Yellowstag

I have a jdm 1994 180sx. So I was poking around my bay trying to look to see if anything was tapped for a boost pressure sensor yet, and noticed a hose to my boost controller solenoid was unplugged from the T valve. I plugged it in and took it for a test drive and it feels like there is now more boost. I’d assumed there was possibly a boost leak somewhere in the stock IC or maybe a crack somewhere. As the car seemed to be running slightly rich(more exhaust pops while shifting and coming off throttle) But I may have been possibly only driving on 7psi. Which makes sense. I taped the line where it was damaged and put a zip tie on it to hopefully keep it in place.



The hose on the left with the rip was hanging disconnected. When reconnected I hear a quick “psssst” of air. Car was running. Knob on right can be seen in this pic.





Location context:






My question is on the stock solenoid there is a knob near the T valve. What in the world does this knob do? I did some googling and really couldn’t find anything at all besides that people forget to include the whole bracket when doing the sr swap.