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BOV on a automatic twin turbo


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I need some advice on whether it would be okay and whether my engine will work properly if I was to install a BOV. Would I need a BOV with an adjustable vent to atmosphere and recirculation? Would I need to have it on 50:50? What BOV would be recommended? Cheers.

 

Also I own a 2001 Twin turbo Subaru legacy automatic.

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I'd imagine you'd be sweet fitting one up. I recommend GFB myself.

 

You SHOULD recirculate some of it (50:50 at least recommeneded) due to the EJ208 (and other EJ turbo cars) having a MAF (Mass Air Flow Sensor).

You can vent it all to atmosphere, but your performance won't be exactly the same, due to when the BOV is triggered, it vents all the air out. And when you accelerate again, it has to build up all that pressure again (more vacuum in the intake of the turbo). Basically your car won't run 100%.

 

FYI - written from the perspective of a manual owner. So I'd imagine with an auto, when you lift off the throttle, it's for a corner or something where you're not going to be going on the throttle again (i.e: when accelerating in a manual).

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13 hours ago, Joker said:

ahh yeah nah BOV's are not for Auto's is there something wrong with the Factory one?

It seems to be a bit worn. So you are saying that a bov will not work on a automatic? If it will work is there any implications that could affect the turbo/engine? 

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2 hours ago, VespertineYacho said:

It seems to be a bit worn. So you are saying that a bov will not work on a automatic? If it will work is there any implications that could affect the turbo/engine? 

 

The reason a BOV vents is because the throttle plate closes creating a difference in pressure between the manifold and the intake tract before the throttle.

With an auto, because you shift without lifting off the throttle, this pressure difference never exists, so the BOV won't vent. Same reason diesels don't have BOVs.

You could deliberately make it vent by lifting off the throttle very suddenly, but it seems like a pointless exercise.

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29 minutes ago, boon said:

 

The reason a BOV vents is because the throttle plate closes creating a difference in pressure between the manifold and the intake tract before the throttle.

With an auto, because you shift without lifting off the throttle, this pressure difference never exists, so the BOV won't vent. Same reason diesels don't have BOVs.

You could deliberately make it vent by lifting off the throttle very suddenly, but it seems like a pointless exercise.

Thank you I understand this a bit better now. Would I would like to know though, as if i was to to lift off throttle while changing gears, would this be bad for the turbo and engine? As I would only be lifting off while appoaching to a stop or around corners.

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Sounds like "George" has moved in!

 

Clubsub's dubbed the noise that sounds like blowing across the top of an empty bottle many many moons ago

 

Yeah leaky bov no good, point of a bov on most turbo cars is for the noise on lift off, autos will be interesting & not entirely sure how well they operate or function (cant be much different than manual & most likely partially open some of the time at cruise speed potentially)

 

but yeah would be a waste spending $350 + on a nice GFB or some-such unit

 

I'd be heading to a garage or wreckers & getting a good second hand unit or new old stock etc (NOS)

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10 minutes ago, Joker said:

Sounds like "George" has moved in!

 

Clubsub's dubbed the noise that sounds like blowing across the top of an empty bottle many many moons ago

 

Yeah leaky bov no good, point of a bov on most turbo cars is for the noise on lift off, autos will be interesting & not entirely sure how well they operate or function (cant be much different than manual & most likely partially open some of the time at cruise speed potentially)

 

but yeah would be a waste spending $350 + on a nice GFB or some-such unit

 

I'd be heading to a garage or wreckers & getting a good second hand unit or new old stock etc (NOS)

Okay, thanks for the advice :)

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25 minutes ago, VespertineYacho said:

Okay

 

be aware of what you 'read' on the internet too, good on you for asking the questions!

 

My experience is only with a Manual car so I'd be keen to head from someone a little more mechanically minded then me too :P

 

or someone who's dealt with a similar issue (I had leaking BOV on my Manual 98 GTB too so yeah went GFB route

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56 minutes ago, Joker said:

Sounds like "George" has moved in!

 

Clubsub's dubbed the noise that sounds like blowing across the top of an empty bottle many many moons ago

 

Yeah leaky bov no good, point of a bov on most turbo cars is for the noise on lift off, autos will be interesting & not entirely sure how well they operate or function (cant be much different than manual & most likely partially open some of the time at cruise speed potentially)

 

but yeah would be a waste spending $350 + on a nice GFB or some-such unit

 

I'd be heading to a garage or wreckers & getting a good second hand unit or new old stock etc (NOS)

We have a GFB on our 99 TT Auto with 50/50 venting but cant seem to get noise had a aftermarket type on but hosing was not  factory we put back to factory but  noise with the GFB adjusted the spring tension but no joy

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