BILSTEIN B12-Pro-Kit Advice

[Tinker15]

I’ve been reading a number of threads recently on E89 handling but I’m still a bit confused.com! So maybe I can seek the advice of those more experienced than myself.

My car is a late 2009 sDrive 30i automatic with standard suspension and about 43000 on the clock. For most of the summer months it is here in France where the roads locally are twisty but by and large well metalled i.e good driving roads. To get here it is mainly long distance cruising on motorways and autoroutes. The tyres are non run flats on 19inch wheels.

I can get the kit locally in the UK for £700 plus £175 fitting and £80 for 4 wheel alignment.

So my questions are:
1 Does the price appear reasonable?
2 I appreciate this should improve handling on the twisty roads but will it adversely effect the comfort when on motorways?
3 There appear to be two alternative shocks supplied the B6 or B8. What is the difference and which one should I go for?
4 The blurb says it will lower the car by approximately 25mm at the front and 12mm at the rear. Are these figures accurate? I don’t want the car to be too low.
5 Is there anything else I should be aware of good or bad before I spend my pension on this upgrade?

Thanks in anticipation.

[Pbondar]

The B6 is the touring version with milder damping for use with standard length springs..

B8 has more aggressive bump n rebound damping designed to be fitted to M Sport E89 springs or equivalent Eibach , body of the damper shorter to suit these springs.

I used bmw Oe m sport brings with B8 and it works very nicely..comfort is good n body control / handling much improved..

Many people find the Eibach springs a bit to harsh for normal street use...

Some people reported quality issues on e85 versions..I’ve nor heard of any E89s with issues..

Would I fo it again ? Yes

Price seems ok ish but I would just get the B8 dampers and get some Oe m sport springs from autodoc..

All imho

[mcbutler]

I have a 35i so same weight as your car (give or take a few KG). I fitted the Eibach springs a few months back, but no dampers (yet). They lower the car a little, flatten out your cornering and are beautifully smooth for cruising.
Make sure you replace all the rubber spring seats at the same time...

[Tinker15]

Thanks very much for replying. I’ve looked on Autodoc (so many springs!) but how to I tell which are the m sport springs. Do they have a name or number?

[Silverstar]

Thanks very much for replying. I’ve looked on Autodoc (so many springs!) but how to I tell which are the m sport springs. Do they have a name or number?

If you put the BMW part number in Autodoc you will see all compatible items to that part number. You can get the part numbers for M Sport springs from realoem

[Pbondar]

https://www.autodoc.co.uk/suplex/8677118

https://www.autodoc.co.uk/suplex/8677085

Suplex / Sachs / lesjofors are OE suppliers...

If you are sourcing B8 dampers you want the M Sport / Auto combination if you’re going down that route..

Slightly different spring rates on auto vs manual

[Tinker15]

https://www.autodoc.co.uk/suplex/8677118

https://www.autodoc.co.uk/suplex/8677085

Suplex / Sachs / lesjofors are OE suppliers...

If you are sourcing B8 dampers you want the M Sport / Auto combination if you’re going down that route..

Slightly different spring rates on auto vs manual

Thank you for the links it’s very helpful. And thanks to everyone who has responded it’s much appreciated. I’m not back in the UK until October so it gives me time to think things over.

[mkinternet]

Hi

I have a 30i 2010 and have fitted the Bilstein b12 kit (b8 shocks and eibach springs). Much better handling, reduced roll and much less wollowy (if there’s such a word). Overall a big and satisfying improvement and well worth the money. from me

[Tinker15]

Hi

I have a 30i 2010 and have fitted the Bilstein b12 kit (b8 shocks and eibach springs). Much better handling, reduced roll and much less wollowy (if there’s such a word). Overall a big and satisfying improvement and well worth the money. from me
[/ quote]
Thanks for letting me know. I’ve not decided on Eibach or M sport springs at the moment but erring towards the Bilstein B12 kit as a company I know will supply and fit at a reasonable price. Decisions, decisions!

[MACK]

Hi

I have a 30i 2010 and have fitted the Bilstein b12 kit (b8 shocks and eibach springs). Much better handling, reduced roll and much less wollowy (if there’s such a word). Overall a big and satisfying improvement and well worth the money. from me
[/ quote]
Thanks for letting me know. I’ve not decided on Eibach or M sport springs at the moment but erring towards the Bilstein B12 kit as a company I know will supply and fit at a reasonable price. Decisions, decisions!

