can anyone enlighten me as to what the little restrictor does in the boost solenoid pipe going to inlet manifold? ('93 wrx)

Can it be removed for improved response or can this cause problems?

cheers

 

It helps to stop boost spikes as you come on boost.
If you remove it boost will spike then the ECU will pull it back to near standard levels.
You can possibley get away with removing it on a standard car. But if you decat it, the spike will probably be high enough to trigger fuel-cut.

I see alot of these already removed. When people then fit my 16psi chip it overboosts causing fuel cut, as the chip has been setup to work with the restrictor.

After lots of hassling emails complaining about overboost, they then find the restrictor is missing, which is the cause of the problem.