There's more than one way to control boost on a turbocharged car. Some methods are more expensive than the turbo they're designed to control, others cost less than the burrito I had for lunch. There are electronic ones, manual ones, and strange homologations between the two. High-tech ones enclosed in fancy looking aluminum or plastic boxes accompanied with PC linking software for things like data logging, bare bones ones that look like a shut-off valve from Home Depot, and ones that really are just a shut-off valve from Home Depot. They all work. Sort of. And unless you're regulating boost solely off the wastegate's pre-set spring, or if you have a wastegateless turbo diesel truck or something, then chances are you have some sort of boost controller already. Or at least you've been meaning to get one.
World Electronics, maker of the pricey but effective TBC-1 boost controller, now offers the newer, more affordable but equally effective PBC-1. We've had a chance to use and get used to the PBC-1 over the last several weeks on Project Laser, but before we tell you what we think of this new addition to the land of electronic boost controllers let's take a look at why you need a boost controller and the different types you can get - or make.
Aside from pulling off to the side of the road and disassembling your external wastegate to swap springs, or change out your internal wastegate actuator, using a boost controller is really the only smart way to control how much pressure your manifold sees. But they do more than that. Wastegates begin working before we need them to. Their valves typically begin to crack open once 50 percent of an engine's desired boost level is reached. Not so good. Boost controllers can keep pressure on the valve to stop this from happening, in turn, improving boost response. There are two types of boost controllers: manual and electronic. Manual controllers consist of either a ball and spring or a bleeder valve. The first uses a spring-loaded ball to temporarily block the boost reference signal the wastegate is supposed to see. Once the desired boost level is reached based on spring tension via an adjustment knob, the ball is lifted from its seat and the wastegate goes back into action. Bleeder valves are somewhat less effective and are really just a more expensive way of poking a hole in the wastegate actuator's vacuum reference line. Ball and spring controllers are fairly cheap but are unpredictable and difficult to adjust on the fly. These are best suited for vehicles looking for high boost values that a typical wastegate spring can't provide, and leaving it there. Bleeder valves are for poor people who probably can't afford the repercussions of turning up the boost anyways. Smart people can make either type.
There's really only one choice for a boost controller if you're looking for in-car, predictable adjustability, and that's an electronic one. Electronic boost controllers control the pressure signal the wastegate actuator sees by using either a stepper motor or a solenoid. Stepper motors control the opening events of the controller's valve, while solenoids either open or close the valve, quickly. Very quickly. Solenoids typically react faster than stepper motors, which means wastegate control can be even more accurate. Electronic controllers also offer digital displays in which users can punch in boost levels and the controller does the rest.