wastegate

[AznVirus]

what is the wastegate on a turbo engine for? whats its purpose? where is it located?

[P10DET]

Originally posted by AznVirus
what is the wastegate on a turbo engine for? whats its purpose? where is it located?

A wastegate bleeds off exhaust away from the turbine to control boost. By diverting exhaust, it controls the speed the wheels spin at (and thus boost).

Some turbos, such as the T28 and T25 have the wastegate built into the turbine housing. Others have it separate from the turbo and is call a divorced wastegate.

[b-b00gie]

Just to further because I know the next question will be: "I thought a boost controller controls the boost?"


A wastegate can be set to 1 specific boost level. This setting will control the max boost the turbo will get. When the turbo gets to that boost level, the wastegate will open and let exhaust gas out so the turbo does not build more boost. (unless the wastegate starts to fail and you get "overboost"). If you want to be able to adjust your boost levels without having to change/adjust the wastegate spring you can get a boost controller.

The boost controller allows you to force the wastegate to allow a certain boost level which is applied to the turbo.

[AznVirus]

is the wastegate that fan looking thing that is external on the turbo? and so a boost controller can control the wastegate electronically?

[b-b00gie]

I think the "fan looking thing" you mentioned is the wheel. I dont have a pic of an internal wastegate. But if you find a pic of a DET stock turbo, you'll see it. Here's a pic of an external one




There are electronic and manual boost controllers. The electronic type send a signal to a seperate unit which you put in the engine bay. That unit actually has a motor in it and depending on the signal it will send a certain amount of pressure through a vacuum line to the wastegate which will control the boost level.

[G-Forces]

Originally posted by b-b00gie
There are electronic and manual boost controllers. The electronic type send a signal to a seperate unit which you put in the engine bay. That unit actually has a motor in it and depending on the signal it will send a certain amount of pressure through a vacuum line to the wastegate which will control the boost level.

I'm not to sure about that. I think the electric boost controls just have the control solenoids outside the control unit. I don't think it possible to set up a boost controller to boost less than the spring in the wastegate.. I.e. if you have a 10lbs spring in your wastegate you can't set a boost controller to 6lbs. Since all the boost controllers I know about intersept the reference boost line and open and close the reference line to the wastegate accordingly.

Brian, you mention that some boost controllers have a motor in them and send extra pressure down the wastegate line? Which ones are those? I could be wrong in my assumption above but I've never heard of what you're talking about.

Generally manual boost controllers are cheap aquarium pressure control blead valves and all an electric boost control has is electronic controls. Both just bacially intersept and fool the wastegate into delaying it's opening.

[b-b00gie]

Jason...

I didnt mean you can get lower boost levels than the wastegate setting. I never actually said you could lower it though. Sorry I wasnt clear. I did say "if you want to adjust" which should have been "if you want to increase" The point is to get higher boost levels...


About the controllers with the stepping motors, well, by far the most popular elec. boost controller in the SE-R community is the Greddy Profec B which uses this setup. There are more expensive controller that use solenoids instead of stepping motors, but I used the motor example because more people know what a motor does than a solenoid.







Sorry for the huge pics!!!

[b-b00gie]

BTW, the HKS EVC-EZ electronic boost controller I have also uses a stepping motor for the control... I just checked the parts list and instructions and it clearly states it is a "stepping motor".

[AznVirus]

what is a "stepping" motor? is it mandatory to have a boost controller when having a turbo. im talking about a DET here btw. if the valve spring is already set to 6 psi, do you still need the controller to regulate it? sorry for all these questions, but ive convinced my parents to get me a P10 and give me around $4000 to spend for the swap. ill be joining the DET groupies soon. im thinking of doing the swap myself, but im still not sure, ive got another 6 months though

[b-b00gie]

No you do not need the boost controller unless you want more boost than the stock setting.


A stepping motor is a little different than a regular motor in say an RC car. Those types of motors have 2 wires to them. Positive and negative. When power is applied to it, the motor will spin and when you remove the power it will "coast" to a stop.


A stepping motor however has more wires going to it. Usually 4 to 10 wires. These types of motors operate on pulses and you can set the exact amount of time the motor will spin depending on the number of pulses applied to the coil and magnets. This allows for very precise movement. They are used a lot in things such as assembly line robots where things need to be moved into place and be perfect. Its a lot more technical than that. I did a lot of work w/ them when I was in school for electronic engineering. Anyhow... you dont really have to worry about that...