Improving the flow of a stock muffler

i opened up a muffler today and i was playing, could i ream out the holes to a larger size (in the baffles) and possibly remove the crimper edges to improve the flow, so it ias not as restrictive, or should i just open up the crimps (im thinking cutting them off and tapering the pipe to get smaller as i have allready removed one

can ne1 offer me some tips?


photos are coming tomorrow

Adam_C wrote:can ne1 offer me some tips?

I think so...

Get a vacuum cleaner, some gaffer tape, various bits of tubing, some rulers, some coloured water etc. and make up a manometer to allow you to measure the pressure drop as the vacuum cleaner tries to suck air through the muffler. (OK, i'm summarising here, but you're setting up a flow bench).

Benchmark the standard muffler, then start the modifications, measuring after each one.

Chances are you'll be mighty surprised at what works and what doesn't. As some of the changes will be irreversible but negative, count on going through several mufflers to get an optimised result. Do what you can with putty and cardboard instead of cutting.

Good luck.

i would be interested in the results please post them after its all done
cheers brenton :thumb

so did the vacuum cleaner get a workout, what was your finding ??

ive got a better way!!! chop it off!!! :thumb

Adam if this is for the 1200 engine... Go see Lee at Volkshaven hes got some origional Sonic headers you just have to find a muffler.

Or if your just playing around then have fun i know one thing it will be louder...

didnt setup the flow bench, but i am just plying around, gona break out the oxe and weld it up soon, then see how it goes..... if its louder and sounds better i miught just leve it on.

sonic headers dave?, what are these? are they worth my while and what kinda muffler do they use (Ie can i stick any modern muffler on there)

Sonic extractors were the thing back in the late 60's & 70s... I had a set on one of My beetles.. they were locally made..
mufflers were very heavy duty.. never wore out.... and chrome plated...
and the muffler just clamps on, so any muffler with a similar inlet pipe size would do... l
Lee

Yeah there good ive got one on my Orange Smoothie... it was S/H when i fitted it.

Yes you can fit a later type muffler to the headers.