Going from a non resonated mid pipe...to a res. mid pipe.
 

Up until a couple days ago I was running a SR stage II single setup with a 3"dp, mid pipe and apexi N1 dual tip. To say the least it was realy loud without the silencers installed. Like get me arrested loud. :D With the silencers installed, it was still pretty loud. Not get me arrested loud...but still to loud.

At work I have all the materials and tools to do all sorts of fabrication and stuff. So I decided to make my own resonated mid pipe at work. (And get paid for it!) I began by taking our plasma torch and cutting hunderds of little 1/16" to 1/8" holes in a 14" section of my mid pipe. Then cut a 4 1/2" peice of steel pipe in two peices. Then putting it around the mid pipe, and welded it back together. After that I welded up one end of the resonator solid to the mid pipe. The next step was to pack the empty chamber with steel wool. (I tried finding SS wool, but was unable localy.) I packed it in realy tight using a steel rod to poke, cram, squeeze and ram it toward the bottom. After it was full, I welded the remaining end back together. Ground down the welds a little bit (Just to make it look a little cleaner.) and installed it. I'll be honest....I was'nt realy expecting much of a noise difference. But I was realy surpised! It was like a night and day difference. I've only put 30 or so miles on it, but so far I feel like this is one mod I should have did earlier. It sounds so much smoother and quiter. Finally a exhaust tone I like!

Some people think that steel wool will burn out after a period of time. Even if it lasts 2 years. (4k miles for me.) I'll be completely happy with this. The way I look at it is that some exhaust shops suggested fiberglass! Steel wool should last longer than fiberglass anyday. From time to time I'll reply back to tell you guys if the noise is getting louder or not. So far, I'm realy happy with it. :) CJ

yep, thats why racing beat banks on selling those things!

I've done a similar thing, but I didn't make the resonator myself. I went to a store called Princess Auto, I don't think it's in the states as well, but it's basically a large Auto and Farm supply warehouse that stocks returns and overstocks. They usually have tones of empty resonators in various sizes basically for tones of custom applications - various farm tractors, deisel trucks, etc.
I cut the end off, stuffed the outer chamber with steel wool fairly snug. So in the end, I spent $10 on the resonator, $5 on steel wool, and got a decent unit. Doesn't look all flashy, but it's under the car and built strong.

This is a great idea. I might have to try this with normal glasspacks, just by cutting the ends off them and removing the glass and repacking with steel wool, then welding the tops back on. :)

Just make sure the glasspack center is straight through smooth. I mean, there are no louvers incorperated in the drill holes to help pull air into the packing chamber. You want smooth holes.

RX7store.net uses a magnaflow 3in inlet/outlet turbo muffler for their resonated midpipe, you can buy one of those mufflers for like $70-$90. Probably would flow better and handle the flames better than steel wool.

go get a brillow pad and put a match to it, guess what it burns!

my favorite is taking strands of steel wool and putting it over the posts of a 6v lantern battery.

nice, but agreed that buying the dynamax muffler does make it easier. I have the RX7 store Res. MP and it nice.

But Ive come full circle and now want a Hi Flow Cat.