SPEC SHEET | A Wolf In Sheep's Clothing
There's always something a bit special about a car being a bit more capable than you thought. A car that looks like any other average road-going car, but packs a serious punch. An Impreza wagon is a fairly unassuming vehicle and it's just about the perfect platform for a chassis that will surprise the guy in the next lane, can make some big power, and stay under the radar of your local law enforcement.
THE BACKSTORY
Jose purchased this vehicle with the intent for this build. It's was an extremely clean chassis that was purchased used, and driven straight here for the build process to begin. The goal was fairly straight forward, he didn't want to run "exotic" fuels, he wanted to make as much power as possible, and wanted the car to remain fairly unassuming. To help accomplish this, we ripped out the ENTIRE powertrain and transplanted a complete 2007 STi power plant and drivetrain into this chassis.
THE BUILD
At the heart of the build is it's Procom Racing built engine. This car came from the factory with a 2.0L engine and that platform was simply not going to cut it for this build. We replaced that with a complete STi 2.5L engine and started the build process from there. This engine starts with a Procom Racing S4+ shortblock. A very stout set up capable of dealing with just over 850whp. That shortblock is then mated to a set of Procom Racing 2.5L STi cylinder heads with the help of ARP 625 head studs and a Procom Racing prepped factory MLS headgasket for optimal combustion chamber sealing. Helping to keep engine temperatures in check is a Koyorad aluminum rad. To help out the oiling system, we added our Procom Racing PRO-Series Billet Oil Filter Adapter with a Wix filter. This improves engine oiling, increases oil capacity, and also increases oil filtration. A MUST-HAVE modification for your modified Subaru.
Engine management is very straight forward on this build. Even though we're running a full 2.5L engine instead of the factory 2.0L, this engine still uses the 2.0L ECU and electronics. So we've simply added a Cobb AccessPORT, and Procom Racing Protune to ensure safe & reliable power.
For now, this engine runs strictly on 93-octane pump fuel so the fuel system is fairly mild. It starts with a single Walbro 450 fuel pump housed in the factory sending unit. Fuel then runs through our Procom Racing "firewall forward" kit, into a set of Procom Racing billet fuel rails, before finally making it's way through a set of Injector Dynamics ID1300, 1300cc fuel injectors.
Jose gave us a fair amount of creative freedom with this build, so we used it as a platform to expand upon our current offering. That led us to get a bit creative surrounding the induction system. We custom fabricated a prototype twin-scroll turbocharger kit that houses an EFR7670 turbocharger. This compressed air is then fed into a Procom Racing "Street Series" front-mounted intercooler with a custom intercooler piping kit. From there, this air runs through a Boomba throttle body and Cosworth intake manifold before making it's way into the engine. After the air is spent within the engine, it needs to get out. Helping us out there and providing a killer sound is an Invidia N1 Race catback exhaust.
Moving on to the drivetrain; the factory 5-speed drivetrain is good for daily duty at the power levels Subaru intended. Once we start to go far beyond that though, the weak links start to show. This typically leads to broken gears and other broken drivetrain components. The STi drivetrain is extremely stout and can deal with regular abuse at this power level without breaking a sweat...or any parts. The drivetrain starts with a complete 2007 STi drivetrain. Everything from the gearbox, rear, axles, driveshaft, hubs, spindles, etc we're swapped in to replace the factory WRX components. Helping manage the driver controlled center differential (DCCD) is a DCCD PRO, which allows adjust-ability of how the power is distributed front to rear. Either automatically or by drive command.
The interior is just as unassuming as the exterior on this car, but we've added an ATi dash pod with the addition of three AEM digital gauges.
POWER AT THE WHEELS: 498whp / 409wtq @ 23psi
This engine has a few different tune settings based on the drivers commanded power request. At it's highest setting the car makes just shy of 500whp at only 23psi. We typically do not go much further past 500whp on pump fuel due to fueling inconsistencies. More and more lately we've seen "93oct" from various fuel stations come short of that rating and will typically lead to a lack in power, knock, and other ill effects. As a matter of engine safety, we stray away from making big power on pump fuel and will opt to switch to either Ethanol (E85) or various racing fuels. Strictly for the better fuel consistency.
-LL
SPEC SHEET
ENGINE
-PROCOM RACING S4+ Shortblock
- AEBS Sleeved Block Case Halves
- Pinned Main Journals
- STi Forged Crankshaft
- Manley Turbo-Tuff Connecting Rods
- Manley Turbo-Tuff Pistons
- King Main and Connecting Rod Bearings
-PROCOM RACING Prepped Cylinder Heads
- BC S3 Camshafts
- BC +1mm Intake and Exhaust Valves
- BC Valve Springs
- PROCOM RACING Mild Head Port
-PROCOM RACING PRO-Series Oil Filter Adaptor w/ Wix Street Filter
-APR Custom Age 625+ Headstuds
-AOS
-Koyorad Aluminum Radiator
ENGINE MANAGEMENT
-Cobb V3 AccessPORT
-PROCOM RACING Protune
-AEM MAP Sensor
FUEL SYSTEM
-Walbro 450 Fuel Pump
-PROCOM RACING "Firewall Forward" Fuel Kit
- Perrin 6-port Fuel Pressure Regulator
- PROCOM RACING Billet Fuel Rails
- AN Fuel Line (-6an)
-Injector Dynamics ID1300 Fuel Injectors (1300cc)
INDUCTION
-PROCOM RACING Rotated Twin-Scroll Turbo Kit (prototype)
-PROCOM RACING Twin Scroll Header
-PROCOM RACING Intercooler Kit w/ Street-Series Core
-Borg Warner EFR7670 Turbocharger
-Tial 44mm MVR Wastegates (x2)
-Invidia N1 Race Cat-Back Exhaust System
-Torque Solutions CNC TGV Housings
-Boomba Throttle Body
-Cosworth Intake Manifold
DRIVETRAIN
-2007 STi Gearbox
-R180 Rear Differential
-STi Axles
-STi Driveshaft
-DCCD Pro center diff controller
-STi Brembo Calipers
-Hawk Pads
-StopTech Rotors
-STi BBS Wheels
-BC Type-BR Coilovers
INTERIOR
-ATi Gauge Pod
-AEM Digital Gauges (Boost, Air-Fuel Ratio, & Oil Pressure)
