Am I correct in thinking that if the actuator arm is 'shortened/tightened' then this raises the boost pressure ?
If this is the case then is it possible to guesstimate what the affect of one turn of the arm would have on pressure , or is this too small to be significant ?

Reason for asking is that my 1998 Forester T/tb makes a very conservative .7bar at full boost(10.1psi). Solenoid has been cleaned, some tubes replaced but still 0.7bar. Despite extensive searching I have not been able to find if this is the oem ecu set figure or not, but assume that it is. Cannot remap this ecu but have it on good authority that this engine runs rather rich anyway and a small raise of boost will not create problems.
Open to opinions ! Polite ones please .

Cheers

JBL

 

Shortening the actuator arm will raise boost pressure, however there's no hard and fast rule about how many turns equal a 1psi increment.

Make sure you don't get carried away increasing boost (as many do). 0.9bar should be ok. Just don't get an FCD and raise it to 1.5bar without checking fuelling otherwise it will be bye, bye engine.

For the trouble of turning the actuator arm, you might want to consider getting a ball and spring manual boost controller. Very cheap and get the job done.

 

Could be worth checking the gauge against a second one.

My wrx engine was showing about 10-10.5psi on the gauge rather than about 11.5psi. To test it I bought a small pressure gauge that ran from 0-25psi from a pneumatics/hydraulics type outlet cost about £8, then T'd it into the line for the original gauge. One kind of like this


Also I got a little non-return valve for fish tanks from a pet shop, about £2. They are just the right size for the tubing. The valve holds the max boost pressure to the gauge(s) until you remove it after testing



Found the original gauge was reading about 1 psi than the test gauge. The test gauge showed the expected psi from the engine