Lowering springs

[Marlon]

Sorry Marlon, know nothing about springs but your car is an absolute stunner!

Well thank you sir

[STUBOY2UK]

I had a facelift 3.0si with 19" wheels and changed the springs to Eibachs. The car looked absolutely stunning but the ride was far too hard for a daily driver. My commute was ok as I knew where all the potholes were but I used to dread having to drive anywhere new on dark and rainy nights where it's difficult to see the road.

[Papa_Zee]

Pic from this years France trip , H & Rs on the left 2 cars & Eibachs on the 2 silver ones though the Alpina is on Bilsteins , can't recall any issues grounding with any of the cars same on a recent run in the Dales with Z4MO who i think is on H&Rs

I didnt know Z4s were religious....?

[JonLeeper]

So I now need to decide on what to do with my 3.0 Si roadster. I use it every day to commute to and from work, @120 miles a day motorway and a/b roads and will do about 4 track days a year. The options;

1. New Bilstein B6 struts and keep the current springs.
2. New Bilstein B6 struts and new standard m-sport springs.
3. New Bilstein B6 struts and Eibach springs.
4. New Bilstein B8 struts and new standard m-sport springs.
5 New Bilstein B12 setup.

I'm not keen on Option 1 as I suspect that the springs, front especially, are quite tired. Option 2 gives the best comfort, if what I read is to be believed. Option 3 is the compromise option of softer struts but the "better"(?) springs? Option 4 doesn't seem to make sense as it's the harder struts and softer springs and Option 5 is the one that lots of people have gone for. There doesn't seem to he a great deal of difference in the price between any if the options. So I guess, in reality, it's really a straight fight between Option 2 and Option 5.

I know that everyone has their own opinion and they differ greatly from person to person but any great words if wisdom before I flip a coin?

[MACK]

Whatever choice you make Option 3 is pointless really from both a technical & financial point of view. The only difference between the B6 and the B8 is the shock rod length is reduced to suit lowering springs (namely Eibachs) with B8s. The compression and rebound characteristics are identical, all you'll achieve is some unnecessary reduction in travel/ preloading of the shock with a B6 over a B8. As the B12 kits (B8 & Eibach combo) tend to be really good value anyway it would seem pointless to buy Eibachs and B8 shocks separately.
What's not of your list are B4s paired with either SE, MSport or Eibachs, on a road going car, especially one doing the commute you do that would be my choice for a comfier setup than the B6/8 shocks. Cheaper too!

[JonLeeper]

Whatever choice you make Option 3 is pointless really from both a technical & financial point of view. The only difference between the B6 and the B8 is the shock rod length is reduced to suit lowering springs (namely Eibachs) with B8s. The compression and rebound characteristics are identical, all you'll achieve is some unnecessary reduction in travel/ preloading of the shock with a B6 over a B8.

I hadn't realised that the difference between the B6 and B8 was just the rod length,. I thought the rod length difference was between the B4 and the B6/B8 with the former being longer for SE / M-Sport springs and the latter for the lowered ones.

As the B12 kits (B8 & Eibach combo) tend to be really good value anyway it would seem pointless to buy Eibachs and B8 shocks separately.

True if the B6 and B8 are only different in rod length then the B12 kit makes perfect sense.

What's not of your list are B4s paired with either SE, MSport or Eibachs, on a road going car, especially one doing the commute you do that would be my choice for a comfier setup than the B6/8 shocks. Cheaper too!

I hadn't looked at the B4s as I thought that they were too short for the standard M-Sport springs. I've not noticed that the price of the B6/8 being very different.

[JonLeeper]

Whatever choice you make Option 3 is pointless really from both a technical & financial point of view. The only difference between the B6 and the B8 is the shock rod length is reduced to suit lowering springs (namely Eibachs) with B8s. The compression and rebound characteristics are identical, all you'll achieve is some unnecessary reduction in travel/ preloading of the shock with a B6 over a B8. As the B12 kits (B8 & Eibach combo) tend to be really good value anyway it would seem pointless to buy Eibachs and B8 shocks separately.
What's not of your list are B4s paired with either SE, MSport or Eibachs, on a road going car, especially one doing the commute you do that would be my choice for a comfier setup than the B6/8 shocks. Cheaper too!

If I went for the B4 M-Sport option would it be worth upgrading the anti-roll bars for the track? The track will be reasonably smooth, so the spring damper arrangement is less important except for roll in the corners, but the softer setup would be better for the commute where the anti-roll bars have less effect.

[philbo909]

Whatever choice you make Option 3 is pointless really from both a technical & financial point of view. The only difference between the B6 and the B8 is the shock rod length is reduced to suit lowering springs (namely Eibachs) with B8s. The compression and rebound characteristics are identical, all you'll achieve is some unnecessary reduction in travel/ preloading of the shock with a B6 over a B8. As the B12 kits (B8 & Eibach combo) tend to be really good value anyway it would seem pointless to buy Eibachs and B8 shocks separately.
What's not of your list are B4s paired with either SE, MSport or Eibachs, on a road going car, especially one doing the commute you do that would be my choice for a comfier setup than the B6/8 shocks. Cheaper too!

