bolt on more power for my Stihls??

[HORSELOGGER]

Russ, I think your question is answered by the statement" I'll take H.P. over waranty any day"

Dan, if he gave out all that info, any old body could just run around with a dremel, charging 40 bucks, makin ms310 hotsaws

[ehp]

it doesnot matter but this is my feelings on muffler mods, 85% is max , of your port area, bigger than that you are going to loss to much back pressure and your saw will lay down on you in a big hard cut, on a stihl all I use is a dual port muffler when making them a ported woodsaw, that is all you need , gives you go power and not real noisey

[Erick]

Just my two cents (this site has to have gotten at least a dollar by now)   I am not a saw builder and dont run race saws so please keep in mind that these guys know alot more about these saws than I do. I'm just a guy who wanted to tinker a little and get some more power out of my saw. I recently bought a used MS460 to play with (didn't want to mess up the 046) I just opened up the muffler on it the other day. I used a dremel tool and ground out the metal around the standard 3/8 round exhaust port to make a square outlet about 70 to 75% the size of the  cylinder exhaust port. I started on the small side since I can always take some more off but its real hard to add it back on, I may open it up more later. I basicly ground out the metal back to the shroud that directs the exhaust flow and up to the top of the muffler where it starts to make the corner bend and to the front just a little past the lip of the shroud (kinda hard to explain may try to post a pic.) .It looks pretty slick almost factory and the shroud that directs the exhaust flow still works as it is should. I also drilled three holes 11/64 in dia. (it was the bit I had handy) in the shape of a triangle in the plate inside the muffler right in front of the cylinder port to kinda strighten out the flow a little (dont know if it helped just going for what I know). Readjusted the carb. and put it to the wood.   The saw is a tad louder but it also has a noticable gain in power.   I kinda like this more power same saw concept I might be looking for a good port job soon   any takers??

Dan, why such a big port??  just a ? from a novice not trying to start anything just always trying to learn.

[dozerdan]

  It makes a huge difference as to the port location. If the additional outlet port in the muffler is directly in front of the exhaust port in the barrel, it should be made smaller. I don't do that. If you look at the picture, you will see that my port is in the lower bracket. The exhaust has to exit the barrel. make a 90% downward turn then make another 90% turn to exit the barrel. Those two direction turns create enough backpressure for the saws to run correctly.
Later
Dan

[jokers]

 It makes a huge difference as to the port location. If the additional outlet port in the muffler is directly in front of the exhaust port in the barrel, it should be made smaller. I don't do that. If you look at the picture, you will see that my port is in the lower bracket. The exhaust has to exit the barrel. make a 90% downward turn then make another 90% turn to exit the barrel. Those two direction turns create enough backpressure for the saws to run correctly.
Later
Dan

Similar to a "head" loss when calculating pipe flow I believe. I`ve found similar results dependent on port location.

Russ

[dozerdan]

Hi
You also have to into consideration that my mufflers use a spark screen. If you make the port to the dimensions that I stated you can still use the screen and have the same effect as a port of smaller size without the screen.
Later
Dan

[ehp]

that was what I figured you were going to say  

[2strokesmoke]

Well since I started this thread I figured I should get back in here. I haven't had a chance to modify my saws yet. I had a good year of use out of them both (210C and MS440). They are now stored for what I assume will be the whole winter. Due to budget, I think I'll first put a 32 inch bar and larger dogs on the 440. My new project is an old Sears Roebuck saw I got from my wife's grandfather. It turns over, has compression, so it has a chance. I want to restore it to running condition. I haven't tried to start it. I don't know much about it. It has a gear reduction drive on it and about a 20 inch bar. I should probably start a new thread, but where do I start when I want to restore an old saw? How do I determine what it is, how old it is, how to get parts, etc? It was well cared for and chainsaw people I've shown it do agree that it is in very decent shape.