Muffler choice

[NateDN10]

I have a Magnaflow exhaust on the Cobalt in my signature. Over the last year the resonator has developed an internal rattle. I don't have the proper paperwork for a warranty replacement, so I'm going to have to buy a replacement and have an exhaust shop weld it in. Now I'm trying to decide what the replacement should be. I'm looking for the quietest alternative.

1) The part Magnaflow tech recommended is 4" in diameter with a 2" diameter core, and 14" long (132 in^3 of sound absorbing material).

2) I could also get one that's 5" in diameter, 2.5" core, 14" long (206 in^3 of material).

3) The final option is 4" diameter, 2.5" core, 18" long (138 in^3 of material).

Would #2, which has the most material, be the quietest? Would the 2" core in #1 make a difference? Would the extra length of #3 make a difference? Is there any way to know?

Thanks!

 

[dparm]

More volume (bigger muffler) = quieter. The "race" series is straight-through and very noisy.

Not sure what the rest of the exhaust system looks like, but make sure you've got the biggest middle muffler/resonator you can fit. That cuts down on cold-start raspiness and drone.

 

[NateDN10]

This is the exhaust system.

 

[dparm]

That thing will be loud. The middle muffler is very small and the main muffler is small too.

 

[NateDN10]

Well, I've had it on my car for the last 30K miles, and while it's louder than I'd like, it's not so bad.

I installed it in college, partly for the looks, partly because it was a fun project. I don't plan on doing it on any future cars.

Anyhow, it's the middle muffler that's rattling and will be replaced. Based on your earlier comment, I'll probably go with option 2 above, since it's the biggest that will fit.

 

[beast3300]

I don't know if it is any cheaper but ZZP has some resonators for your car.

link

 

[NYSteve]

Why don't you get a junkyard stock exhaust and put that in?

 

[NateDN10]

Originally Posted By: beast3300
I don't know if it is any cheaper but ZZP has some resonators for your car.

Thanks. Amazon has the 12865 for $77 w/free shipping.

Originally Posted By: NYSteve
Why don't you get a junkyard stock exhaust and put that in?

I don't mind the exhaust system as it is. It's really not that bad. The only reason I'm doing anything to it is because the resonator is rattling. I don't want to replace the whole thing.

 

[mechtech2]

Get the large internal diameter one for flow.
Get the longest that will fit for best sound attenuation.

Note that when the old one is off, it may be a simple weld fix of a baffle plate .
Just an option that I would not overlook.

 

[dailydriver]

Originally Posted By: mechtech2
Get the large internal diameter one for flow.
Get the longest that will fit for best sound attenuation.

Note that when the old one is off, it may be a simple weld fix of a baffle plate .
Just an option that I would not overlook.


^^^^THIS.

BTW; Even though I doubt you paid the full suggested list, almost $900.00 for a 409 stainless system seems waaayyyy too steep for my tastes. (That even seems high for a completely 304 system for that car!!)

 

[SteveSRT8]

magnaflow is not well respected in many circles due to the low quality stainless steel they use.

any competent exhaust guy should be able to weld that up if the problem is as you say...

 

[NateDN10]

Originally Posted By: mechtech2
Note that when the old one is off, it may be a simple weld fix of a baffle plate .
Just an option that I would not overlook.

Thanks.

Originally Posted By: dailydriver
BTW; Even though I doubt you paid the full suggested list, almost $900.00 for a 409 stainless system seems waaayyyy too steep for my tastes. (That even seems high for a completely 304 system for that car!!)

Yeah, I paid $440 for it. Like I said, I wouldn't do it again.

 

[rjundi]

I just sold a 2004 WRX with factory exhaust in New England. There was barely any rust on it.

My vote is stick with the factory exhaust which someone is likely selling for nothing.

Aftermarket stuff "performance" stuff usually does not last since most owners don't keep the vehicles anyway.

 

[morris]

years and years ago would build my whole ex system from scratch ,i built about 5 total. now that iam older i know i wasted time and money.

 

[SteveSRT8]

Originally Posted By: rjundi
I just sold a 2004 WRX with factory exhaust in New England. There was barely any rust on it.

My vote is stick with the factory exhaust which someone is likely selling for nothing.

Aftermarket stuff "performance" stuff usually does not last since most owners don't keep the vehicles anyway.


Many times all an aftermarket exhaust gives you is noise. It's extremely rare to get any meaningful power out of it, and even if you do it's at high revs and at the expense of a loss of torque at the bottom of the rev range where you really need it.

 

[hardcore302]

Walker Quiet flow has the performance you are looking for, but without the noise.

Have you considered a Pypes M-80 as a resonator?