blow off valve

[TGP Nick]

Go and look at any car that comes from the factory turbocharged and has a blow off valve.  Notice how they all have the BOV mounted within ~18" of the throttle body.  They do this for a reason.  The closer to the TB, the better.

[cobracmdr]

Go and look at any car that comes from the factory turbocharged and has a blow off valve.  Notice how they all have the BOV mounted within ~18" of the throttle body.  They do this for a reason.  The closer to the TB, the better.

Why then?  Think about what the BOV does.  When the throttle blade closes the engine is in vacuum, this draws a vacuum on the pressure port on the BOV allowing the pressure in the charge pipe to open the poppet valve venting off boost to the ambient thus preventing compressor shock.  So if the vacuum source is the same place......why does the position along the charge pipe matter (Neglecting head loss in the charge pipe which is likely insignificant due to the huge charge pipe diameter) the whole charge system pressure is static at this point since you are off the gas so the turbine is spooling down and the blade is closed so the pressure drop due to the venting of the BOV will be about the same across the entire charge system.

All I know is, mine is right after the turbo on the 2nd 90 bend on the way to the intercooler and I noticed a big difference with the manual trans between shifts at wot.  The turbo is way faster to respond between shifts I can see boost pressure of .5 kg/cm^2 which is about 7psi right after shifting!  Before the turbo was not producing any boost between shifts at first.

To each his own, I'll post pictures of my setup tonight.

Ken 

[Bullet]

Go and look at any car that comes from the factory turbocharged and has a blow off valve.  Notice how they all have the BOV mounted within ~18" of the throttle body.  They do this for a reason.  The closer to the TB, the better.

I agree, the pressure begins at the TB when it closes, not at the turbo.

but again, "to each his own" as cobracmdr said

[jimmy]

       where have I heard this argument before...........Oh yea here :laugh:

       Try the search section guys

[cobracmdr]

Ok as promised here is my setup.  Did it myself with my neighbors welder and a little rattlecan.com :) 


Ken

[meltboy11]

       where have I heard this argument before...........Oh yea here :laugh:

       Try the search section guys

this wasn't started as an arugment thread, it was started as a thread about which kind of BOV to get... that's just the way it ended up going, and I like it cuz I am learning a little at the same time.

[bake82]

I have mine in the same place as Cobra....how it works I don't know as I've never driven the car without a major exhaust leak and the wastegate closed...so I should know within a few weeks once the turbo cutty is back on the road!

[killinprixs]

whats more expensive your TB or your turbo , the restriction begin when the tb closes but where else  is the pressure coming from,,, hmmmmm the turbo.

[cobracmdr]

whats more expensive your TB or your turbo , the restriction begin when the tb closes but where else  is the pressure coming from,,, hmmmmm the turbo.

I hear you Ike but I think we need to get this back on topic for Meltboy what BOV are you other guys using REGARDLESS of where you put it.  :laugh:

[intern8tion9l]

i've got the greddy type rs. mounted right near the TB, which is where i've always hear to put it. at any rate it fits perfectly where it is and its pretty damn loud.

cobracmdr, thats a nice lookin weld....i suck

[cobracmdr]

i've got the greddy type rs. mounted right near the TB, which is where i've always hear to put it. at any rate it fits perfectly where it is and its pretty damn loud.

cobracmdr, thats a nice lookin weld....i suck

Hehe my weld sucked too I just piled it on there and ground it back a bunch :)

Ken