unconventional boost controller setup

[ashford]

im not sure if the mechanical end of this setup is touchy or if i just plain suck at pid loops, but i found an unconventional setup that works well.
the car is a 1987 csx shelby
2.4 stratus engine with srt4 pistons/rods, bryan crowler stage 2 cams shortened stratus intake with box and ford 5.0 tb
exhaust is a jgs weld up log manifold, precision 38mm wastegate and a holset hx40 with quickspool valve, 3 inch single exhaust
ms3 no x, jean p&h id1000 stealth 340
running 1.3.?

the boost control was setup using both ports of the wastegate it worked relitivly well in open loop but was very touchy and would change with weather. roughly 1% change in duty cycle was 1 pound of boost. i tried switching to closed loop and just could not get it to hold quite often resulting in overboost when the turbo came "online" best settings were p=35 i=28 d=10 and the slider @48. anything outside that would either oscilate horibly or overboost.

we tried a manual boost controller and it works well, then i had a thought. lets use the boost controller as a 3 way switch, put the common to the wasegate, the no(normally open valve port) to manifold then the nc to the manual boost controller then set up a generic output to come on above 80% throttle. it works awesome below 80% tps there is 11 lbs boost and above it is 18 perfectly smooth. i may try turning on closed loop again with the same hardware setup and see how well it works.