What's the difference between a manual and an electronic boost controller?

A manual boost controller either bleeds off or restricts the air pressure signal going to the wastegate. In effect, the wastegate is fooled into staying shut longer (thus allowing more exhaust to spin the turbo, thus making more boost). MBCs aren't very precise but they're really cheap and do work. They are prone to boost spiking because they aren't very complicated devies. Normally as boost builds, the wastegate creeps open. However w/ a MBC in the middle, when the pressure signal does indeed become strong enough to open the wastegate, the MBC doesn't allow the wastegate to open completely. Call it wastegate delay if you will. A resulting boost spike happens (as the turbo happily spins unregulated). It doesn't last long (by human standards), but hey funny things can happen when you don't have enough fuel for the boost. From: Joshua So (mail@removed.com) "Like I said, manual boost controller tend not to be accurate since they do not account for weather, temperature, barometer ...  more