Boomy exhaust causing everything to vibrate

[stevelatt]

So this is a problem I have been having for quite some time but just got my downpipe installed yesterday and it's worse again. To give a basic chain of events I bought the car new, stock exhaust in quiet > Installed ECS muffler delete and was super boomy/vibrating the car when accelerating around 2800-3200RPM and droning bad on the highway when maintaining speed up a slight incline > Replaced OE resonator with Vibrant 17930 and it helped quiet it down and reduce drone > still too noisey so I replaced the entire catback with an Ultimate Racing setup. Full 3" piping from the cat onwards, one resonator just before where the exhaust bends and then two "muffler" (seem to be the same units at the resonator) just after the Y pipe just before the bends to exit for the tips. I was happy with the sound here but it was still a little droney in those high gear/slight incline scenarios but not bad at all > being that I wanted to go stage two I had to get a downpipe which I know is going to increase volume. I go with Ultimate Racings 3" downpipe, 200 cell metal cat is close to stock location coming in just after the bend out of the turbo, and then a resonator where the secondary cat is in the OE downpipe. Now the car sounds basically like it did when I had the muffler delete done before I added the resonator when accelerating. Super loud in the cabin and vibrating/rattling the whole car you and feel it through the whole seat and everything.

Is this just my life if I want to run a downpipe + catback or is it possible something is installed wrong or loose somewhere? Every connection on the exhaust is a 2 bolt flange with gasket and they're all secured tightly, I double checked everything. The volume I'm fine with but the vibration is what is really getting me. I don't ever see anyone mention this online so that's why I asking. I have also had the soundaktor disabled since I bought the car and it feels less like it's coming from the dash and more like it's coming from right under/just behind my seat which is basically where the vibrations have always felt like they're coming from the whole time even with the stock downpipe.

 

[Acadia18]

Toss a Vibrant back on. Replace the resonator on the UR cat-back, which probably does next to nothing, with a 17950.

 

[stevelatt]

Toss a Vibrant back on. Replace the resonator on the UR cat-back, which probably does next to nothing, with a 17950.

I was thinking that might end up needing to be the move. It's fine when cruising, only a little louder than it was before the downpipe, it's just super bad when accelerating around 3k RPMs. Would you recommend swapping the one further down the exhaust just before the bend or the one where the secondary cat used to be?

Edit: The resonators they provide seem to be similar in size to the vibrant I used to have. A little shorter but wider oval shape vs perfect cylinder. Lots of little holes like the vibrant unit too. Not like the stock one with it's three little lines of holes and thats it. Those barely do anything.

 

[sirnerdington]

https://www.golfmk7.com/forums/inde...cancel-drone-with-a-quarter-wave-tube.372297/

Good information here about using a quarter wave tube to cancel drone as well.

 

[stevelatt]

For anyone finding this in the future. I ended up tracing it back to my tips touching/rattling off my Aerofabb rear diffuser and the heat shield under the trunk being loose. Removed the heat shield and put a little bit of high temp adhesive back rubber on the part of the spat that the tips touch. So far so good.

 

[EpicTech]

For anyone finding this in the future. I ended up tracing it back to my tips touching/rattling off my Aerofabb rear diffuser and the heat shield under the trunk being loose. Removed the heat shield and put a little bit of high temp adhesive back rubber on the part of the spat that the tips touch. So far so good.

The tips on my AWE exhaust constantly rattle against my diffuser, despite me adjusting them all the time. About to trash the Strafe diffuser and get something a little more suitable.

 

[stevelatt]

Yea, I love the way my Aerofabb one looks but there is basically no clearance for 4in tips like I have. I put a few washers in space it out a little and that still didn't help so I moved on to using something to cushion it against the vibrations. We will see how well the rubber holds up in the long term.

The tips on my AWE exhaust constantly rattle against my diffuser, despite me adjusting them all the time. About to trash the Strafe diffuser and get something a little more suitable.