Since the introduction of Subaru's WRX, including its STI derivative, and the first consumer-marketed Mitsubishi Lancer Evolution, many articles have addressed the power and agility of these incredible four-door sedans. From a journalistic perspective, writing anything informational and meaningful about these cars is increasingly difficult. The reason for this is by no means the lack of factory-supplied performance or aftermarket upgrades; quite the contrary, it's the growing popularity and vast amount of performance parts made available from a variety of tuners that makes this subject matter so thorny.
Yet, the easily overlooked fact is that, for an automotive enthusiast, each featured vehicle is as unique as a diamond. No person on this planet is more apt to agree with this statement than one whose vision, persistence and enviably deep pockets are responsible for the brilliance of a finely tuned performance automobile. This is particularly true for Earl Mangune, the owner of a white 2006 Lancer Evolution IX MR.
As an automotive aficionado, Mangune can attest to the irrefutable fact that owning an EVO is more than a simple pleasure; rather it's an expensive addiction. How else could anyone explain the compulsive behavior associated with the attempt to make something essentially perfect even better? After all, the EVO's WRC-spec 2.0L turbocharged four-cylinder engine makes 286 hp and 289 lb-ft of torque straight off the assembly line. However, a true enthusiast's vocabulary doesn't include the word combination "good enough." Better is about more power, faster braking, nimbler handling and distinctive styling. Although the factory EVO IX is a nimble street-legal rally car, much can be done to improve performance in some, if not all of those areas.
Most familiar with automotive performance fundamentals understand the rules of the game; namely that, in terms of tuning, no gain is to be had without certain sacrifices. This is important to keep in mind as the various modifications are considered. This also makes tuning more of an art than a science. Making gains without upsetting the delicate balance that exists between various systems of something as complex as an automobile is always agonizing when striving for perfection.
With that disclaimer out of the way let's identify some of the known issues with the EVO that are worth addressing. The aging 4G63 engine produces an impressive amount of power for a fun-to-drive daily commuter, but the serious go-fast kind of guy like Mangune would find the car slightly underpowered pulling out of corners. This is partly explained by the turbo lag and fuel mapping. Although Mitsubishi has done its part in attempting to address turbo lag with the TD05HR-16G6C-10.5T turbo assembly, which employs a dual-scroll turbine housing, titanium alloy turbine assembly, and increased compressor diffuser cover inlets, the fundamental problem of lag remains.
Arguably, the turbine assembly in the EVO IX is cutting edge; however, Mitsubishi remained conservative with the boost pressure to maintain reliability. After all, one overlooked component of the aforementioned fragile balance is the manufacturer's warranty and potential liability suits that often accompany the performance-oriented EVO IX. Of course, once Mangune committed to sacrificing several warranty items, the door was blown wide open for modifications that made throttle response livelier. Earl opted for one of HKS' fifth generation, race-proven electronic valve controller units to control boost pressure and increase boost pressure stability. In addition, he installed a larger, mandrel-bent HKS downpipe, one of Road Race Engineering's large-body catalytic converters, and ARC's full titanium exhaust to maximize gas flow for a quicker turbo spool. But, in the process of modifying the induction and exhaust systems he upset the balance established by the ECU's programmed fuel maps. Fortunately, XS Engineering's software allowed them to reprogram all of the necessary parameters in the ECU to compensate for the changes. Still, the increased boost pressure resulted in higher intake air temperatures, which needed to be dealt with in order to deliver cool air into the engine. The solution was a more efficient front-mounted ARC intercooler kit. Although measurable engine performance gains weren't immediately available, the observable improvements were evident during the road test. The perkier engine and lightweight flywheel provided more power out of the turns reducing the understeer that's characteristic of the EVO and its Active Yaw Control (AYC) system.