Bov placement question?
11-09-2008, 07:42 PM
#1
Bov placement question? im reading the book turbochargers by Hugh Maclnnes and in one of the sections is shows a Porsche V8 with the Bov mounted on the back of the intake plenum.. is there any advantages to doing this rather than the traditional style?
11-09-2008, 07:46 PM
#2
Launching!
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Maybe, but a blow off valve is designed to let off pressure not volume, so you can put them just about anywhere. I have seen them built into intercoolers as well.
Hopefully someone will chime in with more info!
Hopefully someone will chime in with more info!
11-09-2008, 09:52 PM
#5
On The Tree
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Bov The BOV has to be before the TB. Otherwise it cant do its job. If it was in the intake it would be isolated from the turbo when the TB is closed and would not be able to vent the pressure surge. A bov is there to protect the turbos/intercooler.
11-10-2008, 12:10 PM
#7
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11-10-2008, 12:24 PM
#8
Reminds me of the sport bikes with those butterflies in the individual runners to increase torque down low and increase runner volume when it's @ 10k+, the BOV on our deals has to go before the throttle blade, between the intercooler and TB for it to function correctly.
11-10-2008, 12:28 PM
#9
The BOV can be mounted, if AND ONLY IF you have a SD tune. If you have non SD tune, the car will run pig azz rich when the BOV opens. That will be very hard on the motor as you will be washing down the cylinder walls with gas. The rings will not seal after a short period of time and the oil will be full of gas.
11-10-2008, 02:33 PM
#10
You want the blow off valve before the throttle body, this is to protect the compressor wheel. If the compressor goes into surge (and it will momentarily), the blades of the wheel can break off due to excessive pressure and sonic reversion. Having the BOV after the throttle body will only purge the pressure in the plenum, and still allow the pressure to build up before the throttle body. We do not recommend this layout for the reason I stated (compressor wheel damage).
11-10-2008, 02:49 PM
#12
What you're talking about mounted on the plenum is a POP OFF VALVE. They are mainly used to sanctioning bodies when the rules dictate the amount of boost one can run. Spring tension is the only thing that keeps the valve shut. If boost pressure overcomes that preset tension it opens. A Blow off valve would not even work in that location. It needs vacuum from the plenum after the throttle has to shut to pull on the diaphram to help open the valve. The pressure differential between the vacuum on the diaphram and the boost pressure on the valve I'm sure helps open it as well.
11-11-2008, 05:25 PM
#13
What you're talking about mounted on the plenum is a POP OFF VALVE. They are mainly used to sanctioning bodies when the rules dictate the amount of boost one can run. Spring tension is the only thing that keeps the valve shut. If boost pressure overcomes that preset tension it opens. A Blow off valve would not even work in that location. It needs vacuum from the plenum after the throttle has to shut to pull on the diaphram to help open the valve. The pressure differential between the vacuum on the diaphram and the boost pressure on the valve I'm sure helps open it as well.
11-11-2008, 05:33 PM
#14
As I mentioned, so long as the BOV is mounted before the throttle body (or bodies) it will work. If it is an ITB setup, then the common plenum before the butterflies would be ideal.
