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Turbotrix STi - Building an EVO KillerText and Photos by Michael Ferrara - DragSport.com
You may remember seeing the Turbotrix EVO VIII exactly two years ago on the cover of DSport (August 2004 edition). That 4G63-powered monster became the first American-built EVO into the 9s. This accomplishment helped to ensure that there was always a steady flow of customers to the New Jersey tuning shop. Looking to satisfy the power appetites of more than just the 4G63 community, Turbotrix has been tuning just about every import that you can imagine. From this crowd, one group that has been growing recently is the serious Subaru performance camp. With the STi versus EVO rivalry heating up, Turbotrix decided to add some fuel to the fire by building a STi that would be capable of taking home 9- or, perhaps even, 8-second timeslips.
Serious Subaru Performance
With the exception of Ali Afshar and the Easy Street Street-Class WRX, finding a Subaru with serious performance is not an easy task. While 400, 500 and even 600-plus horsepower EVOs are popping up in cities all around the country, a big portion of the Subaru crowd seems more concerned with how their blow-off valves sound than how their car performs (just visit some of the Subaru forums if you don't believe us). Fortunately, we have recently seen a shift if the Subaru camp toward serious performance. Factory turbos are being replaced by higher-capacity aftermarket units while more Subaru enthusiasts are upgrading the internals of the engines. Turbotrix built this Subaru to show just how far someone could go.
Street to Full-Race
While the original plan was to build a gasoline-fed engine for a street car, Turbotrix changed the plan after tearing the car apart. To get an extra 10-percent more power with an added degree of high-boost durability, Turbotrix decided to build the engine to run on methanol. Methanol is also known as wood alcohol and it's the simplest type of alcohol. However, methanol (unlike ethanol, the alcohol found in alcoholic beverages) becomes extremely toxic if ingested. Just four ounces is enough to cause the victim to go blind or die. The antidote, believe it or not, is ethanol. So if you accidentally ingest some methanol, don't be surprised if poison control tells you to chug down a bottle of vodka. Methanol is the type of fuel used by Indy cars, Top Alcohol dragsters and funny cars. It is also the fuel that gets mixed with nitro methane in the Top Fuel classes of racing. Since you can't find methanol at the pump and since it is also extremely corrosive (methanol must be flushed from the fuel system at the completion of each race), this STi is now a dedicated racecar.
The Powerplant
When you are running methanol instead of gasoline, a few changes can be made to the engine to optimize performance. For starters, the compression ratio of methanol engines can be much higher than a comparable gasoline engine. In the case of this EJ25, Turbotrix opted to have Wiseco build a set of custom 2604-alloy, forged aluminum pistons with an 11-to-1 compression ratio. These pistons were hung on a set of Pauter 4340 forged-steel connecting rods before being set into the Turbotrix high-strength cylinder sleeves. Tony of the Performance Machine division of Turbotrix performed all of the machine work on the block and heads. As for the heads, Jeff Hill hand ported the cylinder heads to Stage-5 spec while upgrading the valvetrain with SuperTech valves, valve springs and retainers. To complete the heads, a set of Kelford WRX cams were chosen to orchestrate the valve events. High-strength ARP head bolts were chosen to clamp the heads to the block.
For more on this article and more grab a copy of DSport Magazine on newsstands and tuning shops nationwide!
Source: DragSport.com - DSport Magazine - Cover Story - Turbotrix STi http://www.dragsport.com/issue/2006/0806_cover_story.shtml
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