Excessive low RPM vibration - Possibly AA Xpipe?

[MShift]

So I've been trying to dig up information about this annoying vibration I have at low rpm (1300-2000rpm) and I've come across some interesting commonalities amongst the threads I found. I wanted to share and see if anyone else has this problem.

Now before someone says its a heatshield or a mount or something, I really don't believe it is. Engine mounts were just replaced and that was not it. Its also not likely something touching because the vibration is more of a shuddering than a high frequency buzz or audible rattle. It coincides with the exhaust frequency and feels like a shaking through the pedals and steering wheel (DCT). It does it both in gear and not in gear.

I know these engines have a natural resonance at that RPM, but this is excessive to the point my interior/wheel/seat shakes with it. I've sat in many other M3's both modified and not and they all have that resonance, but nowhere as bad. I know what nvh from mounts feels like.

The engine itself, if you put your hand on it and rev, doesn't shake around nearly as much as you'd expect it to if the engine was causing the issue.

So having eliminated the most likely culprits I came on here to do a little searching for unexplained vibrations like mine and I kept seeing over and over that the only commonality between the threads was AA x pipes. When I had my BW xpipe the whole car was smooth across the rev range and I don't remember this issue being present.

My exhaust is AA Xpipe with test pipes and an Eisenmann race muffler. I also have a set of cats for this exhaust and it also had the vibration with those on although I think its more pronounced with the test pipes. The vibration is most noticeable at that RPM and mellows down a bit higher up in the revs, but its still present.

Has anyone else run into increased vibration coming from this xpipe or other xpipes? I am running out of ideas as to what it could be. If anyone has any feedback about pls lmk!

[M3SQRD]

I e had two AA x-pipes - one with HFCs and one with no cats/stock cats. I’ve had zero vibration issues with/without cats. Definitely no change in vibration with/without stock cats. I don’t have the forward must exhaust support (removed and misplaced when akra x-pipe was installed) and still no strange vibrations. Only issue I’ve encountered was the HFCs rubbing on speed bumps. Also, have an Akra HFC x-pipe and have had no vibration issues with it too.

[MShift]

Originally Posted by M3SQRD

I e had two AA x-pipes - one with HFCs and one with no cats/stock cats. I’ve had zero vibration issues with/without cats. Definitely no change in vibration with/without stock cats. I don’t have the forward must exhaust support (removed and misplaced when akra x-pipe was installed) and still no strange vibrations. Only issue I’ve encountered was the HFCs rubbing on speed bumps. Also, have an Akra HFC x-pipe and have had no vibration issues with it too.

What do you mean forward most support? The test pipe / catpipe supports? What muffler section when you had the aa x pipe?

[M3SQRD]

Originally Posted by MShift

What do you mean forward most support? The test pipe / catpipe supports? What muffler section when you had the aa x pipe?

The forward most support that’s located near the stock main cats. Apparently, the support arms were removed because the Akra x-pipe didn’t use them.

I’m currently running the AA x-pipe w/oem main cats and Akra axle back muffler. Swap between AA and Akra x-pipes for emissions testing. People want too much money for a stock x-pipe these days. I had a pair of oem main cats so I ordered an AA x-pipe + short adapters for oem main cats (have catless front pipes as well). Haven’t had a chance to swap x-pipes yet and reinstall stage 2 tune with 8600 rpm redline. I miss the tune because I end up hitting the rev limiter almost every time I redline shift. Miss the extra rpm.