Not joined yet? Register for free and enjoy features such as alerts, private messaging and viewing latest posts and topics.

Which Bilsteins for E86 with M Sport suspension option?

2003 - 2009, roadster, coupe, facelift
ionofchios
Member
Member
Posts: 156
Joined: Mon Nov 13, 2017 3:51 pm

Which Bilsteins for E86 with M Sport suspension option?

Post by ionofchios » Wed Dec 13, 2017 7:02 pm

Chris1981 wrote: Wed Dec 13, 2017 1:32 pm
ionofchios wrote: Wed Dec 13, 2017 11:16 am
ph001 wrote: Wed Dec 13, 2017 11:01 am Does the shock really make a big difference to the ‘hardness’ of the suspension anyway? Obviously it controls compression and rebound dsmping but I would have though the hardness is primarily down to the stiffness of the spring.
I guess the more it damps, the more it stops the spring compressing as fast as it otherwise would, so it will be 'harder'.
When i went from OEM to B8's the ride firmed up significantly... although my OEMs were 90k miles old and completely shot!

I believe you've come to this conclusion yourself already but if you have M Sport you need the B8's, image below is front B6 and OEM M Sport, I made the mistake of ordering B6s as I read they are fine to replace M Sport and cheaper than the B8's while offering the same damping rate... but I didn't feel comfortable fitting something so different and the supplier was kind enough to do a straight swap to the B8s!

IMG_0953.JPG
Good pic!

Right, so now I am going to let you all know how dumb I really am :cry: How can it be that the strut designed for lowered springs (the OEM M Sport in the pic) has a longer body than the strut designed for standard sprin (the B6 in the pic)? Wouldn't that mean that the strut does affect ride height? If the flange on the strut the spring sits on is further away from the wheel on the B8/ OEM M Sport strut, doesn't that negate the effect of the shorter springs - so you are lowering the car with the springs, but raising it with the longer strut body, in effect?

Until now, I had been imagining that all struts bodies - B4, B6, B8, OEM M Sport, OEM standard, whatever - were the same length, it is just that some are designed for the shorter piston travel of shorter springs and some not.

User avatar
MACK
Lifer
Lifer
Posts: 3600
Joined: Mon Jun 15, 2015 11:38 am
Location: Manchester

Which Bilsteins for E86 with M Sport suspension option?

Post by MACK » Thu Dec 14, 2017 8:07 am

Chris1981 wrote: Wed Dec 13, 2017 1:32 pm
ionofchios wrote: Wed Dec 13, 2017 11:16 am
ph001 wrote: Wed Dec 13, 2017 11:01 am Does the shock really make a big difference to the ‘hardness’ of the suspension anyway? Obviously it controls compression and rebound dsmping but I would have though the hardness is primarily down to the stiffness of the spring.
I guess the more it damps, the more it stops the spring compressing as fast as it otherwise would, so it will be 'harder'.
When i went from OEM to B8's the ride firmed up significantly... although my OEMs were 90k miles old and completely shot!

I believe you've come to this conclusion yourself already but if you have M Sport you need the B8's, image below is front B6 and OEM M Sport, I made the mistake of ordering B6s as I read they are fine to replace M Sport and cheaper than the B8's while offering the same damping rate... but I didn't feel comfortable fitting something so different and the supplier was kind enough to do a straight swap to the B8s!

IMG_0953.JPG
Interesting that the B8s firmed up the ride alot over knackered old 90k suspension. Your experience confirms what others have said in previous threads and that they're supposed to be uprate anything from 10 to 30%. It's the main reason I have held off fitting them to mine. I may go down the B4 route instead now.
Silver 05 3.0i SE
Mods inc - F/L Xenons Clear Ind Rear Lights M Sport Seats & Wheel Eibach/B4 3.64 DIFF (SOLD)

White E89 20i M Sport
Mods inc- B12 kit, M3 Arms, 18" Zito 935's with PS4's, Decat & Remap, Switchable Exhaust Flap (SOLD)

mjennings23
Senior Member
Senior Member
Posts: 1176
Joined: Tue Mar 21, 2017 11:11 pm
Location: North West

Which Bilsteins for E86 with M Sport suspension option?

Post by mjennings23 » Thu Dec 14, 2017 10:10 am

B4s and Suplex MSport replacement springs here, and the ride is like a different car to the old factory parts. Much easier over bumps, but also much more planted and sure footed than the MSport shocks.

Consider however that replacing old shocks, they're going to be pretty worn out by now if they're factory parts.

Chris1981
Member
Member
Posts: 281
Joined: Wed Apr 05, 2017 11:39 am

Which Bilsteins for E86 with M Sport suspension option?

