Echo 352 Muffler Mod

[Charles Bale]

I have a CS-352. Pulled the limiter caps, got the carb a bit richer, about 1/2 turn on the H. So now its not going to burn up. Happy with the saw. I have watched a bunch of you-tube videos about muffler mods. One guy just dremeled out the exhaust guide, another "stabbed" the matrix from the rear to gut out the internals, and another bent open the seams and gutted the can that way. I raced 2 stroke dirt bikes from the mid 70s till just a few years ago. I know 2 strokes. These saws dont technically have expansion chambers, so I think the idea of the muffler mod is to reduce back pressure. But I know you dont want to eliminate back px completely. I just got ordered a used muff off ebay ($19) and thats going to be my guinea pig.

So my question is what are most people doing to the muffler to wake this saw up? I would think you would want to match the muff opening to the exhaust port. And open up the exhaust guide plate some? My stock muff has internal baffling, but I think the ebay muff has matrix internals that came with earlier serial numbers on this Model

Any help would be appreciated. Here is the ebay muff

 

[ericm979]

Saw exhausts aren't just boxes with backpressure being the only tuning feature. They're just not traditional high performance ones with a head pipe, opening cone, belly, closing cone, tailpipe. A pipe that large would be in the way of normal saw operation. Reducing the space occuipied makes the exhaust less efficient but there's still negative and positive pressure waves reflected up the exhaust port. Just like there are computer models for high performance exhausts there's models for saw type exhausts. Some saw exhausts have short head pipes or baffles simulating head pipes inside the box to tune timing of the reflected pressure waves and will make less power with them removed.

I removed the cat on my 352 using a dremel tool. It's relatively easy though it killed a high speed steel rotary cutter. I recommend a carbide one. The dust is toxic. Don't breathe it. Make very sure there's no shavings left in there as they will end up in the engine. I did not open up any of the holes in the muffler. I figured I'd try it with the catcon gone first. There was not a big performance gain though it runs a little cooler. I'm happy with the performance as a brush cutting saw and I like that it's relatively quiet.

 

[ammoaddict]

I bought a 352 last year. It ran great but got very hot. I took the muffler off and drilled a few holes in the cat and peeled it out with needle nose pliers. I tached it before and after and best I remember it gained 5 or 600 rpm but I couldn't tell any real difference in how it cut, but it does run a lot cooler. It also takes a few seconds longer for it to warm up. I like it. It's a great little saw.

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[mountainlake]

If you muff modd right and tune good they will be at least 30% faster than stock. I've done a few. Steve

 

[ammoaddict]

Can you elaborate on your 30% gain muffler mod?

If you muff modd right and tune good they will be at least 30% faster than stock. I've done a few. Steve

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[mountainlake]

Can you elaborate on your 30% gain muffler mod?

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Have you pulled the limiter caps and tuned, most come lean and don't make much power running lean. You mentioned warm up , when adjusted right they very little or no warm up .. Steve

 

[ammoaddict]

Yes, pulled caps and tuned. Bear it mind, it was last winter when I did this and it took it a few seconds to warm up and run good. In hot weather it probably wouldn't be an issue. But I don't use saws in hot weather. Too many yellow jackets and copperheads around here.

Have you pulled the limiter caps and tuned, most come lean and don't make much power running lean. You mentioned warm up , when adjusted right they very little or no warm up .. Steve

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[svk]

We split the muffler and totally removed the cat however just gutting it works fine too.

I did a test cut before and after on the same log. 11 seconds before, 8 seconds after. So yes it’s a BIG difference.

 

[mountainlake]

Real close to 30% faster same as here, ammoaddict are you sure you have the high rich enough, these saws can sound rich when up against the rev limiter. I start way rich then gradually back in until they cut the best. Also besides getting rid of the cat you need to open up the deflector if you have done that. Steve

 

[ammoaddict]

I did not open the deflector that I remember. I think I did remove the spark screen
I didn't realize these saws had limited coils. What rpm are they limited to? I'm thinking I tuned it to 11,500 but I'm not certain. I will check it out again when cooler weather gets here.

Real close to 30% faster same as here, ammoaddict are you sure you have the high rich enough, these saws can sound rich when up against the rev limiter. I start way rich then gradually back in until they cut the best. Also besides getting rid of the cat you need to open up the deflector if you have done that. Steve

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[Charles Bale]

just for clarification, to tune the H on the carb, do you guys go way rich, then turn in the H screw till in runs clean (stops 4 stroking) in the cut?

going to open up that ebay muff I got coming, and pull the cat out. I will have two exhaust guide plates also, gunna dremmel one out just a little.

you guys see this?

https://www.arboristsite.com/community/threads/real-clean-echo-cs-352-with-decatted-muffler.317302/

 

[svk]

just for clarification, to tune the H on the carb, do you guys go way rich, then turn in the H screw till in runs clean (stops 4 stroking) in the cut?

going to open up that ebay muff I got coming, and pull the cat out. I will have two exhaust guide plates also, gunna dremmel one out just a little.

you guys see this?

https://www.arboristsite.com/community/threads/real-clean-echo-cs-352-with-decatted-muffler.317302/

That was my saw.

I forgot to mention, yes I pulled the deflector. If you hogged out the hole on the deflector but left the actual deflector intact it would probably quiet it down a bit but it’s unknown if it would impact the flow.

 

[sundance]

That was my saw.

I forgot to mention, yes I pulled the deflector. If you hogged out the hole on the deflector but left the actual deflector intact it would probably quiet it down a bit but it’s unknown if it would impact the flow.

Believe that's the one I bought from you. Still haven't really run it but seems to be solid.