Talk:Wastegate

I did a major revision today.

Line 1 implied internal gates y (in a turbocharger), so I generalized it so it would apply to external gates.

Added information on the valve types for both internal and external wastegates.

Generalized external gates, because you can use one with a turbo that has an internal gate, added blurb that this involves welding the internal gate to avoid leaks.

Fixed spelling mistake in wastegate chatter section.

Added a lead in to a link to boost control, but at least explained how the basics of the mechanical and pneumatic boost control system works.

I'm going to propose that the entire wastegate chatter section be removed. I've never heard of this. I think most people know what a blow-off valve sounds like, or what compressor surge sounds like. This seems anecdotal and not related to general wastegate article. Perhaps this is common in some narrow social group, but it is news to me. Never heard of "wastegate chatter". I left it in tact, perhaps I just don't get out enough?? --Freonr2 04:52, 12 August 2006 (UTC)

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proposed changes

I suggest that this statement: "The primary function of the wastegate is to stabilize boost pressure in turbocharger systems, to protect the engine and the turbocharger."

be changed to: "The primary function of the wastegate is to balance the forces on the shaft connecting the compressor to the turbine. This helps stabilize boost pressure in turbocharger systems, to protect the engine and the turbocharger."

Reason: The current statement explains the result of the wastegate and not the task it performs.

And that this statement: "The wastegate will open further as the boost pressure pushes against the force of the spring in the wastegate actuator until equilibrium is obtained."

be changed to: "The wastegate will open further as force resulting from the boost pressure counteracts the force of the spring in the wastegate actuator. The wastegate will stop moving once these forces reach equilibrium."

Reason: Pressure and force are 2 different concepts and should be distinguished. Also, it's important to mention what type of equilibrium is reached - in this case mechanical, forces.

And this statement: "The noise is in fact the air compressed by the turbo passing back through the compressor housing of the turbo after having hit the now closed throttle plate."

Should be changed to:

"The noise results from a shock wave that propagates from the throttle plate upstream to the compressor housing. The shock wave is produced when the throttle plate closes and brings the charge air to rest as a way to conserve the kinetic energy of the high speed air flow."

Reason: The closing of the throttle plate really doesn't cause the compressed air to travel back to the compressor. There is no void created between the throttle plate and the air that, in that scenario, is said to be traveling back to the compressor. The air actually slows down to negligible velocity and a shock wave is created. This pressure wave exerts the force on the compressor housing, causing the chatter sound. Very similar to the water hammer phenomenon.

--Asusa83 07:24, 4 February 2007 (UTC)

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I like all those proposed changes, go for it!

I am scrapping this quoted text at the bottom of the wastegate myth: "This has also been known as "Turbo Flutter" and in some cases, adding a BOV can increase the flutter especially if you have an intake system. Once the air hits the closed plate, the only path it has to exit is through the intake."

It is mostly repetition of the preceding text except "turbo flutter" (I will included in that previous text), and it introduces what seems to be an erroneous claim "adding a BOV can increase the flutter" -- exactly opposite to the sole purpose of the BOV.

Marcoose 17:03, 8 June 2007 (UTC)

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Accuracy Question:

In the section "Atmospheric/divorced wastegates," there is a statement that downpipes with divorced wastegates never return the wastegate exhaust to the rest of the exhaust flow, but that they "[dump] the gases directly into the atmosphere." I'm fairly confident that this isn't the case, and that the two gas streams are recombined later in the exhaust system. --Bounty Hunter 4 hire 07:43, 19 October 2007 (UTC)

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Wastegate sizing

How about some info about wastegate sizing? What is the measurement typically used to size a wastegate? Why is it important to size correctly (boost creep)? --Integracer 22:38, 7 November 2007 (UTC)