Rear bottoming out!!!

[SupremeGoku9]

Your BC Racing coilovers, like mine, have solid topmounts front and rear. That means you've lost the little rubber isolator which absorbed most of the harsh impacts that your springs couldn't cope with. It's possible that this is the source of your noise.

It's possible that you've blown a shock absorber seal, which means it's providing no compression resistance. Check for oil on the body of the shock.

It's also possible that you've set the car too low, and the shock is simply bottoming out.

Yes on inspection there is oil on the rear left side damper.... Gonna speak to BC and see if I can rebuild

 

[SupremeGoku9]

why don't you stiffen the shocks to reduce springs bottoming out?

I did that.. then realized.. why should I be "over compensating" with excessive bump stiffness in a BMW... And it still happen...

I would add it did make it better... But I knew something weren't right... And I was right... Lol..

Will report back when all Is fixed ..

 

[B21]

I did that.. then realized.. why should I be "over compensating" with excessive bump stiffness in a BMW... And it still happen...

I would add it did make it better... But I knew something weren't right... And I was right... Lol..

Will report back when all Is fixed ..

Sounds primarily that the spring rate and/or ride height is too low..probably a spring getting coil bound?

Even the most wonderous Ohlins can get this wrong on E85/E89s…same rear end.

 

[SupremeGoku9]

Sounds primarily that the spring rate and/or ride height is too low..probably a spring getting coil bound?
t of springs t
Even the most wonderous Ohlins can get this wrong on E85/E89s…same rear end.

I would drift towards the rear being too soft... Rather than too low...

The car was set up to "almost" a mix of 3 & 4 all around on the BC knob... Lol

I'm now running 25 front and 26 rear which I love apart from tho mentioned rear issue...

Also to add what I've heard about a particular set of springs.. but I won't go that rabbit hole as I don't even know whats on mines ..

Does feel brilliant when working correctly tho lol

 

[B21]

The Ohlins was too soft and they only did one version for all e89s..mine is a 150kg heavier than the lightest version..

The motion ratio on e85/e89 rears favours a higher spring rate.l