[EclipseRST]

when you recirculate the BOV the MAS already compensates for the air dumped back in so your car runs fine... when you vent the air that was originally dumped back in doesnt anymore and the MAS doesnt change. so it still thinks there is more air entering the motor so you run rich... not worth the troubles like your car stalling at intersections, blowing smoke from running rich. the best way to do this is put a 3-3.5" GM MAF in the upper intercooler pipe after the BOV and run the MAF translator so now it measures the correct amount of air entering the motor!