Your experiences of aftermarket suspension on the Z4 MC

I agree, in most cases lowering springs actually make a car worse!

Let us know how you get on with your adjustables :thumbsup:

While were on the subject, well nearly, what camber is everyone running for fast road and the odd track day? Is the standard geo ok on the track or do you need more?

I'm currently running the standard spec but considering the modification (removing pins or something?) on the front and adjusting the rear so its around 2 degrees all round? Any thoughts?
 
I'd play around with tire pressure before camber. At high road speeds and off track I would not want a different set up than standard. To be honest on lmy tyres I found it OK on track and I don't mind understeer, theres plenty of right pedal to sort that or a tad of trailbraking to tuck the nose in.
 
I've just fitted a strutbrace from Strongstrut see: http://www.strongstrut.com/. WHAT A DIFFERENCE! It's really helped to reduce the front lifting and pitching and the floaty imprecise steering is considerably better. I've had a Strongstrut strutbrace on my Z3MC for the past 8 years and it also makes a considerable difference to that car too.

I chose the Strongstrut strutbrace because it is a very solid but lightweight piece of kit with proper anchor points and rigid fixing of the bar to the tower supports. The only bends in the bar are in the plane that is best able to resist deformation. They're probably far and away the most expensive strutbrace of all: this one has just cost me a total of about £345 including all import taxes, but quality comes at a price and for me it's been some of the best money I've ever spent on both of my Strongstruts. I have absolutely no connection with the company other than as a twice satisfied customer.

I'm just now waiting for the delivery of the suspension that I've bought and I can already see that my Z4MC will have awesome handling when it's been fitted and set up. :D
 
ChawenHalo said:
I'd play around with tire pressure before camber. At high road speeds and off track I would not want a different set up than standard. To be honest on lmy tyres I found it OK on track and I don't mind understeer, theres plenty of right pedal to sort that or a tad of trailbraking to tuck the nose in.
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I agree with all of that. And to add, you can also get around understeer by lifting off and turning in early to get the car using its tyres to scrub some speed off to set up some slip angle before reapplying the loud pedal carefully.
 
ga41 said:
Might your imprecise steering be cause by worn bushings then? :?
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No. When I fitted the Strongstrut to my Z3MC it only had about 8k miles on the clock, and the difference it made was considerable. My Z4MC has only 25k miles on the clock and is as tight as a drum.

I know many people think that a strutbrace has a placebo effect, and it may do with some of the flimsy ones that get fitted, but the Strongstrut is a very solid piece of engineering of an efficient design and therefore satisfies the job it is intended to do. I also have a Strongstrut "butt-strut" on my Z3MC which has a similar effect at the rear of that car.

Unless you've been down the road of modding the suspension you'd never believe the transformation that you can make to the handling of a car.
 
ga41 said:
Might your imprecise steering be cause by worn bushings then? :?
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Watch it island boy :poke:

Anyone changed bushes to Powerflex type ones here? interested to know if they make a difference. :tumbleweed:
 
exdos said:
ga41 said:
Might your imprecise steering be cause by worn bushings then? :?
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No. When I fitted the Strongstrut to my Z3MC it only had about 8k miles on the clock, and the difference it made was considerable. My Z4MC has only 25k miles on the clock and is as tight as a drum.

I know many people think that a strutbrace has a placebo effect, and it may do with some of the flimsy ones that get fitted, but the Strongstrut is a very solid piece of engineering of an efficient design and therefore satisfies the job it is intended to do. I also have a Strongstrut "butt-strut" on my Z3MC which has a similar effect at the rear of that car.

Unless you've been down the road of modding the suspension you'd never believe the transformation that you can make to the handling of a car.
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I thought a strutt brance made the handling more awful on road - as in bumpier choppier ride? :?
 
ChawenHalo said:
Anyone changed bushes to Powerflex type ones here? interested to know if they make a difference. :tumbleweed:
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When I fit my new suspension, I'll take a proper look at the rear suspension and subframe. If the large subframe bushes have voids in them, like on the Z3MC, then I shall make some inserts to put inside the voids because this is a very effective, cheap and simple solution to improving that sort of bushing. I have solid polyurethane bushes on my Z3MC which make a noticeable difference.
 
ChawenHalo said:
I thought a strutt brance made the handling more awful on road - as in bumpier choppier ride? :?
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Not for me it doesn't. From my past experiences, fitting the strut brace and adjustable suspension were always at the top of the list for me with the Z4MC. The choppy ride of the Z4MC is all down to the stiff rear springs and hard rebound damping.
 
exdos said:
ChawenHalo said:
I thought a strutt brance made the handling more awful on road - as in bumpier choppier ride? :?
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Not for me it doesn't. From my past experiences, fitting the strut brace and adjustable suspension were always at the top of the list for me with the Z4MC. The choppy ride of the Z4MC is all down to the stiff rear springs and hard rebound damping.
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Chawen is right IMHO, it sharpens up the front end but on rougher surfaces, i.e. most of my local roads, it made the car even more uncompromising, choppier with more tramling and pulling at speed. After some testing I removed mine and sold it on for that reason.

