578]

@IndianaDoug yes your probably right, I'm dyno testing it against a standard muffler soon so we will see. Thanks again for the input.

[@marklutwyche8578]

I've done comparison muffler testing on my dyno on my latest video and on the tuned up saw big carb ram stack turbo crank ported high compression this new pipe give an extra 2.2 hp over the standard muffler.

[@Alan_Hans__]

I like it.

[@marklutwyche8578]

Thank you 😊

[@user-ec7yr8up1m]

great man

[@wayneberry8703]

I’m very curious as to see how it goes as well, Mark….

[@marklutwyche8578]

There will be a dyno run on here soon.

[@wayneberry8703]

@@marklutwyche8578 sounds great 👍🏼

[@roryrichard5483]

I’m very interested in seeing this run. How do you determine the shape of the cone?

[@marklutwyche8578]

Hi, well the cone needs to be about the same size as the exhaust port