Ok, first my car was chosen as the first fit check for the E90 kit. I don't work for them and honestly, I've always been air skeptical (except for SUVs), and never installed air on any of my cars, this is the first one.
With ownership of three previous rallycars and one road race car, I know there is a huge difference between race performance and street performance and to be honest, wasn't much interested in the street, except for nice ride.
However, no racecars are in the garage at the moment, kids take up more and more time, so I figured I'd go for a "dual purpose" performance car...enter a 135i.
First, my sport suspension car ended up having aftermarket H&R sport springs (29187) from previous owner. Looked cool, but this much lower (Fr:1.8"/Rr:1.2" lower from website) on stock length dampers = jounce bumper hitting crappy ride on the road, not to mention all the scraping! It was great on the track, however.
The AirLift kit has a shorter front strut, giving more usable compression travel while lowering. This can also be adj., so if you have a big dia. 19" or 20" tire setup, you can keep it out of the fender liner.
Front comes pre assembled with air spring, strut, and very nice Koyo bearing camber plates.
Install, no problem, similar to any other suspension. Just have to route and secure the braided stainless air lines.
Rear is more complicated, but no more difficult to install. It comes with a new lower control arm and toe arm which makes room for a larger air spring. This is key to rear grip performance and means the pressures are lower giving better ride.
Then it comes to routing air lines, mounting the pump, manifold, tank.
Are there more steps than a coil over install? Sure, but the system has been designed so well, it's very easy to figure out.
I still have to permanantly mount my tank, but it fits up on the side of the trunk, leaving full trunk space. No problem.
Key suspension alignment finishes the job. Make sure you do it at your desired ride height setting. In mycase it was the same ride height as the H&R coil setup.
Now for ride height play time.
You adj. ride height with pressure to the corners. 0psi = low, bottomed suspension / 100psi = high, topped out suspension
Sorry, didn't take a picture of the controller, but here's a generic pic
You can put more presets in then you would ever need. I currently have 4: Standard ride height (same as H&R spring), Track, Zero-low, and 111-high.
Below is a pictoral of different ride heights and measurements starting with low (not a setting you would drive on) and ending with high (used for clearing curbs).
My car has 225/45-17 BFG Rival's (25" dia.) on 17x7.5 ET40 wheels with no spacers. When I put the OEM wheels back on with 245/275 Hoosiers, I may have to make some adj....
Now for damper play time.
First at standard ride height I notice huge difference in big motion ride events due to the shorter front damper body.
Finally no more crashing front!!!
I've never understood lowering springs with stock length dampers...fine I guess on smooth roads.
The shocks have one damping adj. knob. It controls both rebound and compression, but has a greater influence over rebound. Huge range. From ridiculously (traction losing) stiff to comfortable street compliant soft.
Since a 135 is lighter than a V8 M3, my guess is the M3 or E90 would ride even better. So, full soft on the street, and we will see come spring how it does on the track. There is plenty of damping range for that.
I also did some measuring on the shock dyno, all the parts were extremely consistent, which indicates good valving and build quality.
So, if you want to easily change ride height and damping on the track and drive home comfortable without scraping curbs, this is the kit for you.
Below is cost compare to electronically adj. damping and coil over kits:
AirLift Performance Kit (BMW E46, very similar kit)
http://www.airliftperformance.com/ap...opean/bmw-e46/
2 Front Airsprings / 1-way adj. damping struts (WITH CAMBER PLATES)
2 Rear Airsprings and 1-way adj. dampers
Pump, tank, electronically controlled air manifold, wiring
Jegs $3074
http://www.jegs.com/i/Air+Lift/022/95746/10002/-1
KW DDC coilover kit (BMW E90)
http://www.kw-suspension.com/us/kw_ddc.php
2 coil springs and struts with electronically controlled damping (NO CAMBER PLATES!!)
2 coil springs and adjusters, shocks with electronically controlled damping
ECU, wiring
Bavarian Autosport $3850
http://www.bavauto.com/fland.asp?par...Fa4-Mgod4EYAgQ
If you say wanted to add the new hydraulic leveling system
to get up over those curbs...
KW HLS Hydraulic Leveling System generic kit
http://www.kw-suspension.com/us/kw_hls.php
Front only 19299299 $3600
All 4 19299499 $4750
Bilstein EDC Coilover (BMW E90)
2 coil springs and struts with electronically controlled damping (NO CAMBER PLATES!!)
2 coil springs and adjusters, shocks with electronically controlled damping
ECU, wiring
Turner $2436
http://www.turnermotorsport.com/p-13...FYlDMgodvk4AlA
add Vorschlag camber plates
http://www.turnermotorsport.com/p-21...reettrack.aspx
($474) and your at $2910
And another very nice coilover:
Ohlins Road and Track (BMW E90 M3)
2 coil springs / 1-way adj. damping struts (NO CAMBER PLATES!!)
2 coil springs and adjusters / 1-way adj. damping shocks
GMP $2969
http://gmpperformance.com/index.cfm?...ail&PID=253776
I've considered all of these amazing performance setups. A proper motorsport suspension could be twice those amounts.
Interested?
The kit should be available in a few months.
This is not something you'd put on a trailer'd racecar. But if you use your car everyday, are sick of scraping over small bumps, run it hard on the track, auto-x, and rally-x; it offers great benefits, with less compromises.
I intend to hammer this kit until my car turns into a racecar and continue to review performance, durability, and functionality. This as it relates to the E82/90 chassis. The same components have been well proven on many other chassis. I hope to also review the upcoming bluetooth iphone app.
A strong product. Something to consider for any dual purpose performance car. It's already changed my preconceptions of air suspension. The right engineering can do that.