Suspension - finally

[mmm-five]

After having to use some of my suspension money on the house last year I've finally got my fund back to where I want (coilovers plus replacement of any/all worn bushes/linkages/bearings/etc.).

So...after thinking I was settled on the Bilstein B16/PSS10 (about £2000) my 'spanner monkey' has said I'd be better off with KW Clubsports (£2200) or Intrax 1K2 (£2500).

I've heard that the KWs are better than the Bilsteins, but also that the Intrax are even better than the KWs (and have road seals). But are the KWs worth the extra £200 over the Bilsteins, and are the Intax worth the extra £500/£300 over the Bilsteins/KWs?

Decisions, decisions, decisions...

I'm going to order one of these three in the next month, so anyone have any opinion on the pros & cons of each (besides the price)?

 

[TomK]

I've had the 1k2 before and they are fantastic shockers, however the main downside is that they have to serviced/rebuilt in holland every year or so which can be a pain and is an expense.
If you go down that route I would suggest the black titan coating as this will protect against road grime and extend the period needed between rebuilds. The arc control add on looks to be an amazing bit of kit but that's another £1000 on top.

Depends what you're after though really, if more road focused I would suggest looking at KWv3 or the bilsteins. Track work, you'll want the Intrax or Clubsports.
Enjoy.

 

[mmm-five]

It'll be 20k miles of commuting, monthly trips into Wales/Peak District/Lake District, 3k of Ring trips and 2-3 track days.

Sounds like the Clubsports are the 'middle ground' then.

Would really like the Intrax, but the extra cost for the 'upgrades' would mean another couple of months saving, and I want it all done before I go back to the 'Ring in April/May.

The 'other' suspension bits are looking like they'll add about £1k to the bill anyway, and I'll have an Inspection 2 to be done just before that, so am trying to take the head over heart decision

 

[Beedub]

The clubsport range is around £2400

http://www.demon-tweeks.co.uk/performance/coilover-suspension-kits/car/bmw/z4m/kw-suspension-clubsport-coilover-kit


The middle ground setup is that is comfortable to be tracked and really road friendly is the kw Varient 3, clubsport are a track biased and developed damper, their is even additional welding for the ARB mount location for example, the clubsport is the damper that was used on the m3 GTS. they are great but aren't the most steetable setup, definitely not what i describe as middle ground.

 

[Babw]

The clubsport range is around £2400

http://www.demon-tweeks.co.uk/performance/coilover-suspension-kits/car/bmw/z4m/kw-suspension-clubsport-coilover-kit


The middle ground setup is that is comfortable to be tracked and really road friendly is the kw Varient 3, clubsport are a track biased and developed damper, their is even additional welding for the ARB mount location for example, the clubsport is the damper that was used on the m3 GTS. they are great but aren't the most steetable setup, definitely not what i describe as middle ground.

+1 on this.

Clubsports are valved to run a much higher spring rate. This is coming from someone who bought Clubsports as I felt I could compromise the daily work for the added benefit for TD's only to sell the Clubsports a few months down the line and get V3's on my old M3.

Best thing you can do is try everything you can if possible on BMW's at least. I tried the Clubsports on friends Porsches which as I found out to my cost ride inherently better than BMW's.

 

[mmm-five]

Don't add more options into the mix, I had enough trouble getting it down to these three

Already investigated and ruled out B12s, KW v3, Ohlins Road & Track, Nitron NTR R1, etc. for various (not always logical) reasons.

I can get the Clubsports with top mounts for £2200 direct from KW or £2130 from Larkspeed (weak Euro is helping) - and thought for a couple of hundred extra over the V3s it would be worth it for the extra 'capability'.

The middle ground I was talking about was between the B16s, Clubsports and 1K2s. Sounds like the difference between the B16s and Clubsports are worth it, but not worth spending £500 extra on the Intrax if I've got to have my only car off the road every year for a rebuild.

So it's down to B16s or Clubsports - and Clubsports are winning at the moment. Not ordering until the end of the month, so still time to change my mind...again

 

[TomK]

So it's down to B16s or Clubsports - and Clubsports are winning at the moment.

Those 2 are pretty far apart in terms of application. I would, as said, reconsider the v3, the fact that the clubsports are a little more expensive does not necessarily mean they will be 'better' for your needs. It's your money of course....

 

[Beedub]

Don't add more options into the mix, I had enough trouble getting it down to these three

Already investigated and ruled out B12s, KW v3, Ohlins Road & Track, Nitron NTR R1, etc. for various (not always logical) reasons.

I can get the Clubsports with top mounts for £2200 direct from KW or £2130 from Larkspeed (weak Euro is helping) - and thought for a couple of hundred extra over the V3s it would be worth it for the extra 'capability'.

