Suspension issues?

[lord_farquaad]

I have 2003 3.0 automatic with the M sport suspension (S704) on 17”s. I'm having no end of trouble daily driving it - its far too low and scrapes the underneath and front bumper horrendously. Even small inclines result in me scraping, the amount of times I've nearly ripped the bumper off is not right.

I've read all over the place the different types from Bilstein and people suggesting using Eibech lowing springs to my utter amazement as its pretty much non drivable at this point as it is

I read a post on here regarding suspension, and there was a picture that showed a car with M Sport springs (like mine) and then with Bilstein/ Eibach springs (https://z4-forum.com/threads/bilstein-suspension-b4-b6-b8-b12.106967/), both of these cars appear to be much higher than my car?

I’ve attached images of my white car, both front and back. I know the fronts have Sachs shocks on, but do you think the car might have had extra lowering springs at some point in its life?

Any help would be gratefully received

 

[bigwinn]

I’d say so looking at the arch gap- assume your springs are actually in one piece and not broken?

 

[NaweedM]

Fronts are indeed quite low. For reference, I installed B4's + Eibach Pro's and the gap seems to be just enough to not scrape anywhere. I used an E46 top spring pad as it was 6mm thicker than the Z4 top spring pad, so I got myself some clearance height there.

 

[Rockhopper]

From my research your front Msport springs should be 270mm long. There is a lot of incorrect info out there on may parts suppliers web sites.

 

[lord_farquaad]

Okay I think I've figured it out, spoke to a BMW Indy who claimed to have seen this a few times. . . There are two different MSport springs that differ in length from standard (270mm and 276mm), he also thinks they are slightly different in width also. Buying suspension for MSport cars (or buying second hand suspension from a car with MSport) isn't enough to ensure you get the right ones.

He thinks I've got the 270mm MSport springs when I should have the 276mm MSport springs, it's all about the transmission, 270mm for manual cars, and 276mm for auto and SMG cars. He says the weight of the car is lowering it more than it should.

He also said he had seen it whereby a customer had thought they'd fitted standard springs because the car was to high etc

Think it's time to get some new suspension and springs. . .

 

[Rockhopper]

Mines an auto with the 270mm springs and I don't have any ground clearance issues. Lets compare measurements from the centre of the wheel to the bottom of the wheel arch. Mines 354mm

 

[lord_farquaad]

Mines an auto with the 270mm springs and I don't have any ground clearance issues. Lets compare measurements from the centre of the wheel to the bottom of the wheel arch. Mines 354mm

Interesting!!! So I've just measured it and it's 330 (see image)??? So maybe I do have some other really lowered springs?

Ignore the road rash wheels ;-), I plan on getting some MV2's at some point.

 

[Rockhopper]

It sounds like you may well do - or possibly a bit has broken off them?

 

[NaweedM]

Definitely Jack it up, remove the wheels and inspect the springs. Would be good to check if the end of the spring has snapped, giving you an extra drop

 

[smorris_12]

FWIW, here's my solution to my 2.5Si sitting low:

S

Thread 'Updated: Lowering my 2.5si by a negative amount'

Sep 25, 2022

From the day I bought my Z I was scraping the living hell out of the front splitter. I was used to the idea that it's a low 2-seater but it was ridiculous. Almost any shaped speed hump would grind. I did some googling and found that 2.5si's seemed to be prone to sitting low. I came across the BMW figures for ride height (and then lost them again - repeatedly. I could never seem to locate them reliably when I actually had the time to do some reading. Grrr) and eventually broke out the tape measure and got outside.

With 18s, BMW state 602mm rim to arch, +/-10mm when loaded up. Mine were 585...

• smorris_12
• Replies: 15
• Forum: E85 / E86 Z4 discussion

Regarding the update at the end where it looked high, it's still sat the same, doesn't scrape and looks, in the flesh, spot on.

 

[lord_farquaad]

Sorted!!!!

Fitted new b4's shocks and the correct m sport springs (276) and it's now sitting higher and Im no longer scraping the floor!!! Happy days!!

 

[Gebbly]

Good result. How much higher do you reckon it is sitting now?

 

[lord_farquaad]

It's about 360, but not sure if it has to settle yet?

 

[elfer]

I wonder if old top mounts can also compress. If so, it wouldn't be just the springs that can determine the ride height.

Regardless, the correct ride height for sports suspension and 17s is 590 +/- 10mm front and 576 +/- 10mm rear. Note the measuring method.

33 00 Rear axle - ride height E85​

Ride level height in normal position Attach tape measure to bottom middle of rim flange and measure to lower edge of wheel arch
Tolerance ride height in - normal position max. 10 mm - design position max. 2 mm
Difference ride height between left/right in - normal position 10 mm - design position 2 mm
Series
16” rim	mm ± 10	576
17” rim	mm ± 10	592
18” rim	mm ± 10	604
19” rim	mm ± 10	617
20” rim	mm ± 10	630
Low-slung sports suspension and M sports suspension
16” rim	mm ± 10	560
17” rim	mm ± 10	576
18” rim	mm ± 10	588
19” rim	mm ± 10	601
20” rim	mm ± 10	614

Note also that is with a car in the "normal position". That is:
2 x 68 kg on front seats (seats in central position); 1 x 21 kg in luggage compartment (center) and full fuel tank.