Bilstein B4's and eibach springs.

[ben g]

So I went and ordered a Bilstein B12 kit for my Z4 after my front shocks failed.

I'm still waiting on it, strangely. Unsure why it's taking so long to deliver, but it's got me wondering whether it's the correct decision.

I'm now thinking that perhaps I should replace my current oem shocks with Bilstein B4's and put my eibach springs on them.

Only problem is they don't seem to be recomended for cars with sport suspension, though i always thought the shock absorbers were all the same. It's just the springs that are different. Is this correct?

I was quite happy with the combination of oem shocks and eibach springs, so I feel maybe I should go for B4 shocks this time, rather than the stiffer and smaller B12's?

 

[MDUBZ]

the shocks are different.

the b12 kit actually has b8 shocks in the kit paired with eibach springs. it lowers the car a bit: ~15mm lower than the Sport suspension. bit firm on a bumpy b road, but get on the smooth stuff and they're great. love mine and prefer the subtly lower look too.

Edit: google is your friend: https://www.bilstein-shocks.co.uk/pages/confused-bilstein-buying-guide :wink:

 

[ben g]

I've already used google, but it doesn't say that you can't use B4 shocks on a sport suspension equipped Z4.

Eurocarparts even list the B4's as a replacement shock absorber for my vehicle, hence the confusion.

 

[highway1]

I have Suplex springs all round on my coupe ( springs are M-sport equivalent).

I also have Bilstein B4 which are M-sport equivalent dampers- B6/B8 are upgrades as they are mono tube rather than twin tube.

This combination seems to work better on bumpy British roads ( still firm but better than standard M-sport and dare I say even the B12 set-up as that works better on a nice smooth track rather than the roads!

 

[ben g]

I have Suplex springs all round on my coupe ( springs are M-sport equivalent).

I also have Bilstein B4 which are M-sport equivalent dampers- B6/B8 are upgrades as they are mono tube rather than twin tube.

This combination seems to work better on bumpy British roads ( still firm but better than standard M-sport and dare I say even the B12 set-up as that works better on a nice smooth track rather than the roads!

That's my worry also. The roads here aren't great and it's my daily commuter car, so i don't want to be chucked around all over the place.

You say B4's are sport equivalent shocks, so they should be perfectly fine on my 2003 3.0i with sport suspension?

Bare in mind i will be fitting my eibach springs onto them, which are lower than the sport springs, but only by 15-20mm. Would they still be ok?

The oem shocks seemed perfectly fine with the eibachs fitted, before they died :lol:

 

[MDUBZ]

as per link, if your are lowering it recommends b8s "They are shorter to ensure the all important coil spring pre load as lowering springs are shorter than OE springs."

You could use b4s with shorter springs but the shocks will be partially compressed all of the time so your not getting the full damping and i'd have thought more likely to bottom out and will have s shorter life? personally i thought i'd stick with what bilstein recommend - they have spent more time on RnD than i have.

 

[MACK]

So I went and ordered a Bilstein B12 kit for my Z4 after my front shocks failed.

I'm still waiting on it, strangely. Unsure why it's taking so long to deliver, but it's got me wondering whether it's the correct decision.

I'm now thinking that perhaps I should replace my current oem shocks with Bilstein B4's and put my eibach springs on them.

Only problem is they don't seem to be recomended for cars with sport suspension, though i always thought the shock absorbers were all the same. It's just the springs that are different. Is this correct?

I was quite happy with the combination of oem shocks and eibach springs, so I feel maybe I should go for B4 shocks this time, rather than the stiffer and smaller B12's?

The reason your waiting for the kit is probably due to a lot of Bilstein stuff being on back order . When I got my B4s from Balance Motorsport they could only get me 3 out of 4 shockers from Bilsteins UK stock. Anything not in stock was on back order to February, that was back in early December. Apparently this was due to the factory being snowed under with OEM supply requirements. In the end I got my 4th one from Demon Tweeks who I got to price match Balance as they had one in stock.

The SE shocks and the M Sport ones are different, Realoem will confirm this.
The B4s are the equivalent of SE shocks where as the B6 and the shorter B8 found in the B12 kit have the same dampening (B8s just have a shorter rod.) and although they are listed for M Sport suspension they are actually about 15-20% uprated over M Sport so give a harder ride. Obviously it's up to you but if ride quality is you main concern and your not tracking it then I'd go B4. I have these on mine with Eibachs and it is a good improvement over my tired m sport setup. The B4s, although listed as an SE replacement are also listed as suitable for lowered cars up to 40mm so you will be fine with the Eibachs as your at 30mm over SE lowering wise. After all your already running Eibachs so a 15mm drop on standard M sport shocks anyway.
It was only after I acquired a B12 kit that I learnt how uprated over M Sport the B8 shocks are. In the end it led to me selling my B12 kit before fitting it and going B4 and Eibach instead.

