I'm still running mass air but I have a Dynotune. My question is if I switch to a Tial BOV that vents to the atmosphere will I still have drivability issues or will the tune I have compensate for the lost air?

 

There will be drivability issues, and it'll be best to tune for speed density when you do tune.

 

If you are going VTA, you are going SD tune. VTA and MAF aren't friends and should never be put in the same engine bay

 

LOL, well put.

 

I dont get it! You've been here since 2004 and you still dont know the answear to this Q.

 

I figured it would cause issues and that I would have to get retuned and switch to Speed Density but I figured it wouldn't hurt to get some others' opinions on the matter.

 

In case you don't know:

The MAF "setup" regulates all air the enters the system. It's a closed system, and (assuming no leaks) the only way into the system is through the air filter and then through the MAF, and the only way out of the system is into the intake manifold and into the engine

The diverter valve keeps all of the air in the system regulated by redirecting it back into the system after the MAF (so that it's not "read" by the MAF again). The ECU is counting on this air being in the system and adjusts fuel ratios based on that air.

If you use a VTA DV/BOV on a closed system where all of the air is supposed to be regulated, the MAF has accounted for the air, the ECU has trimmed the fuel for the air, but if the air is released to the atmosphere and no longer a part of the system, the car will run really rich because of all the extra fuel the ECU set aside for it, but the air that was supposed to burn with that fuel was released from the system