Boost Controller: HKS EVC EZ

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

http://images.sportcompactcarweb.com/tech/0207scc_boostcontrol02_s.jpg

The EVC EZ is out there for those who just want a dial in the cabin, and that's all you get. Be forewarned, however; it's a mighty sensitive dial. HKS claims the EZ can take you to 35 psi, which is probably true.

The stepper motor used for boost control is the same as used on the EVC IV. Installation is a simple case of hooking up power and ground. Three hoses need to go to the intake manifold, compressor discharge and wastegate. If you have a twin turbo Supra or RX-7, you can find vehicle-specific instructions in the Japanese manual. They're in Japanese, of course. Unless you purchased the optional installation kit for your vehicle, run out and get a 6mm vacuum tee before you start working, as one isn't supplied. Finally, flip the switch on the back of the unit to select internal or external wastegate and you're all set.

Much like the volume knob on a high-end stereo receiver, the EVC EZ is ready to rock, so tune in cautiously. There's no mention in the one and a half pages of English instructions about problems using the EZ on cars with minor boost creep, but it sure doesn't seem to like it. To be fair, we've had no boost spiking problems on our externally wastegated test car.

Controller: HKS EVC-EZ
Pro: CARB legal. Adjustable from inside the cabin.
Con: Significant boost spike.
Cost: $395. Installation kit, $20-135.
Source:
HKS USA
(310) 763-9600 x203
www.hksusa.com
Aesthetics: Simple and clean.
Ease of installation: Two wires, three hoses.
Clarity of instructions: It missed the most important one, "be careful with the dial." Otherwise, fine.
Features: In-cabin adjustable boost. CARB legal.
Performance: Boost control not as good as a ball-valve.