BOV explained!

[Littlestan]

Hello all,

As some of you know, I just recently bought a almost new and almost

completely stock 1990 TT Supra. The engine (a 1G-GTEU) has been

untouched, so I am eager to start adding parts and have some fun!

However, one of the most confusing things I have come across is the

question of adding a Blow Off Valve (BOV) or modding the Bypass Valve (BPV

or just BV). Several sources/sites/opinions state that adding a BOV can and

most likely will cause a stumble in between shifts since a BOV vents air

directly to the atmosphere resulting in an overly rich air/fuel mixture. I've

literally searched for 30+ hours online for an answer to this problem.

Well, here it is;

The BOV has to be mounted before the MAF. This is because the BOV
vents to the atmosphere. If it was mounted after the MAF, the BOV would
release air that has already been metered. If it vents metered air, then it will
throw off the fuel and will make the A/F mixture rich, since the air that should
be there isn’t there. This is called a blow through sytem.

Phew!! Easy to understand now, hey?

This one's for all the n00bs... ,

-=Littlestan=-

P.S. If you have a AFM (Air Flow Meter) rather than a MAF, then you will probably have to do a AFM ---> MAF conversion in order to mount it after the intercooler. Oi, striving for perfection is a horrible curse...