Boost Controller: HKS EVC IV Silver Edition

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

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The HKS EVC is the granddaddy of electronic boost controllers. Many still consider the EVC II to be the best boost controller out there because it's so simple to use, thanks to high and low presets on its face and a knob that lets you manually dial in a third boost level. It would work with both internal and external wastegates if you knew which dip switches to flip around inside. For years it was the only option, because everything else out on the market didn't work.

The EVC IV shares its case size with all the other HKS electronic components back to the original EVC I. It still has the high- and low-boost modes, but now you also get a scramble mode, integrated boost gauge, over-boost alarm and protection feature. The limited edition silver model we're reviewing here incorporates a handy additional Peak/Hold function on the boost gauge. Peak/Hold is key for programming the EVC IV, because like the PRofec A, it tries to take advantage of a fuzzy logic to optimize boost characteristics. Unlike the PRofec though, programming is a pain.

To do anything you must depress some combination of poorly labeled buttons, and do it quickly. Almost every time the dial is turned, it must be calibrated by turning fully to the right or left. Having used the menu-driven interfaces from other companies, operating the EVC feels like a game of Memory. Plus, all four buttons are fairly small, and pretty close to each other, making it easy to hit the wrong one.

There's an optional harness to remotely mount the scramble trigger, which is great. If you're too cheap, just connect a momentary switch between the orange ground and yellow trig wires.

For weeks we've had the EVC IV running on our externally wastegated test car with no problems. Installing it on the Eclipse was straightforward; it went in just like the EVC EZ. We could get through the learning procedure just fine. Once a boost level was dialed in however, the EVC just seemed to sit back and watch the show. Boost would build quickly, and just keep on going right past our set point. Peak/Hold recorded only a fraction of the pressure run, which was probably the reason the alarm didn't activate. Luckily, we had good fuel in the car, and it was able to survive the 25 psi of boost. We tried reprogramming, swapping out the harness, even using the actuator from the EVC EZ. All the settings were checked by a number of people. Replacing it on the other car proved the unit works fine. It just didn't like our Eclipse.

HKS as a company has been very aggressive in perusing CARB-exempt status on all its products. This effort is by no means trivial, and we applaud its efforts. Here in California, vehicles are being pulled over more and more often for suspected vehicle code infractions. Bottom line: If your car gets inspected by the state, you want an EO number for every aftermarket part you have. HKS is the only one that offers this security.

Controller: HKS EVC IV Silver Edition
Pro: CARB legal, peak / hold boost gauge.
Con: Won't work on a boost creeper. Adjustment dial from hell.
Cost: $735 silver, $675 std. Installation kit, $20-135. Scramble trigger $80.
Source:
HKS USA
(310) 763-9600 x.203
www.hksusa.com
Aesthetics: Nice size, clear display, meaningless button labels, totally lame dial.
Ease of installation: Yes.
Clarity of instructions: Japanese book gets 62 pages. English book gets 5. We must be missing something.
Features: Low, high and scramble boost settings. Boost gauge (peak/hold on silver model). Overboost warning and protection. CARB legal. Adaptive control.
Performance: Needs to be manually set, then doesn't hold true. Scramble works well, though.