3 port boost solenoid? What that all about?
 

Another n00b question, for you, the old 3 port boost solenoid, whats that all about?
Why change to 3 port, what does it do, and why please?
Thanks.

My understanding is that it gives finer control over boost compared to the OE 2 port solenoid

and peak boost can be retained for a longer period..........

The three port gives better boost control. For example, when I swapped my TD04 for a VF35, unmapped, by keeping the restrictor in I could keep the VF35s boost down to 10 or 11 psi, without the restrictor it would overboost to 20 psi and hit the fuel cut almost straight away. Soon as I swapped for a three port, it hit a perfect smooth 15-16psi and held steady every time.

It's just a more capable design.