Hey everyone. I have a question on a topic that I don't have much experiance with. Can someone out there tell me how a "Waste Gate" works on a turbo? I know that it controles the boost, and you can have a manual or automatic boost controler (if you want), but how exactly does the "Waste Gate" change the boost. Thanks.

Walz

 

This is my take on this subject:

A turbo uses exhaust gases to drive a turbine that pressurizes the intake charge. This "boost" must be limited somehow or your blow up the engine. A "wastegate" limits the amount of exhaust gases that is available to spin the turbine in the turbo. Once the desired amount of boost is achieved, any over boost is stopped by shunting some of the exhaust gases through the wastegate and directly out into the exhaust pipe, bypassing the turbo itself.

 

XViper,

Thanks for your input, it is helpful, but I was looking for a lot more detail as of how it rerouts/closes off and feeds back to control the actual amount of spinnage. If it works like an ACM then it would be something similar to a butterfly valve that would control the flow, aka the velocity thru the openingor dumping thru the exhaust and thus controle the pressure to the intake. If you know any more about how it works, my mind is open. Thanks.

Walz

 

Sorry, you'll have to wait till someone much more technical chimes in. Anything more than what I just posted, I'd be guessing.

 

Well, I guess all the hired help has gone away for the weekend. Below is a picture of one of the turbos from my old TT Stealth:
A quick legend:
Incoming exhaust comes in from top right.
Outgoing exhaust leaves from right side - those projections are mounting studs.
Air intake comes in from left side.
Compressed air leaves out the bottom left.
Notice the "solenoid" looking thing that sits on top left with the rod angling down towards the exhaust? This is the turbo wastegate solenoid and actuator rod. This solenoid is connected by a vacuum tube that senses the amount of boost, in this case, 6.8 psi., above which the solenoid pushes on that rod. The rod is connected to a "butterfly" type valve. This valve is normally "open" to allow all the gases to spin the turbine. When the rod is pushed (or pulled?), the valve begins to close and allows more and more of the gases to go out the right side exhaust opening WITHOUT going through the turbine housing first. This exhaust opening, of course, goes directly to the exhaust pipe, through the converter and out the tail pipe. Additionally, this exhaust opening is NOT round as you would expect it to be but a big double circle sort of like a large oval. One side of the oval is where the gases go out if they come through the turbine and the other side of the oval is the gases that "bypass" the turbine housing. Hope this is what you were looking for. So, you gonna go out and blow up an engine?

 

Lol...no I'm not goign to go and blow up my engine...sometimes when I come home from work I just think, and for some reason, this popped into my head and I needed to figure out how it worked. Thank you very much for the explanation. That is great, and what I was looking for. Great graphic and great explanation.

Thanks
Walz