Suspension Upgrade Advice

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Argenta
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Suspension Upgrade Advice

Post by Argenta » Mon Dec 02, 2019 10:56 pm

BMWZ4MC wrote:
Mon Dec 02, 2019 12:18 pm
Argenta wrote:
Mon Dec 02, 2019 11:17 am
Easypeasy - Eibach Pro springs.
Lower & much better ride, and cheap as chips.
For a while, I ran Eibachs / OEM dampers with as much negative camber as possible at the front. I found that improved track behaviour over the OEM setup. However, tram lining was a big problem, especially with 19” wheels, and the handling remained somewhat unpredictable (hence making the changes I’ve listed above).
Now, for trackdays I agree on them being too soft. I’ve done lot of trackdays on them and will swap for bit more hardcore KWV3.

However, trackdays are not on the table here, but everyday driving. Which at was my reply.

More tramlining sounds weird - did you still have 1mm toe in upfront? With maxxed camber, you might need even more.
Here, maxxed out camber wasn’t a demand either.

Michael wont get more tramlining out of just changing the springs, but as I found, a significant ride improvement.

So - simplest solution for better everyday driving - Eibach Pro springs
Last edited by Argenta on Wed Dec 04, 2019 1:13 am, edited 2 times in total.

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Suspension Upgrade Advice

Post by BMWZ4MC » Tue Dec 03, 2019 5:25 am

I was trying to reduce understeer on the track, hence running the geometry that I did. I can only comment on my own experience (albeit not a direct reflection of the OP’s requirements) - running OEM 224s, the tramlining lessened. With CSLs it was horrible.
Fitting Eibachs certainly made mine lower (and it looked better as a result) and I agree they were fairly inexpensive, but the ride was not a significant improvement over OEM.
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Suspension Upgrade Advice

Post by MrPT » Tue Dec 03, 2019 11:16 pm

beanie wrote:
Mon Dec 02, 2019 1:59 pm
Anyone know if the KW V3 allows you to keep standard height or fairly close?
They claim -10mm front and -5mm rear, relative to stock, but you can safely make use of another 5mm or so of thread. I run at max height front (70mm of thread) and +3mm rear (23mm of thread) plus a 6mm spring perch spacer. The spacer is partly because I run a 35 profile rear, but mainly to provide enough adjustability to level up the rear left/right sides without sacrificing clearance.

The V3 spring rates are only slightly higher than stock (unlike the Clubsports) and provide a decent ride, even on our B roads. I suspect the damping is a lot better, even before you take into account adjustability, but I haven’t ever been able to do a back-to-back comparison. The inox construction is brilliant - just give them a good scrub every year and they come out like new.
2008 Z4MC: SG/Imola | +OEM CSLs | +KWv3 | +TMS RTABLs | +VT mounts | +Eventuri | +OEM strut brace | +DB9 front BBK | +cruise - probably looks a bit like your one
2006 Z4 2.5si: gone

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Suspension Upgrade Advice

Post by RedUn » Wed Dec 04, 2019 12:32 am

I've rode in a car on V3s and it was excellent on the road, I'm on clubsports, I find them fine but they are definitely more track focused, I'd recommend V3s to answer your dilemma :thumbsup:
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Post by Anakin » Wed Dec 04, 2019 1:00 am

I just ordered a set of KW V3's for my TT RS. £300 off in the blackfriday sale. The TT's mag ride shocks are shot though, so I had and excuse.
Can't justify a set for the Z4 yet ...
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Post by beanie » Wed Dec 04, 2019 10:32 am

MrPT wrote:
Tue Dec 03, 2019 11:16 pm
beanie wrote:
Mon Dec 02, 2019 1:59 pm
Anyone know if the KW V3 allows you to keep standard height or fairly close?
They claim -10mm front and -5mm rear, relative to stock, but you can safely make use of another 5mm or so of thread. I run at max height front (70mm of thread) and +3mm rear (23mm of thread) plus a 6mm spring perch spacer. The spacer is partly because I run a 35 profile rear, but mainly to provide enough adjustability to level up the rear left/right sides without sacrificing clearance.

The V3 spring rates are only slightly higher than stock (unlike the Clubsports) and provide a decent ride, even on our B roads. I suspect the damping is a lot better, even before you take into account adjustability, but I haven’t ever been able to do a back-to-back comparison. The inox construction is brilliant - just give them a good scrub every year and they come out like new.
Thanks for that, much appreciated :thumbsup:
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Post by MrPT » Wed Dec 04, 2019 12:27 pm

Probably also worth mentioning that you’ll need a 5-10mm spacer on the front axle with the V3s, due to the conical shape of the progressive front spring.

The above doesn’t bother me (it looks better and also clears my brakes!). The only real issues I’ve had with them are:

i) they have a metal spring perch with a composite adjustment wheel that you can damage if you don’t keep your threads clean (easy once you know how); and

ii) the rear spring travel is less than stock and ”bottoming out” can be a problem with soft bump settings. People who have tested the spring rates on a jig have found that you don’t get the full ~4” of travel you get with stock, so coil binding is the likely culprit. Sounds horrendous, given how stiff the rear is anyway, but it’s actually the rear rebound which causes a lot of discomfort, so you can run (for example) 50% open bump damping and 90% open rebound damping and it works well.