 

[MDUBZ]

for some reason i thought the sports had a bigger drop over the SEs, but it's only 15mm; so as above with a total of 30-35mm you are still in tolerance of the B4s so you're good to go. The B8s are firm so if you want a cushier ride you are probably better going for the B4s.. guess it depends on where and how you drive it.

 

[ben g]

So I went and ordered a Bilstein B12 kit for my Z4 after my front shocks failed.

I'm still waiting on it, strangely. Unsure why it's taking so long to deliver, but it's got me wondering whether it's the correct decision.

I'm now thinking that perhaps I should replace my current oem shocks with Bilstein B4's and put my eibach springs on them.

Only problem is they don't seem to be recomended for cars with sport suspension, though i always thought the shock absorbers were all the same. It's just the springs that are different. Is this correct?

I was quite happy with the combination of oem shocks and eibach springs, so I feel maybe I should go for B4 shocks this time, rather than the stiffer and smaller B12's?

The reason your waiting for the kit is probably due to a lot of Bilstein stuff being on back order . When I got my B4s from Balance Motorsport they could only get me 3 out of 4 shockers from Bilsteins UK stock. Anything not in stock was on back order to February, that was back in early December. Apparently this was due to the factory being snowed under with OEM supply requirements. In the end I got my 4th one from Demon Tweeks who I got to price match Balance as they had one in stock.

The SE shocks and the M Sport ones are different, Realoem will confirm this.
The B4s are the equivalent of SE shocks where as the B6 and the shorter B8 found in the B12 kit have the same dampening (B8s just have a shorter rod.) and although they are listed for M Sport suspension they are actually about 15-20% uprated over M Sport so give a harder ride. Obviously it's up to you but if ride quality is you main concern and your not tracking it then I'd go B4. I have these on mine with Eibachs and it is a good improvement over my tired m sport setup. The B4s, although listed as an SE replacement are also listed as suitable for lowered cars up to 40mm so you will be fine with the Eibachs as your at 30mm over SE lowering wise. After all your already running Eibachs so a 15mm drop on standard M sport shocks anyway.
It was only after I acquired a B12 kit that I learnt how uprated over M Sport the B8 shocks are. In the end it led to me selling my B12 kit before fitting it and going B4 and Eibach instead.

That's a great help, thanks MACK!

I've never taken any of my own cars on a track and i have no real desire to do so, so perhaps the B4's are a good shout.

They're coming in at £300 for all 4 corners, which isn't too bad at all. If don't plan on keeping the Z4 forever as it just isn't practical, and I can't see the shocks failing after a few thousand miles with the eibach springs on, so it's probably the better buy for my circumstances.

 

[MACK]

So I went and ordered a Bilstein B12 kit for my Z4 after my front shocks failed.

I'm still waiting on it, strangely. Unsure why it's taking so long to deliver, but it's got me wondering whether it's the correct decision.

I'm now thinking that perhaps I should replace my current oem shocks with Bilstein B4's and put my eibach springs on them.

Only problem is they don't seem to be recomended for cars with sport suspension, though i always thought the shock absorbers were all the same. It's just the springs that are different. Is this correct?

I was quite happy with the combination of oem shocks and eibach springs, so I feel maybe I should go for B4 shocks this time, rather than the stiffer and smaller B12's?

The reason your waiting for the kit is probably due to a lot of Bilstein stuff being on back order . When I got my B4s from Balance Motorsport they could only get me 3 out of 4 shockers from Bilsteins UK stock. Anything not in stock was on back order to February, that was back in early December. Apparently this was due to the factory being snowed under with OEM supply requirements. In the end I got my 4th one from Demon Tweeks who I got to price match Balance as they had one in stock.

The SE shocks and the M Sport ones are different, Realoem will confirm this.
The B4s are the equivalent of SE shocks where as the B6 and the shorter B8 found in the B12 kit have the same dampening (B8s just have a shorter rod.) and although they are listed for M Sport suspension they are actually about 15-20% uprated over M Sport so give a harder ride. Obviously it's up to you but if ride quality is you main concern and your not tracking it then I'd go B4. I have these on mine with Eibachs and it is a good improvement over my tired m sport setup. The B4s, although listed as an SE replacement are also listed as suitable for lowered cars up to 40mm so you will be fine with the Eibachs as your at 30mm over SE lowering wise. After all your already running Eibachs so a 15mm drop on standard M sport shocks anyway.
It was only after I acquired a B12 kit that I learnt how uprated over M Sport the B8 shocks are. In the end it led to me selling my B12 kit before fitting it and going B4 and Eibach instead.

That's a great help, thanks MACK!

I've never taken any of my own cars on a track and i have no real desire to do so, so perhaps the B4's are a good shout.

