What is the quietest Performance Muffler

[Marauder]

I have the Kooks 1-7/8 LT headers, Kooks resonators where the cats used to reside and the complete Corsa exhaust and she's just too loud when I get on it. I was kicking around installing the stock mufflers but I don't want to suffer a 20HP penalty as some say will occur.

With the TVS1900 currently installed and the cam swap to occur next week she will be pushing some decent horsepower but I want to be stealthy like a CTS-V.

Any recommendations?

[LDM]

Maybe GXP mufflers? Not as restrictive as the GT ones, but still quieter than the Corsa.

Edit: GXP mufflers may not be quieter than Corsas, so disregard the above

[cynic783]

subscribed :watch:

[1meand]

The GXP mufflers with headers was way louder than magnaflow mufflers for me. I would think stock mufflers are the only way you will be quiet/stealthy. The perfect solution would be the stock axleback with cutouts in/on the axleback. If Wortec would just sell their bi-mode exhaust in axleback form.

[G8 GT V8]

Maybe GXP mufflers? Not as restrictive as the GT ones, but still quieter than the Corsa.


At WOT, the GXP mufflers are just as loud, if not louder than the Corsas from my experience comparing exhaust systems at the drag strip.

[G8 GT V8]

Stock GT axlebacks are the best deal out there for your needs. Fairly cheap to pick up a set, sound good, no drone, and still flow pretty darn good.

[LDM]

At WOT, the GXP mufflers are just as loud, if not louder than the Corsas from my experience comparing exhaust systems at the drag strip.

I take back what I said then. :) I think I was mixed up thinking of people with the complete Kooks system swapping the mufflers to the GXPs to quiet things down, not the Kooks/Corsa system.

[Slizzo]

I have the Kooks 1-7/8 LT headers, Kooks resonators where the cats used to reside and the complete Corsa exhaust and she's just too loud when I get on it. I was kicking around installing the stock mufflers but I don't want to suffer a 20HP penalty as some say will occur.

With the TVS1900 currently installed and the cam swap to occur next week she will be pushing some decent horsepower but I want to be stealthy like a CTS-V.

Any recommendations?

Judging by your signature, I'd say you would lose, 5HP MAX from having the stock cans on over a high-flow muffler. At higher HP levels you'll lose a little more, but I haven't seen anyone say 20HP loss for just the GT mufflers.

[G8 GT V8]

I take back what I said then. :) I think I was mixed up thinking of people with the complete Kooks system swapping the mufflers to the GXPs to quiet things down, not the Kooks/Corsa system.
I totally understand. Just didn't want him to go buy the GXPs and be disappointed by how loud they are. :(

[Executor999]

Based on my experience, I would say both SLP PowerFlos and Dynomax Super Turbos tie as the quietest performance mufflers. Out of those two, the SLP PowerFlos drone the least. In fact they probably don't drone at all but even these two mufflers were too loud for me and I went back to stock GT mufflers.

[todds87ss]

I have the Kooks 1-7/8 LT headers, Kooks resonators where the cats used to reside and the complete Corsa exhaust and she's just too loud when I get on it. I was kicking around installing the stock mufflers but I don't want to suffer a 20HP penalty as some say will occur.

With the TVS1900 currently installed and the cam swap to occur next week she will be pushing some decent horsepower but I want to be stealthy like a CTS-V.

Any recommendations?

I have a set of modified stock muffs. No drone. Max flow ( only slightly restricted due to internal piping being 2inch). Sounds almost stock at idle, slightly louder than stock. A little more sound as you press the fun pedal. I am looking for more noise. I'd be happy to trade you.

[Marauder]

I have a set of modified stock muffs. No drone. Max flow ( only slightly restricted due to internal piping being 2inch). Sounds almost stock at idle, slightly louder than stock. A little more sound as you press the fun pedal. I am looking for more noise. I'd be happy to trade you.

I may be interested is trading. How did you modify them? I beleive that the Corsa's are not attached in the same manner as the stock mufflers though as I have the complete Corsa exhaust.

[todds87ss]

15785

After cutting open the muff, I removed all of the fiberglass from inside, then "t'd" a 2 inch pipe from inlet to outlet. Then welded them back up.

[jcmGT]

for the science part, the back of the envelope number is 2.2CFM/HP in flow. Some suppliers will give flow in CFM and then you can get the sound attenuation in db to make your pick. You will have to pick as more flow = less attenuation.

Read about it here (http://www.superchevy.com/technical/engines_drivetrain/exhaust/0505phr_exh/viewall.html)

[blkscooby]

I have an x-pipe, mid muff removed, kept resonators and Dynomax super turbos. It is perfect tone IMO. No drone, but you can hear the DOD kick in. Quiet in the car although you can hear the exhaust (which I wanted) but I've been told it sounds awesome outside when I get on it. I will be removing the cats soon too.

[todds87ss]

finally have audio of the frankenMuffler.

http://s452.photobucket.com/albums/qq245/todds87ss/?action=view&current=20110913_000034.mp4

[G8 GT V8]

I like it. Sounds similar to my GXPs...were these the GTs that you opened up and removed some innards from?

[todds87ss]

yes.
The only thing is, they are still too quiet from inside the car. I'd like to get more bark, and the only way I can see is larger diameter pipe. Still working on it. The only way I'm going back inside of those muffs is if I can find a new brain...Abby something...

[tempo8]

GXP mufflers and some high flow cats!

[G8-4-Speed]

If you could get a muffler where the x-pipe is on the mid-pipe, it would be very quiet. Possibly a 4" single muffler. I had a 4" muffler in the x-pipe location and it was quiet WOT. I almost think it was quieter WOT than cruising. Flowmaster hushpower mufflers are also excellent and be quiet.

[ULTRA Z]

The GT mufflers only cost 20rwhp on a all motor car at the 480rwhp mark. I'm probably gonna go back the the Dynomax VT mufflers

[TonyKarter]

And it is frankensteen!!!

[AVIDMOTION]

My 3 inch X pipe right behind the cats on the Kooks completely cut the noise in half and got rid of all drone.

[ULTRA Z]

I got a 3" X Muffler I have been thinking about putting in the place of my X pipe but not sure yet