Originally Posted by MCM5
Yes, this should be how it works. Since it kinda of 'fools' the ECU, without actually altering the ECU settings, if you unplug it & go for service, in theory, BMW should not able to detect anything & thus no issue with warranty. Is that right ?
The other questions are :
- does it actually produce such performance gain ?
- any drawbacks for using this kind of chipbox ?
BMW might be able to detect unusual output signals from the ECU. Ie if the voltage to the fuel pump normally is 11V to maintain normal fuel pressure and on your car the log shows that it's repeatedly running at 12V there might be some issues with BMW (just a very crude illustration).
Performance gains are possible as long as boost and fuel is higher, but these powerboxes have often been over advertised.
The drawbacks are obviously that the ECU are still operating at it's std. maps and believes that the boost pressure still is std. The ECU maps are not altered to advance/retard ignition etc to the higher boost and fuel pressure. Meaning that the map is still for a 560HP engine setup with a given boost pressure and not remapped for higher boost and HP. This can lead to problems with lean/rich mixture, exhaust temperatures etc.