View Single Post
  #3  
Old 01-13-2012, 10:57 AM
MTZL's Avatar
MTZL MTZL is offline
Super Moderator
 
Join Date: Apr 2009
Location: Mountain Zone Lancer (MTZL)
Posts: 4,060
Default

Ok I upgraded the Intercooler set, but what about the BoV (blowoff valve)?

The BoV has many different names, sometimes referred to the Bypass Valve (bpv) since the OEM actually diverts the air back to the intake.

First, let's look at the purpose of the bov:
Edmunds Insideline.com have a great writeup here, so I won't go into detail myself
http://blogs.insideline.com/roadtest...alkaround.html

So understanding it's purpose now, the bov, just like the Intercooler, will never really make power - it just prevents lost power (from leaking boost pressure).

the factory bov on the Ralliart is made of weak plastic and easily leaks. when your bov leaks, you're losing boost pressure right before it enters the engine (the bov is connected to the LICP). All you need is a bov adequate enough to hold the boost pressure you are running/tuned for - there is no power to be gained from having a bov that can hold 60psi, when you're only running 20psi - vice versa.

Again, a used Evo X bov is a great piece for low cost. Since you only need a bov strong enough to hold your boost level, those shiny aftermarket ones are rather unnecessary. Remember the function/purpose of each piece when considering the benefits of upgrading!

I want the bov sound! Can I vent to air/atmosphere (VTA)?
When there is a cut in throttle, the pressurized air needs somewhere to go. When recirculated, this air is reused and sent back to the air intake (and goes through the whole process again). Because of this, your ECU/tune is expecting this recirculated air. When you vent this pressurized air to the atmosphere, you're throwing it away when the ECU is expecting it. This obviously causes stability problems. There's no beneficial point to running a VTA bov setup - other than the sound. If you REALLY want the sound, you can get it from an intake/filter upgrade - I think it's silly to sacrifice performance/stability just for a sound.
__________________
Reply With Quote