I've got the B12 Kit on mine, it's made a huge difference on an M Sport suspension equipped car, Tinker yours looks like it will be on SE suspension so the difference will be even more pronounced.

Some of the below is originally from what I posted when I installed it, some I've updated since in another thread.

The car is massively transformed. It's so much more composed, less jittery and more sure footed on the on the road. It seems to hug the road much more. This was evident to me before I even drove it, as I followed it to and from my friends garage pre and post fitting. You could literally see it wasn't bouncing around as much on the road on the way back. I even got a call from my wife who was driving it to tell me how much of an improvement she thought it had made. High praise from someone who normally relishes the opportunity to tell me she thinks a mod hasn't made much difference!

There's also a fair bit less roll in the bends, which was a major aim for me. There's still a bit more than I'd like, but I'm hoping a move to either Eibach or H&R ARB's, particularly with their bigger rear bar (21mm) will sort the rest of this. The E89's (all models) run a 19mm rear, which is the same size as my 3.0l E85. When you consider how much more heft there is to control on an E89 and also the fact that BMW fitted a 21.5mm to the E85M. It does seem the factory one is definitely a bit on the small/soft side.

I think the thing that has surprised me the most is the ride quality. It feels better than it did on the 8 year old 70k M Sport suspension, a noticeable improvement. I was actually expecting it to feel a bit harder. All in all I'm very pleased with the outcome, as with any mod it can be a bit of a risk and I did have visions of it being too harsh and potentially having to resort to taking it all back off. Thankfully the opposite is true and has for me at least proved there's lots of room for improvement modding the E89 chassis.

[Tinker15]

I've got the B12 Kit on mine, it's made a huge difference on an M Sport suspension equipped car, Tinker yours looks like it will be on SE suspension so the difference will be even more pronounced.

Thanks MACK. Very helpful information. Yes, mine is the SE suspension. Looks like I’m going to have to bite the bullet when I’m back in the UK and spend a few bob!

[Ed Doe]

I’ve been reading a number of threads recently on E89 handling but I’m still a bit confused.com! So maybe I can seek the advice of those more experienced than myself.

My car is a late 2009 sDrive 30i automatic with standard suspension and about 43000 on the clock. For most of the summer months it is here in France where the roads locally are twisty but by and large well metalled i.e good driving roads. To get here it is mainly long distance cruising on motorways and autoroutes. The tyres are non run flats on 19inch wheels.

I can get the kit locally in the UK for £700 plus £175 fitting and £80 for 4 wheel alignment.

So my questions are:
1 Does the price appear reasonable?
2 I appreciate this should improve handling on the twisty roads but will it adversely effect the comfort when on motorways?
3 There appear to be two alternative shocks supplied the B6 or B8. What is the difference and which one should I go for?
4 The blurb says it will lower the car by approximately 25mm at the front and 12mm at the rear. Are these figures accurate? I don’t want the car to be too low.
5 Is there anything else I should be aware of good or bad before I spend my pension on this upgrade?

Thanks in anticipation.

1. Price appears reasonable. Always worth checking through German Ebay to see if you can get them cheaper - I think I got my brand new B12 kit (admittedly for my E86 coupe) for a shade over £500 a few years ago through a German tuning company on German ebay.
2. I found the ride was noticeably firmer, but then that was what I was going for. The B12 kit undoubtedly compromises the car on rougher roads. It is definitely tuned to smoother roads and faster driving - it works well at higher speeds, but can be a bit busy and 'skip' over imperfections at lower speeds. Ultimately I wanted a car that was daily-friendly but a bit more track biased without the faff ofmucking about adjusting compression/rebound rates - the B12 kit filled the brief well for me.
3. B6 & B8 Dampers offer the same damping characteristics, however the B8 is designed for a lowering spring and as such has a shorter stroke, whilst the B6 is designed for OE ride height so has a longer stroke. For reference, the B4 is the OE equivalent Damper. The B12 kit comprises Eibach Pro lowering springs and B8 Dampers - these are a matched set so work well together, and worth going for if you are looking to lower the car in addition to modifying the dampers.
4. I can't comment on precise ride height reductions but I dailied my E86 Coupe for 3 years (~25k miles) on the B12 kit and found the lowering didn't cause any real issues at all.
5. I was fairly impressed with the dampers, but please be aware my nearside front damper failed after less than 25k miles and within 3 years of fitting - a seal burst and all the oil left the damper, resulting in effectively NO damper travel at all. I tried to claim warranty from Bilstein but they didn't want to know. I had to therefore purchase a new front pair which was somewhat frustrating. From what I understand this isn't an isolated incident, and there are mutterings that Bilstein's road dampers aren't really very good any more... Make of that what you will.

