I've search and read pretty much every vibration/rattling thread and still can't find something that relates to my problem.

(I let car warms up for 10min before driving) When i first start driving lets say the first 10 min of driving around cruising/WOT i get no vibration and everyone works like it should everything is smooth. After driving for more than 10 min i get a very aggressive vibration coming from the rear right of the car at low rpm (2000rpm-4000) when shifting at any gear 1-6. It vibrates everything from the rear right windows, door, and rear deck dash. After 4000rpm it stop vibrating and then when i shift to the next gear and the RPM goes down to 2000prm it starts vibrating as i make my way up the band. If i let the car rest for 5 min and start driving again its fine for only 2 min then it vibrate again. Once i reach at gear 6 and cruising there is no vibration and everything is prefect.

I dynomat the rear doors, rear deck, i checked all screws and made sure everything is tight. I drove around with no seats/trunk/door panels and and it still vibrates. I check the exhaust and made sure there was no rubbing. Got a alignment on my car. Please any advice would be helpful im pulling hair with this.

2011 Ralliart, 43,000 miles
SST Fluid was change 4000 miles ago
Oil was changed 3000 miles ago

Mods: FMIC, Custom Exhaust, BC BR type Coilover, GST Tune, Boost Pill, Whiteline sway bar

 

hhmmmhhh...

I would suspect a rear CV joint. The low rpms are the highest 'loading' for the CVs...

Do a jack and shake test on the rear wheels and check both CV joints for play.

 

But it's rpm related, not speed related, and axle vibes follow vehicle speed. Something is unhappy with the cabin resonance in relation to engine rpm. Do you have your original exhaust to try and put that back on?

 

not sure if this is of any help, I had a low RPM vibration which was annoying the hell out of me, sounded exhaust related.
Ended up being all the piping running under the floor pan on the left side of the car. They were all secured and routed how they should be put were vibrating. A little foam wedged in place and I now have solemn silence.

 

I get some vibration inside my car buck it's because of my exhaust, I would swap back to stock like O3chi said to see if there is improvement.

 

Sorry i havent updated my status, but i switch my exhaust last week and it fixed the problem. I got a single exit instead to the dual. I feel like the dual is unnecessary and gives more cabinet vibration.

 

Oh BTW thanks for all your input.

 

I was going to say if might be the aftermarket exhaust.