Still the odd, terrifying thunk, mind! But with no visible wear of the bump stops or top mounts in 25k miles, it’s hard to draw definitive conclusions about damage.
Last edited by MrPT on Wed Dec 04, 2019 12:48 pm, edited 2 times in total.
2008 Z4MC: SG/Imola | +OEM CSLs | +KWv3 | +TMS RTABLs | +VT mounts | +Eventuri | +OEM strut brace | +DB9 front BBK | +cruise - probably looks a bit like your one
2006 Z4 2.5si: gone

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Post by RedUn » Wed Dec 04, 2019 12:38 pm

Indeed, I'd run a spacer on the rear too, help keep the balance in the track widths somewhere near oem
Running the front track 10mm wider in total that the rear is reasonable though and gives a nice balance to the car :thumbsup:
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Post by AndyBeech » Wed Dec 04, 2019 4:06 pm

Hmmmm, so if the PSS10's and V3's were side by side and the virtually the same money, wonder which one to pick? Both have some pro's and con's it seems...

Having to dismantle the boot to adjust settings on the V3's sounds like the biggest annoyance...
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Post by MrPT » Wed Dec 04, 2019 5:01 pm

AndyBeech wrote:
Wed Dec 04, 2019 4:06 pm
Having to dismantle the boot to adjust settings on the V3's sounds like the biggest annoyance...
You don’t need to do that. The top adjusts via a dial inside the wheel arch and the bottom via a hole in the bottom of the shock.

I’ve changed mine in pub/hotel car parks. Get some looks, mind... :D

I should caveat the note re the rear springs - I don’t actually know whether the “thunk” is a genuine hard stop in the suspension or whether it’s just the coils becoming unbound on extension (and hammering the chassis). I suspect it’s the latter but need to do some experiments to find out.
2008 Z4MC: SG/Imola | +OEM CSLs | +KWv3 | +TMS RTABLs | +VT mounts | +Eventuri | +OEM strut brace | +DB9 front BBK | +cruise - probably looks a bit like your one
2006 Z4 2.5si: gone

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Post by AndyBeech » Wed Dec 04, 2019 5:15 pm

MrPT wrote:
Wed Dec 04, 2019 5:01 pm
AndyBeech wrote:
Wed Dec 04, 2019 4:06 pm
Having to dismantle the boot to adjust settings on the V3's sounds like the biggest annoyance...
You don’t need to do that. The top adjusts via a dial inside the wheel arch and the bottom via a hole in the bottom of the shock.

I’ve changed mine in pub/hotel car parks. Get some looks, mind... :D

I should caveat the note re the rear springs - I don’t actually know whether the “thunk” is a genuine hard stop in the suspension or whether it’s just the coils becoming unbound on extension (and hammering the chassis). I suspect it’s the latter but need to do some experiments to find out.
Ah ok thanks, yes the revised design, forgot about that!

Argh, can get the PSS10's for £1580, V3's cheapest seems around £1850-1900. Gravitating towards the Bilstein's but don't really know why! Not just the small price difference TBH but they just sound a bit easier to set up even if not as adjustable as the V3's or quite as well built potentially...decisions decisions. (Sorry for thread hijack OP, was gonna ask a similar question so saves 2 separate topics!)
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Post by RedUn » Wed Dec 04, 2019 6:36 pm

I'd go KW every time for a couple of reasons...

1. Adjustability, they are more adjustable and it will allow you in time to get them how you want

2. They are a twin tube damper not a monotube like the bilstein, hence they ride much nicer

3. The coating is excellent on them, they look like new after several winters when you give them a wipe down

4. People tend to have problems with Bilsteins, I know that's a bit generic but just over the years you pick up comments etc.

5. You can upgrade them to clubsports if you want at a later date

All in my opinion obviously, I've been running continuously on cars KWs since 2005, I've never had one issue :thumbsup:
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Post by beanie » Thu Dec 05, 2019 12:29 pm

MrPT wrote:
Wed Dec 04, 2019 12:27 pm
Probably also worth mentioning that you’ll need a 5-10mm spacer on the front axle with the V3s, due to the conical shape of the progressive front spring.

The above doesn’t bother me (it looks better and also clears my brakes!). The only real issues I’ve had with them are:

i) they have a metal spring perch with a composite adjustment wheel that you can damage if you don’t keep your threads clean (easy once you know how); and

ii) the rear spring travel is less than stock and ”bottoming out” can be a problem with soft bump settings. People who have tested the spring rates on a jig have found that you don’t get the full ~4” of travel you get with stock, so coil binding is the likely culprit. Sounds horrendous, given how stiff the rear is anyway, but it’s actually the rear rebound which causes a lot of discomfort, so you can run (for example) 50% open bump damping and 90% open rebound damping and it works well.

Still the odd, terrifying thunk, mind! But with no visible wear of the bump stops or top mounts in 25k miles, it’s hard to draw definitive conclusions about damage.
Thanks again. I’d forgotten about the need for spacers with the KWs.

As for reliability, I too have read of a couple of issues with the Bilsteins on the Z4M but I have also been warned off KW for similar reasons!

I’d look elsewhere but most other suspension brands are more focused on track performance and I’d worry about ruining the road manners (what there is of them anyway!)

I did read on another forum of someone getting some revalved Bilsteins for the Z4M, I’ll try and find it again and see where he got to.
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Post by BMWZ4MC » Thu Dec 05, 2019 2:11 pm

Anecdotal evidence, but I’ve had KWs on my car for five years and dozens of track days without any problems.
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Post by MrPT » Thu Dec 05, 2019 2:18 pm

For what it’s worth, my impression and personal experience is that reliability is a KW strongpoint. Their support - again, in my experience only - has been excellent. They are still the kind of company you can have a long, nerdy email conversation with someone technical who will go out of their way to help. I don’t even have a valid warranty with them.
2008 Z4MC: SG/Imola | +OEM CSLs | +KWv3 | +TMS RTABLs | +VT mounts | +Eventuri | +OEM strut brace | +DB9 front BBK | +cruise - probably looks a bit like your one
2006 Z4 2.5si: gone

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