Boost Controller: Ball Valve

We hit the dyno with 6 boost controllers and a ball valve.

http://images.sportcompactcarweb.com/tech/0207scc_boostcontrol08_s.jpg

Here it is, the hardware store homebrew that could. DSS' manual boost controller is a simple ball-spring system that delays pressure from getting to the wastegate. An adjustable spring holds the ball bearing against a seat, blocking off pressure from reaching the diaphragm. Once the spring is overcome by boost pressure, most of the air makes its way to the actuator, while a bit is allowed to bleed off to atmosphere. This bleed is necessary, as once you're back out of boost, you don't want the ball-spring to act as a check valve and hold the wastegate open. If you're handy and want to build your own, try these numbers to start: 0.065-inch bleed, 0.375-inch ball, 3 lb/in spring.

In all honesty, it kind of looks like a plumber got his hands on your car, but it sure does work. Turning the black-oxide coated bolt down against the spring makes adjustments. We gained around 1.5 psi of boost per turn. Two springs come with the kit; one is good for about 20 psi, the other even more. We never had a chance to try the other.

DSS has an improved design going into production that should eliminate much of the boost spiking experienced in this unit.

It'll also look much better, is manufactured from billet aluminum and be available in a number of anodized colors.

Controller: JBC/DSS MBC
Pro: Works pretty darn good.
Con: Some boost spiking. Can't adjust inside the car.
Cost: $65. You can get six of these for the next closest competitor.
Source:
Diamond Star Specialties
(805) 541-4483
www.diamondstarspecialties.com
Aesthetics: Looks like your uncle the plumber got his hand on your car.
Ease of installation: As easy as it gets.
Clarity of instructions: See above. Written for DSMs, applicable to all.
Features: Makes more boost.
Performance: Simple, effective and consistent.