My New CBE Drones. Can it be fixed?

EvoX95123 · Jul 9, 2009, 11:18 PM

First, my definition of "drone" is the cabin vibration/resonance with the exhaust note. Is this correct? Let me assume it is for now.

So I got Perrin CBE after researching various internet Evo sites. I was very disappointed that the inside of car drones. If I accelerate normally, I can hear cabin vibration sound between 2,250 to 3,500 rpm. This is very annoying.

I had the performance shop that installed the Perrin CBE double check the bolt tighteness, per Perrin's suggestion. But it still drones.

Can it be fixed? Any pointer will be greatly appreciated.

Td66 · Jul 10, 2009, 05:24 AM

Have performance shop install a resonator on midpipe.

EvoG8r · Jul 10, 2009, 05:34 AM

My Perrin TBE has a very small amout of drone between 70-80mph, but its so mellow that it doesn't bother me or my wife. My wife is very picky about it too. I'm sorry to read that you don't like the sound. A resonator will probebly help, a good muffler or performance shop can just weld it in.

Hiboost · Jul 10, 2009, 06:23 AM

Like others have said a Resonator helps quite a bit. After wrapping my headers, turbo, and downpipe I toned down quite a bit of noise coming from my engine bay area as as well and now the sound is mostly coming from the rear of the car. An upgraded front motor mount can also amplify things if the material is really stiff like the AMS Race motor mount.

EvoX95123 · Jul 10, 2009, 09:30 AM

My drone is rpm dependent, instead of being speed dependent. The only mod I have is the Perrin CBE.

What does a resonator do?

Mj23foreva · Jul 10, 2009, 09:42 AM

yea droning is soo annoying. I did a lot of research before purchasing a catback. I made sure its not too loud and that it doesnt drone.

A resonator will help make the exhaust quieter hopefully it will eliminate the drone.

endGameXIII · Jul 10, 2009, 03:05 PM

Quote:

Originally Posted by EvoX95123

My drone is rpm dependent, instead of being speed dependent. The only mod I have is the Perrin CBE.

What does a resonator do?

it's, in short, a sound neutralizer. the shape and design of the resonator affects how much noise it can dampen and neutralize. oval type resonators work the best, but since we have the drive shaft down there, it's best to go with bottle type resonators.

DarthEvoX · Jul 11, 2009, 10:53 AM

This is interesting. I just installed my Perrin CBE exhaust yesterday afternoon and I'm not experiencing any major drone. It's a little louder inside the car, but that's to be expected compared to stock. You might want to have the installer check everything over because you shouldn't have any vibration in the car from the exhaust.

I did the install myself, and I'm not expert by any means, and I'm not having any problems.

kitw · Jul 11, 2009, 11:44 AM

Weird. My Perrin exhaust doesn't drone very much at all, my wife actually commented that it wasn't louder than the stock exhaust at cruise. The stock exhaust had as much drone in my car.

If you've had it on for awhile, take a look under the car and see if any of the connections are leaking. If the shop was sloppy, they may have incorrectly tightened the v-band clamps... mine were a little tricky to get lined up the right time.

EvoX95123 · Jul 11, 2009, 11:50 AM

I have taken my MR back to the performance shop twice and had two different people double check the tightness of the bolts and clamps. There are only two bolts and two clamps to check.

The folks at Perrin told me that my Evo is the first one that has this issue. Very odd!

I am wondering if the additional sound insulation of the MR package happens to resonate with Perrin's exhaust note. I notice the Perrin CBE has a deeper exhaust note than stock. MR has additional 18lbs of insulation from my reading. Well, just my hypothesis...

wilbdog · Jul 11, 2009, 12:03 PM

Quote:

Originally Posted by Hiboost

Like others have said a Resonator helps quite a bit. After wrapping my headers, turbo, and downpipe I toned down quite a bit of noise coming from my engine bay area as as well and now the sound is mostly coming from the rear of the car. An upgraded front motor mount can also amplify things if the material is really stiff like the AMS Race motor mount.

Is there a thread that shows how to wrap? I've seen a few people do this but I would be clueless on what to do / what material to use. Also, what does wrapping exactly do? Does it actually lessen the sound of the exhaust or just the drone in the cabin? I'm assuming just the cabin because it stops things from rattling?

kelvar13 · Jul 11, 2009, 12:09 PM

i have a test pipe and the perrin cbe on my gsr and I only experience very slight droning at around 1400-1700rpm. It isn't that bad and only happens when the car is warming up so it doesn't bother me.

Clipse3GT · Jul 11, 2009, 12:57 PM

Wrapping is good, but it causes problems in the winter and wet areas, where it traps the water and salt underneath the wrap where it slowly destroys the piping from inside out. Better to have them ceramic coated. Also wrap will soak up any liquid, i.e. oils which will trap in the fibers, not so good.

Better suited for race applications, where exposure to the elements is less than daily experience.

wilbdog · Jul 11, 2009, 01:00 PM

Quote:

Originally Posted by Clipse3GT

Wrapping is good, but it causes problems in the winter and wet areas, where it traps the water and salt underneath the wrap where it slowly destroys the piping from inside out. Better to have them ceramic coated. Also wrap will soak up any liquid, i.e. oils which will trap in the fibers, not so good.

Better suited for race applications, where exposure to the elements is less than daily experience.

Thanks for the info - definitely won't be going down the wrapping road.

EvoX95123 · Jul 11, 2009, 03:23 PM

Quote:

Originally Posted by kelvar13

i have a test pipe and the perrin cbe on my gsr and I only experience very slight droning at around 1400-1700rpm. ...

Which part of your cabin resonates with the exhaust?