Need help diagnosing noise - E36

[PatrickJamesYu]

So I had Racelands on my car and decided to swap them out for BC.

After the install, while cruising around
I noticed I was getting some loud thuds, bangs, hits coming from the car when going over bumps at cruising speeds.
Sounds like bottoming out, car smacking against the floor.
It hits so hard that my AC vents flip down, and my rear view mirror flips down as well.
I never had this problem with the Racelands.

The loud bangs happen over the smallest bumps in the road.
Like basically on flat roads with MINOR imperfections.
I can feel it in my steering wheel too.
Huge thuds

I'm confused
What should I be checking for down there?

The new coils have pillow ball tops, custom eibach 5" springs.

Thanks!

[CandySucker]

First start with all the mounting points for your suspension...

Can you isolate if its coming from the front or back?

Front... check tophats and mounting bolts for coilover to hub (its easy to think you have fully tightened these and when driving they'll still make noise...)

Rear...Deff check the lower bolt for the shock, I grease the mounting hole a little and confirm this is fully tight (again easy to think its tight but when driving could possibly make noise under movement). Also upper shock mount in the rear...

Start with this. If this started after your install 9/10 it has to come from something that was removed and installed (coilovers/shocks)

Keep us posted

[PatrickJamesYu]

First start with all the mounting points for your suspension...

Can you isolate if its coming from the front or back?

Front... check tophats and mounting bolts for coilover to hub (its easy to think you have fully tightened these and when driving they'll still make noise...)

Rear...Deff check the lower bolt for the shock, I grease the mounting hole a little and confirm this is fully tight (again easy to think its tight but when driving could possibly make noise under movement). Also upper shock mount in the rear...

Start with this. If this started after your install 9/10 it has to come from something that was removed and installed (coilovers/shocks)

Keep us posted

I'm 90% sure it's coming from the front.
I want to guess it's the front passenger side
I feel the hit very distinctly through my hands/ steering wheel which is why I assume it's up front

They're fully tight
I double checked sway endlink as well.

Possibly control arm bushings, ball joints, tie-rod?
They seem to be fine, I'm not too sure what to look for in these.
They're dirty, and look ages, but I don't see anything that looks visually concerning
They're just under the car and dirty, along with some motor oil residue.

I noticed my idol is getting rough and the car is shaking a bit in idle.
This is a random visualization I had, but is it possible that the motor is hopping on these small bumps, causing a extreme thud/bang, that I'm mistaking as a suspension issue?

I also noticed a shiny spot at the top of the wheel well.
I not too sure if this is the problem though.
My new coilover spring rate up front is like 40% stiffer

[PatrickJamesYu]

bump anyone?