Evoscan logging problems

[Davezj]

Hi guys and girls,

have any of you loggied what is called wastegate duty cycle. what is it as there is no electrnic point to log on a waste gate it is purely a mechanical part so is this refering to the boost solenoid which controls the wastegate.

if so what should the relationship between throttle position and wastegate duty cycle.

I would have assumed it would be something like thisin it's simplest form:-

1. throttle open, wastegate duty cycle either 100% or 0% depending on what represents open and closed. it should be closed. to allow the turbos to spool.
2. throttle closed, wastegate open to stop backpressure building and stalling the turbo.

in very very simple terms.

Has anyone got a log data of what the it should look like as mine doesn't look right to me.

one other thing, what would be the best sort of drive out to show this on an evoscan log. just so i can post it up for you to take a look at and let me know if i am worring over nothing.

[Kenneth]

I would say not to worry about it.

If it is the boost control solenoid duty, then 100% is most likely representing maximum bleed and 0% no bleed. (max boost and min boost respectively)

It will be tied to RPM rather than throttle position.

[Davezj]

the thing is mine is not 100% and 0% in these situations. that was just my theory about how it should work.

would it be a drive out and go to WOT in 5th and say 40mph, this will build max boost very quickly and be able to sustain that max boost for a good few second before i am getting to silly speeds.
as the boost increases the wastgate/solenoid should be closed. as the max boost is achieved 0.55bar the wastegate/boost solenoid should start to do something to contrl the boost and maintain it at 0.55.

i know you get wastegate creep as the boost build but imagine a perfect system.

what do you recon will happen.

[Kenneth]

The wastegate duty should start high, bleeding off the pressure to the wastegates so that you build boost faster. When the ECU wants to reduce boost, the wastegate duty should REDUCE.


You have to be aware that the ECU does not see MANIFOLD PRESSURE. That means that it cannot read boost level etc.

Instead, it uses a predetermined table of duty cycle at a specific RPM points.

The boost solenoid probably works between about 20% and 80% outside those values, it will be unable to move quickly enough and will just lock open or closed.

[Davezj]

cheers that seem a bit more realistic view of what should go on. so i will do some logging and post the graph up.