I'm running a Corsa on my Formula and love the tone. I installed a high flow cat upstream at the same time as the Corsa exhaust thinking the noise level would be pretty tame but it's still a little on the loud side for my tastes. I'm also running mid length headers and aftermarket Y pipe. I really like the character of the sound, just a bit loud. Thinking of installing a pair of small bullet mufflers in the tailpipes coming out of the muffler but not sure how much this will affect the racket level.

Edit: I've also thought about a variable butterfly setup to restrict the exhaust at low throttle openings like the new 'vettes use. Not much info. out there on that idea.

Any other suggestions on how to tone the volume down a little?

 

The bullets will mellow it, deepen it, but I doubt they'll quiet it any.

Its going to probably take a different muffler to make an appreciable difference.

I'm actually quite surprised the corsa plus a cat isn't quiet enough for you. I'm anti-loud myself, but not quite to your extreme apparently.

 

The Corsa is really loud actually. I have it and its really quiet inside the car but really really loud outside. You might try going with a stock cat. It may quiet it up some. I wouldn't cut up my Corsa to put a bullet muffler in it. I have a bullet in my y-pipe but i'm not gonna put that crap in my Corsa. Hell when i get a cut out i'm gonna go stainless on it and not put that crappy stuff in my Corsa.

 

Thanks for the reply Chris. I definitely fall in there with you on the anti-loud part. The Corsa isn't really obnoxiously loud by any stretch. I just have a $2000 sound system I'm installing that sounds sweet and I don't want to lose the detail from fighting exhaust noise.

I'm not sure about why a small bullet muffler wouldn't clip the peaks off the exhaust pulses (through a little absorption) and drop the volume a little. They certainly help a little on volume compared to a straight pipe if you use them as a primary muffler. I definitely agree that it's not likely to make a really big difference, I'd guess I'm looking for about a 1/3 reduction in racket while cruising. I've used a lot of different performance mufflers, the Dynomax SuperTurbos are about the quietest I've seen. A little too quiet to be enjoyable. Even at WOT they don't put out much racket. Kind of want something that's quiet at cruise and part throttle but you can hear as you roll into the throttle to add to the sensation of speed. I guess a variable exhaust valve might be the single best way to get what I'm after. A **** in the dash that would let you adjust it on the fly for cruise and part throttle would be even better

Thanks for chiming in Chris,

Michael

 

I would probably install a bullet into the y-pipe and see if that tames it down. I definitely wouldn't chop up a Corsa catback though.

 

I have a bullet muffler in my y-pipe and it cleans up the sound but really doesn't make it any quieter. I think with my hi-flow cat on it really cut the sound down a lot. I'm going to go back to my high flow cat once i get my new cam installed.

 

Interesting, for awhile I was driving around with just long tube headers, off-road y-pipe, and the catback. I then had a pair of high-flow cats welded into the y-pipe and it didn't make a different at all in the loudness of the exhaust note, but it did clean it up a bit.

 

That is kind of shocking. I've had 3 cats on my car since i've had it and every time i install one it makes a hell of a big difference in sound. On both my old Borla and now on my Corsa. The bullet might of just barely quieted it down some but it really just cleaned it up and took some rasp away. It still doesn't sound anywhere near as good as it did with the cat.

 

In Alabama we dont have inspections, why would you NEED a cat on the car? I would install a round magnaflow muffler in place of the cat OR put some of those exhaust "cones" similar to what came in a SLP 2 OTL.


David

 

I agree, just put a high flow cat on there which should quiet it down a bunch. Or get yourself an XR1, that will definately quiet the car down. My friends 383 formula with ORY and XR1 sounds very quiet compared to the bullets.

 

Buy these Vortex Exhaust Cones from Marcin. That should do the trick nicely.

http://web.camaross.com/forums/showthread.php?t=500653

 

A twister Muffler in the I will quieten it down. I'm running MAc mids, carsound cats and the twister in the I of a Borla w/no ristrictor plate and it is no where as loud as cars w/out cats an no muff in the I.

 

I would take a look under the car and see if that Corsa is leaking anywhere. You'll see carbon. I've read more than once that the clamps tend to leak on these, even if the installation is done perfectly. Any leaks naturally would make it louder than it's supposed to be. If the carbon doesn't seal it up in a few weeks, then it seems like the best solution is to weld the thing together.

I know mine is leaking some, and I'm going to have it welded once the weather gets warmer. (I think mine is too loud, too, and I'm running a stock cat.)

 

Mine leaks too on the pass side where one of the pipes goes into the muffler. I've thought about getting it welded but i really hate to weld the damn thing together if i need to take the exhaust out.

 

The reason for running a cat is they tend to quieten things down and smooth out the raspy sound usually associated with a straight through type muffler. I've run a Borla system with and without a cat on a 383 with 4" tubing running back. To my ears it was so raspy it sounded like crap with no cat. It's not like you're throwing away 25 horsepower running a new high flow cat
A little of the noise could be leaks at the joints. About half of them I mig welded with stainless wire. The clamps definitely look leak prone. I replaced a couple of them with a much wider I.D./O.D. clamp that wraps around both sides of the joint but these could leak a little too. Haven't checked.
Thanks for the replies,

Michael