My weirdly successful attempt at dual out muffler mod

[WonkoTheSane]

So, here is a quick picture of what my muffler looked like when first opened, and then after a bit of work on it. Along with a colored drawing if what I did inside.

The red is the main entry, capped off, and perforated with 1/2" holes.

The blue is where a added in pipe was installed where the green outline of a added in plate is to create a 4th chamber.

The yellow is a corner piece of the green plate was removed for fitment around the gas entry pipe, and also for a exhaust gas pathway.

The teal blue(?) color will be the exit tips.

Orange is original exit plug

Brown arrows are the flow path, hopefully...


Interior noise is very nice, but outside has a nice idle low rumble hinting it's not stock, with that classic high rpm rasp.

I was first worried it was going to be too loud and need insulation added into the end chambers, but after now hearing it from outside the car, I'm just absolutely chuffed with how the noise and volume level is.

I did have to remove my rubber bumperettes and the lower trim to fit it. Will figure something out later for that. Want to eventually just replace both bumpers to begin with glass pieces, so might just run with it as seen for a while.









https://youtu.be/P4xsSpvgCkE

[Uwon]

Originally Posted by WonkoTheSane

So, here is a quick picture of what my muffler looked like when first opened, and then after a bit of work on it. Along with a colored drawing if what I did inside.

The red is the main entry, capped off, and perforated with 1/2" holes.

The blue is where a added in pipe was installed where the green outline of a added in plate is to create a 4th chamber.

The yellow is a corner piece of the green plate was removed for fitment around the gas entry pipe, and also for a exhaust gas pathway.

The teal blue(?) color will be the exit tips.

Orange is original exit plug

Brown arrows are the flow path, hopefully...


Interior noise is very nice, but outside has a nice idle low rumble hinting it's not stock, with that classic high rpm rasp.

I was first worried it was going to be too loud and need insulation added into the end chambers, but after now hearing it from outside the car, I'm just absolutely chuffed with how the noise and volume level is.

I did have to remove my rubber bumperettes and the lower trim to fit it. Will figure something out later for that. Want to eventually just replace both bumpers to begin with glass pieces, so might just run with it as seen for a while.








Am not sure what code tags are need to make this show as the YouTube video it is, but here is a sample of how the exhaust sounds

https://youtu.be/P4xsSpvgCkE

Nice surgical operation on the muffler. Great sound!
Johan

[NY65912]

Sounds wonderful

[WonkoTheSane]

My welding skills may be a bit lacking, was the first time I touched a welder in about 6 years. Had a miserable of a time spacing the gap of the two shell halfs. When it finally separated open, the top shell half relieved itself into an odd shape, making the need for ratchet straps to try and hold it all back together while I tacked it. Still was left a very big gap in some spots that had to be carefully bridged in with weld. That thin muffler skin sure likes to easily just melt away too.

But, with a little persistence, and some ugly welds it finally managed to come all together. Feel I really lucked out on the two exit tips coming out pretty much bang on centered and level.

Despite the ugly welds, I'm still more than pleased by the outcome.

[Uwon]

Just let the welds age. Nobody will know the difference anyway.
Again, great sound on the video. Have you got any rpm’s with droning or other unwanted sounds?
Johan

[WonkoTheSane]

Originally Posted by Uwon

Just let the welds age. Nobody will know the difference anyway.
Again, great sound on the video. Have you got any rpm’s with droning or other unwanted sounds?
Johan

I had about a 70 mile drive home from the shop when I finished it up. Honestly didn't notice a single bit of drone at any RPM. In fact I was actually worried at first that the muffler was too quiet with how it sounded from inside the car.

[Black 993]

Great stuff. Sounds fantastic.

[Bill Douglas]

Excellent.

And good welding skills getting it back together.

[Gretz]

Great job. This is really interesting to me. I've listened to (and owned) a number of single in / single out mufflers and none sounded how I wanted. Back at Luft 2019 I heard one that sounded great. I approached the owner and he said he used the Dynomax 17676 and had a shop custom create the routing. So I did the same. I just wish it were dual outlet as yours has been modded to be. I guess I need to learn to weld!