Originally Posted by Maxwell
Also how do you plan on operating the throttle body, with your by-passed ecus system? yeah you can feed the beast fuel and boost and play with the timing, but what makes you think the Motronic ecu will open it's mouth for you?
its not a piggy back thats how ... a auxillary injector controller functions fully apart from the main computer ... thats the secret ... the stock computer operates its stock function unknowing that the auxillary unit is peeping at the TPS values and firing another injector.
been there done that ... built a 8 injector system for a 2.0 DOHC i built a system based around a T3 super 60 ... all custom hand work in my spare time from sourcing the exhaust manifold from a mexican production vehicle (no emissions laws meant they had beastly engines when we were getting crap in the late 90s) to build the auxillary controller, 8 injector manifold, blah blah blah ....
and just like back then all you have to do if the stock ECU wiggs out when it sees boost is clamp the signal the MAF/MAP sees ... so you wire up a probe to the signal wires to check voltage and rip on the car when it is NA ... record the max voltages it sees then use a potentiometer (POT/variable resistor) to "clamp" the signal.
it works like a charm and the car drives like stock out of boost.