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View Full Version : New Exhaust Too Noisy- Ideas to Fix it?



cp308
05-18-2004, 11:39 PM
I just got my exhaust system done. Im running ported exhaust manifolds into 2-1/4 SCP down tubes with cats in to a dual 2-1/2 in, single 3 out, 18 long Magnaflow resonator. From there 3 pipe back to a Flowmaster Y into 2-1/2 pipes back to Dynomax super turbo mufflers in the stock locations. Im very happy with the performance, but the sound is a problem.

I went with this setup because I wanted a nice compromise between quiet and flow. Everything I read said to keep the cats and go with a 18 Magnaflow resonator and dual turbo style mufflers. But now when the engine is under load and between about 1500 and 3000 RPM I get a constant low frequency tone (the dreaded drone?). I suspect (but canr really say at this point) that the sound is coming mostly from the resonator up through the floor of the car. I would really like to be able to enjoy my stereo again, but I have been annoyed by this sound ever since the exhaust system went in a couple weeks ago.

Does have any ideas about how to minimize this sound (short of putting the stock exhaust system back in, (which of course aint gonna happen)? Is there some kind of high temp acoustic blanket / wrap I can put around the exhaust components, or blanket on the passenger compartment floor or something?

scbird1
05-19-2004, 01:11 AM
Mine did this too but after a while it went away. Break in I guess.

j rick kirby
05-19-2004, 08:06 AM
I've got virtually the same set up w/ no symptoms you describe.I did however have a problem after initial install w/ my mid pipe rubbing that flimsy cross brace and vibrating so I bent it a little and that stopped that.Check that cross brace.

cp308
05-19-2004, 09:36 AM
Thanks, I'll check the brace. I looked at the system while it was up on the lift after it was installed, and didn't see any rubbing, but who knows, something could have shifted I guess.

Regarding the break-in, I have noticed that sometimes it seems to be much worse than others. Usually when everthing is still cold, it is not to loud, but after warming up, then it seems to be much worse.

BlackbirdSC
05-19-2004, 04:03 PM
B-Quiet Extreme (http://www.b-quiet.com/extreme.html)

Take out the seats, lift up the carpet and cover the floor with a couple layers of this stuff. If you think it's loud with those muffs, there's not a thing you'll do to make it as quiet as stock without adding more sound deadener.

92silverlx
05-19-2004, 04:18 PM
tell ya wut i'll trade ya my stock exhaust for yours LOL!

XxSlowpokexX
05-19-2004, 06:59 PM
Thats about as quiet an exhaust youre going to get..Perhaps you are vibrating somewhere???

cp308
05-20-2004, 10:11 AM
Thats about as quiet an exhaust youre going to get..Perhaps you are vibrating somewhere???

My headliner is out at the moment- and it does vibrate some- this could easily be contributing to the noise. I'm going to attach some stick on vibration dampening material the the sheet metal and see how that goes.

If there is enough room between the head liner and the roof, maybe I can put some acoustic foam in there or something.

j rick kirby
05-20-2004, 10:32 AM
You didn't mention you are riding around in an empty oil drum.Why don't you put in a headliner?When you yell does it echo?

MartianBob
05-20-2004, 02:36 PM
I've tinkered with my exhaust a few times. Each time I wasn't happy with it right after it was done. But each time it did sound much better after about a month. I put about 50 miles on the car each day.
It will get better.

Cheers
Bob

cp308
05-20-2004, 03:08 PM
You didn't mention you are riding around in an empty oil drum.Why don't you put in a headliner?When you yell does it echo?

No, it doesn't echo. I removed it because it had a bunch of rips in the cloth cover. I plan to clean it up and re-cover it. I can't really see it making much difference for low frequencies, though. It's just a very thin cardboard like molding with a layer of thin cloth over it. I think it will help once I get the vibration dampening sheets installed on the sheet metal. Maybe I can fill the space between the headliner and the roof / dampening sheets with dacron stuffing or some kind of foam.

cp308
05-20-2004, 03:11 PM
I've tinkered with my exhaust a few times. Each time I wasn't happy with it right after it was done. But each time it did sound much better after about a month. I put about 50 miles on the car each day.
It will get better.

Cheers
Bob


This is interesting, You are the second person who has described what seems like a breaking in effect. I wonder if it is really better, or people just get used to the sound. Like I said before, mine seems much worse at times than others. And I'm convinced it's not just depending on if the windows are down or not :-)

j rick kirby
05-20-2004, 03:15 PM
No, it doesn't echo. I removed it because it had a bunch of rips in the cloth cover. I plan to clean it up and re-cover it. I can't really see it making much difference for low frequencies, though. It's just a very thin cardboard like molding with a layer of thin cloth over it. I think it will help once I get the vibration dampening sheets installed on the sheet metal. Maybe I can fill the space between the headliner and the roof / dampening sheets with dacron stuffing or some kind of foam.
easy now.Just kidding.