Thinking about adding a BOV......Is it Worth It?

[vortecfiero]

Re: Thinking about adding a BOV......Is it Worth It?

this is something I posted a while ago.. hope it helps

I found a recycling valve to be a huge benefit for spool up from cruise (2 way OEM style) to max boost and of course maintaining some of the rpm in the turbo between shifts. At cruise a turbo wants to spin from the exhaust velocity and a bit from the pressure. Since the throttle is almost closed the small amount of pressure has nowhere to go so it causes the turbo to not spin as fast as it could at cruise... waiting to make boost. Having the recycling valve open at cruise allows the turbo to spin a little faster, closer to the point where it makes boost. Opening the throttle closes the recycling valve and the turbo now is closer to boost mode.

In my set up from cruise to boost with no recycling valve was about 2 seconds.
With the bov it was about one HEARTBEAT... instantaneous and lots of adrenalin.
Between shifts the small amount of lag completely disappeared.
also at the moment the throttle is closed at high boost... the boost has somewhere to go rather than poping off any intake connections

Not all bovs function the same.. most just blow off between shifts (they do not draw air... only blow off air)

Most OEM units work both ways so the benefit at cruise is available. I use a Bosch unit from an Audi. A friend of mine uses 2 of them on a 400 whp turbo 4 cyl

you should try to mount the bov as close to the throttle as possible (or just before the A/W IC on a sy/ty) and run vacum from the intake plenum. Otherwise the intake charge has to re pressurize and get the velocity up again from the bov to the throttle body.

on systems running high boost and high turbo rpm serious damage to the compressor as the throttle is slammed closed. It could go into surge, spin up way past its safe range and grenade.

this info is what i have seen first hand... no it wasn’t mine that grenaded lol but I saw and heard it lol OUCH

The recycling valve makes a slight blowoff sound if you have a free flowing aircleaner.. Its subtle but there lol

 

[gmcturbo]

Re: Thinking about adding a BOV......Is it Worth It?

i had one that always leaked boost. the concept is sound though, if there were any that didnt leak..

 

[LandryPoole]

Re: Thinking about adding a BOV......Is it Worth It?

I have a question about these things. Without a BOV, when you go from WOT to idle throttle after a run, wouldn't the boost pressure in the system spike? In other words, the boost pressure would surely have to go way high, since the system is at max at WOT, and now you are closing the throttle blades. With that, wouldn't that increase pressure? With increase in pressure, doesn't that add heat? With added heat, that in turn would help to heat up the IC and piping, would it not? The BOV then it would seem would serve two purposes. One to blow off excess pressure, which in turn, drops intake charge pressure upstream of TB, causing a temp. drop, instead of a rise. I would think this would be a good thing all around. Of course this is all theory based on waht smarts I have, which mind you ain't much. But at least I sound smart. LOL! Any input here? I just bought an HKS, and I like the sound of them. Why? Because I can't get anyone to race me, not even at the track. A little bit of noise might intice a few to want to run. That is a good thing too.

 

[attackdog]

Re: Thinking about adding a BOV......Is it Worth It?

summerwolf:
What do you mean when you say you "crush" the top of the BOV valve? Do you have info on how to do it and what it is for? Thanks.
-Deano