Started 440 hybrid pipe.

[Evan]

Ran my piped 372 today . That things revs like a monster. Couldnt resist doing the 440.
This saw makes alot if midrange grunt so i decided to try and make the pipe longer.
Dont know if it matters but i try lol.

Chain brake works just clears.

Gota brace it off the case and do a spark screen and finish weld it. Pipe is port matched to the exhaust.

Cant run it till i order a coil or plug cable. It fell apart today.

 

[Tomos770]

How do you calculate backpressure of that pipe?

 

[Evan]

Fill cylinder full of water then make pipe long enough to hold that much water.

Idk actually know. Just glue stuff together and hooe it makes a positive gain

 

[jack-the-ripper]

Buckin' Billy Ray, a tree worker from British Columbia, runs a pipe similar to that on a 572XP . He also has a 500i with port work done by Ripsaws. Check out his videos. Here's the link.

 

[Mike mike]

Awesome design nice craftsmanshipThat a side I would think building a muffler for a chainsaw on this caliber I would think the muffler would have to be more like a two-stroke dirt bike pipe off the head standard size goes into a bigger chamber and then tightens up coming out to give back pressure to the engine but that's just my two cents I think if you narrowed the end of that pipe it would run possibly better and be more tunable

 

[Tomos770]

I was aiming at the same direction....with my previous post!

What I did to my Partner 351 (Poulan 2x5x).....but with the original muffler.

 

[sean donato]

Awesome design nice craftsmanshipThat a side I would think building a muffler for a chainsaw on this caliber I would think the muffler would have to be more like a two-stroke dirt bike pipe off the head standard size goes into a bigger chamber and then tightens up coming out to give back pressure to the engine but that's just my two cents I think if you narrowed the end of that pipe it would run possibly better and be more tunable

That is not how tuned exhaust works. It has nothing to do with back pressure and everything to do with sound waves. Put quite simply there isn't enough room in a chainsaw to get a proper tuned exhaust built into the area a muffler resides. Next best things is what even is doing, really there's no need for the curly bends in it, you're just looking to dump exhaust as fast as possible. It's really only helpful at wot and high rpm, then you have the noise to consider. Muff mods, are a mix of the straight pipe and noise dampening. A well designed baffle system with enough surface area to not slow down the exhaust charge and a free flowing outlet will yield a well preforming exhaust that favors power output with out the obnoxious noise that straight pipe have.

 

[sean donato]

This is a very good read about tuned exhaust in a loop charged 2 stroke.
https://www.prestwich.ndirect.co.uk/tunedpipetheory.htm

 

[Evan]

My 372 is less curly. Buckin is running one of my 372 pipes

 

[Evan]

Really no clue what im doing. I just like fabbing stuff. I did see gains on the 372 or atleast i think i felt gains.

Thanks for all the comments so far keep em coming.

I like pictures to so here's 2 stroke exhaust one.

 

[Evan]

Buttoning stuff up also rolled it back under the chain brake.

Last will be lower mounting point to cases with spacer incase i go back to 440 cylinder.
.

I have some spark plug wires/boots might go out and see if i cant fix mine and fire this thing up.

Had it tuned pretty good. Will be interesting seeing what affects this pipe has on the tune