Solid FCAB options for Z4M

[Spun Crankhub]

Hey guys and gals, moving over from F82 and going full track mode on my Z4MR. Gonna do solid bushings wherever possible, and wanting to start at the FCAB. Did a quick search and it seems like most of what I saw was PU. What have you gone with? Thanks!!!

[Coi]

Hello and welcome. My recently-acquired Z4MR is in need of both FCAB and RTAB so I've been looking into some options. Because it's a street car I'm going with mild PU FCAB and OEM RTAB w/shim kit, so I can't speak from experience on what's good for track.

Most important things to know are that Z4M uses offset FCABs and shares controls arms with E46 ZHP, not E46 M3. This limits choices because many options wrong size (those for m3) or are not offset (those for e46 non-M). Many websites will list centered bushings are compatible with Z4M but this is not correct. A non-offset bushing will cause loss of caster, obviously not acceptable for a track car.

In terms of polyurethane, Powerflex seems to be the most popular choice. Most people seem to have positive impressions but one forum member did have it fail due to track use. Lots of people have these on their track cars without issue though. I'm going with Whiteline pu offset bushings on my car even though there aren't many reviews out there. They're a very good price and I know people who are happy with WL bushings on other cars. They're not even as stiff as powerflex so maybe not the best for track. Other options include Condor Speed offset bushings, which I guess are technically UHMW rather than PU if that makes a difference.

There aren't many options for solid bushings with spherical bearings that fit our cars. Need the bearing because the control arm rotates inside the bushing. The only option I saw are the SLR Speed adjustable billet lollipops. These might actually allow you have more caster than possible with a normal bushing, but it's also another adjustment you'll have to factor in to your alignment. I've not familiar with this company or the quality of their products, so maybe that's worth looking in to before purchasing. There might be other options available if you search more.

Edit: Just wanted to update and say that I decided against the Whiteline poly offset FCAB because I'm worried it reduces caster compared to the OEM Z4M bushing. (Forums say the Z4M bushing increases castor by 1 deg compared to a centered one but Whiteline claims theirs only does so my 0.5 deg. This could result in my caster on my Z4M being reduced by 0.5 deg. Now this may not actually be accurate but no one seems to actually have bought or reviewed the offset Whiteline to say otherwise.)

[AriuSen]

Originally Posted by Coi

Hello and welcome. My recently-acquired Z4MR is in need of both FCAB and RTAB so I've been looking into some options. Because it's a street car I'm going with mild PU FCAB and OEM RTAB w/shim kit, so I can't speak from experience on what's good for track.

Most important things to know are that Z4M uses offset FCABs and shares controls arms with E46 ZHP, not E46 M3. This limits choices because many options wrong size (those for m3) or are not offset (those for e46 non-M). Many websites will list centered bushings are compatible with Z4M but this is not correct. A non-offset bushing will cause loss of caster, obviously not acceptable for a track car.

In terms of polyurethane, Powerflex seems to be the most popular choice. Most people seem to have positive impressions but one forum member did have it fail due to track use. Lots of people have these on their track cars without issue though. I'm going with Whiteline pu offset bushings on my car even though there aren't many reviews out there. They're a very good price and I know people who are happy with WL bushings on other cars. They're not even as stiff as powerflex so maybe not the best for track. Other options include Condor Speed offset bushings, which I guess are technically UHMW rather than PU if that makes a difference.

There aren't many options for solid bushings with spherical bearings that fit our cars. Need the bearing because the control arm rotates inside the bushing. The only option I saw are the SLR Speed adjustable billet lollipops. These might actually allow you have more caster than possible with a normal bushing, but it's also another adjustment you'll have to factor in to your alignment. I've not familiar with this company or the quality of their products, so maybe that's worth looking in to before purchasing. There might be other options available if you search more.

Originally Posted by Spun Crankhub

Hey guys and gals, moving over from F82 and going full track mode on my Z4MR. Gonna do solid bushings wherever possible, and wanting to start at the FCAB. Did a quick search and it seems like most of what I saw was PU. What have you gone with? Thanks!!!

This is closest you will find to solid. I have them.

https://www.millway.se/eccentric-con...-z4m-66mm.html

[Spun Crankhub]

Originally Posted by Coi

Hello and welcome. My recently-acquired Z4MR is in need of both FCAB and RTAB so I've been looking into some options. Because it's a street car I'm going with mild PU FCAB and OEM RTAB w/shim kit, so I can't speak from experience on what's good for track.

Most important things to know are that Z4M uses offset FCABs and shares controls arms with E46 ZHP, not E46 M3. This limits choices because many options wrong size (those for m3) or are not offset (those for e46 non-M). Many websites will list centered bushings are compatible with Z4M but this is not correct. A non-offset bushing will cause loss of caster, obviously not acceptable for a track car.

In terms of polyurethane, Powerflex seems to be the most popular choice. Most people seem to have positive impressions but one forum member did have it fail due to track use. Lots of people have these on their track cars without issue though. I'm going with Whiteline pu offset bushings on my car even though there aren't many reviews out there. They're a very good price and I know people who are happy with WL bushings on other cars. They're not even as stiff as powerflex so maybe not the best for track. Other options include Condor Speed offset bushings, which I guess are technically UHMW rather than PU if that makes a difference.

There aren't many options for solid bushings with spherical bearings that fit our cars. Need the bearing because the control arm rotates inside the bushing. The only option I saw are the SLR Speed adjustable billet lollipops. These might actually allow you have more caster than possible with a normal bushing, but it's also another adjustment you'll have to factor in to your alignment. I've not familiar with this company or the quality of their products, so maybe that's worth looking in to before purchasing. There might be other options available if you search more.

