Need some advice regarding BC Racing kits and other suspension refurbishment

G

ga41

Veteran
 Paphos
Hello all, long time no see. Still have my Z4MC, driving it very rarely now but not planning on selling any time soon!

Last time i was out a several weeks ago i noticed that one corner was sagging, the strut must have collapsed so it's finally time to upgrade.

Im thinking of the BC Racing DS-DS kit with rubber centred top mounts, the RM model with its inverted dampers would be a nice too but i would hardly ever track the car now so not really worth the inconvenience of having the adjustment on the bottom and pillowball top mounts would be wasted and add NVH for a mostly normal and fast-road car i think and for the same reasons (plus cost) I dont want to splurge on KW V3s or Bilstein PSS10s...

Now i do have 12.5mm spacers all around to fit by Stoptech big brake kit, do you think this would be OK with the kit? The kit says it's 5-8kg springs, is this OK or should i go heavier?? Im a bit clueless on this.

What else should I renew since im going to have this done anyway? I guess rear shock mounts? Rogue Engineering? Or something else? What are your suggestions?

I tried reading up as much as i could but i would like to hear your feedback

Thanks!! :thumbsup:
 
Hello,

I installed BC RS coilovers (RA w/ rubber top mounts essentially) last year, I shared all my impressions on my thread, here towards the bottom of the page.

Your spacers/BBK won't affect anything; I run 12/15mm spacers without issues. Just beware of the lack of camber adjustability with the rubber top mounts - without hub spacers - you'll get -0.5° of camber with the struts all the way inboard in the slots. The kit will come with some spacers that allow as low as -1.5°, but I found this wasn't enough for my (fast road) needs/balance preference.
 
Useful post thank you and a great thread! I had the front strut alignment pins removed almost as soon as i got it and got a fair bit of negative camber but i will take that into account
 
I have the entry-level BC BR series with 6/10 springs and am happy with them, although I think I'd prefer a touch stiffer at the front.

From reading the specs it seems the main difference between the DS and the RM is the digressive damping on the DS versus the inverted dampers on the RM. Personally I'd go for the RM for a road car, as digressive dampers can deliver a harsh ride on our bumpy roads. Don't know if the RM series can be had with rubber top mounts, though.
 
Hmm i was not aware of such issues with digressive valving. Our roads here arent much better than the UK... Now im second guessing everything
 
Although my comment about ride was a generalisation - there are so many variables that come into play and a damper that suits one chassis might not suit another. And I've not got any real-life experience driving a Z4 on digressive dampers.

Worth asking BC for their input.
 
I described my driving habits (street and fast road) and car and the sales person told me that the DS would suit my needs better but :idunno:

I just asked a mate of mine who's had both the RM and DS but on different cars and he told me that the difference in ride is very minor and he would choose whichever had the top adjusters because bottom adjustment is a pain in the ass...

Of course different cars, different setups etc..
 
I have the DS on a different car 😀 but impossible to compare that to my Z4.

Digressive can let you get away with softer springs, so a 5/8 digressive setup may possibly (in theory) be comparable to a 6/10 linear setup in terms of ride comfort.

In fact, digressive might suit my needs as I would like more body control at the front end of my Z4 than my 6 kgs linear setup gives me. A digressive damper would provide that, without needing to fit a stiffer spring.

I've probably just confused you further now...
 
:scratchhead:

I think I'll go with DS and be done with it. How bad can it be (famous last words)...

Anyone know what length extenders I would need for the rear adjustment? And other suggestions for accompanying mods/replacements I should do? I don't have an unlimited budget but 200-300 euros on top of the coilovers wouldn't be a problem
 
The usual bits if they they haven't been done recently: front LCAs and lollipops, RTABs, possibly rear axle-csrrier bearings.
 
You must log in or register to reply here.
Back
Top Bottom