The middle ground I was talking about was between the B16s, Clubsports and 1K2s. Sounds like the difference between the B16s and Clubsports are worth it, but not worth spending £500 extra on the Intrax if I've got to have my only car off the road every year for a rebuild.

So it's down to B16s or Clubsports - and Clubsports are winning at the moment. Not ordering until the end of the month, so still time to change my mind...again

The clubsport is an awesome setup if you can stomach it everyday... really really top quality stuff, i would not want to DD with them as i find myself constantly avoiding drains and road imperfects like the plague, KW recommend a 30k rebuild life for the clubsport range and also they come with zero warranty unlike the other kw items due to their intended use, aside from the pitfalls on my car they feel insane, track times with semi slick are up their with the big boys for sure. The build quality is nothing short of perfect, no rattles, no squeaks, no chatter, The solid mount uniball top mounts offer a nice additional level of feedback from what I'm experiencing.

 

[Babw]

I would consider Bilsteins to be a road only coilover at least as they're setup spring rate wise from factory.

I would consider KW V3 more track capable but better road manners than Clubsports.

Intrax are very much track biased with a fully coilover rear and all the downsides of the maintenance etc.

If you're planning some track time personally I would discount the Bilsteins, they make great road suspension but you will be disappointed for track work.

Don't Ohlins make a R&T kit for the Z4? (Sorry to add even more to the mix!)

 

[Beedub]

I would consider Bilsteins to be a road only coilover at least as they're setup spring rate wise from factory.

I would consider KW V3 more track capable but better road manners than Clubsports.

Intrax are very much track biased with a fully coilover rear and all the downsides of the maintenance etc.

If you're planning some track time personally I would discount the Bilsteins, they make great road suspension but you will be disappointed for track work.

Don't Ohlins make a R&T kit for the Z4? (Sorry to add even more to the mix!)

don't forget we require a barrel rear spring too, not sure if they offer this but its not suitable to run a coil-over in the rear of the z4 platform without re-inforcement, this WILL lead to the sheet metal failure of the turret, its simply not designed to take this load .

 

[TomK]

don't forget we require a barrel rear spring too, not sure if they offer this but its not suitable to run a coil-over in the rear of the z4 platform without re-inforcement, this WILL lead to the sheet metal failure of the turret, its simply not designed to take this load .

^^^ this
I believe both Intrax and Nitron now offer this arrangement as opposed to the full coilover for Z4s.
The Clubsport also uses this as do the other options

 

[mmm-five]

Hmmm, didn't realise the Clubsports had no warranty - obviously due to their intended motorsport use - I suppose this will be the case with the rest of the track-focussed suspension offerings too!

Just throws a another spanner in the works.

As for maintenance, I was going to get them 'serviced' at every inspection, which is about 6 monthly intervals.

 

[tertius]

Hmmm, didn't realise the Clubsports had no warranty - obviously due to their intended motorsport use - I suppose this will be the case with the rest of the track-focussed suspension offerings too!

Just throws a another spanner in the works.

As for maintenance, I was going to get them 'serviced' at every inspection, which is about 6 monthly intervals.

I have Intrax 1K2 with a barrel setup - they are very nice indeed. No problem in the road, and as a single adjuster (vs 2 on the KW v3 or Clubsports) they are very easy to play with.

They may "say" rebuild once a year, but if don't think they really need that, though your mileage is pretty high, so worth factoring in for any adjustable shock.

Mine have been back to Intrax once in my ownership and their turnaround is pretty good.

As an aside I have also owned KW v3 Clubsports (on my 911) and I'd be hard pressed to choose between them. My favourite shock is actually Nitron, which I had on my Elise.

 

[exdos]

Tony,

Bearing in mind the specific use of your car, with high miles on public roads, I'd like to suggest that you go for a dual-purpose adjustable suspension rather than a more focussed track-biased kit. There's no "one-size-fits all" suspension set-up, such as the OEM suspension, that will perform as well on track as it will on the road and vice versa. For your (and my) requirements you have to be prepared to adjust your suspension when you arrive at the the track and when you leave. I've twice made the mistake of driving the 550miles home from The Ring (in my Z3MC with KWV3 and my Z4MC with ACS Racing suspension), and very quickly realising that, even with mostly motorways, my Ring suspension settings (very firm all-round) don't work on public roads.

