359 muffler mod

[NORTHERN NYer]

Here is a pic of the muffler mod I did on my 359 with the cat muffler. I have learned alot researching old threads and learning the whole process from the muffler mod all the way to removing limiters and readjusting the carb. What a difference just this alone made, I would love to get my my hands on one thats had a full mod. Thanks to all for sharing your wealth of knowledge.
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[Hack]

That's sweet! You weld that extension on?

 

[Lakeside53]

It looks real good... The only problem you may run into is setting logs on fire when cutting big wood - the exhaust at full power can really burn the bark quick, so be careful in dry conditions.

You might consider welding a deflector in front of the muffler. Best to have everything set back from the front of the saw though.

Did you remove the Cat or leave it inside? If you left it , the exhaust gases are super hot..

 

[Urbicide]

Nice looking mod. It looks very clean. What size pipe is that? Did you remove the catalyst bar? I'm hoping to do my 359 here shortly.
Take care
Vince

 

[pbtree]

Looks very good!

Any photos of the work in progress?

 

[Four Paws]

What do the insides of the catalytic convertor mufflers look like? Do they have that 'brick' in there like automotive catalytic convertors have? Catalytic convertors are very restrictive, just wonder how bad they have these saws choked up?!

 

[NORTHERN NYer]

That's sweet! You weld that extension on?

Yupp I tig welded it on. Its actually a 1/2" npt pipe cap with a 5/8 hole drilled in the closed end of of it. I took the screen out of the top exhaust opening, cut it so it fit nicely under the pipe cap and welded the cap on.

 

[314epw]

Good looking job! Did you set the engine up with a tach?Mine was running 14200 when done had to back her down(richen) I have to check her again, because after a couple of tank fulls shes sceaming again.
Ed

 

[NORTHERN NYer]

Wish I had taken pics of the inside of the muffler and the progress of the mod now. Not too famliar with the cats, and this is the first saw muffler I have actually taken off to look at, so I am not really sure what they are calling the cat. Looking from the exhaust opening in the back there is a "waffled" wall plate that seperates the 2 halves of the muffler with a bunch of tiny holes through it maybe 1/8". I drilled my 5/8" hole straight through this in the center. At the bottom of the plate there is a tube that runs to the top of the muffler for the original exhaust. And of course You have the 2 pipes that run on both sides for the mounting bolts. So pretty much The only place to put a hole was in the center.
From the front I found where I wanted my hole and drilled straight through. Now on the inside tight to the front cover there was another bar or plate, I think it was about the width of the ridges on the front of the muffler. Im not sure what purpose this serves. I drilled through this also. Then welded my pipe cap over the screen and hole. So what is supposed to be the cat? I am unsure, can anyone help?
Sorry if any of this is confusing pics would have definetly been easier to explain.

 

[buck futter]

The waffle is the cat. the way it works is the coating has a chemical reaction. Husky says not to scratch or cut the cat material because it is carcinogenic. I definately wouldn't want to make a living cutting them out but I can't imagine one or two would hurt.

buck

 

[NORTHERN NYer]

314epw, no I havent set it up on a tach. I been looking for one, I have a few buddies that do small engine stuff but none of them have one. I see you can get one fairly reasonable now a days. anyone have any suggestions on which one? I did have to back it down a bit, actually a bit more than the limiters allowed so I had to get rid of them.
Thanks to all for the compliments.