Suspension

alexman

Member
One thing that lets the Z4M down is the clutch (which I can live with) and suspension that gives a "crashy" ride. I'm not suspension expert and every car I've had has used stock suspension, so I've no idea what I'm looking for in a replacement so I need some advice. It isn't the fact the stock Z4M suspension is firm per se which I've loved in other track focused cars, its that a lot of this gets transmitted into the drivers seat as a "crashy" feeling. I don't want to smooth everything out I just want to improve the handling with as reasonable investment as is needed. Has anyone else changed their suspension to something better but still relatively firm (race focused) that has given better results?
 
alexman,

I have a Z3 MC which I bought in OEM condition and ended up completely modifying the suspension with front and rear strutbraces, H&R anti roll bars, KW V3 suspension, polyurethane bushes, camber/caster plates at the front and camber/toe brackets at the rear, larger wheels and tyres and spacers, and the handling of the car is now awesome. It now handles with minimal/no bodyroll and minimal pitching on braking and squatting on acceleration, with great feedback from the tyres. The car has been completely transformed for the better. To me, the OEM Z4 MC feels like the Z3 MC with just uprated anti-roll bars, where bodyroll is considerably reduced but still with too much pitching and squatting. I pick up my Z4 MC tomorrow and the first job I shall do is fit KW V3 suspension and set it up to considerably reduce the pitching and squatting.

With KW V3 , as well as adjusting the ride height/rake, you can independently adjust the rebound and bump/compression settings on the dampers to give at one extreme, a hard ride suitable for on track, to a soft compliant ride for bad B roads, and all shades in between. With my Z3 MC I've found that because the seats are just in front of the rear suspension, the rear damper settings are the critical ones that determine my perception of the ride, and I expect that I'll find the same in my Z4 MC. I therefore find for road use that the rear dampers need to be set towards the softest settings whilst the front dampers are mid-range, but for track, I have all dampers set at almost their hardest settings. Hope this helps.

BTW, where are you based? I'd be happy to show you the KW suspension.
 
I always accustomed the crashy ride to the stiffness of the chassis but yeah good point we do sit very close to the rear dampers. When you compare the E46 M3 you have a bigger floorpan and car to absorb some more.

I always thought the rebound was quite harsh too.

Eibach springs helped mine especially driving at lower speeds but bumps still upset the car, you get used to it.
 
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