Wanted to share my experience when I replaced the springs,
bars, and exhaust on my new 335i e90. I replaced
the stock sport zsp parts with Eibach Pro Springs, Koni adjustable
yellow's, Eibach sway
bars and Borla exhaust. When I did all
the work I was careful to use a torque wrench to remove various
nuts and bolts. I wrote these values down to help with reassembly.
I know it's not perfect but at least I had some values to start
with because I didn't have a service manual. Use your own
judgement. I noticed a lot of the suspension DIY posts didn't
show any torque values. I also took pics so I hope this helps
someone. I work pretty slow and it was much slower taking notes
and pics. It took me a full day and a half to complete every-
thing but nothing seemed too difficult. So here goes:
1. Jack up all four corners of the car. There are six jack points.
The front one is a metal plate centered between the front wheels,
This one is very unstable. I would never consider using a jack
stand here. I used one of my hydraulic jacks here but always had
2 side stands on the front side jack points as I raised the car.
The rear jack point is the differential body but not the differ-
tial cover. I used 4 jackstands on the 4 side jack points. Since
these jack points are indented into the plastic, I cut up some
pieces of wood from an old hockey stick handle that fit into the
indentations perfectly. Then I used some 2x4 lumber on top of the
jackstands so none of the underbody plastic would be damaged.
Once jacked up safely, remove all 4 wheels.
Jacking up using front jack point.
All four corners jacked. Notice tape on front fender for protection.
2. I worked on front suspension first. Remove front undercover.
There are 16 8mm sheet metal screws holding it on.
3. Remove front sway
bar link top nut. Use 17mm endwrench and 16mm
socket. (34 ft/lbs.)
bar link freed. There are also wires to be unclipped from strut.
4. Loosen compression bolt and nut on back of front strut. Use 18mm
endwrench and 18mm socket (55 ft/lbs.). Now is a good time to
spray penetrating oil around the pinch mount to help remove the
strut later on. On driver's side pop off the headlight sensor
arm from the lower control arm. Use a flat bladed screw driver.
You can see the pinch bolt and nut are loose but still on.
5. Remove 3, 13mm nuts on top of strut mount. Use 13mm socket and
endwrench. (30 ft/lbs.) There is an alignment nipple which I
marked to remind me to mount it correctly during reassembly.
6. Compress spring using Autozone Spring Compressors (free rental
and much better than Harbor Freight). Use 19mm ratcheting end
wrench (Harbor Freight)
7. Push steering knuckle/brake rotor down so top of strut clears
fender. Remember the tape on the fender just in case.
8. Slide off black top ring but mark alignment with nipple for re-
Notice alignment nipple
9. Remove plastic top cap to uncover 21mm nut on top of strut.
10. Remove 21mm nut (55 ft/lbs). Use 21mm socket and MAKE SURE COIL
SPRING COMPRESSOR is still fully compressing spring. Otherwise,
car parts and your body parts may be damaged!
11. Carefully remove swivel hat, washer and spring from top of strut.
Remove strut assembly from pinch mount by spreading mount with pry
bar and using hammer from bottom of strut.
12. Remove spring compressor from spring.
13. Place OEM lower rubber spring cushion onto new Koni strut.
14. Place OEM rubber dust boot and bump stop onto Koni strut.
15. Place new Eibach spring onto strut and use spring compressor to
16. When spring is compressed, place OEM upper rubber spring cushion,
metal spring top cap, washer, and upper swivel hat onto new strut.
These are all held together on the strut by a new Koni supplied
lock washer and 19mm nut.
17. Leaving spring compressor on, place new strut assembly into lower
pinch mount. Make sure strut is fully seated. Then push down on
rotor/steering knuckle and carefully slide upper part of strut past
fender and into recess for strut. Slowly release pressure from
spring compressor until it can be removed. Attach top of strut
with 3, 13mm nuts. Make sure alignment nipple is properly aligned.
Remember the alignment marks you made. Then tighten 18mm bolt and
nut on lower pinch mount.
18. I didn't attach sway
bar link to strut since I was replacing sway
bar with a new Eibach unit.
Now let's continue with the Front Sway
1. Since the sway
bar link is already unbolted from the strut, just
bar link from the sway
bar. (34 ft/lbs.)
2. Remove the sway
bar bushing brackets. They are held on by 4, 12 mm
nuts (16 ft/lbs). Use Deep well socket.
3. Lower the sway
bar down and shift it to the driver side of the car.
You'll have to tip and rotate the sway
bar but it comes out easily.
4. The Eibach sway
bar is thicker and comes with a much firmer bushing.
Liberally grease the bushing with the included sticky grease and
use the OEM bushing brackets to secure the new sway
have to rotate the sway
bar to find the "sweet spot." Reattach
bar links and you are done.
Before I started with the Rear Sway
Bar I realized it would be easier
if I removed the exhaust first.
1. Remove midpipe shield/chassis brace. There are 8 bolts. Use Torx
T50 (15 ft/lbs.)
2. Support exhaust with a hydraulic jack.
3. Disconnect mid pipes from down pipes. I used penetrating oil before-
hand to make it easier. I used an extension and a universal joint.