Others on here also had the same experience and remove the middle bar for road driving.
 
Beedub said:
John what suspension have you choose?? The AST top line units are great.
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I got fed up of trying to deal with Curtis for the AST suspension. I couldn't believe how hard it could be trying to give someone my business!

I've gone for the AC Schnitzer Racing suspension. I prefer not to have to fit spacers just to make a suspension system fit, which can cause rubbing issues and can be a pain with the MOT and the ACS set up isn't a coilover set up so is a straight swap for the OEM. I also want to keep the OEM top mounts and don't see any need for fitting camber plates because there is already some adjustability for camber with the strut towers. I know the AC Schnitzer Racing suspension for the Z3MC is very good, so I fancy trying this. It's essentially the Bilstein B16 PSS9 kit but made specifically to AC Schnitzer's specification for the Z4MC. I'll discover in due course whether I like it.
 
daz05 said:
Chawen is right IMHO, it sharpens up the front end but on rougher surfaces, i.e. most of my local roads, it made the car even more uncompromising, choppier with more tramling and pulling at speed. After some testing I removed mine and sold it on for that reason.

Others on here also had the same experience and remove the middle bar for road driving.
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TBH the OEM Z4MC handles pretty similar to the way the OEM Z3MC does with uprated ARBs and stiff rear suspension. The StrongStrut was the first mod I did to my Z3MC and it's been on for 9 years and I wouldn't dream of taking it off. The front suspension of both Z3MC and Z4MC are almost identical.

I live in the sticks and have to drive for at least 6 miles on the twisties with uneven surfaces to get anywhere, so my experience seems to be somewhat different to that of others. I've found that on the Z4MC the Strongstrut has made the steering so much more precise and has partially got rid of that floaty feeling on hard acceleration that I despised. Stiffer springs with my new suspension will sort out the rest of that problem. IMO, the OEM strutbrace is a bad design because it has a bend in the bar in the wrong plane and IMO the StrongStrut does what it is supposed to do and helps to preserve the static geometry in dynamic situations, which helps to make the car handle in practice more in line with the way that it was designed to do in theory. Does anyone else on here have a StrongStrut strutbrace?
 
I use the OEM strut brace on the track but I take out the centre bar on the road for insurance reasons. Once or twice I've forgotten to do so and I've found that on really awful road surfaces it can be as Daz05 describes...but I'm talking about roads that would break an entire crate of eggs on the seat of a 2CV :D

I must say that on the track the best mod I've done that markedly decreased understeer was binning the OEM Contis on the front in favour of Michelins (I actually quite like the Contis on the rear - thanks Flimper!)
 
exdos said:
Beedub said:
John what suspension have you choose?? The AST top line units are great.
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I got fed up of trying to deal with Curtis for the AST suspension. I couldn't believe how hard it could be trying to give someone my business!

I've gone for the AC Schnitzer Racing suspension. I prefer not to have to fit spacers just to make a suspension system fit, which can cause rubbing issues and can be a pain with the MOT and the ACS set up isn't a coilover set up so is a straight swap for the OEM. I also want to keep the OEM top mounts and don't see any need for fitting camber plates because there is already some adjustability for camber with the strut towers. I know the AC Schnitzer Racing suspension for the Z3MC is very good, so I fancy trying this. It's essentially the Bilstein B16 PSS9 kit but made specifically to AC Schnitzer's specification for the Z4MC. I'll discover in due course whether I like it.
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I've looked at that with Dan at ACS UK. Its good value I think and reassuring that its been thouroughly developped. Thing is its for 19" wheels I think.
 
ChawenHalo said:
I'd play around with tire pressure before camber. At high road speeds and off track I would not want a different set up than standard. To be honest on lmy tyres I found it OK on track and I don't mind understeer, theres plenty of right pedal to sort that or a tad of trailbraking to tuck the nose in.
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Thanks I'll see how I get on, it was more a general question for tyre wear as I'd hate to roll off the edges of the tyres and scrub them off. I haven't found the car to be understeery yet though so it may be ok as you suggest.
 
ChawenHalo said:
I've looked at that with Dan at ACS UK. Its good value I think and reassuring that its been thouroughly developped. Thing is its for 19" wheels I think.
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I like the look of the OEM 18" wheels and won't be changing them, I know from my past investigations of brake temperatures that the design will also be one of the best for cooling too. If the ACS suspension has been designed around 19" wheels, and since the tyre walls form part of the suspension "spring", then I would expect that it might just mean that I'll use slightly stiffer suspension settings than those ACS recommends. At the end of the day, I set up my suspension to the way I like the car to handle and the settings are irrelevant as long as the range of adjustment is sufficient wide to give very soft and rock hard extremes. :thumbsup:
 
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