Advice: Eibach springs on Z4M (do or don’t)?
Advice: Eibach springs on Z4M (do or don’t)?
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Franzino

Original Poster:

502 posts

184 months

Wednesday 29th December 2010
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Yes; I know there is a search function, but I did not work... frown

I have a Z4 M roadster with some 19” CSL wheels. After fitting the 19” wheels the car looks a little high for my taste (a small drop would be nice, but it is not a must have if there is a downside in handling). I have also read that the rear springs can brake at the base by 25K. Is this really that common and how can I feel or hear this on my car? I found a picture on how it looks like



In this EVO Z4M buying review they say the same thing about the oem springs….
EVO said:
The road springs have been known to snap at 35-45k, so check the car sits level and there are no rattles from the corners when driving. Some owners fit uprated Eibach springs.
I’m afraid that fitting Eibach pro-kit springs on my stock M shock absorber will make my Z4M ride worse. I have driven a Z3 with oem M shocks and AP lowering springs, the ride was comfortable but the car was really wobbly and not stable. It looked good, but the suspension was really soft and this made handling in the corners worse then original. The car did not give me a confident feeling. We did a test and the shocks were not worn out.

Eibach pro-kit springs will drop the car 20mm (0,8”) in front and 10mm (0,4”) at the rear.
My Z4M has 50.000Km (=31.000 miles) on the clock. Will fitting these aftermarket springs wear out my original shocks prematurely? Are they to old to fit aftermarket springs and how my Z4M handle with these springs?

Thanks for the input...!

daz4m

2,914 posts

219 months

Wednesday 29th December 2010
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Hi Franzino,

IMHO, fitting Eibachs offers an improvement on the ride, softer in town, bumps are much less sharp at low speeds. The lowering itself is quite subtle but you can tell the difference and it definitely looks better. The front is lowered more so than the rear.

It feels more planted at speed and more stable under hard braking.

Your rear oem springs will most likely break at some point too. You may start to hear clunking from the rear at slow speeds and speed bumps will feel sharper than they did before.

If you can get under the car its very easy to see if they have broken or not.

Hope that helps.



Salom

230 posts

200 months

Wednesday 29th December 2010
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My advice would be to replace all 4 springs with Eibach 15mm lowering springs and replace all the shocks with Bilstein B6s. The ride and handling will be improved massively!

tractor 2990

27 posts

184 months

Thursday 30th December 2010
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at least the springs wont break

Franzino

Original Poster:

502 posts

184 months

Thursday 30th December 2010
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For now; I'm not going to change the shocks. I know Z4M drivers sometimes complain about the oem suspension of the Z4M. I personally like how it handles in the city, on the highway and on a track. I think the suspension is a okay compromise between handling and comfort. I don’t mind that the car is a little less comfortable on bumpy roads. I’ve had cars in the past with coilovers suspension that were a lot less comfortable then the Z4M. It all depends what you use to drive in the past. So in general I have no complaints about the standard Z4M suspension (besides that it would look nicer a little lower and that the braking rear springs is a concern issue)… That's why I'm a little worried; I don't want to make the road-holding worse after fitting aftermarket springs.

Porscheplayer

381 posts

214 months

Thursday 30th December 2010
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Salom said:
My advice would be to replace all 4 springs with Eibach 15mm lowering springs and replace all the shocks with Bilstein B6s. The ride and handling will be improved massively!
Have you done this?

griff7

765 posts

189 months

Thursday 30th December 2010
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eibach will be fine and not too harsh.

ruebdo

293 posts

190 months

Saturday 1st January 2011
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i have 19" CSL's and Eibach springs. The ride is alot better than on OEM springs, in every aspect!!

Franzino

Original Poster:

502 posts

184 months

Sunday 2nd January 2011
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In every aspect! That's good news wink I love the Z4M road-holding in fast corners and on a track... So how many miles/km are you already running the Eibach springs on your original Z4M shocks without issues? Do you think these springs will wear out the original shocks prematurely? When they do a new alignment, is this the factory set-up or do they change the alignment to compensate for the lowered height?

Thanks,

ruebdo

293 posts

190 months

Sunday 2nd January 2011
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i have done about 2000 miles on the new springs. Will it effect the shocks, apparantely not according to the forums etc, but i honestly have no experience of this so am probably not the best person to ask. I changed the alignment to be more track focused (but there are so many different opinions etc on this) and put pilot sports back on. Definately not worth taking out in cold weather :-)
The engine strut base makes a very big difference too.
The trouble is there are so many people with so many opinions that really you just have to take a view and see what works best for you.
I have owned 2 Z4M coupes, and my business partner has a bog standard one. I drive his very rarely, and when i do, i realise how big a difference the subtle changes make. He will agree, and having driven his on the track, there really is no comparison.
If you want to drive mine you are more than welcome!!!

Franzino

Original Poster:

502 posts

184 months

Monday 3rd January 2011
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Thanks for the advice...! After reading all the comments I'm going to order the Eibach springs.

@ruebdo
The strut brace is also coming on my car in 2011. The guys of EVO magazine were very enthusiast about fitting original CSL wheels + the BMW strut brace on the Z4M. They reduce the unsprung weight and improve the handling. I don’t feel the difference in weight, but it did feel that front end grip was improved with the CSL wheels and that the car felt more confident.

EVO said:
Like us, Davies was frustrated at the Z4 M Coupe’s lack of front-end grip, rightly attributing it to BMW’s risible decision to fit it with ContiSportContact tyres which are some two generations out of date. Having decided to replace them with Michelin Pilot Sports 2s, Davies also chose a set of gorgeous M3 CSL rims, which in addition to transforming the Z4 M’s looks also increase the rim diameter by an inch (to 19in) and reduce unsprung weight by a total of some 7kg.

Where the standard car lacks incisive turn-in and, ultimately, front-end grip, Davies’s car is more immediate and confidence inspiring. It also has the grip to back up the instant turn-in, so that you’re more prepared to commit to the corner, safe in the knowledge that the nose isn’t about to wash wide of your intended trajectory.

It’s not a complete transformation. Indeed, as Davies readily concedes, the car still displays the same sharp-edged low-speed ride and remains keen to trigger the ASR system when accelerating hard on lumpy tarmac. However, the sharper, grippier front end is better able to harmonise with the rear, which makes it a much more positive machine to hustle – more intuitive and entertaining when you want to provoke it, yet sweeter and more cohesive when you want to make smooth, swift progress.

A definite improvement, both dynamically and visually, Davies’s upgrades release more of the Z4 M Coupe’s obvious potential.
Edited by Franzino on Monday 3rd January 00:25