Quote:
Originally Posted by Coi
I made a thread about this on ZPost but with the regular E85 Z4 having an electric rack and the Z4M being a very rare car I didn't get any responses. I've seen several posts across forums about the pros/cons of poly front control arm bushings but none specifically about steering feel.
I've owned by Z4M for several months and have been very happy with it in almost every single way except for the steering feel. While it's better than any electric rack I've driven and certainly has feedback, it's still not on the same level as the E93 I used to have or my buddy's low-mileage 987.2 Cayman. My FCABs show some signs of wear/age but I don't think they're totally shot because turn-in is still precise and the car does not wander.
I was thinking of just replacing these with new OEM offset rubber bushings, but wondered if anyone saw improved steering feel with aftermarket polyurethane FCABs. I know the primary reason people upgrade these is to decrease deflection on track, but are they worth the downsides (harshness, potential noise) on a street car for improvement in road feel?
If anyone is interested, these are the options I'm considering:
New OEM BMW rubber offset bushings for Z4M (31107838575) ~$60
Could get them pre-pressed into lollipops from a forum member ~$120
Whiteline caster bushing set, polyurethane (W52606) ~$60
I know this company is relatively reputable but I can't find any reviews of their FCABs on any BMW, let alone the offset ones, so that does give me some hesitation. Price is good.
Powerflex 66 mm offset bushing, aluminum/polyurethane (PFF5-5601G) ~$220
These are the most aggressive option being mostly aluminum, and are several times the price of the others. Some people report noise from these as well as an increase in ride harshness. They're pretty commonly used by forum members through on various models.
I know there are other factors that affect steering feel like alignment and tires (I have factory alignment specs and Michelin PS4S right now), but I figure if I'm replacing FCABs I should get the best option.
Thanks!
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The FCABs wear our very quickly on the Z4M (owned one for 12 yrs)
This is primarily due to the bushing being offset which leads to very little bushing rubber on one side.
You should be able to inspect and see if there are breaks & cracks in the bushing rubber material.
The Z4M has amazing steering feel when everything is in good shape, so you must have something going on with yours.
Also be sure to check other control arm bushings/bearings , tie rods etc.