So boost overshoots by 3.5 psi at around 4700RPM which is not bad at all but will try routing to top and bottom of ports to see if it improves. Also around what rpm range is recommended to start letting in say 20psi? I know too much boost at low rpm can risk bending a rod...

 

Just curious, how does the 4 port help with spool time over the 3 port? Haven't heard of this before.

 

Without the top line, the waste gate is controlled by spring pressure. Say it has a 15lb spring, it doesn't just open at 15lbs it gradually opens and will be fully open at 15lbs. It'll start to crack open at a much lower boost which will let gas bypass the turbo and equals a slower spool.

This is part of the reason you see guys use CO2 for wastegate control. A cheaper way to achieve a similar (but not quite as good) result would be to put a line off the boost controller to the top of the gate. That will help to keep the gate shut until the specified boost is reached.

 

Yes but a 3 port solenoid can also be used for the top and bottom ports

 

I guess you could do it that way but you would have less control of the pressures

 

This is how ive re routed the lines to make use of both top and bottom wastegate ports. BUT its not working. Solenoid wont make more than wastegate spring pressure(4lbs) am i doing something wrong? Do i need 2 solenoids?

 

Make sure the solenoid is actually working. Check your boost duty table and Put it at 100% duty. You should hear it vibrating,

 

Dont hear the vibration when put to 100%duty cycle, i tested the solenoid im using a mac solenoid now it clicks when hooked up to battery. I shouldnt of messed with it everything was working well . The two wires leading to boost solenoid show 9v with key on and no change in voltage either at 0% 50% or 100% boostduty. Any ideas?

 

The top ports in the aforementioned diagram are functional equivalents (just plug whichever one you're not going to use). The option to use the top most port or not allows the wastegate to be mounted where space is limited.

 

Went back to how i had things set up. Im using the provided borgwarner boost controller but i want to change to a MAC boost controller so i can use push to connect fittings. Heres the way to set it up if it helps someone in the future.