Like ours of this month: time-attack. As of this year's Super Lap Battle finals and Import Tuner's own STI vs. EVO Shootout at Buttonwillow Raceway in California, and Japan-based Rev Speed magazine's Super Battle at Tsukuba circuit in Japan, EVOs (with STIs following closely) are the fastest platforms in competition, two years running. That they're consistently beating built touring cars at what is essentially their own game proves their level of refinement. But just what makes them so good? Elliott Moran, organizer of Super Lap Battle and owner of the C-West-clad EVO X on these pages has his opinions. "It's simple," he starts, grinning and counting with his fingers, "Turbo four-cylinder engines are light, and capable of more than enough power with a little work. All-wheel-drive is perfect for racing-you have four wheels on the ground most of the time, if you get power to the right ones at the right time, you get more traction. Front-to-rear weight transfer under acceleration is even, and the front-engine layout is easier to drive for most people. And each model is revised every two years." He's quick to point out that EVOs have so far been faster than STIs on the streets, drag strips, and in time-attack. Controversial as it may be for it's wild modification and fabbed strut towers, Japan's HKS CT230R is recognized as the fastest production car of any make in competition, but Sun Auto's faithful Cyber EVO is closing in on its records, having clocked a 54.392-second Tsukuba lap only weeks before this writing. In the U.S., Sierra Sierra's EVO VIII is closing in on the CT230R SLB record after only its first year competing, and AMS' EVO X is arguably the fastest EVO X in the world, itself also after just one season. At face value, it would seem the Subies have some catching up to do.
Paul Yim, owner of the Santa Clarita-based Subie dojo Yimisport, has his own opinions on the matter. He's owned and tuned EVOs and STIs alike, and the Laguna Seca Blue STI laid out on the pages in front of you has served as his company's test bed since it was purchased new in November of '07-meaning it, and its 536 whp have stood at the forefront of STI tuning technology. "If you're looking to drop $30K on a solid, fast, practical street car out of the box, the Subie's perfect-loads of torque, it's comfortable . . . and have you seen the EVO's trunk space? It's a joke." He continues, "But if you want to tune your car a little, make more power and beat everyone at the track on the weekends without worrying that it's going to blow up, you probably want the EVO." He reconsiders, "Then again, if you're loaded and your only goal is to build an all-out track monster . . . they're pretty much the same." Yim points to two fundamental differences with each car. "The EVO's engine has always been bulletproof. Even the new 4B11 has proven its stock block can take some serious abuse. If the U.S. STI's EJ25 came with forged pistons and a better head design like the 4G/4B-like the JDM STI engine-they'd be every bit as strong." He continues, "And the EVO chassis just feels more responsive on the track; twitchy, almost. It responds to every steering and braking input, which is good, but also makes the STI way more comfortable on bumpy, unpredictable roads, like the ones most of us drive everyday." A product of their extensive rally heritage, we suspect, where competition-built Subarus outnumber, and outright own their EVO rivals.
STIs have a proven overheating problem when driven hard-especially the '08+ cars, which are equipped with radiators half as thick as in previous years. For emissions' sake, they also run a factory-preset closed-loop 14.7:1 air/fuel tune until 4,000 rpm, which severely limits timing advance and power output. And then there's the problem of them blowing up. "There are certain steps you should take when building an STI," explains Paul Leung, Yimisport's lead tuner, "First, get an Accessport and have it tuned the day you buy your car. Then buy bolt-ons, a good suspension and lower the car a little, do your alignment, and have fun." But he cautions, "Make sure to upgrade the oil pan, intercooler and radiator, and add an oil cooler before you go racing. And if you upgrade the turbo and injectors, build the block. Replace the pistons at the very least-stock ones don't usually last long." Typically, cylinder four leans out and detonates due to excess back-pressure that builds at its near-90-degree exhaust port, keeping the proper amount of fuel from entering combustion. "A good turbo manifold and some mild porting will take care of this," Leung advises.
Modifying an EVO is a slightly different story. Super Lap Battle's 2008 Street AWD and 2009 Limited AWD class-winning car, Ryan Gates' AMS-powered EVO X, has raced two entire seasons on a stock-block, 500+whp 4B11 engine without a hitch. Elliott's car has managed to run faster than most with comparatively little added to it-even 1.081 seconds faster than Yim's STI at our STI vs. EVO Shootout (though in Yim's defense, he was testing a larger turbo on the car, the powerband of which was too "peaky" for his driver's liking on street tires-a more fitting turbo replaces it now). Still, they aren't without their hiccups: "The MR's twin-clutch SST transmissions are known to overheat on the track," explains Elliott, "but it's not much of a problem with an aftermarket transmission cooler. And all EVO Xs experience fuel starvation during hard cornering when the gas tank is less than half full." He continues, "Those are the only two drawbacks I know of." Flexing an off-the-shelf Tein/Hotchkis suspension, a slight APM/AMS/Project Mu brake upgrade and making a fat 391 whp, his car is on the verge of sub-two-minute passes at Buttonwillow. "It might've been able to break two minutes-the driver didn't get a lot of seat time with it this year. But with the Voltex aero it has now, it shouldn't have a problem," he claims. To put this in perspective, a stock Z06 'Vette and Porsche 911 Turbo (997) won't run better than a 2:02. A stock EVO X GSR will do about a 2:05.