Why can't you use VTA BOV valves in Evos?
 

Every thread states that the engine stutters and idles poorly when using an aftermarket BOV that vents to atmosphere (vta).

Why is that? I've have two other turbo cars and neither of those had this issue.

What is the way to fix it? Aftermarket ECU ala Vishnu?

because....the computer looks for the measured air, and then suddenly its not there no more (it got blew out into the atmospere)

I understand that, but isn't that the same way it worked in the Eclipse, RX-7s, Supras, etc? None of those have this problem...

they have map sensors not mas sensors (except the eclipse). You can get an AEM EMS and compensate for it but that is a tad extreme, some people have had reflashes and dont seem to have any problems

It's not really that big of a deal, I plan on just recirc myself, but I'm surprised by the number of pepole on this board having VTA problems.

If you fit an open element air filter, you'll get some of the noise (if thats what you are after), since you are taking the air out of a 100% sealed environment.

Some cars seem to be more affected than others (not just Evo's, but Subaru's, etc as well). But the correct way is to recirc, until you convert to full MAP and ditch the MAF

I tryed VTA and If you are picky about driveablity then spend your money on a intake like the AEM. You will get two things for the price of one. Vent sound just like VTA and better topend once you start adding mods.

so like guru del said, it will effect it the same as an eclipse would??? cuz i have my greddy type S on my eclipse VTA, it does have a wierd idle but the cams have alot to do with it

actually i have my hks ssbov recirc and i have weird idling now....

i really want VTA actually.. heh my recirc is loud..but i want it louder! yay it just sounds soooo badazzz... pssssssssssssshhh!

what really happens is that you are reading your air volume coming in through the mas which is before the BoV.... so when your computer corrects your fuel and then you end up VTA you end up being extremely rich and this cause stalling and extremely bad gas milage..... most 2gen dsms can;t vta with out a VPC... which takes the MAS out of the loop....
So if you can get a conputer like the AEM you will be able to remove the MAS and have no problems VTA....
hope this somewhat clarifies things