overboost

[concept_R]

hi,

I am running a 7psi spring in my Tial MVR wastegate, properly plumbed and connected to the boost controller (the one that DIY sells).
For some unknown reason, I do get a good amount of over-boost. (~15psi, right when overboost protection kicks in)
I checked but can't seem to find the problem.

see log & tune attached


Thank you!!

[nathaninwa]

Id unplumb the boost comtroller till you can run wastegate line alone. Leave the top port unconnected and run boost pressure to the bottom port only. This will give you your true wastegate line boost pressure. Zero DC is being used so its not the cause of your overboost.

Replumb and get a WOT throttle datalog

[concept_R]

Thanks!! But my boost controller settings are all at 0, wouldn't that have the exact same effect?

Oh and I'm getting boost reference from manifold pressure only, I dont have a boost only port right now. Not ideal -- I know -- but it can't be the reason for that much boost I assume?

[nathaninwa]

I'm just thinking to get rid of any plumbing problems. If you pull the top port off this will start you over just for testing. With the top line off you should be able to blow through the line, if you can't it will pressurize and slow down the gate opening

I just like to start from the beigging and locate problems furtrher up stream is all

And running vacuum isn't ideal into the gate, could cause a pinch point and tear the diaphragm causing your issue too

[concept_R]

Thank you so much for your input!! I finally found the problem!
Attached the log with the top port of the gate disconnected (to atmosphere)

I ran another test and when the controller is off the top and bottom ports of the gate are connected. When I turn the controller on via test options in TunerStudio it vents the top port to atmosphere.
So I guess I only have to swap the polarity in the boost control settings from normal to inverted.

Right now I get around ~9.5psi of boost which makes sense given the fact that I get the boost reference from the manifold.
I will change that so I get boost reference right at the compressor housing which should give me a more accurate control.

[nathaninwa]

Did you double check the air plumbing? I've ran 4 of the diy valves at at normal polarity

[concept_R]

yes I am 100% sure the plumbing is correct.

The fact that turning it on with the I/O Test in TunerStudio vents it proves that the polarity is wrong? Please correct me if I'm wrong.
As far as I understand 100 duty cycle (= ON) should connect top to boost level. However, it's doing the opposite right now.

thanks!