Talk:Wastegate

I did a major revision today.

Line 1 implied internal gates only (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)

 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)

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)

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)

I agree. Divorced wastegates can recombine waste gate bypass gasses with the primary exhaust gasses further downstream where they do not interfere or cause turbulence around the turbine. Atmospheric wastegates are to atmosphere as the name suggests. James Bates 21:57, 25 January 2012 (UTC)

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)

to the two wankers up the top of the talk section. i found the complete post to be acurate and credible, without the need for your input. maybe next time youd like to write a useful and informative article yourself than sitting around questioning somebody else's expertise. turbo flutter, or wastegate chatter as it is commonly mistaken for does exist and is very common on poor designed, modified systems. i should know. im a charger tuner for capa. push your coke bottle glasses back up your nose 2 inches and CHILL OUT!

I think the text around the blow of valve link needs to be tidied up. Who cares about welding an internal wastegate? I did non read through the size section, but I think it is interesting that screamer pipes are always smaller than the main exhaust. This hot exhaust stuff is nonsense. Downsizing is a current buzzword for car engines and now all manufacturers use turbos for gasoline and diesel engines. The max temperature is 1300 °C and thus far below the temperatures in gas-turbines and a lot of materials can be bought commercially which sustain these conditions. It is even not that expensive: early aircraft turbines where made of wolfram, now inconel (nickel based stuff) can be used. The waste gate is less hot than an exhaust valve and less abruptly moved than an exhaust valve or the turbine. Cars are just very cost sensitive and therefor gasoline turbos are limited to premium models.

I am interested in aerodynamics and want to know more about the turbulence after the wastegate. Compared to variable guide vanes in the turbine the wastegate is an aerodynamic nightmare: It has sharp edges and needs airtight seals and lots of plumbing. The two advantages I see is that only one link from the hot exhaust to the cold actuator is needed and that it can be expanded to a sequential turbo system. The 90° turn popped valve itself can probably not be avoided. Maybe some of you know my interest in merge collectors. I would weld the waste gate on a free header pipe of the merge collector. In this way the high pressure pulses are shot onto the turbine and the waste gate can be wide open and a low base back pressure is reached. If the screamer pipe is merged into the exhaust, how large is the increase in back pressure due to the turbulences? If a large waste gate and a convergent "screamer" pipe is used, there should be less turbulence and more of a fast jet after the merger. -- Arnero (talk) 10:11, 30 November 2009 (UTC)

"It sounds like FftFftFftFft not ShuShuShushu" Best. Description. Ever. — Preceding unsigned comment added by 146.200.19.215 (talk) 14:35, 14 August 2014 (UTC)

Removed wastegate chatter section
Absolutely horrid section. It seems that it was proposed that it be removed in 2006... ten years ago! So it is way past time for it to go. If someone can find good sources (read: secondary, and reputable) for it, then feel free to re-write it and put it back in. A ir ♠ C ombat  What'sup, dog? 03:36, 18 July 2016 (UTC)

Electrical wastegate actuators
Some modern engines uses eletrictal wastegate actuators. The electrical actuator has a higher torque, so it is much faster than the pneumatic one and it reduces the leak air. Additionally it is possible to control the position independent of the boost pressure (e.g. overboost). Example: The turbocharger of the 1.8 TSI EA888 Gen 3 http://thewolfweb.com/photos/00525022.JPG --SuperDiarrhoe123 (talk) 15:27, 24 March 2017 (UTC)