Damper Choice

[board]

What's the current recommendation for new dampers all round?

I've been looking at Bilstein but haven't been able to get a definitive answer on whether it should be the B6 or B8 for the M variant of the Z. The companies ask if it was specced with sports suspension in which case it would be the B8, which is what I'm leaning towards as in my mind that should be the stock setup with it being an M, but another company said that is not the case and it would be the B6.

I'll keep the original springs as I'm not looking to keep it OEM. I could just go straight to BMW but have been advised by a specialist that the Bilstein dampers would be better over the OEM these days.

Can anyone shed any light please?

 

[Nodzed]

B6 and B8 are the same in performance. The B8 is a shorter rod for lowered cars, B6 longer for standard suspension.

 

[Ianmc]

My (non M) Z3 has a Bilstein B12 suspension kit (Bilstein B8 shocks). Car lowered by about 20mm.

 

[petecossie]

B6 and B8 are the same in performance. The B8 is a shorter rod for lowered cars, B6 longer for standard suspension.

Agreed, I've been looking into this myself as I'm looking at replacing my suspension on my Coupe this year (114k on original struts/dampers, front springs replaced with OEM ones after one spring snapped a couple of years back - only discovered at MOT!!)
If you look on Bilstein UK site it explains all the specifications.
Also looking at OEM units, going to check with BMW Vertu (Boldon) to see what they come with as they have been very supportive with the BMWCCNE monthly meetings and are offering a discount.

 

[board]

B6 and B8 are the same in performance. The B8 is a shorter rod for lowered cars, B6 longer for standard suspension.

So would the M be considered to have sports suspension as the B8 would be used for sports suspension option on a 3.0 Z from what I have been told so far?

 

[board]

With the discount at Soper the OEM is about the same price as Bilstein but talking to my indy he would go with the Bilstein over OEM these days as the quality isn't what it used to be back in 1998

 

[Nodzed]

So would the M be considered to have sports suspension as the B8 would be used for sports suspension option on a 3.0 Z from what I have been told so far?

Yes the M has sports suspension and is 15mm lower as standard than stock non sport. If you are leaving the springs as is and they are oem M springs I would still fit B8s as they are for lowered cars and cars fitted with sport suspension.

I fitted B8s to both my Z3Ms and Z4 e89

 

[Peewee]

I've also been looking at this for my 3.0 sport. I, like you, want to retain my OEM (sport) springs - as new ones are no longer available from BMW (and I'm not aware of a direct aftermarket equivalent).
I've concluded that the choice I have for new dampers is either OEM sport (Sachs) from BMW or Bilstein B6. Ask your indy why he prefers Bilstein as I would go with Sachs every time. Price could be an issue, although with BMW discount the difference between these and Bilstein narrows. I was quoted just over £800 (incl. discount) for a set of OEM Sachs sport dampers from BMW a couple of months back. Not committed yet though!
I would not go to Bilstein B8 matched with OEM sport springs as these dampers are shorter still and matched to the 30/40mm lowering springs as offered in their B12 kit. OEM Sport springs only lower the car by around 15mm and although B8's would likely fit, they are shorter than both the B6 and Sachs sport units. So, depending on how you drive, you have a greater risk of over stroking them.
Also, don't rely solely on information quoted by aftermarket suppliers. Do your own research using manufacturers info.
Let us know what way you decide to go..................

 

[Nodzed]

I've also been looking at this for my 3.0 sport. I, like you, want to retain my OEM (sport) springs - as new ones are no longer available from BMW (and I'm not aware of a direct aftermarket equivalent).
I've concluded that the choice I have for new dampers is either OEM sport (Sachs) from BMW or Bilstein B6. Ask your indy why he prefers Bilstein as I would go with Sachs every time. Price could be an issue, although with BMW discount the difference between these and Bilstein narrows. I was quoted just over £800 (incl. discount) for a set of OEM Sachs sport dampers from BMW a couple of months back. Not committed yet though!
I would not go to Bilstein B8 matched with OEM sport springs as these dampers are shorter still and matched to the 30/40mm lowering springs as offered in their B12 kit. OEM Sport springs only lower the car by around 15mm and although B8's would likely fit, they are shorter than both the B6 and Sachs sport units. So, depending on how you drive, you have a greater risk of over stroking them.
Also, don't rely solely on information quoted by aftermarket suppliers. Do your own research using manufacturers info.
Let us know what way you decide to go..................

That's not the advice Bilstein give, the B8 is only 5mm shorter so fitting the B6 on a suspension 15mm lower than non sport will over compress the shock by 10mm would it not, so your over stoke scenario would apply to the B6 not the B8.

