Suspension change

G

Gareth161

Member
 Cornwall
Have just changed from a 2.8 Z3 to a 2004 3.0 Z4 and love the additional creature comforts and the much improved roof.
However not quite so sure about the ride as seems much firmer and tends to wander on a poor road surface(plenty of those around!!).
Obviously with the sports suspension, the car sits lower which is no problem but is there anything I can do to improve the ride.
Car came with an odd mix of tyres so thought that might be the problem so have just changed to 4 new 18 inch Yokohama Advant sport v105 tyres which has only helped slightly.
Probably not a common done thing, but can these cars be fitted with standard springs as on the non sports suspension cars (presumably would also need new shocks), or would it throw everything out?
If yes, would it make a noticeable difference or is it just a case of me getting used to the different feel of the car.
Thanks for any advice/comments
Gareth
Will post some pictures when it stops raining enough to take some!!
 
Eibach springs will make the ride less crashy but will lower it further. If that's not an issue for you then they are a good bet and cheaper than the snap-happy OE springs.
If you plan on keeping long term and have a relatively high miler then you could also consider shocks. My ride is great now on B8 dampers, the rear shocks were very tired at 80k though still serviceable.
The other option is coilovers allowing you to select the ride and height you like. BC seem to have a reasonable price point but I have no experience of them.
The wandering was helped on mine with a set of Poly RTABs. Again, depending on mileage/budget/how long you'll be keeping a proper refresh with new control arms, ARB bushes etc. will improve the ride and feel no end.

If you decide to go for std OE springs then you can keep your own shocks.
 
Thanks for the useful info.
Don't really want to go any lower as speed bumps are already a pain and if anything a slight increase in height would be good as wont be driving car that hard around corners.
Mileage is 73k and as far as I know still on original shocks although from the mot history, there was a broken rear Spring a few years back and presumably replaced to pass mot?
Who makes the b8 shocks as not heard of them
Gareth
 
B8 are Bilstein HD (Heavy Duty) absorbers that are meant for lowered springs.

Are the new Yoko tyres you fitted runflats? The car will tend to tramline but a good alignment should minimise it.

Yes, you can opt for the non M sport springs and absorbers which should raise the height by 10-15mm or so and will definitely improve ride quality. If the absorbers have never been changed before, they might be on their way out. Check to see if there is oil webpage around the shock body.
 
Thanks
The Yokos are not run flats as did read that run flats give a bad ride and the tracking was checked & OK.
Any recommendations for what I need to actually buy to change to nom M springs and shocks?
Presumably I should keep what I take off in case I ever resell and the new owner wants the lower springs?
Regards
Gareth
 
I think it will just be the 4 pcs of springs and 4 pcs of shock absorbers that you need to change/swap out. Part numbers I don't have but you should be able to get them off realoem.com
 
Following on from the above good advice, does anyone have a standard suspension set up lying around (in good condition) which they have taken out when upgrading to a sports suspension which they would like to sell?
Have also just done the DISA valve using one of the eBay kits and fairly straightforward.
Gareth
 
Hi OWM
Thanks for the info but still having trouble working out which are the non M sport springs/shocks.
Does anyone have any ideas please.
Must take some pics of car & post on Newbies section!!
Thanks
Gareth
 
Have you tried inputting your car VIN no. on realOEM.com? You will get the part numbers there.

Else you can check here as well:
https://www.ecstuning.com/BMW-Z4-3.0i-M54_3.0L/Suspension/Springs/
 
Hi OWM
Thanks - I did try realOEM and found the 2 different numbers for the shocks but nothing re the springs?
Will try the above link.
At least the DISA valve has now been done with the Ebay kit and hood re proofed- Amazing what you can do when its not raining every day!!
Gareth
 
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