quick ? on a BOOST/C

[214kka-et240sx]

ok, i made a cheap boost controller from a valve i bought a home depo, now i remember some guy here made one too, and he also had a way to make the boost hold, i kinda remember, but i think he used a biring and a spring, or if anyone has a better way of doing it, i just bought a new t28 and stock boost is 8 psi,put when i move the valve to make 12 psi, it will spike to 12, then drop to 8, so i wanna hold boost can some one tell me how , thanks

[Structure240sx]

get a good boost controller not something you want to go cheap on and spike to 25psi on pump gas

plus your car is sexy as hell