Subaru
WRX STI / WRX VA / VB · 2015 – present
Boxer rumble, valves wide, with absolutely nothing about your STI to give it away from the front.
- Fits valved aftermarket back-boxes for VA / VB chassis
- Compatible with Cobb / Invidia / Milltek valved systems
- Pocket fob, two buttons
- Reversible, no ECU changes
Free UK shipping
2-year warranty
Fully reversible
The honest pitch
What this actually does to your WRX STI / WRX
Most STIs run aftermarket exhausts now, and most of those are valved. The valve programming is usually too conservative for what owners actually want.
Open Valve overrides that with a single signal swap. The boxer burble stays on whenever you want it.
Fitment
Subaru WRX STI / WRX VA / VB
Years
2015 – present
Install time
~10 minutes
Tools needed
None
Long read
The Subaru WRX STI / WRX valve story
Most VA/VB STIs run an aftermarket exhaust by now — the OEM cat-back on either generation is uninspiring, and the most popular upgrades are valved systems from Cobb, Invidia, Milltek and Tomei. The valve programming on these systems usually follows a conservative default — flap shut in Comfort, opens under load.
Open Valve overrides the close command. The flat-four boxer rumble then stays present at every throttle position in every mode. The characteristic 1-3-2-4 firing-order burble — the bit STI owners chase — is unmuffled.
Single-module kit covers VA and VB chassis with most popular aftermarket valved systems.
Install — step by step
- 01
Raise rear of car.
- 02
Locate aftermarket exhaust's valve actuator.
- 03
Disconnect 2-pin connector, plug module inline.
- 04
Velcro module body to chassis.
- 05
Refit any displaced trim.
- 06
Pair fob, test.
In the box
- One valve override module (one per actuator)
- Two-button RF key fob (CR2032 pre-installed, spare in the box)
- OEM-pattern connectors — no cutting, no splicing, no scotch-locks
- Printed install card with model-specific photos and a workshop QR link
Fitment notes
- ·VA (2015–2021) and VB (2022+) WRX and WRX STI with aftermarket valved exhaust.
- ·OEM-only exhaust without flap not applicable.
- ·Compatible with Cobb, Invidia, Milltek, Tomei valved systems.
Subaru WRX STI / WRX — FAQ
Does it work with my Cobb / Invidia / Milltek valved exhaust?+
Yes if the system uses a standard-pattern 2-pin actuator (almost all do). Check connector style if unsure — happy to confirm before shipping.
What about OEM STI cat-back?+
OEM cat-back doesn't have a flap. Not applicable.
Will it throw a warning light on the dash?+
No. The module sits in the signal path between the ECU and the actuator motor. The ECU sees a normal actuator response back, so there's nothing to flag. We've shipped thousands of these and not had a single check-engine call linked to the module itself.
Is it reversible?+
Yes, fully. Unplug the module, plug the OEM connectors back into each other, refit the trim — about three minutes' work. There's no permanent change to the car, no part cut, nothing in the ECU. Dealer service visits, MOT, sale to a new owner — pull it out and it's like it was never fitted.
Does it work with an aftermarket exhaust?+
If the aftermarket back-box retains the OEM-pattern valve actuators (most do — Akrapovic, Milltek, IPE, Capristo all run the factory motors), yes. If the system is a straight-through with no valves, there's nothing for the module to override.
Affects AWD or Driver Controlled Centre Differential?+
No — completely independent.
Will it work with a Stage 2 tune?+
Yes — module is signal-level. Tuned cars sound considerably more characterful.
Disclaimer
Open Valve modules are intended for off-road and motorsport use only. Please confirm your car has factory valve-actuated exhaust before ordering — if you're not sure, message us first. Professional installation recommended. Use at your own risk.
