I found this post on the same topic

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/vacum-question-boost-silenoid-630330/

I've got my build so far in the signature. Just reread my signature, I also have a custom TID bout 4" ID and an Apexi cone filter. What I'm wondering is if I'm safe removing my duty solenoid valve? My car, like most everyone else in the community, is a work in progress as I educate myself, decide what is best for my car and get the funds together to make it happen.

I rarely ever do it for fear of doing damage to the car, but if I romp on the gas boost pressure will reach around 10 psi. Other than a FCD I don't have any fuel or boost management. Is the solenoid valve serving any purpose? I have the UIM off and would love to simplify the rats nest. For a temporary removal am I safe simply unplugging the solenoid valve and capping the vac line coming off the turbo and at the solenoid?

 

The S5 turbo duty solenoid works as an air bleed in the line going to the wastegate actuator. The wastegate spring is still only a 5 psi spring on S5s, but the air that gets bled off under certain conditions allows the max boost to reach 7.5 psi before the wastegate is fully open.

That being said, if you remove it and cap the connections, you will reduce maximum boost (when not creeping), if you don't already have a boost controller of some kind.

 

Thanks for the feedback. I ran out of time today and left the solenoid as is.