Z4 Coupe 3.0SI *Stiffer springs*

R

rocky79

Member
Hello,

I am looking to reduce the body roll on my 2007 Z4 coupe W sport suspension. ( 153,000 miles)
I already installed Koni Yellow Shocks.

My question is will the Eibach pro Springs E10-20-010-04-22 work well? Tuner shop says that they are for the Z4M Coupe and will not fit my car.
I don’t want aggressive lowering, only 20mm Front, 10mm rear. The ones for the Z4 coupe have pretty aggressive lowering.

Has anyone tried them on a stock Z4 coupe? Any recommendations is appreciated

https://www.tunershop.com/eibach-springs-20-10mm-e10-20-010-04-22-for-bmw-z4-coupe-e86-z4-e85-pro-kit.html
 
The H&R have excessive lowering. I don’t want to go too low.
The Eibach pro lowers 20mm Front, 10mm rear.
My main concern is fitment on my Z4 Coupe.
 
rocky79 said:
The H&R have excessive lowering. I don’t want to go too low.
The Eibach pro lowers 20mm Front, 10mm rear.
My main concern is fitment on my Z4 Coupe.
Click to expand...

They are not really a stiff spring. You will still get body roll.

I think you would get all you wanted out of a set of adjustable coilovers.
 
Not really looking for coilovers.
The Eibach are stiffer than stock for sure and that’s what i am looking for.

The question is still open, will the Eibach pro Springs E10-20-010-04-22 work on the Z4 non M coupe? and if anyone has tried them.

Thank you
 
No offense but you seem really set on trying to reinvent the wheel wheel which in this case will turn out more like a square.

Will it fit? It could depending on whether the top mounts are same for M and non-M, but I guarantee it will ride like crap. You want stiffer springs without the aggressive drop and so perhaps your thinking is the Z4 M will suit your needs based on its advertised drop. But you're ignoring the fact that the Z4 M's factory suspension is lower to begin with so even a moderate drop for the M will translate into a relatively bigger drop your car. Not to mention the weight of the cars is very different. IIRC the S54 is heavier by 150lbs or so the the M spring rates aren't compatible with the 3.0si.

I would just buy springs intended for your model. If any of those options are not appealing, then just get an adjustable or thicker front sway bar which will effectively increase the spring rates. My first year tracking with my old si was stock suspension + H&R sway + Dinan fixed camber plates and I thought it handled great both on street and track.
 
dubbedown said:
will it fit? it could depending on whether the top mounts are same for m and non-m, but i guarantee it will ride like crap. you want stiffer springs without the aggressive drop and so perhaps your thinking is the z4 m will suit your needs based on its advertised drop. but you're ignoring the fact that the z4 m's factory suspension is lower to begin with so even a moderate drop for the m will translate into a relatively bigger drop your car. not to mention the weight of the cars is very different. iirc the s54 is heavier by 150lbs or so the the m spring rates aren't compatible with the 3.0si.
Click to expand...
Good point and i realized that after posting. different springs based on front and rear loading which is not the same between M & non M

dubbedown said:
i would just buy springs intended for your model. if any of those options are not appealing, then just get an adjustable or thicker front sway bar which will effectively increase the spring rates. my first year tracking with my old si was stock suspension + h&r sway + dinan fixed camber plates and i thought it handled great both on street and track.
Click to expand...

Great advice. I didn’t know about the stiffer sway bar. Would you still recommend them?
My main issue with the suspension is there is a quite a bit of body roll when I hit the mountain twistees.
Btw,
This is the Eibach spring kit for the 3.0SI - Let me know your thoughts on them. I don’t mind a mild drop but i still want the car
to have good ride quality for daily driving.
https://www.tunershop.com/eibach-springs-30-20mm-e10-20-010-05-22-for-bmw-z4-coupe-e86-pro-kit.html?srsltid=AfmBOoqptlVXkA-wTWGAZyWBWtRj_18Z7m1qnKAk523p59MxqBgU7ywm
 
I would not recommend aftermarket spring unless you have a strut to match. If your Koni yellows are for oem spring heights, I would stick with that. I think the car sits pretty low as-is, anything lower will just cause headache later (fender rub, bumper scrape, riding on bump stops). But to answer your question, I think the H&R front sway will help with spring rates. Don't bother with the rears, do fronts first and see how you like it.
 
Dubbedown said:
I would not recommend aftermarket spring unless you have a strut to match. If your Koni yellows are for oem spring heights, I would stick with that.
Click to expand...
I have this koni yellow. It says "Best Koni shock for all lowering springs, featuring adjustable damping".
This should work in case I went this route, right?
https://www.ecstuning.com/b-koni-parts/shock-strut-kit-sport/z4konisport/

Dubbedown said:
But to answer your question, I think the H&R front sway will help with spring rates. Don't bother with the rears, do fronts first and see how you like it.
Click to expand...
Thanks for the advice.
Would you recommend this part? it’s 27mm
https://www.ecstuning.com/b-h-and-r-parts/front-sway-bar-27mm/70276/
 
rocky79 said:
I have this koni yellow. It says "Best Koni shock for all lowering springs, featuring adjustable damping".
This should work in case I went this route, right?
https://www.ecstuning.com/b-koni-parts/shock-strut-kit-sport/z4konisport/
Click to expand...

