Need to raise height of Koni FSD/Eibach combo

[Revelate]

I had the Koni FSD shock / Eibach Pro-Kit spring combo installed on my 135i by a reputable independent mechanic a couple years ago and one of the nagging issues I've had is how extreme the lowering was compared to what what expected (indicated) from the manufacturers of said products.

The rear height is actually pretty good with plenty of clearance, but the front dropped well over 2" from stock M-Sport suspension and the front end scrapes all the time, even driving through intersections with typical drainage dips and transitions from road to parking lots when there is a reasonable change in pavement height. Others who have installed this same setup in an M-Sport 135i have indicated a ~1" overall drop. I know there are many reasons why this could have happened, but I'm not sure what to replace/correct to raise it at least 1/2", up to 1".

Possible causes that I can think of are:

- Lower spring perch on the Koni FSDs are not at the same position as OEM shocks.
- Spring pads did not get installed/reused when the new suspension was installed.
- Eibach Pro-Kit springs are soft and saggy

Possible solutions that I can think of are (in order of my preference):

- Verify that the OEM spring pads are installed and consider stacking multiple pads or adding custom-fit rubber pads
- Replace the springs with a style that advertises less lowering
- Replace the shocks with a style that has a threaded lower spring perch
- Re-engineer the suspension altogether with a goal of improving handling but retaining close-to-stock ride height

Things I would like to avoid:
- Coilovers
- Returning to all OEM suspension

Suggestions? Opinions? Similar experiences?

[Sixle]

Do you have pics?

[fboutlaw]

Originally Posted by Revelate

I had the Koni FSD shock / Eibach Pro-Kit spring combo installed on my 135i by a reputable independent mechanic a couple years ago and one of the nagging issues I've had is how extreme the lowering was compared to what what expected (indicated) from the manufacturers of said products.

The rear height is actually pretty good with plenty of clearance, but the front dropped well over 2" from stock M-Sport suspension and the front end scrapes all the time, even driving through intersections with typical drainage dips and transitions from road to parking lots when there is a reasonable change in pavement height. Others who have installed this same setup in an M-Sport 135i have indicated a ~1" overall drop. I know there are many reasons why this could have happened, but I'm not sure what to replace/correct to raise it at least 1/2", up to 1".

Possible causes that I can think of are:

- Lower spring perch on the Koni FSDs are not at the same position as OEM shocks.
- Spring pads did not get installed/reused when the new suspension was installed.
- Eibach Pro-Kit springs are soft and saggy

Possible solutions that I can think of are (in order of my preference):

- Verify that the OEM spring pads are installed and consider stacking multiple pads or adding custom-fit rubber pads
- Replace the springs with a style that advertises less lowering
- Replace the shocks with a style that has a threaded lower spring perch
- Re-engineer the suspension altogether with a goal of improving handling but retaining close-to-stock ride height

Things I would like to avoid:
- Coilovers
- Returning to all OEM suspension

Suggestions? Opinions? Similar experiences?

Your springs had creep strain over time and their natural state is now shorter. I'm seeing the same thing with Dinan Springs.

For your options:
- Verify that the OEM spring pads are installed and consider stacking multiple pads or adding custom-fit rubber pads
-- Don't do this. You'll rub the rubber on rubber and it will prematurely wear both parts. Also depending on how many you stack, the spring could unseat. Bad news.

- Replace the springs with a style that advertises less lowering
-- Acceptable option. Dinan drops less. HPA has some options. Or see what I'm going to be linking below.

- Replace the shocks with a style that has a threaded lower spring perch
-- Acceptable option. See what I'm going to be linking below.

- Re-engineer the suspension altogether with a goal of improving handling but retaining close-to-stock ride height
-- Best option, but costly.


Check this out:
http://www.tcklineracing.com/webdocs...Details424.cfm
It allows you to convert your Koni shocks to coils. Totally controllable ride height and spring rates for about the same cost as your above options.

[RaceTruk]

Originally Posted by fboutlaw

Your springs had creep strain over time and their natural state is now shorter. I'm seeing the same thing with Dinan Springs.

For your options:
- Verify that the OEM spring pads are installed and consider stacking multiple pads or adding custom-fit rubber pads
-- Don't do this. You'll rub the rubber on rubber and it will prematurely wear both parts. Also depending on how many you stack, the spring could unseat. Bad news.

- Replace the springs with a style that advertises less lowering
-- Acceptable option. Dinan drops less. HPA has some options. Or see what I'm going to be linking below.

- Replace the shocks with a style that has a threaded lower spring perch
-- Acceptable option. See what I'm going to be linking below.

- Re-engineer the suspension altogether with a goal of improving handling but retaining close-to-stock ride height
-- Best option, but costly.


Check this out:
http://www.tcklineracing.com/webdocs...Details424.cfm
It allows you to convert your Koni shocks to coils. Totally controllable ride height and spring rates for about the same cost as your above options.

The height adjusters only work with larger diameter springs.
Not on eibach.
They said they had an adapter that may work but they were pretty sure it wasn't big enough still.

[Revelate]

Originally Posted by Sixle

Do you have pics?

I do but they are mostly irrelevant. Shadows, different camera angles and the tire tucking under the fender don't convey the ride height very well.

Regardless of the drop, it's just not useable for me. A combination of low ride height and available suspension travel causes occasional scraping during my "normal driving routine" of going to and from work and driving around town. I am very careful about angling and creeping into and out of parking lots and avoiding questionable transitions but it still happens.

My comparison test is to use a thin steel ruler and slide it between the tire and fender, then ball park the angle of the ruler. On my front tires, the ruler angles down about 15 degrees. On the rear tires it's essentially flat with just a slight upward angle.

Another functional measurement - the lowest section of the front airdam is 3.6" off the ground (disclaimer: I have the BMW Performance front bumper and CF splitters). The plastic "lug bolts" that attach the CF splitters are nearly sanded off from scraping.

[Blacksport]

You say you don't want to use coil-overs, but they are the answer to your problem....I have the Eibach Pro-Street C/O's...I can go from stock height to about a 2" drop.....I'm running them about 5/8" (15mm) down...further than that causes the steering arms to be angled too much (IMO)....

[128Convertibleguy]

Go back to stock springs. Easy, relatively cheap, won't affect your handling much, particularly if you add a bigger front antiroll bar. Will improve the ride. You're not going back all the way to OEM, the Konis will still be good. Probably better, the FSDs are actually designed to work best at stock ride height.

Very cheap if you saved the stockers. Or if you can find someone who did.

[TS135i]

Question: Koni FSD mated with BMW Performance Springs a good match?

Some comments suggest to just keep OEM springs for FSD, but I'm looking for "slightly" firmer ride without going to adjustable struts.

[Dackelone]

Originally Posted by TS135i

Question: Koni FSD mated with BMW Performance Springs a good match?

Some comments suggest to just keep OEM springs for FSD, but I'm looking for "slightly" firmer ride without going to adjustable struts.

Performance springs would be a nice choice. Also Cobb makes nice springs that don't seem to be on anyone's radar. I like them. Send a PM to @kleach18 he has them on his 135i with stock shocks and the ride is really quite nice, with a slight drop over stock. Its a really mild drop like the Perf springs.

Dack