Air Suspension category referenceSpecial order · Estimated lead time: typically 2-4 weeks
17-18 Honda Civic Si - Airtech Executive Air Suspension
Choose year, make and model to confirm this application-specific product fits — you can add it to your cart either way.
Verify fitment- Four 36-way air struts, four vehicle-matched air bags and four ride-height sensors
- 5-gallon lightweight air tank with two 1/4 in and two 3/8 in ports, mounted on a black carpeted board
- One VIAIR 444C compressor, 165–200 psi pressure switch and two 30 A relays
- Four-corner electronic control unit, full-color OLED remote, vehicle charger and separate backup remote
- 25 m of 1/4 in air line, 1 m of 10 mm air line, power wire and the listed tank/control fittings
- Application-specific tool kit with spanner wrenches, damping knobs and brake-line brackets, plus the owner’s manual
One approved application: 2017–2018 Honda Civic Si · Adaptive Damper will not function
- Ships from Mesa, AZ
- 12-month limited warranty
- Special order: typically 2-4 weeks
Specifications — CHD421-AEX
Product details
The Executive air package for the 2017 and 2018 Honda Civic Si, part CHD421-AEX, is built around four vehicle-matched air bags and four ride-height sensors. The four 36-way air struts are set up to level the car automatically at each corner, and a VIAIR 444C compressor with a 165 to 200 psi pressure switch and two 30 A relays provides the air.
Control comes from a four-corner electronic control unit and a full-color OLED remote that displays bag and tank pressure, with a standard 4-button backup remote and a vehicle charger in the box. Plumbing includes a lightweight 5-gallon tank with two 1/4 in and two 3/8 in ports on a carpeted board, 25 m of 1/4 in air line and 1 m of 10 mm air line, plus a tool kit with spanner wrenches, damping knobs and brake line brackets. The Adaptive Damper will not function on this Civic Si. Raise time varies with the vehicle and plumbing, so check fitment and plan a professional install.
Supported features
The OLED color-screen remote displays tank and bag pressure at all four corners and charges from the included vehicle charger. A standard 4-button backup remote is included.
36 levels of damping adjustment on every strut using the included damping knob.
Sleeve-type and double-bellow bags engineered to match the vehicle and its OEM suspension design.
Fine-tune ride height at any pressure through the adjustable lower mount.
One VIAIR 444C compressor, a 165–200 psi pressure switch and two 30 A relays are included. Raise time depends on the vehicle, plumbing, pressure and installation.
Available on certain MacPherson-strut applications.
Compatible applications (3)
Choices for this system
Basic (paddle valves and gauge), Deluxe (electronic switches and remote), Pro Plus (OLED remote, four-corner control) and Executive (adds height sensors and auto-leveling) are separate part numbers for this vehicle; compare them on the Air Suspension page.
Available on certain MacPherson-strut applications; ask a technician whether they apply to this vehicle.
The kit includes an OLED color-screen remote plus a standard 4-button backup remote.
Installation
Bolt-on struts with supplied hoses, wiring and manuals; professional installation is recommended. Recheck the system after the first 500 miles or one month; to check for leaks, inflate to 70 psi and spray each fitting with soapy water.
Air suspension setup and careWarranty & service
12-month limited warranty to the original purchaser against defects in materials and workmanship. Racing use, exterior finish and improperly installed or modified parts are not covered; keep your original invoice for any claim.
Warranty terms and service requestsOther published pages for MPN CHD421-AEX
These page names share this MPN; they do not confirm fitment. Verify your vehicle before ordering.