They're coming in at £300 for all 4 corners, which isn't too bad at all. If don't plan on keeping the Z4 forever as it just isn't practical, and I can't see the shocks failing after a few thousand miles with the eibach springs on, so it's probably the better buy for my circumstances.

Ben give balance motorsport a go. I think it was about £260 for all 4 corners and they're a legit uk business (unlike some of sh!te you see on ebay etc) knowledgeable and helpful too. I'd recommend them assuming they can get stock.

 

[ben g]

Give balance motorsport a go. I think it was about £260 for all 4 corners and there a legit uk business (unlike some of sh!te you see on ebay etc) knowledgeable and helpful too. I'd reccomend them.

Cheers mate, i've just gone onto their website and it's now coming in at £270 delivered. Bargain if you ask me

I think i'm set on going for these now. I should've listened to the advice on here when i ordered the B12 kit, as looking through other forums, the consensus that they're very firm seems to be universally recognised :lol:

They'd be fantastic if it was just my weekend/fun car, but as a daily commuter who enjoys the occasional B road blast at the weekend (read: incredibly bumpy and pothole ridden roads), the B8 dampers will most likely be much too firm for my ageing body (i'm 2 months away from turning 30)

I assume i can re-use my eibach springs on my existing shocks? They aren't cracked and seem to be in great condition.

 

[MACK]

Give balance motorsport a go. I think it was about £260 for all 4 corners and there a legit uk business (unlike some of sh!te you see on ebay etc) knowledgeable and helpful too. I'd reccomend them.

Cheers mate, i've just gone onto their website and it's now coming in at £270 delivered. Bargain if you ask me

I think i'm set on going for these now. I should've listened to the advice on here when i ordered the B12 kit, as looking through other forums, the consensus that they're very firm seems to be universally recognised :lol:

They'd be fantastic if it was just my weekend/fun car, but as a daily commuter who enjoys the occasional B road blast at the weekend (read: incredibly bumpy and pothole ridden roads), the B8 dampers will most likely be much too firm for my ageing body (i'm 2 months away from turning 30)

I assume i can re-use my eibach springs on my existing shocks? They aren't cracked and seem to be in great condition.

Yes you'll be fine with your existing eibachs. I paired my new shocks with used eibachs I bought through the forum so I could sell the b12 kit complete. To be honest even the top mounts I had would of been fine going back on but seeing as I had bought lemforder ones I stuck them on. Just be careful with mounts, I normally rate meyle hd but the rear mounts are a bad design on these that causes knocking. This and E46 forums saved me there!

 

[ben g]

Oh ok, lucky I went for Lemforder front and rear top mounts then!

Just need to order bust boots and bump stops now. I've tried looking online but no one seems to list a kit for the Z4. Probably best getting them from the dealer, they can't be that expensive for a bit of foam and plastic :lol:

One of my existing boots has a crack in and a bump stop has a piece of foam missing, so definitely worth replacing these too.

 

[MACK]

Just for a bit of added peace of mind, the m3 fraternity have sworn by the B4's for many years. Just check out the e46 forums. To be honest the sach boge stuff fitted to the zeds as standard is terrible in terms of quality/longevity. I've seen posts on here where folks have taken then off at as little as 40-50k and they've been fooked. Mine were knackered as well and I don't think I've ever seen a post on here where when removed the originals haven't been obviously screwed.

 

[AC5L4T3R]

Sorry to bring up such an old post. I got a set of H&R springs for my 2.5i E85, would the B4's be OK on them or would I have to get the B8's?

 

[dougie1142]

Another vote for B12's and Eibachs here. Got them and love them!

 

[ben g]

Sorry to bring up such an old post. I got a set of H&R springs for my 2.5i E85, would the B4's be OK on them or would I have to get the B8's?

B8's are probably best, as the H&R springs give quite a big drop compared to Eibach springs.

 

[davros]

Another vote for B12's and Eibachs here. Got them and love them!

Yep, I love mine too. The B12’s give the Zed the perfect stance IMO

 

[AC5L4T3R]

Sorry to bring up such an old post. I got a set of H&R springs for my 2.5i E85, would the B4's be OK on them or would I have to get the B8's?

B8's are probably best, as the H&R springs give quite a big drop compared to Eibach springs.

Sorry I actually wrote the wrong springs.. I have eibachs :rofl:

 

[mjennings23]

Sorry to bring up such an old post. I got a set of H&R springs for my 2.5i E85, would the B4's be OK on them or would I have to get the B8's?

B8's are probably best, as the H&R springs give quite a big drop compared to Eibach springs.

Sorry I actually wrote the wrong springs.. I have eibachs :rofl:

B4s are fine with Eibachs. B8s are a better shock insomuch as they're a more advanced technology etc, but they're also a hell of a lot harsher a ride on an already very harsh riding car, I cetainly wouldn't have them on a road car in the UK.