Part Six: The Exhaust System

[Backtroller]

To get an accurate beginning point would you use a ringless piston placed into the cylinder and trace the exhaust port carefully with sharpie and measure that area?

 

[Chainsaw Jim]

Has anyone else noticed how carburetion plays a role in exhaust tone and volume level?
I've had quite a few builds get ear bleeding loud after the muffler mod, but then quiet back up to a tolerable level after modding or upgrading the carb.

 

[Johnmn]

I would just mic the exhaust, half the time I guess and it ends up close when I check it. I bet a tape measure would even work if you don't have a mic.

 

[RIDE-RED 350r]

I don't have a set formula, but what seems to be working for me on most saws is adding a second exhaust port roughly the same size as the factory port, maybe a little smaller, before any baffles if there is one. I haven't opened up any mufflers to remove baffles as of yet, but I think that is because I have been able to work around them with the particular models I have done. The muffler on my 372 is just an open can, my 357 has a baffle, but placing the extra port behind the seam lets exhaust out before the baffle comes into play. My main goal is to let the heat out a bit easier and more efficiently since these saws are spooling higher than stock.

First pic is my 372 muffler mod, second is my 357, third is my 394, all are ported, 394 with the most extensive work done. All are very strong runners. With the 372 and 357 I used 288 deflectors and screens, 394 got a Red97 deflector with no screen and I also cut off the baffle in the factory deflector.

 

[Deets066]

There are giant holes underneath these deflectors, you can tune them by opening or closing the deflector a little bit. I was always a fan of lots of opening. 100-125 percent

 

[Deets066]

Love the sound

 

[Deets066]

The solo has been modded further since that vid

 

[mdavlee]

With screen or a deflector over the putlet 200% will idle fine.

 

[RIDE-RED 350r]

Got some pop to em eh Deetsy???

 

[Manofstihl066]

Love the sound

Great sound! the louder the better to me. I have a 590 also that randy ported for me, it sounds like a lil top fuel car at idle.

 

[Deets066]

Got some pop to em eh Deetsy???

It would sound REAL good if I fired my 064 up and let it idle with em. It has a mean pop like a 288

 

[Deets066]

Great sound! the louder the better to me. I have a 590 also that randy ported for me, it sounds like a lil top fuel car at idle.

Joe ported that 590 and it's the meanest sounding saw at idle that I've ever heard. It's rediculous

 

[Manofstihl066]

That's a nice muffler outlet bet it sounds awesome.

 

[Deets066]

The vid does it no justice, you can feel the pop in your chest when holding the saw.

 

[Deets066]

That's a nice muffler outlet bet it sounds awesome.

It has another on the other side.

 

[XP_Slinger]

Braaap

 

[XP_Slinger]

I go fairly conservative on muffler mods as well. Enlarge the factory port and add a second port, normally on the clutch side. Like a few others have said, I like to leave the front alone for reflection.

 

[huskyboy]

Interesting to me how when I had a DP muffler cover on my 044, and then after it was ported by the mad scientist Dr. Al and DP cover swapped for the closed cover and flywheel side deflector added along with opening up the clutch side it was louder than the DP but the tone was way less obnoxious and rough. Sounds way better than the DP and I believe works better too. Seems to like the wave reflection off front cover maybe? Maybe the wave reflection helps with expansion of gases somehow?? Maybe someone more knowledgable than me can weigh in on this lol.

 

[XP_Slinger]

Interesting to me how when I had a DP muffler cover on my 044, and then after it was ported by the mad scientist Dr. Al and DP cover swapped for the closed cover and flywheel side deflector added along with opening up the clutch side it was louder than the DP but the tone was way less obnoxious and rough. Sounds way better than the DP and I believe works better too. Seems to like the wave reflection off front cover maybe? Maybe the wave reflection helps with expansion of gases somehow?? Maybe someone more knowledgable than me can weigh in on this lol.

That's what I think as well. I'm just not smart enough to put the science behind it.

 

[XP_Slinger]

The vid does it no justice, you can feel the pop in your chest when holding the saw.

Btw, that fugger sounds nice Deetsy