unclebens

iTrader: (2)

Most turbos do not come with anti-surge covers and anti-surge covers actually decrease efficiency slightly so some people stray away from then unless necessary on their setup. Anti-surge covers aren't designed vent off air during deceleration like when you run without a bov although they may work for that. The are designed to stop 'real' compressor surge during acceleration when the turbo/motor setup creates a condition that leads the turbo into the left side (surge side) of a compressor map.

New turbos, especially ball bearing, can handle a lot more abuse without a bov.

At stock airflow and boost levels, the grand nationals were fine without a bov. Once modified, many install a bov. I've heard of grand nationals blowing off their air filter because of no bov

I'd say low boost is ok with no bov but high boost should have one. Some air is going to go into the engine, even with the throttle shut, some is going to bleed out the air filter.

ninety4three4

iTrader: (13)

This is a matter of opinion and not cold hard truth, I would personally never build a FI set-up with out some sort of bypass valve. To me it is just an added piece of mind against compressor surge. I have seen many 1000+ Hp cars without any type of bypass valve that have had no turbo damage result. Then again I have seen many low Hp cars without a bypass valve that were toast after a year. Turbo damage is determined by many other factors then just having or not having a bypass valve. Again its all preference I will always use one if possible. All turbos do not come with anti-surge housings many do but many do not...

robbyredneck

iTrader: (1)

i own a gn and run it at 20psi- no bov. i am now building another regal with lq4 and t76. my turbo supplier says "no bov no warranty" and in my experience any time an o.e. can deny a claim they will. so i will be putting one on. my valve has 2 feeds,pressure and vacuum. it seems to me that there is no vacuum in the system until the blades are shut and thats when the bov actuates provided the source is on the intake side. if that is true then the opposite should be correct that when you take your signal from the pressure side of the throttle you can use your bov as a type of limiter provided the spring pressure is set up right. is this thought correct.
thanks robby

imma_stocker

iTrader: (19)

I think that would just create a closed loop that never actuates the bov. If I'm reading that right, the pressure difference would always be the same on both feed lines (+ to +).