| things one must know about how the boost control system works and how one would go about controlling it to understand the parameter settings in the profec BC. Make sure the controller is in psi mode. Refer to the manual on how to switch to psi from kilopascals. When you turn the car on and turn the knob, there will be a number flashing that increases or decreases as you turn the knob. This is the duty cycle. The duty cycle refers to the pulsing of the solenoid. Time high vs time low, or time open vs. time closed. a 75% duty cycle means the solenoid is allowing air to flow through it 75% of the time and 25% of the time it is closed off. The boost control system is a bleeder-type, meaning, the more air that is bled away from the turbo's actuators, the higher the boost pressure will be. The solenoid is your bleeder control and your link to boost control. The duty cycle of the solenoid's pulses directly correlates to the boost pressure you will achieve. The higher the duty, the higher the boost. There is a parameter called "gain set" I believe and this refers to the pressure at which it begins pulsing the solenoid at the duty cycle you have specified. Set this to zero. The "gain" parameter is used to enhance the response of the turbos and prevent spiking. Set this to 0. The boost limiter parameter should be set to 0 until you have everything configured. Be sure this is set to 0 else you may end up creating some odd characteristics in the boost that may leave you wondering what is going on. Using only the duty cycle, increase the duty until the engine reaches your target boost. Start around 30 and increase in intervals of ~5 points and fine tune with single unit changes until you reach your target. Configure your "gain set" parameter to about 1psi lower than your target pressure. Finally, increase the "gain" setting and work your way up until you just begin to note spiking, and then back it down a few points. You might want to jump upward in intervals of 2-3 units and then fine-tune it with single unit adjustments. If you want to specify a boost limiter, you can configure that as well. I would suggest setting it to about 3psi higher than your target and have it limit the duty cycle by about 10%.
The duty cycle controls the pulse-width-modulation signal sent to the solenoid. By manipulating the pulsewidth train, you can effectively control the rate of flow of bleed air.
The set gain parameter controls the pressure at which the solenoid initially begins its pulse routine while the boost is increasing. By setting this parameter to just under your target pressure, you are instructing the system to keep the turbo wastegates completely shut just until you get close to your target pressure. This enhances the response of the turbos. The gain parameter controls the duration of time that the solenoid pegs wide open at the pressure speficied by the set gain parameter. This duration of time is necessary so as to fill the actuator lines with pressure so that the wastegates can be quickly opened to avoid spiking. Once this duration of time passes, the solenoid begins pulsing at the duty cycle specified. If this gain setting is too short, it will cause a brief spike in turbo pressure because the actuator lines have not been given ample time to fill with air and generate enough pressure to open the actuator. If the gain is set too high, the boost will hit your target and then fall several psi and rebound back to the target and then fall and so on and so forth - this is called feedback. Find a nice balance by working up from 0 until you just note the boost spiking and then back down a couple of points. Typical values are around 5 to 15. Quicker spooling turbos will require a lower setting to prevent spiking. Keep in mind that the duty cycle is your base configuration for your target boost pressure. The "gain" and "set gain" parameters are secondary functions to enhance the spoolup of the turbos. Once you have found the duty cycle that produces your target boost pressure, do not change this parameter during your configuration of the other parameters. If something odd is going on, try turning everything back to zero except for your duty cycle and make sure that the car is hitting your target pressure. If the engine is producing the boost you want, then proceed again to the "set gain" and then to the "gain" parameter. Remember, any time you make a change to a parameter, you must push the knob to lock in the new setting. Be sure not to let too much time pass when you change to a different parameter - the controller will default back to its display after a few seconds and turning the knob will affect your duty, not the other parameters (since the duty parameter does not require any buttons to be pushed to change the setting - the knob only needs to be turned to change this). Good luck!
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ProfecB Spec2 is a great controller but there are some - 
