BMW
M5 / M5 Comp / M5 CS F90 · 2018 – 2023
S63 4.4 V8 in full thunder across every drive mode — saloon, M5 CS, doesn't matter.
- Fits F90 M5, M5 Comp and M5 CS valved exhausts
- Holds both banks open simultaneously
- Plug-and-play, no coding
- Removable in under a minute
Free UK shipping
2-year warranty
Fully reversible
The honest pitch
What this actually does to your M5 / M5 Comp / M5 CS
The F90 M5 has one of the angriest factory engines BMW has ever shipped and a valve map designed for a neighbour who works night shifts.
Open Valve removes the muzzle. The V8 sounds the way it does when an M Performance car drives past you on a B-road — only it's you, all the time.
Fitment
BMW M5 / M5 Comp / M5 CS F90
Years
2018 – 2023
Install time
~10 minutes
Tools needed
None
Long read
The BMW M5 / M5 Comp / M5 CS valve story
The F90 M5 has one of the angriest factory engines BMW has ever shipped — the S63 4.4 twin-turbo V8, in M5 Comp and M5 CS trim — and a valve map designed for a neighbour who works night shifts. The flap spends most of its time shut at part throttle in every drive mode.
Open Valve pins both rear flaps open. The S63 then runs in full M5 CS voice across every mode. The cylinder-on-demand stuff stays active in the ECU — module only touches the valve.
Two-module kit. Install via the boot floor — about twenty minutes.
Install — step by step
- 01
Boot floor up, both rear carpet flaps back.
- 02
Disconnect both 2-pin connectors, plug each module inline.
- 03
Velcro both module bodies to parcel shelf underside.
- 04
Refit trim.
- 05
Pair fob, test.
In the box
- Two valve override modules (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
- ·F90 M5, M5 Comp, M5 CS (2018–2023).
- ·F95/F96 X5/6 M use the X5/6 M-specific kit.
- ·Compatible with M Performance valved aftermarket systems.
BMW M5 / M5 Comp / M5 CS — FAQ
M5, M5 Comp and M5 CS all supported?+
Yes — all three F90 variants share actuator hardware.
What about the F95 X5 M / F96 X6 M?+
Same S63 engine, very similar actuator — pick the X5/6 M-specific kit, which has the correct firmware.
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.
Will it affect M-Drive presets?+
No — M1/M2 preset memory continues to work normally. They'll all just sound louder.
Does it interfere with xDrive switching or 2WD mode?+
No — drive mode logic is independent of exhaust valve.
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.
