looking for some advice about 3 port boost solenoid as reading conflicting stories on here. im running a 2005 sti type uk, some people believe a 3 pbs is not needed on these, but others believe them to be a neccessity when going for a map. i understand they help the mapper control the boost but what gains do you see from them? im also running an md321h

 

anybody?

 

hmm no idea if they are or not mate but im in the process of going for 330-340 with my bugeye and he told me its a definite for a map along with 550's vf35 , fuel pump , 3pbs and STI TMIC , think they are just the better valve for mapping if you intend to do so ..

 

For what they cost they are worth in IMO, I have one on my Spec-C, As you already know it helps with the fine tuning of the boost control when mapping so cant be a bad thing for £60 or what ever they cost now

 

Helps when getting car set-up, finer control when boost being set. I would imagine a 2005 sti will already have a 3 port fitted.