Going Faster: Engine Upgrades
There's no such thing as too much power, right? The Evo's 4G63 engine is as old as dirt (it first surfaced back in '87 or so), and as tough as a rock. The latest version still has a cast-iron block, but the internals -- crank, pistons, and rods -- are forged. This makes for tremendous strength, and the ability to handle loads of power. The compression ratio is 8.8:1, though, which is pretty high for an engine that runs 19 psi of boost right from the get-go. Most of the easy power-adding mods have to do with freeing up intake and exhaust restrictions, and optimizing fuel and timing, rather than simply adding more boost.
While we're on the subject of horsepower, we think the Evo is conservatively rated. Mitsubishi published a crank horsepower figure of 271, and torque of 273. We got 250 and 265 at the wheels, respectively, on an AWD Dynapack dyno with our bone-stock Evo. This dyno usually reads around 168 hp for a stock Subaru WRX, which is rated at 227 crank horsepower. Using anything close to the same percentage loss gets us over 300 hp at the crank for the Evo. Quarter-mile trap speeds of 102 mph or more (common for stock Evo's) would also back up the 300+ hp number.
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