This is great info! I have used Whiteline adjustable sway bar end links with good success previously, so I will have to check them out. Thanks

[Spun Crankhub]

Originally Posted by AriuSen

This is closest you will find to solid. I have them.

https://www.millway.se/eccentric-con...-z4m-66mm.html

Definitely saw those while doing my research. Did you notice any improvement in feel or lap times after installing?
Thx

[lelandr]

Per Mike's recommendation, I ordered the Condor bushings. They installed pretty easily and look to be well made. My only concern is rotation of the outer bushing, but hopefully the inner sleeve will alleviate that problem.

[AriuSen]

Originally Posted by Spun Crankhub

Definitely saw those while doing my research. Did you notice any improvement in feel or lap times after installing?
Thx

Feel yes.
Laptime impossible to say. Too many variables at the track

[Michael9218]

Originally Posted by AriuSen

Feel yes.
Laptime impossible to say. Too many variables at the track

The Millway FCAB looks like it is for round control arms. Do they work with the hex arms?

[AriuSen]

Originally Posted by Michael9218

The Millway FCAB looks like it is for round control arms. Do they work with the hex arms?

Have been working for me.
I used in my previous track car for over 40 track days.

[3002 tii]

Bump for old thread… I am in same boat trying to decide between OEM rubber offset vs aftermarket offset:

1. Powerflex ‘Black’ (link)
2. Whiteline (link)
3. Condor Speed offset (link)
4. Millway Motorsport (link)

Powerflex doesn’t publish durometer but they claim Purple (street) is ~130% stiffer than original and Black is another ~30% stiffer. Folks here have shown Purple doesn’t hold up well from track use. MSRP is $260.

Whiteline is not as popular as PF but not a small brand either. I ran their subframe inserts on my old 135i and was very happy with it. One thing worth noting is despite being offset like OE, you still lose a little caster (0.50 more than centered but 0.25-0.50 less than OE offset). This may necessarily be a bad thing considering dialing down caster slightly may alleviate the common wheel rub issue we have. And best of all, MSRP is $60.

Condor Speed - they offer a ton of BMW products. I can’t speak to their quality but take it FWIW, they manufacture in house and supply parts specific to the Spec racing crowd. Their bushing is priced right in middle at $95, and you can even pay to have them pre-press into a lollipop for an extra $100. Not that it’s difficult but nice convenience if you don’t have a press, and all in still comes out cheaper than PF. Here’s also a video (scroll to 19:24) on difference between UHMW vs poly.

Millway - smaller operation compared to other options but they look legit. The install is slightly more involved but I like their design a lot. Price is highest among 4 because of international shipping, roughly $275.

Also Michael9218 - re your question above on hex shape, I confirmed center part is round polyurethane that is formed to the hex form on the control arm once pressed onto the arm.

[maupineda]

I would run OE. Not much to upgrade here.

[the fly]

Originally Posted by maupineda

I would run OE. Not much to upgrade here.

Agree. The Z4M units are solid rubber units and thus have pretty good longevity. This is opposed to the fluid filled oneson the XI and other non-M units. For those models, a good poly like PF is the way to go. For Z4M, I don't think the justification is as clear.

[cbpip]

Have been using the Rouge engineering FCAB , they are a hybrid greaseable with poly insert. Two different degrees of hardness for the insert.

https://www.rogueengineering.com/Rog...-20_p_100.html

[mmm-five]

Originally Posted by cbpip

Have been using the Rouge engineering FCAB , they are a hybrid greaseable with poly insert. Two different degrees of hardness for the insert.

https://www.rogueengineering.com/Rog...-20_p_100.html

Are they for the Z4M or just the Z4 though?

[the fly]

Originally Posted by cbpip

Have been using the Rouge engineering FCAB , they are a hybrid greaseable with poly insert. Two different degrees of hardness for the insert.

https://www.rogueengineering.com/Rog...-20_p_100.html

But do they have an offset version for Z4M?

[3002 tii]

Quick bump but ended up going with Condor. Happy to report no NVH in the limited testing I’ve done so far.

[3002 tii]

Originally Posted by the fly

But do they have an offset version for Z4M?

The Millway I linked above have same feature

[cbpip]

Originally Posted by mmm-five

Are they for the Z4M or just the Z4 though?

Work for either M or non M FCAB. If I hadn't gone with the Rouge versions, the Condors would be next choice.

[3002 tii]

Originally Posted by cbpip

Work for either M or non M FCAB. If I hadn't gone with the Rouge versions, the Condors would be next choice.

I should’ve read Rogue’s description more carefully. I didn’t realize their “track” bushings meant offset. I assumed it meant harder material. Had I known I would’ve considered those as well. That said Condor’s are almost half the price of RE. Will post review later after I’ve had chance to try these out on track over next few weeks.

[gaseosx]

How far are you supposed to set the fcab on the condor set? Are you supposed to bottom out?

[gaseosx]

Originally Posted by 3002 tii

I should’ve read Rogue’s description more carefully. I didn’t realize their “track” bushings meant offset. I assumed it meant harder material. Had I known I would’ve considered those as well. That said Condor’s are almost half the price of RE. Will post review later after I’ve had chance to try these out on track over next few weeks.

Where does it say offset? Images show the track bushing still centered so I’m unsure. This would be a great option state side with the zerk fitting.

[3002 tii]

Originally Posted by gaseosx

How far are you supposed to set the fcab on the condor set? Are you supposed to bottom out?

Yes till they bottom out but I also measured the depth against the factory one to be safe.

Originally Posted by gaseosx

Where does it say offset? Images show the track bushing still centered so I’m unsure. This would be a great option state side with the zerk fitting.

You are correct. I looked at the pics on my phone in portrait mode so the bushings appeared offset lol.