Post by Chris1981 » Thu Dec 14, 2017 10:13 am

ionofchios wrote: Wed Dec 13, 2017 7:02 pm
Chris1981 wrote: Wed Dec 13, 2017 1:32 pm
ionofchios wrote: Wed Dec 13, 2017 11:16 am

I guess the more it damps, the more it stops the spring compressing as fast as it otherwise would, so it will be 'harder'.
When i went from OEM to B8's the ride firmed up significantly... although my OEMs were 90k miles old and completely shot!

I believe you've come to this conclusion yourself already but if you have M Sport you need the B8's, image below is front B6 and OEM M Sport, I made the mistake of ordering B6s as I read they are fine to replace M Sport and cheaper than the B8's while offering the same damping rate... but I didn't feel comfortable fitting something so different and the supplier was kind enough to do a straight swap to the B8s!

IMG_0953.JPG
Good pic!

Right, so now I am going to let you all know how dumb I really am :cry: How can it be that the strut designed for lowered springs (the OEM M Sport in the pic) has a longer body than the strut designed for standard sprin (the B6 in the pic)? Wouldn't that mean that the strut does affect ride height? If the flange on the strut the spring sits on is further away from the wheel on the B8/ OEM M Sport strut, doesn't that negate the effect of the shorter springs - so you are lowering the car with the springs, but raising it with the longer strut body, in effect?

Until now, I had been imagining that all struts bodies - B4, B6, B8, OEM M Sport, OEM standard, whatever - were the same length, it is just that some are designed for the shorter piston travel of shorter springs and some not.
Sorry, the photo is a bit deceptive... the tapered part at the bottom of the OEM extrudes below the front Hub and the Bilstein doesn't. That brings the spring pads inline when fitted on vehicle but makes the height difference even greater.

Bilstein
bilstein.PNG
bilstein.PNG (1.2 MiB) Viewed 1832 times
OEM
OEM.PNG
OEM.PNG (1.34 MiB) Viewed 1832 times
E86 Coupe 3.0si Sport - Montego Blue, Pearl Grey with Piano Black dash
BC BR series Coilovers, powerflex bushes, 15mm spacers, Custom SS exhaust, CDV delete

User avatar
NickDE
Senior Member
Senior Member
Posts: 1170
Joined: Sat Oct 01, 2016 12:21 pm
Location: Newcastle upon Tyne

Which Bilsteins for E86 with M Sport suspension option?

Post by NickDE » Sun Dec 17, 2017 11:36 pm

I'm running B4s along with the Suplex equivalents to the M Sport springs. I'm happy.
Darkness gone, go Darknes2, go Frozen, go Tronic

highway1
Member
Member
Posts: 205
Joined: Fri May 13, 2016 8:57 pm

Which Bilsteins for E86 with M Sport suspension option?

Post by highway1 » Mon Dec 18, 2017 9:20 pm

NickDE wrote: Sun Dec 17, 2017 11:36 pm I'm running B4s along with the Suplex equivalents to the M Sport springs. I'm happy.
Same here. On bumpy british roads, a better choice than B12 kit.

ionofchios
Member
Member
Posts: 156
Joined: Mon Nov 13, 2017 3:51 pm

Which Bilsteins for E86 with M Sport suspension option?

Post by ionofchios » Mon Jan 15, 2018 7:05 pm

I now have all the bits to rebuild the front suspension on my e86 with M Sport suspension: Bilstein B8s (35-124122, 35-124115) and Suplex springs (06248). The instructions that came with the Bilsteins don't show any rubber spring pads at the top and bottom of the springs (RealOEM parts 8, 11 in the diagram), nor any dust protection collar (RealOEM part 5 in the diagram).

So, do I need these parts? I guess the collar is a good idea, as it might keep some crap out of the bearing in the strut mount, but what about the pads?

RealOEM diagram:
http://www.realoem.com/bmw/enUS/showpar ... Id=31_0648

Bilstein instructions attached.

mjennings23
Senior Member
Senior Member
Posts: 1176
Joined: Tue Mar 21, 2017 11:11 pm
Location: North West

Which Bilsteins for E86 with M Sport suspension option?

Post by mjennings23 » Mon Jan 15, 2018 9:50 pm

Pretty sure you re-use the oem spring pads etc. hence the diagram showing them with OE arrows pointing to them. No external bump stop needed on the fronts though as the B8s have internal ones.
Not sure if the same is true for rears.

Edit: effectively against the RealOEM drawing, you re-use 1-2, 4-8 and 11 from what I see. The new struts will have a new locking nut to replace 3 and a dust boot to replace 10, 9 is not needed with B8s.

ionofchios
Member
Member
Posts: 156
Joined: Mon Nov 13, 2017 3:51 pm

Which Bilsteins for E86 with M Sport suspension option?

