Originally Posted by Karlos G

Det is normally caused by either not enough fuel and/or too much advance.
Perhaps the MAP sensor in the ECU is dead, quite common these days, not pulling the timing back as it should when boost increases, try another ECU before you go stripping the engine!! lol
You say anything over 12 degrees and it dets, is that static timing? If it is then it should be pulled back to around 8-10 degrees anyway, you cant run much boost at 12 degree's let alone more advanced than that.