I am planning on turbocharging my Maxima in the future, and a thought popped into my head yesterday after watching some turbo Maxis. I know when you shift on a M/T, when you let off the gas, that is when the BOV releases the built up pressure. I am an auto. How exactly would the BOV work on an A/T?

 

Its probably the same thing. I get the blow off when I'm still on the pedal and the a/t shifts.

 

Think about it this way...

At the moment of shifting, the turbine is still "free" spinning at a given speed (and pushing out a X amount of air) but when the engine rpm drops the required air decreases....

On a manual you lift up and a definite vacuum registers (opening the BOV)... on the auto... hmm... that may be a mystery... haha (at least during the times you don't release the gas pedal).

 

I notice it more when I lift off of the throttle. I'll have to watch the boost needle more closely next time I stomp the throttle and see how much it drops when shifting and listen for the phssst sound.

 

yeah, i'm really interested to know how that works. i've never really seen a turbo A/T car up close, and don't know anyone who has one that can answer my question.

 

a bov will work the exact same way on an auto as it will on a manual.... when you let off the throttle the bov opens.

now, since with a manual tranny you let off the gas to shift (you don't have to though ) the bov will open up between shifts. on an auto since you keep the throttle down the whole time the bov won't open since there is no vacuum to open. since the rpm's do drop off you might see the boost drop off on a turbo and you would definitely see a boost drop on a s/c since the s/c rpm drops with the engine rpm.