Wideband O2 sensor and piggyback controller

[The Radium King]

piggyback can't modify closed-loop - ecu will trim everything back to 14.7:1. so, piggybacks are only good for open loop - lean out the mixture a bit - closer to 14.7:1 more more power and fuel efficiency. i think it was insite who did some work with this? there is also the resistor method - install a resistor on the maf to modify the signal; again, ecu trims car back to 14.7:1 in closed loop so you are only setting afrs for open loop. most guys use a potentiometer; put the car on a dyno with a wideband, and adjust the potentiometer until they get the open-loop afrs where they want them.