1997 Mitsubishi Eclipse GSX

The formula for making a second-generation DSM fast was written years ago. It goes something like this: Big turbo, big injectors, magic electronic box.

However, the formula for making a second-generation DSM fast and subtle is still being carefully honed on the streets of Southern California. There are plenty of tasteless Eclipses and Talons roaming around, with their stereos blasting and their body kits dragging on every driveway. Too often, any hopes the owner had for performance were lost in the quest for bling-bling supremacy. With a sleeper, efforts are focused on going fast rather than looking brazen. Since surprising the unsuspecting is the sole purpose for a sleeper, picking the right car is critical.

Any real sleeper has three decisive characteristics. First there's abundance. One must pick a car that is readily available and easy to find parts for. And it doesn't hurt if there are already thousands of them roaming around to make your ride even less obvious. Second, starting with a capable platform is vital. After all a sleeper must be able to make gobs of power in a benign package. Third, and this one is critical, a sleeper must be overlooked by anyone who might care-not being noticed is a must. In other words, the Mitsubishi Eclipse GSX is the perfect candidate.

Just ask Ronnie Diaz. He's the owner of this 1997 Eclipse and is responsible for both its looks and performance. The former remains fairly tame. The latter doesn't. Any real DSM enthusiast knows how capable these cars can be with only a few effective modifications. The ubiquitous Eclipse was the perfect choice for Diaz, who knew its abundance and familiar looks would help it fly under the radar of other enthusiasts.

He began his adventures into the world of DSM tuning in an Eclipse GS-T but quickly tired of the front-drive grip issues. After about three months of searching, he found the Eclipse on these pages and began making changes to suit his unassuming taste. However, before getting too radical, he went to the track armed with only a boost controller and the stock turbo. The result was a 13-second time slip and we're guessing one seriously overworked turbo.

Diaz knew he'd topped out the stock turbo's potential and went to Road/Race Engineering in Santa Fe Springs, Calif. for more power. He left with a Mitsubishi 16G turbo that helped get the car into the high 12-second range down the 1320, but that clearly wasn't enough. Another trip to RRE left a Mitsubishi 20G hanging off the Eclipse's exhaust manifold-a surefire way to improve power. The quarter-mile time dropped again to 12.30 seconds at 110 mph. By now, the car had certainly achieved sleeper status-deep into the 12s and still looking relatively stock. But Diaz wasn't finished. A third replacement turbo was in order and with it came a host of other changes.

In its current form, the Eclipse uses a Turbonetics T3 exhaust manifold and Tial 35mm wastegate with the Turbonetics T04B ball -bearing turbo. The turbo feeds a GReddy front-mount intercooler via plumbing from RD Engineering of Oxnard, Calif., which houses a blow-off valve from a first-generation DSM. A K&N filter replaces the stock Eclipse airbox. Downstream of the turbo, there's an RSR turbo-back exhaust. However, Diaz stuck to the sleeper theme by replacing the stock melon-shooter exhaust tip with two less conspicuous tips designed to look stock.

Several upgrades were made to help the engine keep up with the added flow. A Denso 150 liter per hour fuel pump and 660 cc/min injectors provide additional fuel. A GReddy Profec B boost controller ensures manifold pressures appropriate for the 4G63's entirely stock bottom end while an A'PEXi Super AFC modifies the airflow meter signal to the stock ECU.

Subtlety was the name of the game when it came time to replace the wheels and tires-no chrome monsters here. Enkei RS-Evolution wheels sized 17x8-inches replace the stock rollers while 225/45-17 Falken Azenis tires are enlisted for grip duties.

Suspension upgrades are mild, with KYB AGX shocks replacing the stock dampers and Neuspeed race springs mildly lowering the car. AEM 12.8-inch front rotors are perhaps the only not-so-subtle upgrade visible from the street.