Anyone else gut their factory muffler?

[cabmandone]

I'm using my brothers thread SC, Carrera Bischoff Muffler Modification, Mod, Gut, Gutting, Dual, Two Out to begin the process of gutting my own muffler.

I'm thinking of increasing the outlet size and going with a single out rather than two. I know, I could go out and buy a muffler but I've got a spare stock muffler and I thought it would be fun to see what kind of sound I can make from it. Has anyone else played around and gutted a stock muffler?

I want some good low end growl rather than what I think is now more of a hum. My high end sounds nice. I think it has more growl at the high end because I have a cat delete pipe but I'd like a little more rumble from the idle range up to 3,000 range.

My stock muffler is the same design as the one my brother had. I'll post pics of mine when I get a chance.

I don't know if increasing the outlet will help with sound or not so I'm looking for ideas. And if anyone has pics or better yet sound clips from their gutted muffler that would be great.

[Arne2]

Can't say from experience with Porsche mufflers, but generally a larger outlet equals a little louder exhaust.

[JAR0023]

Go for it.

Don't have any sound clips but my 86 had a gutted muffler when I purchased it along with the large stainless tip. With the cat installed it wasn't that loud. My wife even commented she thought there would be more sound from a Porsche. I would have never guessed it was modded. When I installed a gutted cat...whoo boy. It was loud. Basically two large echo chambers. I have a good friend that lives about a mile away across the woods. He could hear me crank my car in my driveway. Think T-Rex gargling rocks loud. I don't know what mods were made just that the top half was cut away to make the mods.

That was way too much. I swapped in a pre-muffler and that tames the sound a good bit at low RPMs but it still wailed up top. Never really sounded that loud inside the car, no drone ever with the single out. One thing that helped (I think) was the larger tip that pointed stock style down and back. Pointing the sound down tamed the higher pitched sound and left a low deep rumble. Riding by bridges etc and the sound echoed back much louder. Even a low curb would throw the sound up. Easy enough to sneak through the neighborhood without pissing my neighbors off. Still up top had a nice snarl but not as smooth sounding as what people describe as the "flat six" sound.

Currently running a pre-muffler and a Monty 1 in/1 out. Same deep rumble at idle, much smoother and quieter sound at higher RPMs. While I like the Monty (wife and friend love the Monty sound) there are times I think about going back to the gutted Bischoff. -J

[cabmandone]

My brother thinks I'm nuts. He just installed his 3.2 rebuild with headers and a B&B muffler (if you want to call it that). It rumbles and it's loud. I like it, he thinks it too loud. He is getting old though

I figure the worst case is, I'll hate it and put the factory muffler on my car now back on.

[weseeeee]

I gutted one and made it a dual outlet. I run headers and it screams at higher rpm's! It's fun for a while but I keep a dual inlet single outlet around and switch them about once a year.

[cabmandone]

Originally Posted by weseeeee

I gutted one and made it a dual outlet. I run headers and it screams at higher rpm's! It's fun for a while but I keep a dual inlet single outlet around and switch them about once a year.

How much of the piping did you remove when you gutted yours? I'm looking for suggestions to go with my larger outlet idea.

[kenikh]

Here ya go:

[RichardNew]

I just added the Rallye tips. I didn't gut the muffler. It does seem a little louder though.



Richard Newton
Repairing Your Gauges

[cabmandone]

I was going over all the posts in the link above and found the pic below. WOW that one could get quite noisy I'd think. It appears they dumped everything in the center chamber which is what I'm thinking. I'm thinking of cutting and capping the exhaust in tube on the right chamber and then drilling holes in the center chamber exhaust in tube on both sides of the baffle. Adding a 2.5 or larger outlet pipe with tip.

[weseeeee]

Cabmando, we cut the muffler in half and took nearly every thing out of it. Then we welded the two pieces back together. Wish I would have taken pics. It is kind of loud and there is a drone that gets to me after a while, but it's so easy to change back to my other muffler that I keep it around for when I want to hear the old flat six scream!