Yes those Koni sports were intended for lowering springs like Eibach, H&R, etc.


rocky79 said:
Thanks for the advice.
Would you recommend this part? it’s 27mm
https://www.ecstuning.com/b-h-and-r-parts/front-sway-bar-27mm/70276/
Click to expand...

That is correct bur FWIW, the factory 27mm Z4 M front sway bar should fit the 3.0si. You can't buy them new anymore but they pop up on eBay pretty frequently and go for less than half of what that H&R bar would cost you. And should you go the used M route, you may want to replace your stock bushings.

Fwiw, I would not replace springs & front sway at same time as you may find the ride too jarring, especially on uneven pavement. I would do one or the other and take it from there. If you don't mind inconvenience/hassle of lower ride height, go springs first, else front sway bar... but that's just me.
 
Dubbedown said:
That is correct bur FWIW, the factory 27mm Z4 M front sway bar should fit the 3.0si. You can't buy them new anymore but they pop up on eBay pretty frequently and go for less than half of what that H&R bar would cost you. And should you go the used M route, you may want to replace your stock bushings.
Click to expand...
Great advice. I appreciate it.

Dubbedown said:
Fwiw, I would not replace springs & front sway at same time as you may find the ride too jarring, especially on uneven pavement. I would do one or the other and take it from there. If you don't mind inconvenience/hassle of lower ride height, go springs first, else front sway bar... but that's just me.
Click to expand...

Since my car has the sport package it’s already lower by about 15mm than the standard non sport package.
The Eibach pro springs drops 30mm from the standard package so I am essentially getting additional 15mm drop. It’s still significant but not too bad.
The car stock is already barely comfortable on long drives( stock springs + Koni yellow sport) , Since you mentioned it, I am leaning towards doing the sway bars instead.

PS: I noticed the Eibach pro springs for the 3.0SI are linear for the front and progressive for the rear. The M version are progressive all around.
 
rocky79 said:
PS: I noticed the Eibach pro springs for the 3.0SI are linear for the front and progressive for the rear. The M version are progressive all around.
Click to expand...

Not sure where you read that but Eibach pros are not linear.

Either way, I would go sway over springs as well. Even at stock heigh, M or non-M barely get by without scraping. I just repaired/replaced a bunch of plastic from. It’s crazy how much these go for new (assuming you can even get them at the dealership).
 
Dubbedown said:
Not sure where you read that but Eibach pros are not linear.
Click to expand...
Only the fronts. The Technical sheet for the springs straight from Eibach website.
 

Attachments

  • eibach tech.jpg
    eibach tech.jpg
    187.7 KB · Views: 415
  • eibach .jpg
    eibach .jpg
    95.6 KB · Views: 415
The original Eibach Pro-kit (at least what was offered in US) came with two different part numbers. Pre-facelift models were assigned P/N 2073.140. Facelift models were assigned P/N 20102.140. I assumed you were referring to one of these kits, both of which featured progressive springs front and rear.

However, when I look up P/N E10-20-010-05-22, I see this is the latest offering and is described as "part of the B12 Pro-Kit chassis kit", which I take to mean the same as the Bilstein B12 kit. I guess Eibach offers a springs-only option for those who don't want to buy a spring/shock combo and calling it the [new] Pro-kit.

But here's what I find really interesting -- the P/N for the Bilstein kit is 46-181237 and that kit appears to be packaged with progressive springs: https://www.bimmerworld.com/Suspension-Steering/Suspension-Packages/Bilstein-B12-Pro-Kit-Front-and-Rear-46-181237.html

And to the extent BW used generic stock photos, or say US and Euro markets get different hardware, I checked Schmiedmann and they have actual pictures of the kit which also show progressive springs. (Ignore the fact it says E89 as the pictures clearly show it installed on an E85). https://www.schmiedmann.com/en/product/1962289-new?product=46-181237#gallery-9

So unless there’s 2 versions of the B12 kit, all of the above leads me to believe that either the spec sheet may be incorrect OR my eyes are playing tricks on me and those are in fact linear springs in the B12 kit. Admittedly I am getting older but those front coils look unevenly spaced to me.

Not that any of this matters since you made up your mind on the sways but figured I'd post these P/Ns in case others encounter the same question.
 
rocky79 said:
Dubbedown said:
spec sheet may be incorrect
Click to expand...
I emailed eibach tech support and they confirmed that the fronts are linear :)

What size wheel spacers would you recommend front and back?
Click to expand...

:thumbsup:

Curious, did you ask if they’re the same ones in the Bilstein kit?

Install suspension first, get alignment done and then decide spacer size. Too many variables at play between static camber, wheel and tire sizes to guess in advance.
 
Dubbedown said:
Curious, did you ask if they’re the same ones in the Bilstein kit?
Click to expand...
No, I didn’t.

Dubbedown said:
Install suspension first, get alignment done and then decide spacer size. Too many variables at play between static camber, wheel and tire sizes to guess in advance.
Click to expand...
Alignment before spacers? I am guessing it should be after, no?
 
rocky79 said:
In case the spacers do affect the alignment somehow.
Click to expand...

Spacers go on your hub, independent of alignment settings. Dial in suspension and alignment first. Do spacers last to fine tune offset / stance. You don’t want to optimize your alignment based on the spacers you run.
 
You must log in or register to reply here.
Back
Top Bottom