4. Remove rubber hangars from exhaust. Use pry bars. Also, disconnect
vacuum line to solenoid exhaust valve at rear by the muffler. You'll
have to plug this line if you are installing aftermarket exhaust.
5. Remove mid pipe brace. Use 8mm socket (25 ft/lbs)
6. The exhaust is HEAVY so have a helper help you lower the jack while
you stabilize the exhaust.
Now we can go to the Rear Sway
Bar. I wish the Rear Sway
Bar was as easy
as the front but IT IS NOT. But be patient and methodical and you will
1. Unclip ABS wire from upper control arm, so it is free from control
arm. While you are unclipping the wires, notice there is not enough
room to unbolt and remove the sway
bar bushing brackets. That is the
2. Disconnect sway
bar from sway
bar link. I used thin vise grips and
16mm socket (40 ft/lbs).
You need something to hold the sway
bar link stud or else it will spin.
3. Disconnect upper control arm from rear hub. Use 18mm socket(95 ft/lbs)
Rotate upper control arm up and out of the way.
4. Loosen heat shield around rear drive shaft. Use 10mm socket. In
retrospect, I'm not sure this was even necesarry. I didn't need to
drop the subframe/differential unit that much to get the sway
out. I thought that it might damage the heat shield and it is very
easy to loosen. Use your own judgement.
5. Loosen lower shock mount. Use 10 mm socket (35 ft/lbs). You don't
have to remove bolts. Now remove lower nut from shock. Use 17mm
deep well socket (15 ft/lbs).
Everything is very accessible under the lower control arm.
6. Place jack under differential but NOT under differential cover.
Loosen 6 subframe bolts but do not remove altogether. You can
do that later if you have to lower the subframe more to remove
bar. Use 14mm and 16mm sockets (65 ft/lbs).
7. Remove the sway
bar brackets and bushings, and pull and rotate the
bar out from the Drivers side of the vehicle. Be patient and
lower the subframe more if you have to. Just be careful not to
stretch any wires too much.
Pic from passenger side. Now you have room to remove the brackets.
8. Installed new Eibach sway
bar in reverse order. Kit comes with new
firmer bushings and grease. Use all the grease. Before I raised
the subframe, I went on to replace the OEM zsp rear shocks and springs
with Koni yellows and Eibach Pro springs.
Before I continue with the Rear Shocks and Springs, I want to tell
everyone I lost my notes for this part so take the next steps with
a grain of salt. Let's get to it.
1. You have to take the trunk liner out to get to the top shock mounts.
There is a plastic trim piece on the rear of the trunk and side liners
that you have to remove. There are many plastic push type rivets to
remove. The best way is to get a set of plastic tools from Harbor
Freight or any auto parts store. I have both metal and plastic tools
to remove trim pieces and plastic rivets and the plastic tools work
the best without breaking anything.
2. Once the trunk liner is removed the top shock mount is accessible.
I used 2 end wrenches to remove the shock top nut.
3. On a previous step during rear sway
bar removal I had already removed
the shock lower nut and loosened the lower shock bracket. So now
it is very easy to remove the old shock and install the new.
4. Because the subframe is still lowered the rear shock spring is already
loose and ready to come out. I didn't have to touch the lower control
5. I replaced the OEM springs with the Eibach Pro Springs. At this point
it was easy to reverse the order and get the rear suspension buttoned
up and the trunk liner put back together. No extra bolts or nuts and
none of the plastic rivets even got scratched, so I felt good.
6. The last thing I did was install the Borla exhaust. It came with mid
pipes so I didn't have to cut up my OEM exhaust. The Borla exhaust is
super light compared to the OEM. The tips are a little larger than
stock. Idle is definitely louder but driving is very unobtrusive. With
the stock I didn't hear any exhaust except when revving it up. The
Borla works for me because it is lighter, a little louder but without
any drone in my automatic trans car. If you are picky you might say
it has a tiny low drone around 1600 rpm cruise but I think it sounds
great for a daily driver.
Pics of my car after the mods:
With the Eibach Pro springs expect .5 inch lower on rear and 1 inch lower
on fron compared to OEM zsp suspension.
Afterthoughts: I think these mods, including the sway
bars can be done
by anyone with a decent set of tools. My wife has a supercharged 350z
with full Stillen suspension and my son has an STi with coilovers and my
previous car was an EVO 8. My 335i with zsp suspension had a too
much understeer and bodyroll compared to the others and the suspension
seemed harsh. Now without the runflat tires and the Koni yellows and
Eibach springs and sway
bars the change is significant. You can definitely
feel less understeer and body roll even at daily driving speeds. Plus
the ride is more compliant. My car will never see the track so I'm happy
with this setup. I was thinking about KW or FK coilovers but after talking
with the guys from Supreme Power I'm glad they recommended these products
for my situation. Plus the shocks, springs, and sway
bars were $1100 from
them with no labor costs. Easy decision. If I wanted to do everything
gradually and try and save money I probably would have done the non runflat
tires first and then the sway
bars second. But these cars do look nicer a
Lastly, the Borla exhaust saved a ton of weight, fit was excellent and
sound was only a little louder but not obnoxious. Hope this all helps
someone, as I have received a lot of help from you guys and gals here.