# balancing actuators - and why aren't there servo-actuated turbo wastegates??



## kismetcapitan (Nov 25, 2005)

is there any particular way to do this, other than to just make the arms the same length?

I know this would be hard to do, but it occurs to me that one way to balance front and rear turbo airflow is to adjust the actuators; if one consistently overwhelms the other, triggering shuffle under light load cruising, then adjusting the actuator might help?

And does shortening the actuator arm length make the turbo output less, or less quickly, or is it the other way around?

And all of this would be much easier if these internal wastegates could be actuated by a servo, and the arm position could them be trimmed from the servo controller. Furthermore, you could have much better control - set it up for max spool (like cranking the gain on a boost control all the way up) at lower RPM, then quickly back off in the mid-RPM range to hit the target boost.

Vacuum hoses and a diaphragm is just a imprecise way of controlling a wastegate IMHO....


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## Sub Boy (Jan 28, 2008)

You can pressure test them with a vacuum gun to match them.


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## 8ren (Apr 17, 2008)

There are such things as electronic actuators and yes they are far more accurate but unfortunately they are prone to failure because of the heat. For this reason they are better on diesel engines and would probably fail very quickly on a high output petrol engine. Maybe one day when they can make them tough enough. I would be interested in them too


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## lightspeed (Jul 11, 2002)

Bicycle tire pump works very well to set them up. Shortening the arm increases the preload and hence the wastegate opening pressure is increased.


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## kismetcapitan (Nov 25, 2005)

two years later...any developments in the world of turbos regarding direct servo-actuated wastegates?


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## Swobber (Oct 8, 2006)

VW runs them on some of the diesels.

PSA has acutators with build-in potentiometers for their 2.0HDI 136 (RHR engine).

Why re-invent the wheel? Its not like you need to. There is no need for electric actuators (Wont stand a change against the heat) or any other complicating stuff - its just more stuff that can fail/break! And it will break! 
And im pretty sure that a good ECU with closed-loop boost control could do whatever you want it to. Boost control with inputs like RPM, load, engine/oil temp - It all should be possible.

Maybe something like the Syvecs S8 can do this?


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