The Hallman Pro RX Kit has a ceramic ball instead of the 316 stainless ball that comes in other Hallman valves. The ceramic ball only weighs a fraction of what the stainless steel balls weighs. This weight difference allows the ceramic ball to act very quickly as it is constantly changing directions during operation. The ceramic ball in conjunction with the use of a lighter spring will allow very fine adjustment of boost up to 4 to 5 pounds of boost over stock. Boost has been able to be adjusted in half pound increments very consistently with this valve.
This kit was specifically designed for those that only wish to add a few pounds of boost over stock and have a great amount of control over those few pounds. This is the kit that Hallman recommends for RX-7's. This kit also includes the heavy spring for those that would like add more than 5 pounds of boost and still take advantage of the ceramic ball.
The Hallman Pro RX kit contains the Hallman Pro Valve w/ ceramic ball, light and heavy springs included, 3 feet of vacuum line, mounting bracket, hardware packet and complete installation instructions all in one kit. The Pro RX kit was designed to allow very specific control of boost.
