Mate I understand where you are coming from so I will leave it at that!
( To each his own! )

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I think you meant to say if you think 1200rallycar is a wank, good on ya!
( Nah just jokking! )

The importance of a BOV, why it saves your turbo.

The BOV will vent the excess pressure when you back off to the atmosphere. This excess pressure otherwise would bounce off the shut throttle buterfly and back into the copressor wheel and produce a massive shock load.

If the engine has a BOV the turbo will have a more sustained life and the engine should have more durability and driveability.

I think that the Pssccchhhttt sound is great and if I had a turbo I would get a noisy BOV for the "wank" factor alone. But I very much doubt whether a BOV will give you a measureable power gain.

1200rc, I know you didnt mean to say the wastegate vents air back into the motor, did you?

For anyone who is interested:

An internal wastegate is combined with the exhaust turbine housing. The internal wastegate will limit the boost supplied to the motor but will not control the boost, if you know what I mean. The internal wastegate will open at a set limit and send the wastegate air straight into the turbine outlet air. In other words it takes some of the exhaust gas and bypasses the turbine wheel but vents it to the other side where the exhaust gas goes.

This is not an ideal setup as the excess wastegate air will cause more turbulence at the exhaust turbine wheel reducing the flow. So you can create a pipe to run off the internal wastegate that diverts the wastegate air further down the exhaust pipe to reduce turbulence. Or you can not plumb it back into the exhaust but vent it to atmosphere, this is very loud. It is called a "screamer pipe", for obvious reasons.

An external wastegate works similarly to an internal one. It is mounted on the exhaust/turbo manifold before the turbo, but obviously is not part of the turbo. It needs a boost line from the compressor cover that will open the wastegate.

I will stop dribbling

yeah i just meant into the pipe work somewhere, just didnt know where, now i do

barpk

one more benefit of BOV: -
if we use a Loop BOV(first used in 911 turbo) in a turbo, what happens in normal BOV is that the excess pressure from BOV is released into atmosphere, while in a loop setup, the excess pressure is redirected into the intake of turbo 's Turbine, which keeps it spooling and reduces back pressure even further, increases throttle response and improves lag
my 2 cents
and does anyone of u knows what turbo is present in a Starlet IC Turbo motor?
barpk

sounds good for emmisions but must increase intake temp quite a bit

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it lowers the temp! cos the air from BOV is not exhaust but fresh air. which is certainly low in temperature then of the turbine wheel.
barpk

Barpk we all agree that it is lower than the exhaust temp in the turbine wheel!
but the thing is when you compress air it generates heat and by feeding this compressed air straight back into the inlet it will be compressed again and will generate more heat!
That's all he means!

I ran a BOV woth my set up but It gave me the ####s and proved nothing much so I took ti out and the turbo's are still alive now