Thanks all, but the credits bellongs to the french guy who made the plans, i only built the kit and "found" the wires to use on the ecu. I only have minimum electronics knowledge
tonight i'll try to solve a problem i have with the boost (boost falls from 12psi to 5psi a 5500rpm

). But despite that, the car feels a lot stronger than before.
Vrg3 & Czo79 : The Safc works with 8 ranges. in the initial config, you set the 'Center RPM' (for WRX : 3600rpm), wich will split the 8 pots. 3600 / 4 = 900. Each Potentiometer (?) is used for a 900rpm range.
#1 : 0-900rpm
#2 : 900-1800rpm
#3 : 1800-2700rpm
...
#8 : 6300-7200rpm.
On mine, i setted the middle-point a 3300rpm, so each range is 825rpm wide.
For the electronics, i don't remember exactly what is involved exactly, but i remember that there is a ADC wich selects wich pot. to use,.. there is also a TLC0820, but i'll have to check this evening.
the boost control has 2 settings : SpoolUp PSI and Stabilised PSI.
let say you want 12psi, you set the SpoolUp PSI a 11psi , and stabilisez psi at 12psi. that way, your boost raise quickly to 11psi, then raise and stabilise at 12psi.
The estimated cost for each of these units will be around 125-150$USD, (~175-200$CAN) (depending on the prices of the parts, i may be able to find better prices...) all assembled, and basic setup done.
also, since it's a cheap home-made product, you'll have to cut wires on your ecu plug to install it ... hope you're not affraid of that
