You're mate's right in that there's a lot to know about aftermarket engine management and I won't pretend that I know a huge amount, however it is one of the key aspects to a turbo conversion and it's a very big decision as to which way you want to go about things.
When turbocharging/supercharging their K11's, most people completely ditch the factory computer located behind the dash and install an aftermarket ECU (computer). These computers, unlike the factory item, will allow for all sorts of variables to be modified - like timing and fuelling for a start. Standard ECUs are generally sealed units and in the case of our cars, pretty much have no scope at all for modification. No one down here in AUS reprograms the CG13 ECU as far as I'm aware and it's generally not worth fussing about with it.
A full ECU is a complete replacement for your original one. It should handle all the functions that the original ECU did. Full ECUs will often cost between $1-2K depending on what you get and what features you ultimately want/need. Because of the flexibility and (depending on the ECU you get) the extent of integration to the original sensors that you can get, this is the recommended way to go if you're going to want a neat, reliable conversion.
A "piggyback" or "interceptor" ECU is one that is run in addition to the standard ECU that comes with the car. What they do is they attach (piggyback) to certain wires that control ignition and fuelling, then they 'intercept' the figures transmitted by the ECU and sensors in the car and modify them so that the engine will have enough fuel to compensate for the additional air and whatnot. These are often not recommended for turbo applications as they're difficult to get a good tune on and can be unreliable.
There are also fuel-only ECUs like the Haltech F5, that a few members on the forum are using to supply the engine with additional fuel as needed. The way it works is that at around 3-4psi, the standard injectors start running out of puff, so an additional injector drilled into the throttlebody kicks in and injects the extra necessary fuel required to stop the engine from running dangerously lean.
It's best to have a look around and speak to any tuning places that might be in the area to get an idea of what people are used to tuning. After all, even if you get the best computer out there, if you can't find a workshop that can tune with that specific computer, you're stuck! There's always workshops that will have a red hot go at anything, but you're better off using a computer that not only works with the car, but one that is also familiar with whoever is tuning it.
Or you could do something even cooler and slap a gas research carby on it and go in a completely different direction to what anyone else has tried on here!
It would be different, but would certainly be trouble getting help from people here if something goes awry with the gas setup.
Hope that's enough to get you started. Welcome to the forum
Edit: Or you could look at what fred's done with his ultra-super-budget turbo buildup. Can't argue with it though if it's still going!
---dens
