STEP 1
Checking coilover clearance and springs
CLEARANCE
Make sure you have enough clearance around the coilovers, the air cups are 120mm in diameter, the fitting is 17mm. (110mm air cups available on request)
SPRINGS
The air cups can only be installed on linear springs, it will not fit on ''shaped'' springs as shown in the figure. In some situations shaped springs can be changed to linear springs.STEP 2
Measuring
DAMPER SHAFT
Measure the thickest part of the shaft, we strongly recommend to measure with a caliper.
Air cups are available for coilover shaft diameters: 12.5mm, 14mm, 15mm, 16mm, 18mm, 20mm, 22mm, 25mm, 40mm, 44mm, 44.2mm, 44.5mm and 45mm.
SPRING DIAMETER
Maximum outer diameter: 99mm.Minimum inner diameter: 61mm. (57mm on request)
Maximum outer diameter for 110mm air cups: 89mm.
STEP 3
Installation
RIDE HEIGHT
In most cases the air cup will take between 20 and 30mm of height. The stack height of the air cup itself is 20mm but with most coilovers the top hat comes on top of the air cup, this will take around 10mm. If there is enough thread left on the coilovers to lower the springs, it won't be a problem. If not, you will need to install shorter springs.
SPRING ADJUSTMENT
The lift from the air cups requires droop / rebound from the coilovers. If you don't have enough droop, the air cups can't lift the full 50mm. The damper strut simply will top out before achieving the full lift. If you're using the standard spring rates that came with your coilovers, it should be fine. If you're using higher spring rates we recommend to use helper springs to get the full lift.WHAT IS DROOP?
Droop, also called rebound, is basically the amount of travel you have between ride height and full extension. Too much preload will decrease droop, we recommend to set a minimal preload. If you're using extreme high spring rates, higher than the original rates that came with your coilovers, the weight of the car won't compress the springs enough to create enough droop. This problem can be solved by installing helper springs, these will create enough droop for the air cups to lift.CUSTOM REAR CUPS
Separate spring and shock
FITMENT REQUIREMENT
Custom rear cups are available for cars with a separate rear spring and shock.
- Linear springs needed. For the 350z platform you can use a linear spring adapter to install linear springs
- Minimum spring length used with custom rear air cups: 160mm
- Spring perch thread diameter: max 50mm (Suitable spring perch)
- Minimum spring inner diameter: 61mm
- Maximum spring outer diameter: 105mm
CUSTOM REAR CUP SPECIFICATIONS:
- Diameter: 130mm
- Height: 83mm
- Air cup stroke: 25mm (results in 40-50mm actual lift)
- Air cup stack height: 30mm
LIMITED APPLICATION
- 350z platform (350z 370z, g35, g37, genesis coupe)
- BMW E90 / F30 / F80 series (E90/E91/E92/E93/F30/F32/F33/E82/F80/F82/F83/F87)
- Supra A90
Possible available for more cars, but not tested yet.
INSTALLATION:
The custom rear cup will take 30mm of height, If there is enough thread left spring perch to lower the springs, it won't be a problem. If not, you will need to install shorter springs. For the 350z platform, keep in mind that the linear spring adapters also will take 30mm of height.
Recommended spring lengths:
- BMW E90 / F30 / F80 series: 180mm
- 350z platform: 160mm + linear spring adapters
- Supra A90: 220mm
An air cup lift system is also known as air cup suspension, an air cup kit or a coilover lift system.