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Discussion Starter · #1 ·
I'd like to see if anyone else has experienced the vibration type NVH I am now with a new exhaust just installed on my RS. Exhaust = Full Race catback, installed for 1 month now.

Symptom: At medium to full throttle, I feel and hear a vibration or fluttering starting above 3.5k and 10psi boost. The motor revs freely when not in gear so it's when under load. I thought it might be the valve flap fluttering in the exhaust breeze but it also does it when the flap is held hard open. The valve does leak at idle and is not held firm in either position.

I have other things I don't like about this exhaust but will leave that for another discussion.

Is this just an increase in acoustic NVH or what else could it be? This didn't happen to my 2.3lt turbo Mazdaspeed3 with a very similar aftermarket exhaust design and exit path, no valve tho.
 

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I do have a Ford performance exhaust by Borla, practically a valved ATak and no issues.

Mine was fitted less than 2 weeks of owning my RS in 2018, also it's the stock hangers.
 

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2016 SG RS2
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I do have a Ford performance exhaust by Borla, practically a valved ATak and no issues.

Mine was fitted less than 2 weeks of owning my RS in 2018, also it's the stock hangers.
I love my Borla Atak(no valve) paired with CPE catted DP. No NVH that I can notice from it. Got that after installed full CPE mounts and lighter flywheel. I do get a lot of compliments with the sound from that combination. I did have to get the cross member channeled right where the DP and exhaust meet. No matter how much I adjusted the hangers at low RPM it would hit it. Scared the crap out of me the first time as its almost right under the seat...lol
 

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I also have a full race cat back with the same exact problem. Even idling though I have some really annoying NVH, but I noticed mine is only when the valve is closed. Never when actually driving in sport or track with the exhaust valve open. I am almost certain it is either the exhaust valve itself rattling when closed, or the actual heat shield above it rattling from weird frequencies. please update when you figure it out!! I love that this exhaust has the valve in it, but the vibrations when closed drive me nuts!
 

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I also have a full race cat back with the same exact problem. Even idling though I have some really annoying NVH, but I noticed mine is only when the valve is closed. Never when actually driving in sport or track with the exhaust valve open. I am almost certain it is either the exhaust valve itself rattling when closed, or the actual heat shield above it rattling from weird frequencies. please update when you figure it out!! I love that this exhaust has the valve in it, but the vibrations when closed drive me nuts!
you still get the valve vibrations even with the OEM sys
only way to kill is to remove/delete the valve
 

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you still get the valve vibrations even with the OEM sysonly way to kill is to remove/delete the valve
Yes. I have a catless DP of "unknown origin" (and parentage for that matter) with a Borla S type cat back and NO valve. Never had any problem with noise or vibration of any kind. Fingers crossed! 🤞 :LOL:
 

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Yes. I have a catless DP of "unknown origin" (and parentage for that matter) with a Borla S type cat back and NO valve. Never had any problem with noise or vibration of any kind. Fingers crossed! 🤞 :LOL:
ok...no valve = no vibration
if i program my valve to stay open...there is no vibration noise
 

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ok...no valve = no vibration
if i program my valve to stay open...there is no vibration noise
Okay so always running the valve open solves the unwanted NVH from the back of the car, now how do I fix the unwanted noise from the occupied passenger seat caused by the new unwanted drone going down the highway? 😂
 

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Okay so always running the valve open solves the unwanted NVH from the back of the car, now how do I fix the unwanted noise from the occupied passenger seat caused by the new unwanted drone going down the highway? 😂
if you have no muffler...there is going to be an absurd amount of drone. it will damage your ears.
the valve will reduce the drone by 10% maybe. but still too loud.
you need a muffler.
 

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Okay so always running the valve open solves the unwanted NVH from the back of the car, now how do I fix the unwanted noise from the occupied passenger seat caused by the new unwanted drone going down the highway? 😂
Sorry, buddy. There's no muffler in the world that can silence THAT. I learned that long ago.🤣
 

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Mmmmmm?????? How would Red Green handle a baffling and persistent quality of life issue like too much drone?

Small metal trash can (the kind with a metal lid), cut holes in the bottom and lid to accept inlet and outlet portions of the exhaust pipe; stuff can/muffler full of steel wool or USED (don't want soap in your muffler!) SOS/Brillo pads. Cut exhaust system down to fit new muffler; attach muffler to exhaust using preferred method (i.e. J. B. Weld, duct tape and ultra high temp silicone sealer, etc); hang new muffler using any expedient type of wire (i.e. coat hangers, fence wire, etc). Voila! (y)

Mom always wanted me to be an engineer! ;)
 

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Discussion Starter · #14 ·
Meldy50 - thx, yes I do get the idle flap closed noise but no other rattles. My issue is a vibration type thing under accel that I can hear with along the engine. Weird Sh***t I've never experienced. I had other chassis work done to the car at the time of install and will have to go under retorquing everything down and a good visual. Not what you want to do after getting work done by a "reputable" shop. I know! Do it yourself and try to all the time, but just not this time.

Drone?!! Oh yeah big time @ 100db interior level @ around 100Hz between 2-3k. iPhone RTA App verified. Really bad when open. Quieter when closed but disappears while 4k and above either open or closed. I'm not even complaining about that for this issue. Just an FYI.

Also, FYI, the lead pipe starts @ 2.5". wtf is right. All of these systems come 2.5-2.75 due to the OE DP. So I would def replace that if going 3" DP. Soul performance said they could make up a replacement 3" lead pipe when I need it.
 
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