XFI open loop vs closed loop analog 8 boost control help

[leirch]

I'm trying to get the FAST closed loop analog 8 boost control working and am having some weird issues(atleast they seem odd to me..).

I have the fast boost solenoid wired to the factory boost solenoid plug and tapped into the 5v from C24 on xfi and plugged the pressure sensor into C19 for analog 8 input.

I can flip to open loop boost control, set boost DC to 70%, xfi controls the solenoid perfectly and boost seems pretty solid. You can also see the wastegate PSI on the same screenshot.. So I used this wastegate PSI info to help me get a start on the Closed loop analog 8 configuration..but whenever I flip to use Analog 8 closed loop control, I can't get the wastegate PSI to register anything past 0-4psi..

Now, if you look at the next screen for my analog 8 attempt, you can see the boost DC registers(I had it set lower as a test..) but wastegate PSI doesn't seem to increase hardly at all.

I've attached the logs as well if that helps.


I'm using a precision 39 wastegate with a 6.9lb spring.

I placed the boost solednoid up near the pass side hood hinge and the pressure sensor is about 18 inches down from that.

I wanted to keep the heat away from both of these the best I can, but I will relocate one or both if needed.


PID is 40 , 25, 15... I tried lowering to 20, 5, 1 , didn't notice any changes.

 

[leirch]

I forgot to mention, I'm using an autometer 0-100psig sensor... I had to adjust the gain offset to 50 from 25 to get a 0 psi wastegate reading at idle.

 

[turbobitt]

I'm trying to get the FAST closed loop analog 8 boost control working and am having some weird issues(atleast they seem odd to me..).

I have the fast boost solenoid wired to the factory boost solenoid plug and tapped into the 5v from C24 on xfi and plugged the pressure sensor into C19 for analog 8 input.

I can flip to open loop boost control, set boost DC to 70%, xfi controls the solenoid perfectly and boost seems pretty solid. You can also see the wastegate PSI on the same screenshot.. So I used this wastegate PSI info to help me get a start on the Closed loop analog 8 configuration..but whenever I flip to use Analog 8 closed loop control, I can't get the wastegate PSI to register anything past 0-4psi..

View attachment 286392


Now, if you look at the next screen for my analog 8 attempt, you can see the boost DC registers(I had it set lower as a test..) but wastegate PSI doesn't seem to increase hardly at all.


View attachment 286391



I've attached the logs as well if that helps.


I'm using a precision 39 wastegate with a 6.9lb spring.

I placed the boost solednoid up near the pass side hood hinge and the pressure sensor is about 18 inches down from that.

I wanted to keep the heat away from both of these the best I can, but I will relocate one or both if needed.


PID is 40 , 25, 15... I tried lowering to 20, 5, 1 , didn't notice any changes.


View attachment 286393

Your PID setting look really low. For example I'm running 100/60/30. What is you slew rate set to ? What are you commanding for boost % ? Anything =/<20% will yield no additional boost control pressure.
Also what is your min map set to ? Are you running PA time based or TPS based control ?
AG.

 

[leirch]

Here are my boost control tables, I can get to 21psi in open loop. I'll need to turn analog 8 back on and increase my pid settings again to see if that helps. I have tried setting min kpa to 120kpa and up to 150kpa but maybe its just the PID settings.

I have all PA boost settings disabled for now, just trying to get it working in the most basic form right now.

 

[leirch]

Ahh yes, the PID was definitely the problem.

Here are some much better results, now it looks like I need to tune them down a little since its commanding 100% Boost DC even when I have 80% boost control set in the boost table?

Thanks for the help thus far!

 

[turbobitt]

Ahh yes, the PID was definitely the problem.

Here are some much better results, now it looks like I need to tune them down a little since its commanding 100% Boost DC even when I have 80% boost control set in the boost table?

View attachment 286483


View attachment 286484


Thanks for the help thus far!

Do some reading on the Help file. If your commanding 80% boost control it will try to achieve 75 psi at the gate. There is a good chart that you will need to familiarize yourself with so you can target the proper gate pressure. I would leave the PID as is and maybe change the min map KPA to at least 100kpa or slightly higher or something in the boost cells. This basically will max out the wastegate DC until that map value is acieved and then it will regulate gate pressure. So if you set the min map to 168 KPA(About 10 psi boost) it will have 100% wastegate DC until it hits 168 KPA and then it will regulate gate pressure. I would start by commanding about 30% boost control (at 100% TPS) and see if it will regulate 13 psi per the chart. If it can maintain the target than the PID is close to correct.
AG.

 

[leirch]

Thanks for the help AG.

I played with the settings after reviewing the Wastegate PSI charts.

I first set the boost table to max of 30% and min KPA to 120kpa
But I cannot get the wastegate pressure to anything under 40psi and commanded boost DC stays at 100% no matter what.

Here is a couple screens of lowering min KPA to 110kpa and max boost dc commanded to 30%. I also lowered PID to 70/etc(tried 100, 80 and now at 70..)

I'm wondering if placement of my solenoid/pressure sensor is the reason for the lack of control? And the bottom of the wastegate is going to the turbo compressor housing, top of wastegate(solenoid) goes to the back of the intake, drilled and tapped for push connect fitting.

I also have a blow off valve , but I wouldn't think that would cause an issue?

 

[turbobitt]

Did you verify the Autometer sensor is reading correctly at different pressures ? And is it definitely on Analog 8 pin C19 ?
Edit - I just reviewed your post again and it appears your something is wrong with your sensor calibration. If your source for wastegate pressure is your intake than there is no way it should be reading 40 psi. You will have to provide more info on the sensor to give accurate gain and offset numbers.
AG.