hi folks, since being gently helped to realize that i am wholly missing the wastegate control line on my garrett turbocharger, i learned that it's also where a boost controller gets plumbed, so i have been noodling around looking for one. most of them seem to have a tiny breather vent (e.g. "Breather vent stops wastegate lockup between shifts!"). on an OM617, is this feature good or bad?

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'77 240D, 504H, OM617.952, etc.

Instead of a breather vent to the atmosphere I used a 1 way valve back to the compressor. This way theres no boost leak and the WG closes quickly again. Its a simple "dawes device" plus 1 way valve in the opposite direction. The dawes device is set to open at 12psi and the 1 way valve only takes 0.5psi differential to open.
http://i.imgur.com/qygS8Xl.jpg

The disadvantage of the breather vent is that it will take some trial and error to figure out the exact size hole to use. Make it too big and you'll never open the WG. Too small and it won't close fast enough between shifts. Venting back into the compressor through a large (relatively speaking) 1 way valve take all the guess work out of it.

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CENSORED due to not family friendly words

You have baffled Me. Mine with an automatic Transmission has a simple and Stock Hose going from the Intake Manifold to the Waste Gate. If the Manifold Pressure gets too High the Waste gate is supposed to open and keep the pressure to the level set by the Waste Gate Spring Tension.

Once in a while People have wanted to boost the pressure at which the Waste Gate opens to boost their max possible Manifold Pressure. But, they are unable to adjust the Spring to increase the Spring Tension. I that situation some have installed a Manual Boost Controller in the Waste Gate Hose.
The Boost Controller has its own Spring Valve you can adjust what Manifold Pressure the Waste Gate gets.

"most of them seem to have a tiny breather vent (e.g. "Breather vent stops wastegate lockup between shifts!"). on an OM617, is this feature good or bad?"

I have not ever read the info in your Post being mentioned in conjunction with a Diesel Engine; so far.
The Fuel on a Gasoline Engine is controlled differently from a Diesel. Perhaps the Vent issue is for them.

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84 300D, 82 Volvo 244Gl Diesel

Diesel911;

I think the vent in question is to allow the waste gate to close QUICKLY when you take your foot off the throttle. Without the add on pressure controller, the waste gate actuator has a clear shot back to the intake manifold to dump the air pressure that caused it to open. With the pressure controller, the return path for air from the waste gate actuator to the intake manifold is blocked by the valve in the pressure controller.

The one way valve in tjts1's setup provides a path around the valve in the pressure controller when you lift your foot, and it allows the pressure controller to operate as intended without bleeding off any air like the small vent hole does.

Just figuring these things out for myself, hope that helps.

Bill

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Why do we drive on a parkway and park on a driveway?

1984 300 SD Black Runs but still needs work.