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Posted by Ari [Email] (#2847) [Profile/Gallery] (more from Ari) on Wed, 24 Jul 2002 14:10:26 Share Post by Email
In Reply to: Re: no boost please help, sully, Tue, 23 Jul 2002 14:14:17
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Remember how and why the Hooter valve works-
You're driving along under boost - the throttle is open, and the turbo is spinning, pumping air into the intake through the open throttle.

Now, shut the throttle (say you're going down hill, or just coasting up to a light). The turbo is still spinning, and that column of air is still moving towards the intake. But it slams into the closed throttle plate, and like the idiot who stops at the bottom of the escalator, all that air start piling up behind, pressurizing everything and stalling the turbo.

That's where the hooter valve comes in. When the throttle closes, you have high vacuum in the intake (thin hose from intake to hooter valve). This OPENS the hooter valve, which ports that high pressure air from the pressure side of the turbo (output) into the intake side of the turbo. No high pressure buildup at the throttle, and the turbo can keep spinning.

That means that at low intake manifold pressure (vacuum), the Hooter valve is open. If the car is sitting there idling, the throttle is closed, and you've got low intake manifuld pressure (vacuum). So at idle, the Hooter valve IS open. It's when the manifold isn't at vacuum that the Hooter valve closes.

So to test the hooter valve, check it with the engine off. That way the input to the hooter valve is at atmospheric pressure. Under that condition, you shouldn't be able to push a lot of air through.

Those are big hoses on the hooter valve - they can move a lot of air.

Good luck!

posted by 140.157.4...

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