[cabmandone]

Originally Posted by weseeeee

Cabmando, we cut the muffler in half and took nearly every thing out of it. Then we welded the two pieces back together. Wish I would have taken pics. It is kind of loud and there is a drone that gets to me after a while, but it's so easy to change back to my other muffler that I keep it around for when I want to hear the old flat six scream!

I have mine cut in half but I'm stuck on just how much to take out. I will be keeping my original muffler if the gutted one turns out to be crazy loud. I'm not sure I want to remove everything but thanks for the tip.

[gregk1]

this is what I did to my two in and one out stock muffler
had to add one short tube to make the tubes all even for good flow
needed to remove some fiberglass packing in the ends
routed the tubes to the center of the muffler and out it fits around the valance so no cutting of the bumper or valance is needed sounds great not loud at all
the sketch is rough but shows the flow thru the tubes and out

[cabmandone]

So here's where I'm at now.

I removed the tailpiece from the muffler and had a 2.5' tailpiece bent at a local shop. I ordered a 2.5 inlet to 3 outlet tip for the end. I'm contemplating taking a small (thinking 1.25") tube from the lower exhaust inlet tube where it's capped and bending it up and into the exhaust outlet tube. I have some friends with heavy conduit benders that I think can bend the tube or I might cut and weld a U tube to do the job. I figure that should give me some good sound.
If anyone reads this and thinks I'm doing wrong with the U tube, let me know.

[cabmandone]

Something I'm concerned with is taking away too much back pressure. It is my understanding that the engine needs a certain amount of back pressure for low end torque. Is this correct?

[SCWDP911]

A few years back, I didn't just gut mine, but also sectioned it and the end result was about 10 lbs and most that heard it liked it. In the end though, nothing sounds as good as an M&K (IMHO). I am embedding a link to a couple of sound clips from the "first fire". Search my name and you can see more on what was done.

https://www.youtube.com/watch?v=w5slCoyF3Is

https://www.youtube.com/watch?v=K5TFfkW6zA0

[afterburn 549]

The BEST thing to do is get rid of it.
It is mounted in the Worst Possible location.
I have had no dyno loss with a cut dwn muffler of my choice located along side the engine.

[Trackrash]

Originally Posted by afterburn 549

The BEST thing to do is get rid of it.
It is mounted in the Worst Possible location.
I have had no dyno loss with a cut dwn muffler of my choice located along side the engine.

Pics?

[afterburn 549]

Shortened a 30 dollar muffler.(once)
Next time found one ready made at Advance.
both mounted (with some fabrication left side along valve cover.
Weighs a BUNCH less and not behind rear wheels!

[tazzieman]

Ain't gut mine anymore, just a Monty

[cabmandone]

Originally Posted by SCWDP911

A few years back, I didn't just gut mine, but also sectioned it and the end result was about 10 lbs and most that heard it liked it. In the end though, nothing sounds as good as an M&K (IMHO). I am embedding a link to a couple of sound clips from the "first fire". Search my name and you can see more on what was done.

https://www.youtube.com/watch?v=w5slCoyF3Is

https://www.youtube.com/watch?v=K5TFfkW6zA0

Shane,
Your garage video isn't coming up for some reason. The road clip sounded nice. I'm going to do some searching on your name today and see what I find.
Did you have a cat delete on your car? I don't recall seeing your configuration in the thread.

Originally Posted by afterburn 549

Shortened a 30 dollar muffler.(once)
Next time found one ready made at Advance.
both mounted (with some fabrication left side along valve cover.
Weighs a BUNCH less and not behind rear wheels!

AB,
So you must have removed the cat and installed directly to the 2 pipes the cat attaches to right? That's an interesting idea I might have to play around with. I simple cherrybomb (oh man that would be loud) in place of the cat.