exhaust mod help

[njforestfire]

Looking for input on the optimal size for opening up the muffler exit port. I remember somethijng from a few years back on this site but don't have the actual number. This will be on a Husky 365 and something like 80% of the jug exhaust port area sticks in my head. Any input would be appreciated.

 

[woodyman]

Looking for input on the optimal size for opening up the muffler exit port. I remember somethijng from a few years back on this site but don't have the actual number. This will be on a Husky 365 and something like 80% of the jug exhaust port area sticks in my head. Any input would be appreciated.

They say 80 to 85% of the exhaust port at the cylinder and I have heard 100%.I have an 288 deflector on its way for my 372.I should have it on by next Sat. night.I will go as big as the opening will allow and use a spark screen which reduces the size of the hole.

 

[bluesportster02]

80%. If you go with a spark screen i would go a little bigger.

 

[pioneerguy600]

The 85% rule works well with stock engines, the 100% works better with ported engines that have the intake modded to allow for increased flow.
Pioneerguy600