Electronic boost controllers are among the most sought after objects of desire in the Super Street world. One of these sexy little boxes mounted on your dash or in your center consoles tells the ladies: This puppys turbolets hook up. How many of you out there know exactly what an electronic boost controller does? Tougher still is choosing one for your turbo car.
First, heres a basic rundown of how boost is controlled. Standardized boost regulation relies on a diaphragm-equipped wastegate. While the turbo builds up boost, the diaphragm stays closed until a certain pressure is reached. At that pressure point, the diaphragm opens and releases any excess boost that the turbo may produce. By altering the pressure signal before it reaches the diaphragm, one is able to increase boost levels beyond that of a stock wastegate. A major controversy in boost controller land is whether to use stepping motors or solenoids to alter that pressure signal. Stepping motors resemble a climate-controlled air conditioning system. They constantly monitor manifold pressure and adjust in order to maintain stable and linear boost increases. Solenoids act as an open/close switch, holding pressure until the exact moment it has to be released, offering quick turbo response. So, which one is really better? Neither. They both get the job done in different ways.
The Apex Super AVC-R, Blitz Dual SBC-I-D, GReddy Profec B, and HKS EVC IV are the most sought after electronic boost controllers on the market right now. We brought them all down to R&D Dyno to test out all the different buttons and knobs on Junko Hyodos 90 240SX, equipped with an SR20DET Silvia turbo motor. A base dyno run, with no boost controller installed, showed figures of 185.5 hp at the rear wheels with .5 BAR (7 psi) of boost. Next, we installed each boost controller on the 240SX and upped the boost to .85 BAR (12.5 psi). Since the stock SR20DET uses an internal wastegate, we had to preset each unit to control an actuator (swing valve) type wastegate. Remember not to raise boost levels higher than your fuel system can handle or else you can kiss your motor good-bye.