Well, after some boost problems with a friends WRX due to overfilled with oil I tried some different "ideas" I had about boost control (after the cleaning procces on boost solenoid, hoses etc)
First, I changed the hose that goes from the solenoid to the intake with one slightly bigger and secondly I changed the small coupling that is before solenoid and joins the small hose that comes from the T connector to the other hose that directs to the solenoid(if you have a close look there are two hoses joined together with a coupling).
Believe it or not the car has the same boost on 4th and 5th gears but higher and better controlled boost on 1st,2nd and 3d gears, drives milles better and on the DD road dyno files the power curve is much smoother than before with smaller peaks or dippings!
I am going to try it in my car before I fit my exhaust as it costs about 2-3 pounds and isn't dangerous in every case as ECU still has the control and peak boost remains the same!
JIM


PS: I don't suggest this mod before I try it in my car, just want to let you know what I found and ask your opinion why it happens!

 

Its a std thing to do when remapping, the joiner acts as a restrictor limiting the pressure flow from the actuator hence restricting boost remove or open out and ... more boost, need to be v careful though.

bob

 

I did a similar mod to my WRX 01. I replaced my restrictor witha joining piece with the diameter of 4mm and it did seem to bring on the boost harder than before. It didnt translate to the RR though. Have since taken it back off and refitted the original restrictor.
Spooks

 

So if it's good mod Bob why have to be very careful?
As I understand the only problem with higher boost on lower gears is the gear box but this is the same dangerous with a MBC that increases also boost on lower gears, right?

 

Do you need a new remap after fitting a bigger T-piece.
I just had an Ecutek remap, but it's a 3 hour drive to the mapper....

Creepy

 

Be careful as your std ecu is set up to suit the original setup, by modifying you can get boost spiking and oscillation, hence "be careful". Note I said "when remapping", you may need to tweak the restricot a tadge if not. (cars will vary in this)

bob