Preference for a high pitched BOV u say? ........... to each his own man. My point was this... would u really sacrifice performace (irregular low idle issues and erroneous MAS readings), for a loud BOV???

Woa now wait-a-minute ... I never called anybody that chooses to run VTA "stupid," as u falsly stated. I simply 'suggested' that one could have low self esteem in regard to wanting to be noticed ... via the sound of a lOUD VTA BOV, opposed to changing the BOV to a recir unit that does what it is designed to do -- HOLD BOOST and increase hp withOUT all of the adverse issues!

Guys, no need to flare up up at me ... my point is clear. Running VTA has proven to actually decrease performance on da evo, so one may be better off with an open air filter kit to achieve the VTA-type sound. I was brought up just fine TUVM!

All WORKS customers are smarter, better looking and have more money. All the money saved by going with quality WORKS performance goodies buys a lot of books, clothes and gym memberships.

Back to the discussion... the EVO's ECU does in fact rely on the MAF (Mass air flow) sensor (aka Air Flow Meter) to set the air/fuel ratio. Since the air is metered as it passes through the MAF, the ECU has no way of accounting for air volume lost along the way (e.g when it is vented to atmosphere). As such, during shifting or when the throttle is released, the AF/R will run very rich -- in fact, far too rich.

So, venting to atmosphere is certainly not optimal from a performance standpoint. That said, I run a VTA BOV on my personal track car (not an Evo) which is equipped with a MAP (mass air pressure sensor). Since there is no ill effect for me, I have come to enjoy the "woosh" sound and appearance of a bling-bling BOV. Would I have done the same if my car were equipped with an Air Flow Meter? Most likely not.

While there would likely be no serious long-term repercussions from doing so, I personally would not compromise my engine's performance even a little for a cool sound or shiny BOV under the hood. Actually, I know a lot of guys with AFM equipped turbos running straight exhausts that like spitting flames out the tailpipe and can only do this with the VTA BOV inducing the super-rich mixture. For these people, the cool sound, flame throwing, cool looking BOV is worth the compromise. In fact, the VTA sound, looks and occasionally flames are the reason they chose to buy a turbo car in the first place.

I will talk to our ECU team about whether there is a correction factor that can be used in the WORKS Brain flash for VTA BOVs, but my guess is that there is not. So, for the time being, choose based on your personal priorities/preferences and know that this debate has been ongoing in countless car forums for just about as long as there have been turbo cars to mod.

-- DavidV

David, what's up! Hey man give me call ... I need to talk to you . I spoke to Dan earlier (at your shop) and I'm not sure if he can hep. Anyway, pm me if you forgot my # .... it will just take a sec.

ok cool, man i aint trying to flare up at you. you just kinda came across as "holier than thou" and i didnt see a real need for all of that. anyhow Like i said i dont know much about turbo cars (yet) so i am still learning. i am on here to get help and guidance so i dont destroy the poor car. with that said how much performance are we talking about and what erroneous map readings are you talking about. Im askin as a fellow owner what would be the best way about this? you obviously know more about this than i do so i am coming to you for help.

PD

Thanks for the info, i hope u keep us up to date. oh and the works brain flash is the first mod i plan on doin.

PD

If its about making you better looking......good luck!! Some things can't even be fixed by buying Works products!

Sorry dude......couldn't resist !!

Hey man no problem ... I'm also here to learn, as well as inform others of what I have learned.

OK, go back to page 2 and read N10S post about erroneous MAF readings. Our Karman (KAR) air system does not seem to function properly with a VTA BOV, although I believe it is possible to trick the MAF with a S-AFC (this feature is called 'deceleration air upper limit setting'). I just installed an S-AFC in my evo so I'll let u know what I find.

The best way to hold boost and still have the VTA-type pssssssst sound, is to purchase an aftermarket recirc BOV, such as Forge Motorsport, and then go with an $80-100 open air filter kit to get the sound. However, an aftermarket BOV should NOT even be necessary until you start to run higher boost ... such as 20-21+ psi for example. Also, the open air kit has not really proven to make much extra power, so I decided to hold off on it .... however, I do not prefer I big sound like that anyway. Even though it's a cool sound .... I would most likely grow tired of it. CAI (cold-air intake) open filter kits are in the works for our evo right now ... so I've decided to hold off until some of them hit the market.

Back to your issue .... if you are looking for a nice sound .... just go with an open air filter kit instead of a VTA BOV, and u will stay away from adverse issues. If you decide to get one right away, I recommend Buschur Racing .... nice open air filter kit for only $80.

You are something else Jeff ....

Wouldn't u like to know the project I'm working on?
Jeff -- I'm going to the dyno today ... I'll email u later to give u an update and fill you in on the road I've decided to take.

Definitely keep me posted, I am always interested in different options to make more hp!