Bilstein B6 on Z3 1.9i stock springs

[hgg]

Hi,

I have the Z3 1.9i 2002 with stock springs (non sport) and its time to replace the shocks.
I do not want to lower the car (terrible roads) so I will be using the stock springs.

According to official Bilstein my only options are either the B4 which is OEM or the B8.
The B8 though is tuned for lower springs so I am thinking on using the B6 instead.

Every store here in Greece is suggesting the B8 and are telling me that if I use
the B6, the front of the car will sit taller at least 1cm because of the high pressure
of the B6s. If this is the case I will reduce the aerodynamic profile of the car and I
do not wan't to do that either.

Does anybody have any experience with this setup? B6 with stock springs?
Do you think that they will raise the front?

Thanks.

 

[DrWong]

hi and welcome from the north of England,

I have no experience of Bilsteins but I recently replaced my non-sport front shocks and springs and wanted to keep it OEM, so went with Monroe Reflex shocks (which are well regarded on here) and Suplex springs. The Monroes are cheaper if you're willing to consider alternatives to Bilstein.

 

[hgg]

Hello,

What about the Bilstein B4 in terms of cheaper solution?

 

[DrWong]

My understanding is B4 is the replacement for standard OEM. It’s what I would’ve gone for if I was getting Bilstein

 

[hgg]

Indeed, I think I will go for the B4s as well.
If they are just a bit tighter than the stock Sachs, I would be happy.

 

[Dino D]

I have fitted B6 to a Ford Smax and they made the car higher on standard springs . They are much firmer than stock and for the Smax designed to deal with greater weight bettter when loaded (which is what I wanted for the family bus). They have improved the handling and squat/dive but feel pretty firm when the cars is not loaded however perfect when it has some people and luggage in..
Not sure if the effect would be the same in Z3 fitment though.

 

[hgg]

Hi, did you notice if the front was raised more than the back?

 

[Dino D]

Hi, did you notice if the front was raised more than the back?

Couldn’t say for sure.

Given the Z3 has a very short spring at the rear it’s hard to tell what the effect would be but you can be sure of one thing- if your car is still on original shocks then they are going to be dead and the car is sitting lower than it was when it left the factory anyway. The bushes at the rear will also be worn which makes the rear squat even more so when you refresh it tends to sit higher.

Personally on a car like this I could only run adjustable shocks as I like to be able to set the height and dampening the way I like it.

We have bad roads here ( a lot of roads on Greece can better than the roads in Kent believe it or not!) so being able to adjust the dampening I find useful.
For example making it soft in winter or very bumpy drives gives much more grip than on the firm setting:

Where in Greece are you?
I’d love to take my Z to Greece and go around the mountains there... (roof down at night only, too hot otherwise!)

 

[hgg]

These are its second set of shocks and it has done 175.000km / 108.000 miles.
I have just replaced the rear subframe bushings with Powerflex polyurethane ones
and have indeed made a difference. Car rear more tight now.

A dealer here in Greece insists that the B6s are going to raise the front by 1cm in comparison
to the rear. I am trying for days to think how is this possible since both rear and front shocks
are monotube high pressure. I can understand a small rise symmetrically but why more in front ???

I lived for two years in Canterbury Kent and another 4 in Essex and don't remember seeing roads
as bad as here in Greece! I live near Athens but I always go for rides on the islands which are
really nice. I used to go around roof down in the middle on the day, Greek sun in full mode, and
I had no problems. I really liked it. Now I am getting old and the sun is bothering me in the morning
and the cold during the night..

 

[Dino D]

Shock last round 70k miles on any car I’ve found, changing around then is always noticeable.

The travel at the rear is very limited due to the set up and the front is a full length coil over so that’s probably why it will be different front to rear?
From the factory they say a bit high at the front.

Seen some amazing older Bmw Rally cars out there, must be some good specialists around Athens for these?

Small world - live in Canterbury and also lived in North Athens for years - for me the roads around Pentelis and down to Drossia/Schinia are epic, even in a 1.4 Clio with 100bhp (it probably the most driving fun I’ve had of any car, big power is useless in some of that shiny smooth tarmac!)

I want to go back to Evia with my Z one day.
Heading to Porto Germanos direction was also good and of course Peloponnesus.

Crete has excellent driving especially rounds the mountains on Channa side. Miss it very much.

The roads in Kent are just diabolical for going out on a good drive with a Z3! Essex and beyond is much better to be fair.

 

[hgg]

Wow! You know all the roads where I live! Small world indeed.
I liked Canterbury a lot. I was there before the dug the whole city ...

Indeed Penteli and Dionysos are excellent for the Z3!
Whenever I need to check any new mods on the car that's where I go to test them.
The most boring road for the Z is a straight road.

I guess you are right about the limited travel or the rear suspension.
It makes sense. I've tested the B6 on a E36 3 series and it was amazing.
I don't really wan't to raise the nose of the Z3 though because it will affect the
weight distribution and the aerodynamics with high speeds.

Maybe I will go for the B4s.

Bilstein suggests for the Z3 1.9 with stock springs the B8s.
It seems wrong to me. They are tuned for shorter springs and the
shocks will work extra hard. Maybe hit the bump stops more easily as well.

 

[Sean d]

Monroe Reflex are a good option, I have put them on 2 Z3s and they are excellent

 

[hgg]

With stock springs? Regular chassis Z3 or M pack?

 

[Sean d]

With stock springs? Regular chassis Z3 or M pack?

I dropped it on Eibach pro -30mm 2.8 z3 and 2.0l z3, I believe @mrscalex has them on standard springs

 

[mrscalex]

I dropped it on Eibach pro -30mm 2.8 z3 and 2.0l z3, I believe @mrscalex has them on standard springs

I used H&Rs (same drop/reputation as Eibachs) on the Monroes I fitted. But I didn't like them (too low) and next time I would use -15mm factory Sport springs. On either a Sport or non-Sport.

I have to say the car handles fantastically though. But you have to be so careful over speed bumps.

 

[hgg]

I am trying to find the part number for the 15mm factory sport springs and I cannot find it.
Do you happen to know the part number for these springs? Thanks.

 

[mrscalex]

I am trying to find the part number for the 15mm factory sport springs and I cannot find it.
Do you happen to know the part number for these springs? Thanks.

BMW don't publish them. You have to talk to a dealer and quote your VIN.

They are approx twice the price of Eibachs. Hence why the Eibachs are so popular.

And no one else makes -15mm springs than BMW. Well if they do I've never found them despite extensive searches.

 

[hgg]

You can find all the part numbers except the springs!
Do they have any magic sauce?

 

[mrscalex]

You can find all the part numbers except the springs!
Do they have any magic sauce?

Yes that's correct. BMW are very protective of the philosophy that each car left the factory with different weights due to different options being fitted.

Though in reality the only difference I can determine around options is whether the car has air-con or not. Yep sounds crazy.

And recently @Lee told us that however it was meant to work when the cars left the factory all the different spring part numbers map to either a Sport (-15mm) or non-Sport (0mm) these days. Even no difference for 4 cylinder or 6 cylinder.

it's a very murky world. And you're probably seeing now why people say stuff it and just fit Eibachs.

Meantime you'll see I have a wanted ad on the forum so I can pick up their old Sport springs they displace

 

[hgg]

all the different spring part numbers map to either a Sport (-15mm) or non-Sport (0mm)

Exactly.

Because I want to fit the B6 on my car (1.9) and it looks like they will raise the front by 10mm I was thinking
if I can replace only the front springs with the M sport 15mm ones and leave the rear stock. This way I will
not change the ride stance and weight distribution.

Is this a good or bad idea?