I have a Synapse BOV installed. This one acts differently than most....it is open until I hit a little bit of boost, then it closes and I can build more boost. The boost keeps it closed.

My question is regarding fuel efficiency. Since the BOV is open and venting air until I actually start building boost, it vents a lot of the air that the turbo generates, which gives the restriction of the turbo in the exhaust but without the benefit of the better airflow into the manifold.

Do you guys think that this would very negatively affect gas mileage? It makes sense to me but I wanted to get some other opinions.

 

Since you are in vacuum does it make a difference? Turbo plumbing confuses my feeble old brain. What are you getting for mileage right now?

 

Your BOV should be fully shut buy the time you get to 0 vac...

Edit: it should just barely be closed when sitting idling

 

I thought most (TiAL, etc) were closed all the time, except when purging excess pressure when the throttle blade shuts.

 

The actual charge pipes never see vacuum. Vacuum is only generated behind the throttle body.

 

Wow that new one to me.

 

Yes that how mine works

 

Ya, most of them are, it depends on how stiff the spring is. If properly setup, the spring should just be set tight enough to hold it shut at idle, but then when you let off the throttle while boosting, the boost pressure and higher vac you pull when in decel should fully open the valve until the pressure is fully release.

 

Just a thought, I swear mine makes a chatter noise when you let off the throttle in vacuum.

I dont think it would have a huge effect, do u get into boost that much, maybe try to keep the tc unlocked a bit more. That itself helps me stay outta boost quite a bit.

 

yea but the synapse bovs are very wierd they dont have diaphrams. we put one on a procharger murauder at my shop im kind of up in the air about them.