EDIT

Info on B6 vs B8 Dampers from Bilstein website for info

https://www.bilstein-shocks.co.uk/blogs ... ilstein-b8

[Pbondar]

Some observations on what was posted above...

It seems that the ride behaviour with Bilstein B8s on E85s is harsher than the B8 on E89s based on multiple posters feedback..

Although B6 and B8 share the same damping g technology the damping rates are not and could not be the same given different spring rates of the different springs...Bilstein state that B8s are ‘tuned’ for each car ..B6s aren’t so the ‘tuning’ must be to do the dsmomg rates..

[Ed Doe]

Some observations on what was posted above...

It seems that the ride behaviour with Bilstein B8s on E85s is harsher than the B8 on E89s based on multiple posters feedback..

Although B6 and B8 share the same damping g technology the damping rates are not and could not be the same given different spring rates of the different springs...Bilstein state that B8s are ‘tuned’ for each car ..B6s aren’t so the ‘tuning’ must be to do the dsmomg rates..

Nothing more dangerous than anecdotal evidence, but to some extent I agree. I'd suggest the e89 being a) heavier and b) designed as much more of a gt than the e85/6, and so has a much softer setup as standard. I'd therefore suggest the bilstein kit has more of a tightening effect on the e89, whilst the additional weight also softens the effect of the firmer damping.

You're simply incorrect in your assertion regarding b8 and b6 comparison however - as is clearly indicated in the link I posted. How could any damper be specifically tuned to multiple springs and rates, irrespective of the ride height, and indeed the type of spring (linear vs progressive). No both dampers are designed to offer the same 'damping' compression and rebound, but suited to different strokes to cope with the oe spring height or the lowered spring height. I did a lot of research at the time I purchased my bilsteins, and in fact the damper unit part number is the same for all engines for the e85/6, and it will be the same for the e89. This despite a significant difference in weight between the engines, and also weight distribution.

When looking at 'performance' suspension (or indeed any performance component for cars), it is worth remembering the following;
To someone wanting more mass or roll control, a firmer damper will of course feel like a step on from an oe damper - but without any necessity for performance metrics there's absolutely no desire from a company like bilstein to optimise the damper to a specific application. Compare this to a competitive situation - Racing teams will have different ride heights and springs with different rates for every single track they race on, and indeed for dry or wet running, along with optimised damper compression and rebound settings to suit - this is to achieve the best laptime - ie a performance metric in a specific application. By contrast an aftermarket tuning manufacturer has a far broader operational range to try to make a damper work in, and no performance metric except for it to feel sportier than (let's be honest) a tired oe damper, which is what most of us will directly compare it to after replacing them on our cars.

[MACK]

I agree with the above that the B8 is the same dampener as the B6, but with a shorter rod length. It's the info I got from Bilstein pre fitting B4's with Eibachs to my E85. I did get a few recommendations on here and other forums to try B4's with Eibachs on the E85 instead of the B8's and Eibachs (B12 Kit) as the B12 is really quite harsh on that particular car. In fact I was told it's quite bouncy on uneven roads affecting progress and is much better suited to track use.

Before I fitted the B12 kit to my E89 I was quite concerned the above might also apply, but a few folks recommended it and I thought the E89 is starting from a softer base so I'll take the chance, fully aware I might be taking it back off quick smart. Fortunately it worked out and my thoughts on the B12 kit on the E89 are posted earlier in this thread, so I won't bore you by repeating them, however what I will say is that the B4s with Eibachs on the E85 is way harsher than the B12 kit on the E89. I can say this with a degree of confidence as I've driven then both back to back with exactly the same set of wheels and tyres rotated from one car to the other.

The B12 kit if anything is more compliant on my E89 than the 70k M Sport stuff that came off and road holding is much improved. Obviously fresh vs old dampeners will make a difference, as will the different dampener ratings. But this will also be due in part to the Eibach springs, as Eibach claim they start off at a more compliant rate than the M Sport springs that came off.

Price wise I sourced mine via ebay germany too, it worked out a fair chunk cheaper and delivery was swift