550xp and 421 question

[Johnny2186]

I just picked up one of each of these saws new never gassed from a relative who's plans changed. I ran one tank through each yesterday and really like both. My question is does either of these saws benefit from a slight muffler mod?

 

[Mkinslow]

I just picked up one of each of these saws new never gassed from a relative who's plans changed. I ran one tank through each yesterday and really like both. My question is does either of these saws benefit from a slight muffler mod?

Dont know about the 550,but if you have a Dolmar ps421 and it has the muffler with the catalytic converter inside then yes it will help when you remove the catalytic converter. You'll have to retune the saw some though. Helped mine a lot

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[Johnny2186]

I thought I heard a cat cooling in the 421.

I am really interested in what the 550 responds like to a slight mm and opinions on it. Does it gain a little or does some torque leave? Just curious.

 

[Backtroller]

I had an advanced 2252 with a big 1” pipe out the side. It was noticeably stronger all over compared to my stock 545. I had one that I drilled a few holes inside and just opened it up under the deflector as big as I could and rewelded the deflector cover. It did not feel as strong but close. I was however, a great deal quieter.

Be warned that they get loud with a mm

 

[Farmchuck]

I had an advanced 2252 with a big 1” pipe out the side. It was noticeably stronger all over compared to my stock 545. I had one that I drilled a few holes inside and just opened it up under the deflector as big as I could and rewelded the deflector cover. It did not feel as strong but close. I was however, a great deal quieter.

Be warned that they get loud with a mm

They absolutely get louder after a muffler mod. I’m definitely no expert in this area but the one I had muffler modded has a pitch that is downright painful to my ears. When I run it I wear both plugs & muffs. May just be my ears but I want to share that for everyone’s benefit. We only get one set of ears.

 

[Backtroller]

I totally agree with you. That’s why I stopped using the one with the pipe. It bothered my ears. However the guy I sold it to loved it. Go figure. We’re all different

 

[MG2186]

Another thing to remember when modding these mufflers is to get the heat out and away from the cylinder. I did that 2252 muffler, it actually was my saw. It was a can with a pipe and I plugged the top outlet to try and direct all the heat out as far as possible. They do get loud but do respond quite well with this mod, these auto tunes seem to gain more than most saws with a healthy mod, some just get loader but these actually do get faster

 

[quattro90]

my 545 rebuilt from the ground up had a mild MM and responded really well. it looked stock because i merely opened the existing holes inside/outside without tearing apart the muffler (even though it had been beat to heck and prolly would have improve the muffler appearance). afterwards i decided to play around with the gasket delete which required me to make a beer can gasket to get to exactly .020" aside from that, it was fully stock and cut very very well.