 

[Peewee]

Thanks and good info from Bilstein as I was considering damper extension rather than compression. The OEM standard and sport dampers are apparently the same natural length. The OEM sport version is therefore pre-compressed by an additional 15mm when fitted, due to the shorter springs. Bilstein advise that their B6 is the same natural length as OE so will also pre-compress by the same amount on a sport spring. So no issues there it seems.
I was led to believe that the B8 was a lot shorter. As it's only 5mm shorter, it will still pre-compress, but by an additional 10mm, rather than 15mm. The risk of over extending is therefore virtually no different to a OEM/B6 set up. All this is of course in addition to the pre-compression provided to the damper in the non sport damper/standard spring set up.
Great - I'm clearer in my mind now. Always happy to be put right.
All seems good and is a matter of personal preference and how much to spend.................still getting a budget together!

 

[board]

I'm not sure how accurate investopedia is but they state that BMW uses the following supplier;

• Thyssenkrupp: Supplies steering columns, shock absorbers, and suspension parts

Bilstein | Dampers

thyssenkrupp offers complete BILSTEIN product range for all requirements. As a shock absorber specialist we supply the right systems for each requirements: ✓ Conventional ✓ Electronically controlled ✓ Modules/suspension struts

www.thyssenkrupp-automotive-technology.com

I think my Indy was saying when the car was built it was Bilstein and may have changed since unless investopedia is still accurate. I just called Soper BMW and they have no way of telling who supplies them now. I guess OEM will be black in colour opposed to the yellow which might be the only difference apart from price haha

When I got a quote last month I think there was only about £20 difference between OEM and Bilstein B8's

 

[Peewee]

I've taken a deep breath, and ordered a set of sport dampers from BMW on the understanding that they will take them back if they're not what I'm expecting. They have to come from Germany, hence the slight mystery and delay.
The production date of my Zed is Jan 2002 and has had Sachs sport dampers from new - the BMW and Sachs labels are still on them. Earlier sport and M versions may well have had Bilsteins who knows? - maybe other members on here can chip in.
So, I'm expecting the new dampers arrive early after Easter so if it helps and if you can wait, I'll let you know what actually turns up!

 

[PofC]

I had the same decision to make on my own when I got the car 4 months ago and it came with bad OE struts (leaking). So I replaced them with Bilsteins B6. IS the best for the car and I trust Bilstein since I'm using them for the past 40 years on most of my 45+ cars. I personally don't trust dealers but is up to you for the final decision.

 

[board]

I've ordered the B8's at £748.14 for all four and should hopefully get them before the 1st. I just need to wax oil the sills and put the car back together ready for the nicer weather

 

[AntStark]

I've taken a deep breath, and ordered a set of sport dampers from BMW on the understanding that they will take them back if they're not what I'm expecting. They have to come from Germany, hence the slight mystery and delay.
The production date of my Zed is Jan 2002 and has had Sachs sport dampers from new - the BMW and Sachs labels are still on them. Earlier sport and M versions may well have had Bilsteins who knows? - maybe other members on here can chip in.
So, I'm expecting the new dampers arrive early after Easter so if it helps and if you can wait, I'll let you know what actually turns up!

I’d interested to know what you get from BMW as I thought Sachs discontinued the replacement OEM Sport dampers a few years ago. I got the normal ones and use with my sport springs ..work really well. Definately replace your top mounts at the same time !

 

[Peewee]

Standby all, I'll post the results as soon as I get them.

 

[board]

The B8's arrived yesterday but it will be a week or two before they get fitted so will try and get some pics comparing the OEM and B8's if that helps anyone in the future

 

[Peewee]

I've now collected my new dampers from BMW.
There is no Sachs sticker like on the originals but it suggests they are Sachs as they have the Sachs part number included within the BMW sticker. The Sachs numbers are the same as on my original dampers. BMW agree but have not been able to absolutely confirm from Germany.

Interesting are the dates of manufacture and location, BMW part numbers are:-

Front Left
BMW 31316753261 (Sachs 4903556927) Turkey, 04/11/22

Front Right
BMW 31316753262 (Sachs 4903556928) Turkey, 21/02/23

Rears
BMW 33526753263 (Sachs 4901556912) Germany 07/01/17

Clearly some older stock and some very new (surprise!), with Sachs manufacturing in Turkey now (maybe under licence I guess).

As for overall length, see the photos, but as best I can measure from the very end of the rod are:-

Fronts 575mm

Rears 604mm

Would be good to see how they compare with other manufacturers dampers.

Would also be useful to confirm that these Sport dampers are indeed the same length as non Sport ones (just a bit stiffer), - but to ensure a like for like comparison, dimensions would have to be from a 6 cylinder non Sport - M52/M54.

Hope this is useful and extends our knowledge a bit.

I have only just started to gather all the parts needed for a suspension refresh, but am hoping to get them on the car by the end of the year if all goes well! I'm sure I'll have many more queries as I progress................



Front


Rear

 

[AntStark]

Are these definately sports dampers ? Does it say that on them ?

 

[Peewee]

Actually doesn't say on them E36/7 Sport like my originals, but they have exactly the same part numbers. So have to assume identical specification.
Non Sport dampers are still listed as having different part numbers from Sport S 704A option) and this was confirmed by BMW when I ordered them.
If I had bought these from anywhere other than BMW directly I would likely have a doubt as to the exact specification though.