You've seen the sort of roads around where I live, which are much like those in Wales, The Peak District, Cotswolds etc. and after spending a lot of time messing with the suspension, particularly the Z3MC, I've found that for fast B-road driving, softer settings, particularly at the rear of the car, are by far and away the best. Therefore, I'd suggest that with the track-focussed suspension kits it may not be possible to adjust them soft enough for the majority of your use. Before, I bought the ACS Racing suspension for my Z4MC, I did the research and narrowed it down to three adjustable systems: KWV3, Bilstein B10 and AST. Both KWV3 and AST have separate adjusters for rebound and compression, whereas B10 is a single combined adjustment. Since I'd already got KWV3 on my Z3MC, I'd found that separate adjustment for rebound and compression gave a better adjustment than simply matching the settings for both rebound and compression by the same amounts, so my choice was between KWV3 and AST. I decided that I would opt for the AST because the adjusters for compression on the rear KWV3 are a bit fiddly to use, whereas the adjusters for compression on the AST are a simple dial. I actually ordered the AST suspension but eventually cancelled because the supplier was useless. I was then going to buy the KWV3, but at that time, the ACS Racing suspension had been on sale on Pistonheads for some 2 months and it hadn't sold, so I made a ridiculous offer for it and the deal was done. I was quite prepared to fit and try the ACS Racing suspension (Bilstein B10 made to ACS's spec) and if I didn't like it I would've moved it on and gone for KWV3. However, the potential problem that I saw of only having a combined, single adjuster has not been a problem and I've found that there is sufficient range of adjustments to be able to find two totally different set-ups which allow me to switch between fast B-road settings and track settings.

Having driven hundreds of laps around The Ring in both the Z3MC and Z4MC with KWV3 and ACS Racing suspensions, but using road tyres (including Michelin PSS) I don't see either suspension as being a problem, or the limiting factor to performance around there. To take the performance further, track day tyres are required as the next step after you've got your suspension properly sorted.

IIRC, the KWV3 carry a lifetime warranty whilst the car is in the ownership of the original purchaser.

If you'd like to experience the suspensions on my cars before you make your final decision, then I'd be happy to demonstrate both the KWV3 and ACS Racing suspensions and would be happy to make adjustments to the set-ups so that you can see how this alters the ride and handling and how important it is that your suspension can be set SOFT enough for public roads.

 

[mmm-five]

Thanks for all your help guys - it's keeping me busy

My rationale for going for the suspension overhaul is that it's now coming up to 130,000 miles old and getting a bit 'wayward' - or as my specialist says "Are you trying to effin' kill me!". Don't have a huge problem with it myself and I quite like a 'lively' rear end

My man-maths says why not take the cost of a full OEM replacement and add to that to go aftermarket and have the choice of dialing it in for track use or road use.

Whilst the car will visit the track/Ring occasionally, you wouldn't call me a track day warrior as I keep a fair amount in reserve these days - so I might even keep the road settings a the track (especially in the wet).

The first couple of cars I had with aftermarket suspension (Polo G40 and Corrado VR6) simply had me crank them to their hardest settings for track use and then leave it there all the time. The only time I had issues was when the car was 4-up and we went over yumps. However the suspension on those was nowhere near as expensive as those I'm looking at now (I think it was Eibach springs with Koni adjustables).

My original plan (about 2 years back) was to get either the B16/PSS10 or KWs with their electronic damping offerings for about £200 more (Damptronic and DDC IIRC) so that I could do very quick settings changes from an app/dial in the car. However, both have said they've got no plans to do such a kit and if I requested a custom kit it would probably double the cost. So I went back to the drawing board.

I then settled on the Bilsteins as I had a friend/spanner monkey who was affiliated with them and could ensure there would be a direct link between purchaser/fitter/supplier if a fitting/component failure arose.

Since then he's had a change of heart and now recommends the Clubsports for my type of driving - which he's seen plenty off on our very quick Welsh trips

I suppose the difficulty in asking opinions is that I might consider someone else's 'too hard' setting perfect for me, of find a 'road setting' too soft :?

I've got about 2 weeks to make my mind up, but I'm thinking that whatever I go for it will be better than 130,000 mile old OEM springs & struts

 

[Beedub]

Thanks for all your help guys - it's keeping me busy

My rationale for going for the suspension overhaul is that it's now coming up to 130,000 miles old and getting a bit 'wayward' - or as my specialist says "Are you trying to effin' kill me!". Don't have a huge problem with it myself and I quite like a 'lively' rear end

My man-maths says why not take the cost of a full OEM replacement and add to that to go aftermarket and have the choice of dialing it in for track use or road use.

Whilst the car will visit the track/Ring occasionally, you wouldn't call me a track day warrior as I keep a fair amount in reserve these days - so I might even keep the road settings a the track (especially in the wet).

The first couple of cars I had with aftermarket suspension (Polo G40 and Corrado VR6) simply had me crank them to their hardest settings for track use and then leave it there all the time. The only time I had issues was when the car was 4-up and we went over yumps. However the suspension on those was nowhere near as expensive as those I'm looking at now (I think it was Eibach springs with Koni adjustables).

