I bought a godspeed type rs( looks kinda like turbosmart raceport)50mm
It said 8psi... I really dont understand how they rate bovs... Anyway this lil jewel limits me to 9psi boost
The guy who tuned my truck took off and capped the vac line... Not sure why... But i think it leaks i hooked it back up and pressure drops..(no complaints its fast as **** for street vehicle) idk what is goin on with this thing👈 i guess this is what im askin...

 

BOV or wastegate

 

Its a blow off valve typical ebay story...
Id like to get a different one or learn how to make this work...
On the cheap

 

toss a Tial 50mm on there and be done with it

if that is too pricey for you then pay sloppy mechanics a visit and preach to them

 

That's strange. A blow off valve should really always be closed unless there is vacuum applied to the top. If you think about, you should have boost pressure on both sides of the the blow off valve while in boost, essentially cancelling each other out. Then with the help of the built in spring, it actually applies more pressure to the top, in addition with boost to keep it closed.

How is it all plumbed?

 

The bov needs to have a spring rated at idle in neutral vacuum maybe a few pounds higher. You want the valve closed and when you do a hard run and close the throttle vacuum will go up last your idle vacuum and bov off the boost pressure.

 

Ya its plumbed in right..vac line from manifold to top port on bov... But the tuner unhooked it when he tuned it... But like i said when i ordered it it said it was rated at 8 psi and i figured without vac line attached boost will bleed thru it around 8-9 psi- which im pretty sure its doin.. I got a 7 psi spring in turbosmart wg and a mbc and no matter how muck i crank on it all i see on the gague is 9psi boost...and afr at wot is right at 10.2:1 since i put my truetrac in...so i can prollygo a lil more..

 

The BOV have nothing to do with regulating boost psi. The wastegate controls boost psi, the BOV releases the pressure on the cold side when the throttle is closed to prevent turbo surge at the compressor on the turbo. It must see boost pressure under boost and vacuum at all other times. The guys posting on here know their stuff. if your having problems holding/making boost then its either a wastegate or exhaust routing/restriction issue.

 

Ok... If the bov has a 8psi spring (as advertised) and i do not have a vacuum line attached, when manifold pressure builds past the springs strength with no pressure to hold it closed it would bleed off.. Is that making more since? Am i wrong in thinking this
I dont mean any disrespect and not doubting anyones knowledge on the subject..

 

What your saying could be true but the BOV is meant to have pressure under boost to stay closed and only open under vacuum to vent boost when TB is closed or under a high vacuum. It is not meant to regulate boost pressure.