Show off your muffler mods
- Thread starter TreeLife
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4mm
whitesnake
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M4 rivnuts here
millerlite
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Just read a pile of this thread and have a rant to add.
You 100 percent can turbo a piston ported 2 stroke. A properly sized turbo has turbine drive pressure less than boost or 1:1 typically, but during spool it is more like 3:1. Regardless, you are basiclly buulding a 2 stroke that essentially runs at a higher atmospheric pressure.
Example, we are sitting in around 15 psi at sea level. At 15 psi boost, the exhaust drive pressure is around 15 psi, making the motor 'see' 30 psi absolute on the intake and the exhaust. Even if the exhaust or intake pressure doesnt match, it still "works" due to how a 2 stroke works in the first place. Youre essentially just increasing atmospheric pressure. When you go from 4000 ft to sea level does your saw all of a sudden defy physics and fail to run? A stock muffler has far more backpressure than atmospheric pressure, like a turbo during spool. Does the saw just quit? Nope its just running at less volumetric efficiency.
The issue is why turbo a saw? Turbos are heavy, have packaging constraints, and something appropriately sized doesnt exist unless you are talking 140cc plus saws.
My take on pipes and muffler mods is there is obviously science involved. There are noise harmonics and waves bouncing around. There are also pressure and temperature gradiants. Air, exhaust, etc. All has a mass and hence kinetic energy when its flowing. As you know accelerating a decelerating mass takes energy and time. Additionally in a two stroke, you want some back flow at the appropriate time to act as an exhaust dam. I've built a lot of whacko exhausts from mufflers to pipes. You just cant predict whats going to work the best unless you run it. A dyno is beneficial and likely is my next project.
You 100 percent can turbo a piston ported 2 stroke. A properly sized turbo has turbine drive pressure less than boost or 1:1 typically, but during spool it is more like 3:1. Regardless, you are basiclly buulding a 2 stroke that essentially runs at a higher atmospheric pressure.
Example, we are sitting in around 15 psi at sea level. At 15 psi boost, the exhaust drive pressure is around 15 psi, making the motor 'see' 30 psi absolute on the intake and the exhaust. Even if the exhaust or intake pressure doesnt match, it still "works" due to how a 2 stroke works in the first place. Youre essentially just increasing atmospheric pressure. When you go from 4000 ft to sea level does your saw all of a sudden defy physics and fail to run? A stock muffler has far more backpressure than atmospheric pressure, like a turbo during spool. Does the saw just quit? Nope its just running at less volumetric efficiency.
The issue is why turbo a saw? Turbos are heavy, have packaging constraints, and something appropriately sized doesnt exist unless you are talking 140cc plus saws.
My take on pipes and muffler mods is there is obviously science involved. There are noise harmonics and waves bouncing around. There are also pressure and temperature gradiants. Air, exhaust, etc. All has a mass and hence kinetic energy when its flowing. As you know accelerating a decelerating mass takes energy and time. Additionally in a two stroke, you want some back flow at the appropriate time to act as an exhaust dam. I've built a lot of whacko exhausts from mufflers to pipes. You just cant predict whats going to work the best unless you run it. A dyno is beneficial and likely is my next project.
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395XP with @tree monkey large deflector with a Husqvarna screen and Stihl exhaust gasket. All three line up perfectly and work together perfectly. The gasket ensures a better seal. as well as reducing screen vibration, this increasing it's longevity. Attached with 5mm rivnuts and stainless steel screws with a dab of hi temp loctite.
What I like is that it looks like it came from the factory that way.
