Since many of our customers address the issue of closed exhaust flaps and full-load driving, we would like to provide some information on this below.
What happens in the exhaust system when the flaps are closed?
Under full load and high engine speed at the same time, there is a large throughput of exhaust gas in the exhaust system. If the exhaust gas flaps are closed in this driving range, this leads to a higher exhaust gas back pressure and, as a result, to a higher exhaust gas temperature than when the flaps are open. The higher temperature could have a negative effect on the cat or turbocharger. However, time plays a decisive role here, since the exhaust gas temperature does not simply rise suddenly.
What do I have to pay attention to if I have installed an RX1 flap control?
In normal driving you can safely drive with the flaps closed and you don't need to worry. In these driving ranges, the flaps are usually closed as standard. Even brief accelerations at full throttle are not dangerous, since the exhaust gas temperature does not rise so quickly that it could cause problems.
However, if you are on the racetrack or drive at full load on the motorway for a long time, it is advisable to open the flaps or switch to series mode. You don't have to push it to the limit unnecessarily and driving at full throttle also needs the right sound!
Incidentally, most exhaust systems today are already very large ex works, which means that there is often no danger even with closed flaps.
Why don't the flaps open automatically at higher engine speeds?
Our RX1 flap controls are deliberately not located in the vehicle's CAN bus. As a result, our systems are independent of software updates and cannot cause any far-reaching problems in the event of an error. Without the connection to the CAN bus, however, we have no vehicle parameters such as the engine speed and cannot evaluate them, for example to open the flap at a certain engine speed.
However, since our systems offer three modes (open, closed, series), this is not necessary. The customer can choose the mode himself at any time, independently of the vehicle settings (driving profile, etc.) and has full control. This means that our control can only be operated with the "Open" and "Series" modes and achieve the desired result.
This fundamentally distinguishes our module from devices or programming that are linked to a driving profile selection and force the customer to close the flaps by selecting, for example, "Comfort mode". At this point, automatic opening becomes necessary because the flap position is linked to a vehicle parameter. In this case, the customer no longer consciously decides to “close the flaps”.