Stihl 025 muffler mod info

[stihl025]

I have searched the threads to find a ton of info on modifying the muffler. The only problem is that there are so many theories to accomplish the task that I am not sure what or which I should be doing. Can anyone out there give me some good solid guidelines as to the basics so that I don't do something to lose performance.

Here is what I have learned. All external exhaust holes should add up to 80 - 85% of the muffler mount side of the exhaust port. Is it true that it doesn't matter what you do to the inside baffles, just as long as they flow more than the external exhaust holes? The screens could cause flow restrictions, so either make the openings bigger or lose the screens.

Am I pretty close?

Ed

 

[fishhuntcutwood]

Yep. Some guys look at opening mufflers as a science. Some look at it as an art. I don't know how I look at it. I know that you can go too much and just make your saw louder without any coresponding performance gains.

This is not a slam on the 025 in any way, it's a fine saw, but it's not exactly a screamer, so your gains may not be as evident as on say, an 066 or 046. Airflow is airflow. No need to get overly complicated on a saw that's not racing or tackling timber on a regular basis, and that may not gain 10% on a mod. This is a firewood saw, correct? Put a couple of additional holes in it, maybe fashion a screen if you're cutting in dry conditions, or on state or federal land and roll with it.

Common sense goes along way on muffler mods. 80%-85% is safe and will help your saw without going too far.

Welcome to AS.

Jeff