henry r
ArboristSite Operative
I want to fit a spark arrestor when i muffler mod my husqvarna 359.
What i want is a muffler that flows like a modded one, arrests sparks at least as well as a stock one, is reasonable to maintain and does not add a heap of weight. (Plus not cost hundreds of $ in custom machine work etc)
I am aiming for a restrictive opening of 85% of the exhaust port. (Keeping in the middle of others recommendations of 80 to 90% for optimum back pressure)
Obviously the mesh needs to flow considerably more than the 85% to allow for clogging and to not be the constriction point.
Question 1. Where do i find out what 30 mesh flows at as a percentage of an open port of the same size?
It is listed as having an open area of 45% but i imagine the airflow at muffler pressures would have to be a far smaller %.
Question 2. With 2 stroke chainsaw mufflers do you want the point of max constriction to be as the exhaust exits the muffler or at some point through the muffler with expansion chambers on either side of it?
Question 3. Will there be any adverse effects on flow/back pressure or spark arresting performance if the screen is well before or well after the point of greatest constriction?
Question 4. Has anyone tested how quickly screens clog up?
I would like to be able to run enough screen area that it will last a days work without needing to be cleaned but have no idea how much extra screen will be needed. (I haven't run the saw with the stock screen)
Thanks.
What i want is a muffler that flows like a modded one, arrests sparks at least as well as a stock one, is reasonable to maintain and does not add a heap of weight. (Plus not cost hundreds of $ in custom machine work etc)
I am aiming for a restrictive opening of 85% of the exhaust port. (Keeping in the middle of others recommendations of 80 to 90% for optimum back pressure)
Obviously the mesh needs to flow considerably more than the 85% to allow for clogging and to not be the constriction point.
Question 1. Where do i find out what 30 mesh flows at as a percentage of an open port of the same size?
It is listed as having an open area of 45% but i imagine the airflow at muffler pressures would have to be a far smaller %.
Question 2. With 2 stroke chainsaw mufflers do you want the point of max constriction to be as the exhaust exits the muffler or at some point through the muffler with expansion chambers on either side of it?
Question 3. Will there be any adverse effects on flow/back pressure or spark arresting performance if the screen is well before or well after the point of greatest constriction?
Question 4. Has anyone tested how quickly screens clog up?
I would like to be able to run enough screen area that it will last a days work without needing to be cleaned but have no idea how much extra screen will be needed. (I haven't run the saw with the stock screen)
Thanks.