e-tech 353 muffler mod ok?

[MikeD]

searched long and hard for info on this, but found nothing so I'm adding yet another post about a muffler mod - apologies in advance

can you mod an E-Tech muffler? if so, are there any instructions (pics would be great too!) on this site that someone can point me to?

looks like either two 1/2" or 5/8" holes are the recommended size for the non catalytic 353 models.

I went out and took the muffler off and peered inside. there is a plate mounted at the seam line with small holes drilled in in that allow gas to pass from the exhaust port side to the forward side of the muffler. on the bottom of the exhaust side is a tube that seems to pass thru the plate to the other side and then loop back to the exhaust side and connect to the port in the top. looks like a ton of heat gets gathered in there for the catalytic process...

thats what I know -- did I mention that it's a royal PITA to get the muffler back on while trying to keep a spacer and a heat shield all lined up?

If I had to guess I'd say that whatever holes get drilled on the outside, either 1/2 or 5/8's, then the same holes need to be drilled on the baffle plate too.

 

[Heilman181]

I am new to this too, but want to throw out the idea of putting a Non-Cat muffler on.

Would a non-cat muffler be much of an improvement over the stock cat muffler? How much carb adjusting would be required just changing from a cat to non-cat muffler?

Thanks!

 

[MikeD]

I've seen the ~$39 muffler noted with PN on this site, but my understanding was that even with the new non cat muffler that it still needed to be mod'd to come alive. reel me back in if'n I'm wrong on this...

with the cat muffler you could probably drill a monster hole in the baffle plate at least as big as the exhaust port, and then two 1/2" holes on the exterior of the muffler

 

[lawmart]

mike there are 3 post dealing with the same thing right now, i am in the same boat that you are in , as miked has stated i think that baffle and the exhaust tube should be removed to allow proper air flow out of the muffler. thats what i did on my 371 i did most of that through th intake hole of the muffler but it was allot bigger on the 371. the 353 is to small, hence me trying to slit mine down the seam.

Lawmart

 

[MikeD]

lawmart, saw your other post on the same subject - where is the 3rd thread?

if the muffler won't come apart after being cut in 1/2 then the only thing to do would be to grind out as much of the baffle as possible and drill the exposed side. have any pictures of the muffler after it's been cut in 1/2?

here is lawmart's other post

 

[rahtreelimbs]

Just about any muffler can be modded. Just be sure to de-burr all you freshly cut edeges!

 

[MikeD]

You know, as a former racer/tuner of two stroke bikes I'm surprised that there is no tuned pipe in the exhaust -- its pretty much just a straight thru pipe.

It would seem like some sort of small tuned pipe that provided a back pressure pulse and would be able to fit in that space would be better than just an open box. Has no one ever put a small tuned pipe like that together before? I know the hot saws use a larger tuned pipe, but a small tuned pipe that would still keep the stock appearance would be interesting to see.

 

[scottr]

unique muffler

MikeD , if you go to the 'Ok lets talk tech' thread and then go to the top of page 4 , you'll see Manges' picture of a HVA MS90 muffler that you were discribing .

 

[brent denny]

I have a european muffler (no converter, baffle, or screen) on the way for my 353. I will let everyone know how it works out next week.