Sometimes on Ebay I see some chipped fuel ECU passing for the ke jetronic RS Turbo.
I thought that only the ignition ecu could be chipped.
What is then changed in the fuel ECU? Because a chip only release the boost limit on a RS Turbo;
Regards

 

That's what I understood, I had a chip in the silver box on mine and it over-rode the factory boost limiter.

The fuelling on the rs is controlled by the electronic block on the side of the metering unit (grey on s1 and black on s2). When the flap is moved in the metering unit the electronic solenoid varies the amount of fuel pressure in the top chambers of the metering unit and hence how much resistance the flap has and therefore affecting how far open it goes and therefore how much fuel is delivered. The black ecu essentially has a map for this solenoid.

The easiest way to up the fuelling is to remove the solenoid/actuator block and on the back is a grub screw which adjusts the tension on the metal lever inside the device. Or use a bigger metering unit from a merc or porsche 924 etc
Don't believe the fuel ecu itself can be remapped and not sure it could really be called a map.

Least that's my understanding of it, there are some useful guides on the net for the kjet system and the rs just uses a slightly modded version (kejet)