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Z4m Coupe Anti Roll Bar Upgrade

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InterlagosMC
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Z4m Coupe Anti Roll Bar Upgrade

Post by InterlagosMC » Sat Dec 17, 2022 9:00 am

Im looking to upgrade the anti roll bar setup on my z4m coupe and wondered what my option were. I like the look of the H&R e46 m3 kit but it doesn’t list as compatible with the z4.

Has anyone had experience fitting these and were any modifications required.

Thanks
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Jembo
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Z4m Coupe Anti Roll Bar Upgrade

Post by Jembo » Sat Dec 17, 2022 9:40 am

Morning

Regret unable to answer your question

However, interested to learn why you feel it’s necessary to upgrade this, as there’s other parts I’d normally expect u start with way before this

Cheers
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InterlagosMC
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Z4m Coupe Anti Roll Bar Upgrade

Post by InterlagosMC » Sat Dec 17, 2022 10:16 am

My car has bilstein b12 kit at the moment with wheels that anre flush with the arch and it already has poly bushes on front and rear anti roll bars but just want a tighter feel on the back end more than anything. The front is pretty good already
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Z4m Coupe Anti Roll Bar Upgrade

Post by plenty » Sat Dec 17, 2022 10:26 am

If you still have the original rear springs you could experiment by fitting them as they are stiffer than the Eibach springs you have on now. They are also slightly taller meaning your rear ride height will raise slightly, but that may not be a bad thing as it will give your car positive rake which has an effect equivalent to stiffening rear spring rate.

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Z4m Coupe Anti Roll Bar Upgrade

Post by Jembo » Sat Dec 17, 2022 10:35 am

InterlagosMC wrote: Sat Dec 17, 2022 10:16 am My car has bilstein b12 kit at the moment with wheels that anre flush with the arch and it already has poly bushes on front and rear anti roll bars but just want a tighter feel on the back end more than anything. The front is pretty good already
I found the B12 front springs too harsh for our pants UK roads with the B12 kit, so reverted back to OEM springs but the shocks & softer Eibach rears made huge difference

For the rear, suggest
1. RTAB’s & RTAL’s (Rear Trailing Arm bushes & Limiters) make a huge difference - I did both with Rogue Engineering
2. Then there’s the 3 rear diff bushes… if that baby’s squirming about it’ll never let the rear settle
3. Getting M track mode coded in
4. Rear top mounts tend to go sloppy so another area
5. A e46 CSL geo setup, though u may need front camber plates to get 100% settings

Suggest u look on forum for these first as will yield (from my experience & others) the best results
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Z4m Coupe Anti Roll Bar Upgrade

Post by InterlagosMC » Sat Dec 17, 2022 11:08 am

Thanks for the info, I will have a look at all of these options, Im planning lots of maintenance and upgrades in the coming year and want to get the handling spot on.
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Z4m Coupe Anti Roll Bar Upgrade

Post by plenty » Sat Dec 17, 2022 11:27 am

Just to be clear, I wouldn't actually recommend what I'm describing above. Jembo's advice is very sensible. Z4M handling benefits from a softer rear than OEM.

Adding rear spring rate, whether via OEM springs or a larger bar, is a backward step. I'm just mentioning swapping springs as a way to achieve a similar effect to a larger bar, that's easy to experiment with and see for yourself.

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Z4m Coupe Anti Roll Bar Upgrade

Post by peteslag » Sat Dec 17, 2022 11:50 am

I upgraded the arb's on my old z4 3.0. It massively reduced understeer but didn't seem to do much for the rear of the car. More lively perhaps.

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Z4m Coupe Anti Roll Bar Upgrade

Post by Ed Doe » Sat Dec 17, 2022 12:24 pm

peteslag wrote: Sat Dec 17, 2022 11:50 am I upgraded the arb's on my old z4 3.0. It massively reduced understeer but didn't seem to do much for the rear of the car. More lively perhaps.
Precisely what arb tuning is about - you stiffen the axle you want to take grip away from, or soften the axle you want more grip from.
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Z4m Coupe Anti Roll Bar Upgrade

Post by mmm-five » Sat Dec 17, 2022 2:09 pm

I put the e46 M3 28mm front and 21mm rear Eibach ARB kit on mine (kit no. E40-20-001-01-11) - no longer listed on www.eibachshop.co.uk though.

This was in combination of poly-bushing, Bilstein B16, and Porsche brake upgrades (and 12mm spacers).
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Z4m Coupe Anti Roll Bar Upgrade

Post by BMWZ4MC » Sun Jan 01, 2023 3:32 pm

I’ve fitted H&R ARBs to mine, but that’s in combination with KW Clubsports and camber/castor plates,
RTAB limiters,
Rogue Engineering rear shock mounts,
an OEM strut brace / strut tower reinforcement plates and
Vibratech competition engine mounts.
I had to change the drop links to get the front ARB to fit with the KWs which, in turn, need spacers with some wheels (including the OEM wheels).

The result is an extremely stiff car which handles amazingly well on the smooth tarmac of a track but skitters around on broken roads even with the dampers backed off to their softer settings.
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Ed Doe
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Z4m Coupe Anti Roll Bar Upgrade

Post by Ed Doe » Sun Jan 01, 2023 4:15 pm

BMWZ4MC wrote: Sun Jan 01, 2023 3:32 pm I’ve fitted H&R ARBs to mine, but that’s in combination with KW Clubsports and camber/castor plates,
RTAB limiters,
Rogue Engineering rear shock mounts,
an OEM strut brace / strut tower reinforcement plates and
Vibratech competition engine mounts.
I had to change the drop links to get the front ARB to fit with the KWs which, in turn, need spacers with some wheels (including the OEM wheels).

The result is an extremely stiff car which handles amazingly well on the smooth tarmac of a track but skitters around on broken roads even with the dampers backed off to their softer settings.
That could be written about my car :lol:
Carbon Black '07 M Coupe: Intrax 1k2 Coilovers, AP-Racing, Raybestos ST45s, Tillets, Schroth, Vibratechnic, Apex EC7, Strongstrut, Eventuri, H&S, RTD, 4.1FD :evil:
Silver Grey '06 3.0si Coupe - SOLD :(

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Z4m Coupe Anti Roll Bar Upgrade

Post by BMWZ4MC » Sun Jan 01, 2023 4:21 pm

Ed Doe wrote: Sun Jan 01, 2023 4:15 pm
BMWZ4MC wrote: Sun Jan 01, 2023 3:32 pm I’ve fitted H&R ARBs to mine, but that’s in combination with KW Clubsports and camber/castor plates,
RTAB limiters,
Rogue Engineering rear shock mounts,
an OEM strut brace / strut tower reinforcement plates and
Vibratech competition engine mounts.
I had to change the drop links to get the front ARB to fit with the KWs which, in turn, need spacers with some wheels (including the OEM wheels).

The result is an extremely stiff car which handles amazingly well on the smooth tarmac of a track but skitters around on broken roads even with the dampers backed off to their softer settings.
That could be written about my car :lol:
Intact vertebrae are overrated :lol:
Image
Z4MC - heavily fettled for track use
Lotus Exige - sensible daily driver on the mods slippery slope
Westfield SEiW - in hibernation
Modified RS4 Avant - back in Blighty
S2000 GT - gone

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