"Parmas" Motor

[changchewsoon]

hi parmas, i do agree with you that having a bov is important for turbo cars as without it when your throttle plate closes and the air would have no where to go but to hit back the turbine and causing surge.

what i was trying to suggest is that if your car setup still retains the MAF sensor it will be good to perform a recirculation from the BOV back in to the intake. Post MAF but pre turbo.

recirculating will not cause the air to be forced back in to the engine because your throttle plate is already closed. it will recirculate through the bov to the intake, back to the bov again to the intake and the cycle continues. hence its called "recirculation".

i know what you mean by removing the bov and having air to remain "ready" in the intake, well you can't remove the bov totally because if you do that you're gonna hurt your turbo in the long run.

however, with a recirculation setup most ppl will notice an increase in throttle response due to the fact that the air is "there" the moment your throttle plate opens. remember, its post MAF and pre turbo, so its just air circulating within your intake, you could call it close loop if you want, which many factory fitted turbo cars such as audi and VW is practicing. if you look at a stock turbo subaru or evo, you would notice they are running close loop intake as well.

my argument is that your MAF has already registered a certain amount of air passing through it and sends signal to the ECU to send fuel to match it, when you vent it out to atmosphere the ECU has no idea and hence you run rich.

the recirculation is not meant to improve power, it is meant to prevent MAF equipped cars to go rich every time you shift gears and messing up with your fuel trims. some cars will even stall between gear shifts if they do not perform recirculation.

im not saying it is a must for you to recirculate, im just suggesting that for MAF equipped cars recirculating is a better option rather than venting to atmosphere so you don't run rich, mess up your fuel trims and face chances of stalling thats all.