some of you may already know this ,but it is a new discovery for me.take a borg warner check valve(ec601).install it inline with your map sensor.black side to the throttle body and white side to the map sensor.at the base of the white side,drill a tiny hole(i used the smallest bit i had.can't remember the size).make sure and slide the vacuum hose back far enough as not to cover the hole.you now can make as much boost as you want without throwing a code.the check valve blocks boost completely and the hole is there to allow the map sensor to get atmospheric pressure while under boost.the ecu sees 0 psi under boost.if it does not see atmosphric pressure it will trow a code.i figured this would be very good,especially for the afc hack peoplewanting more boost.

 

Ive done that several times with the stock check valve for the brake booster. Good idea though