If I went for the B4 M-Sport option would it be worth upgrading the anti-roll bars for the track? The track will be reasonably smooth, so the spring damper arrangement is less important except for roll in the corners, but the softer setup would be better for the commute where the anti-roll bars have less effect.

If you're tracking it, you might as well get some coilovers

[JonLeeper]

Whatever choice you make Option 3 is pointless really from both a technical & financial point of view. The only difference between the B6 and the B8 is the shock rod length is reduced to suit lowering springs (namely Eibachs) with B8s. The compression and rebound characteristics are identical, all you'll achieve is some unnecessary reduction in travel/ preloading of the shock with a B6 over a B8. As the B12 kits (B8 & Eibach combo) tend to be really good value anyway it would seem pointless to buy Eibachs and B8 shocks separately.
What's not of your list are B4s paired with either SE, MSport or Eibachs, on a road going car, especially one doing the commute you do that would be my choice for a comfier setup than the B6/8 shocks. Cheaper too!

If I went for the B4 M-Sport option would it be worth upgrading the anti-roll bars for the track? The track will be reasonably smooth, so the spring damper arrangement is less important except for roll in the corners, but the softer setup would be better for the commute where the anti-roll bars have less effect.

If you're tracking it, you might as well get some coilovers

Except I'm tracking it 4 times a year and commuting in it every day. Also decent coilovers are £2,500 and the Bilstein B12 set is £700.

[Capa]

I'll be honest, I've thought long and relatively hard about this.

It's getting B4s and standard springs. One of my biggest gripes with the car is the ride quality, and truth be told I don't want to be in the position of investing more money and ending up with more backache than I already have. A few of my favourite roads are simply undriveable as it is - I mean, I can get from A to B, but not at any real pace.

As another upvote for B4's, I have them on the front of my road rally car, and they actually work really well on that. Not a Z4, but something to consider.

But. Your views may vary. Mine's never going on track, just down Hampshire's rutted broken road surfaces.

[philbo909]

If I went for the B4 M-Sport option would it be worth upgrading the anti-roll bars for the track? The track will be reasonably smooth, so the spring damper arrangement is less important except for roll in the corners, but the softer setup would be better for the commute where the anti-roll bars have less effect.

If you're tracking it, you might as well get some coilovers

Except I'm tracking it 4 times a year and commuting in it every day. Also decent coilovers are £2,500 and the Bilstein B12 set is £700.

Then I recommend bilstein b4 and msport springs (basically an oem refresh) for £200-£300, mime was night and day compared to old shocks

[Silverzedtom]

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I’m running eibach’s and couldn’t go a mm lower. I dread the thought of any speed bump or steep driveway as it is. I would have preferred h&r’s based on the feedback people have given about the ride. I didn’t find the eibachs to be worse than the Sport springs to be honest although they aren’t an improvement in terms of damping.

The above pic is with two heavy suitcases in the boot but you can see why I wouldn’t want to go much lower.

All in all it sounds like you might be better off putting it off for a year or so and saving the pennies for coilovers if possible, a lot of money but the only real solution for spot on damping and a lower car imo.

[Sideways Steve]

For reference, I have the Eibach Pro Kit springs on my Z4 with MSport shocks, 18" Rims with NON Runflats and the ride is really nice.

I also have the Eibach's and MSport shocks on my E91 Touring with similar tyre & wheel combo and again the ride is spot on.

The Mini has the JCW shocks with the Eibach pro kit, 18" JCW rims with non-runflat tyres and is a little bit harsh on really bad roads but even using it daily its perfectly comfortable.

I guess my point is, 3 different cars but essentially the same spring/shock/tyre & wheel combination on them all and don't have any issue with ride quality.

[Capa]

Because you have a back made of steel.

And quite a nice coloured car.

[JonLeeper]

For reference, I have the Eibach Pro Kit springs on my Z4 with MSport shocks, 18" Rims with NON Runflats and the ride is really nice.

I also have the Eibach's and MSport shocks on my E91 Touring with similar tyre & wheel combo and again the ride is spot on.

The Mini has the JCW shocks with the Eibach pro kit, 18" JCW rims with non-runflat tyres and is a little bit harsh on really bad roads but even using it daily its perfectly comfortable.

I guess my point is, 3 different cars but essentially the same spring/shock/tyre & wheel combination on them all and don't have any issue with ride quality.

So it's either stock M-Sport springs and B4s or Eibach springs and B4s!

I guess if I go for the Eibachs I can always revert to my current tired M-Sports or upgrade to B8s if I want to change!