My original plan (about 2 years back) was to get either the B16/PSS10 or KWs with their electronic damping offerings for about £200 more (Damptronic and DDC IIRC) so that I could do very quick settings changes from an app/dial in the car. However, both have said they've got no plans to do such a kit and if I requested a custom kit it would probably double the cost. So I went back to the drawing board.

I then settled on the Bilsteins as I had a friend/spanner monkey who was affiliated with them and could ensure there would be a direct link between purchaser/fitter/supplier if a fitting/component failure arose.

Since then he's had a change of heart and now recommends the Clubsports for my type of driving - which he's seen plenty off on our very quick Welsh trips

I suppose the difficulty in asking opinions is that I might consider someone else's 'too hard' setting perfect for me, of find a 'road setting' too soft :?

I've got about 2 weeks to make my mind up, but I'm thinking that whatever I go for it will be better than 130,000 mile old OEM springs & struts

stick with the clubsport then and run them as soft as they can go, as i agree, everybody else's too hard is simply an opinion... sometimes u got to bite the bullet and do what you thinks best, the clubsport is a mega coilover if the trade offs are to much of an issue for you! I've done very long motorway stints on them and they feel great, i happen to love some of the downsides too, a harsh ride quality for me isn't really an issue and the added feedback and directness to the hole feel of the car is worth all the downsides, the difference really is something.

 

[mmm-five]

So how much of a concern is the no warranty of the Clubsports? Is this standard on all track suspension (i.e. Intrax, Motons, Nitrons, etc.)?

I assume that it's because they expect the suspension to do a few hundred/thousand miles of smooth track work a year, and be serviced after every event? Whereas I'll be doing 25,000 a year on them and less than 1000 of that on tracks.

 

[Beedub]

So how much of a concern is the no warranty of the Clubsports? Is this standard on all track suspension (i.e. Intrax, Motons, Nitrons, etc.)?

I assume that it's because they expect the suspension to do a few hundred/thousand miles of smooth track work a year, and be serviced after every event? Whereas I'll be doing 25,000 a year on them and less than 1000 of that on tracks.

That particular question can surely only be answered by the purchaser, for me its not a massive issue but if it was a DD it would be, I'm guessing all the track biased setups with have warranty limitations of some sort.

 

[exdos]

If you've read anything I've previously written about the Z4MC's OEM suspension, I've always said that the front is too soft and the rear is too stiff. The front springs are made from 11mm diameter wire and the rear is made from 19mm diameter wire. I'm sure that you'll find that any aftermarket suspension will redress this gross imbalance. The ACS Racing has front spring of 14mm and the rear is 16mm, so you can see that in the case of the ACS at least, the front suspension is stiffened and the rear is softened. I think that the the KW Clubsports use similar wire diameters.

Although the springs remain the same with any specific adjustable suspension system, such as KWV3, the adjustment of the dampers between the softest and firmest of the settings coupled with the differences between the front/rear settings, makes a huge difference to the ride and handling. Although some of the high end suspension dampers have a total of, say, 30 or more "clicks" in the range for adjustment between softest and hardest settings, in reality, to make any noticeable changes, you'd be making adjustments of at least 3 clicks at a time, to have any initial noticeable change, so in effect, this is essentially the same as adjusting a damper with a range of 10 clicks by one click at a time. My KWV3s have 14 clicks in their range, whereas the ACS Racing has 9 clicks. I haven't found the difference to be a problem with the ACS Racing because both KWV3 and ACS racing suspensions have enough of a range to give a very noticeable difference between softest and firmest settings with a good transition between each setting.

If I were you, I'd ask Beedub or BMWZ4MC if you could have a ride as passenger on the roads in their cars with the Clubsports fitted to see how they feel before I spent my cash.

I also have Rotax Max go-kart and I certainly wouldn't want suspension as stiff as that on the roads, it's bad enough on any little bumps on track!

 

[mmm-five]

Thanks for all your help guys.

I've decided to keep it fast-road focused and go for the Bilstein B16/PSS10. Don't see the need for adjustable top mounts, or really aggressive lowering (want to keep rear close to normal height and have a slight lowering of the front). I'm guessing that I'll notice a huge difference no matter what I'd fitted as the stuff on the car is well overdue for replacement, and the week it'll be off the road will be plenty of time to replace all my mounts/bushes/linkages/arms/etc. so that it will be like new.

I now have a direct link to the UK sales/tech office of ThyssenKrupp Bilstein in Leicester, and will be buying direct (via my spanner monkey - who's done a few thousand laps of the 'Ring with his Bilstein contact in a professional capacity).

It's not the cheapest method of buying them (i.e. about £150 more than I could have got them for), but I won't have to worry about warranty arguments as we'll be working with Bilstein direct.