Post by ionofchios » Tue Jan 16, 2018 7:28 pm

mjennings23 wrote: Mon Jan 15, 2018 9:50 pmPretty sure you re-use the oem spring pads etc. hence the diagram showing them with OE arrows pointing to them. No external bump stop needed on the fronts though as the B8s have internal ones.
Not sure if the same is true for rears.

Edit: effectively against the RealOEM drawing, you re-use 1-2, 4-8 and 11 from what I see. The new struts will have a new locking nut to replace 3 and a dust boot to replace 10, 9 is not needed with B8s.
Cheers!

The only OE-labled parts in the Bilstein diagram are the top spring plate, the washer and the strut mount - I can't see any lower or upper spring pad.

But, regards re-using the parts you list from RealOEM, I reckon you're probably right.

mjennings23
Senior Member
Senior Member
Posts: 1176
Joined: Tue Mar 21, 2017 11:11 pm
Location: North West

Which Bilsteins for E86 with M Sport suspension option?

Post by mjennings23 » Tue Jan 16, 2018 8:30 pm

ionofchios wrote: Tue Jan 16, 2018 7:28 pm
mjennings23 wrote: Mon Jan 15, 2018 9:50 pmPretty sure you re-use the oem spring pads etc. hence the diagram showing them with OE arrows pointing to them. No external bump stop needed on the fronts though as the B8s have internal ones.
Not sure if the same is true for rears.

Edit: effectively against the RealOEM drawing, you re-use 1-2, 4-8 and 11 from what I see. The new struts will have a new locking nut to replace 3 and a dust boot to replace 10, 9 is not needed with B8s.
Cheers!

The only OE-labled parts in the Bilstein diagram are the top spring plate, the washer and the strut mount - I can't see any lower or upper spring pad.

But, regards re-using the parts you list from RealOEM, I reckon you're probably right.
That was the case when I installed my B4 kit, albeit I also used OEM bump stop and dust boot.

ionofchios
Member
Member
Posts: 156
Joined: Mon Nov 13, 2017 3:51 pm

Which Bilsteins for E86 with M Sport suspension option?

Post by ionofchios » Wed Jan 24, 2018 8:17 pm

Got an email reply from Bilstein, and, yes, you are supposed to re-use spring pads and dust collar, and no bump stop, as was mentioned before. Makes sense.

Anyways, I fitted this lot on the weekend and results are good. It sits a bit higher than it did with old suspension, even after a few drives, but that means it is now level with the back - I think there might have been lowering springs on ont he front originally, since there always used to be more clearance in the rear arches than the front.

Feels good - smoother than before, and has made further reduced twitchy, tram-liny steering issue I have been trying to correct. Old struts were not in good shape. Also replaced the dog-bones with Meyle HD at same time, so maybe that is responsible for improving steering.

Now all I need to do is work out why it pulls left under heavy acceleration. Also gonna try https://z4-forum.com/forum/viewtopic.php?f=3&t=100725 to see if it improves steering further.

ionofchios
Member
Member
Posts: 156
Joined: Mon Nov 13, 2017 3:51 pm

Which Bilsteins for E86 with M Sport suspension option?

Post by ionofchios » Wed Jan 24, 2018 8:19 pm

Some pics.

mjennings23
Senior Member
Senior Member
Posts: 1176
Joined: Tue Mar 21, 2017 11:11 pm
Location: North West

Which Bilsteins for E86 with M Sport suspension option?

Post by mjennings23 » Wed Jan 24, 2018 8:46 pm

You mention pulling left, but I see no mention of having a full alignment done? Will absolutely be needed after new struts, guarantee your camber is going to be out at least.

Get it done at a good alignment place and it transforms the car. I couldn't believe the difference in mine.

ionofchios
Member
Member
Posts: 156
Joined: Mon Nov 13, 2017 3:51 pm

Which Bilsteins for E86 with M Sport suspension option?

Post by ionofchios » Wed Jan 24, 2018 8:52 pm

mjennings23 wrote: Wed Jan 24, 2018 8:46 pmYou mention pulling left, but I see no mention of having a full alignment done? Will absolutely be needed after new struts, guarantee your camber is going to be out at least.

Get it done at a good alignment place and it transforms the car. I couldn't believe the difference in mine.
Thanks! Yes, am planning to do that. It pulled left before I touched anything, and I think it still does it, but it is hard to tell, since weather is really bad here at the moment (snow and ice). Am also thinking about changing rear struts as well, so might do that first.

Post Reply