How it works
Not a tune. Not a remap. Just a signal.
We get this question more than any other. So here's the honest engineering version, without the marketing froth.
What your car already does
Every modern performance car with a valved exhaust has one or two small electric actuators bolted near the back-box. Open the boot floor, you'll usually spot them. The ECU sends each actuator a low-voltage signal that tells it where to sit — fully shut, half open, fully open, anywhere in between.
The map that decides when to send each signal is conservative. It has to be. The car is sold in 60 countries with 60 different noise rules. So "Sport" or "Race" only opens the flaps inside narrow RPM and throttle bands, and slams them shut again the moment you back off.
What Open Valve does
The module sits between the ECU and the actuator. When the remote is OFF, it does literally nothing — the OEM signal passes through untouched and your car behaves identically to factory. When the remote is ON, it intercepts that signal and replaces it with a "fully open" command, full stop.
It does not touch fuelling, ignition, boost, or any other ECU function. It does not throw codes. It does not require coding via OBD or VCDS or Bimmercode. The only thing it changes is where one tiny mechanical flap sits inside your back-box.
Why we don't force the valves shut
Some cars use the exhaust valve as part of their cold-start strategy, or to manage backpressure under certain load conditions. Forcing it closed when the ECU wants it open is a great way to confuse the engine — and occasionally to damage things.
So the "OFF" button on your remote doesn't slam the valves closed. It hands control back to the car. The ECU then decides whether the valve should be open, closed, or anywhere in between, exactly as Audi/BMW/AMG/Porsche shipped it. Safer for the engine, safer for you, and it means the module is 100% reversible.
Will it pass an MOT?
With the remote off, your car is bit-for-bit factory. Valves operate as standard, the noise meter reads what it always read, the exhaust hardware is unchanged. Switch the module out for the MOT if you'd rather not explain it to the tester — it pops out in under a minute. We sell this product for off-road and motorsport use, which is the legal position the industry uses; the practical position is that nothing changes when the unit is in its "off" state.