PC tied into Engine Computer > Check it
I've been working on this for some time now with great success. I've been developing an interface to make modification of the ECU (Engine Control Unit) code to manipulate engine performance. I've put together a page that details all of it, but the screen shots are old and there are a host of other parameters the user can manipulate.
I have also edited the code in the ECU to use control circuits for devices that aren't important to engine operation to allow for control sequences for things like nitrous oxide injection, aquamist injection and for boost control. It is only available for the 300ZX twinturbo and naturally aspirated, but I have good reason to believe that with only slight modification of my interface, it can be used on other nissan vehicles.
Check it out!