Closed-Loop boost control not usable

[VegasAWD]

I'm having the car remote-tuned by a well-known tuner in the states and we have ran into issues with closed loop so much that the tuner has given on it. For my own curiosity, I'd like to hear other people's thoughts. The car is a 2L 4g63 with an XR71-64s with a 0.64ar exhaust housing. It has a recirculated 44mm wastegate setup with I believe an 8psi spring. First, the car won't make any less than 15psi. Second, we've tried my old ingersol-rand 3 port and now a GM 3-port setup and neither setup has worked. As you can see, the boost just skyrockets past our targets. The tuner thinks it's low pressure in the manifold/and or poor wastegate position that makes the closed loop way too sensitive to work. Has anyone seen anything like this? I've never heard of this issue. I've attached 3 consecutive revisions in the links below. Thanks

https://1drv.ms/f/s!AqYM2sKDG5eJgasUsdFM6nx2ZxRrkQ

https://1drv.ms/f/s!AqYM2sKDG5eJgasSWOdI3TR2mWNdwA

https://1drv.ms/f/s!AqYM2sKDG5eJgasRWaN3DqufnXaF9A

 

[remski2]

Hi.

First thing.. you have no knock signal coming in, so that alone questions the tuner.

 

This is what I would do...

1. Setup the knock sensor.. unless you dont care aobut your engine. 

2. I'd clear the boost tables and run wastgate just to confirm it shows steady ~8psi. (if thats your spring) 

Based on the above you'll know if that header works or not.

3. Only if the wg is working properly I'd start increasing the wg duty.. 

 

 

 

 

[VegasAWD]

39 minutes ago, remski2 said:

Hi.

First thing.. you have no knock signal coming in, so that alone questions the tuner.

 

This is what I would do...

1. Setup the knock sensor.. unless you dont care aobut your engine. 

2. I'd clear the boost tables and run wastgate just to confirm it shows steady ~8psi. (if thats your spring) 

Based on the above you'll know if that header works or not.

3. Only if the wg is working properly I'd start increasing the wg duty.. 

 

 

 

 

1) My ecu does not support a knock sensor currently, and I'm running e85 where knock is not very useful.

2) As stated in the post, 15psi is the lowest boost I can run on my wastegate.

[Adamw]

In the first map the PID is zeroed out - this means it is running open loop.  With that file the first time you go WOT the boost shots to the moon and hits the boost cut.

In the second file closed loop is enabled, but again at WOT the boost runs away until the boost cut is hit - the closed loop was already pulling 8% duty cycle out trying to get it under control.

In the 3rd file the only difference is the stage 1 duty is lowered, again the boost runs away until it hits the boost cut, this time with the CL pulling 13% duty out.

 

So, you need to get it working well in open loop first, the first map/log shows it doesnt, there is no point adding closed loop until open loop controls well.  I would also only start tuning with one boost table, it seems crazy to try to tune two interpolated tables working.

 

From the photo, the wastegate placement doesnt look great so that may be some of the problem, but having said that I have seen worse designs actually work ok.  Do you know for sure that it is a genuine tial gate, not a copy?  

Does it control ok with the DC tables zeroed out?  

 

[VegasAWD]

Hi @Adamw, thanks for the reply.

 

1) Both tables appear to be the same if you're referring to DC table 1 and 2. OR is there another table you're referring? It wouldn't a problem interpolating if both tables are equal right?

2) We're continuing on with open loop tuning so maybe there is light at the end of the tunnel.

3) I'm pretty certain the Tial is genuine.

4) I'm not sure what you mean by control ok. When I'm on just spring pressure it starts low around 8-9psi and creeps all the way up to 15psi as rpms increase. 

[Adamw]

Tune #6 has different wastegate DC tables.  It looks like that was later changed.  

 

4 hours ago, VegasAWD said:

4) I'm not sure what you mean by control ok. When I'm on just spring pressure it starts low around 8-9psi and creeps all the way up to 15psi as rpms increase.

Yeah that is not particularly good.  You should have a near flat line on spring pressure with that size gate.  It suggests flow isnt happy turning that 90deg corner.