Quote Originally Posted by SwiftGTiRacer
I always thought the SAFC takes the output from the ECU, and increases it according to the MAF's output but letting the ECU run stock signalling.

Swifty
what it does is intercept the signal of the maf and adds/subtracts depending on your adjustment and sends that to your ecu. this in turn tells the ecu what vac/boost table you should be in and then spits out a signal to the inj for the amount of fuel in that particular part of the table, but at the same time is sending a signal to the dizzy for the amount of timing in that same part of the table.