Blow off valve and auto trans

Maybe a silly Question:

I know that using a blow off valve vents the pressure buildup (forgive me if I am thinking simplistic here) that is left so that it does not go back to the turbo. A friend has a 5 speed and I hear it doing it's job.

My question: is there a reason to use one with an automatic tranny? It seems like it might be better to let that pressure build on an auto since there is really only a very short period of time (compared to shifting with a manual) that the engine has no load.

Am I missing something about the way it works? Thoughts?

A BPV / BOV serves 2 purposes: First, it protects the turbo from the pressure spike when the throttle is closed under high boost. This pressure spike can damage the turbo, and even bend compressor blades. Second, it keeps the turbo spooled between shifts. On an auto tranny car, the second purpose is moot, but the first purpose is still true with an auto tranny.

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 00 Windstar (wifes vehicle)

Got it now. Thanks Jeff. I'll search on it and see how to hook one up.

I've thought about doing this for my TC. Are there any particular brand names of blow off valves that work great with the 88 TC. If so, where do I get it, how much and does anyone have easy instructions for installation.

Later