Jump to content

Subaru Impreza WRX GC8 wastegate valve not being activated


Recommended Posts

Hi guys.

I am looking for some help. I have tried to enable the boost control for my external waste gate form the Link G4X ECU rather than the HKS EVC-S (because I want to fine tune and it is not user friendly).

I have read the topic "Subaru wrx sti V7 Wastegate %DC - Active map" and I followed the LINK help file for the correct plumbing of the valve.

Please note that HKS is using their own valve and I used the Denso OEM valve which I tested using Link test tool and it is working fine. They are both 3 port valves.

The initial plumbing was with one pipe coming from turbo boost side, then into the valve common port. And then from the valve NO port to the wastegate bottom side. The wastegate top side was open to the atmosphere. This setup was working and I could boost 1,3-1,4bar.

I have tired to plumb it as below which I believed it is more correct as it requires less effort from the valve. Please note that I used the Denso OEM valve. Unfortunately this setup was not working. The turbo was boosting 1,6bar and beyond instantly and then it was cut off from the ECU engine protection.


After spending hours to figure out what is wrong, I dumped this setup and I plumbed as it was working before but again on the Denso OEM valve.

In regards to the MAP, I chose to start with OPEN LOOP control. I have used very similar to the recommended values that Adam posted to the above topic which I mentioned above (please see below for your ease):


Unfortunately again, even with the initial plumbing and the above MAP, the valve is not being enabled at all to any RPM or Boost to increase the boost further ( I do not hear it either) and now the max boost is up to 0,8bar which is the spring strength (I believe). From what I see, there are only two conditions. The MAP pressure which I set it even lower to 50kPa and the RPM which I left it as it was to 2000RPM.

Here is the MAP: https://1drv.ms/u/s!AjaHKcNV8KOYixG_OiTOm0zwhfn2?e=tTnM4U

Here is one LOG: https://1drv.ms/u/s!AjaHKcNV8KOYixLBLvICeaFRc2oO?e=qFELI2


Can you please tell me what I am doing wrong and the valve is not being activated?


Any help is appreciated.




Link to comment
Share on other sites

It sounds more like a plumbing issue. 


8 hours ago, Christoforos said:

The initial plumbing was with one pipe coming from turbo boost side, then into the valve common port.  And then from the valve NO port to the wastegate bottom side.

Common is the "middle" port on the denso, this should be connected to the actuator.  NO is the top port, this should go to the boost source.  The bottom port should be vented.  

Link to comment
Share on other sites

Hi Adam.

Thanks for the swift feedback. Attached you can see that they are connected correctly.

I have mentioned above that with this plumbing is boosting 0,8bar which is the pressure that the wastegate springs can hold. To me, this seems that the plumbing is ok. Can you please confirm?

How about the MAP? Is there something not configured correctly and the solenoid is not activating to increase the boost further?




Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...