I wanted to take a few minutes to describe my car and the work that's been done to it since buying it to turn it into the dedicated autocrosser it now is. I bought this originally as a stock 1999 Subaru Impreza Outback Sport. Prior to 2007, the car had nearly all suspension and handling modifications, but power modifications were on tap for this past winter. Prior to 2008, the car made 98 HP and 105 lb-ft of torque (according to a G-Tech Pro SS). The newly-built engine is in and my G-Tech power numbers are a peak HP of 112 HP and a peak torque of 120 lb-ft. I can't wait to get some engine management happening - that will really push those numbers up even further, I suspect. The car weighs 2680 lbs (without driver, with 1/2 a tank of gas) with a 55/45 F/R weight distribution.
My car was featured as an AutoBlog Reader Ride of the Day
Pictures
Suspension:
- Megan Racing street-series coilovers with camber plates
- Camber bolts at each wheel
- Rear strut tower bar
- Whiteline 22mm adjustable rear sway bar, on stiffest setting
- Modified Kartboy rear endlinks
- Rallitek/IPD 22mm front sway bar
- Custom-made heim joint front endlinks by Small Fortune Racing
- Hoosier A6 autocross tires in 245/45RR17
- -3 degrees of rear camber, -2.25 degrees of front camber, and 1/8" front toe out.
Bushings and Mounts:
- SuperPro Steering rack bushings
- STi GroupN Engine Mounts
- STi GroupN Transmission Mount
- Reinforced Pitch Stopper: This started as a JDM STi pitch stopper and was further reinforced with polyurethane by Deyeme Racing
- Kartboy front/rear shifter bushings
- Kartboy transmission crossmember bushings
Suspension Work:
Drivetrain Equipment:
- Phantom Grip rear limited slip differential
- Exedy organic clutch
- ACT Street Lite flywheel
Engine Modifications:
During the winter offseason from 2007-2008, I built an EJ22 motor (from a 2000 Outback Sport) to the best Street-Prepared motor I could muster. The only rules I didn't take full advantage of were balancing the crank (which I've heard varying opinions on it being useless or nearly useless for Subaru boxer motors and the max allowed 0.047" overbore. The 0.020" overbore I did could be accomodated by pistons and rings from Subaru for really cheap, whereas the full allowed overbore would have required I commission custom-made pistons.
- Porting the intake manifold: I'll worked with Small Fortune Racing to get better flow out of the stock intake manifold. It looks decent to begin with and seems to have a good flow already, but cleaning out the casting leftovers and porting and gasket-matching seems to have improved it. Results here and here.
- Phenolic Spacers from Grimmspeed, to increase intake plenum volume and reduce intake manifold temperatures.
- Smoothing the throttle body: There's a small seam in the throttle body that probably negatively disrupts airflow through the throttle body. Small Fortune Racing worked on this with the intake manifold. Results here.
- Reshaping the heads' ports: The intake ports and exhaust ports both have a lot of excess material available to widen the ports and increase head flow. Small Fortune Racing worked on this with the rest of the intake. Intake port results here and here. Exhaust results here.
- Planed the heads: The heads were planed 0.012" as specified in the service manual for a little extra compression.
- Bore out the cylinders: The cylinders can be bored out up to just over 0.040" diameter according to the rules, assuming you can find new stock-weight/shape pistons to fit. I used the Subaru 0.020" second standard overbore pistons (they don't make bigger) and had the machining/boring done at Performance Automotive Technology.
- Intake: The intake is a high-temp flexible rubber hose paired with a nice K&N cone filter in the fender well for lots of forced cold air.
- Exhaust: A set of aftermarket equal-length exhaust headers for the single-port engines doesn't exist. I got a high-flow cat from Random Tech and had a local shop connect that up to a FlowMaster Series 40 muffler with 2.25" piping and two Vibrant Technology 12" resonators. Headers will have to wait and I'm not sure I need them anymore, as power definitely felt better when I added the resonators.
- Lightweight and Underdriven pulleys: I've got a power steering pulley (from Group A), alternator pulley (from Unorthodox Racing), and an underdriven crank pulley (from Unorthodox Racing).
Interior Modifications:
- STi v5 seats
- STi v5 steering wheel
- G-Tech Pro/SS in-car performance computer
Brake Modifications:
- Goodridge stainless steel brake lines
- ATE Super Blue or Typ200 brake fluid
- Single-stage brake booster
- Porterfield R4-S pads/shoes
- Brake vacuum reservoir: This will come in handy since I've been frustrated more than a few times by having my power brakes cut out on me after lots of left-foot-braking without releasing the gas pedal, like in extended slaloms.
Other Modifications:
- Removed Air Conditioner (~30lbs, 25 of which in front of the front axles)
- Odyssey PC680 lightweight battery, relocated to rear of the car (35lbs in front of the front axle moved to 15lbs in back)
- Removed roof rack (10lbs from roof))
- Removed Fog Lights (5lbs from front bumper)
- Removed stereo and amplifier (30lbs)
- Swapped for a plain 'L' hood (5lbs from over the front axle)
Plans
- Engine management: I'm not entirely sure what direction I'm going to go here. The Perfect Power 6 is a potential (and economical) option, as it's relatively commonly used for NA Subaru engines. Dedicated ECU replacements that can keep the car street-legal (OBD2-compliant) are far too expensive for my budget. A very enticing option is the MegaSquirt which fits very well with my open-source idealogy, but Subaru-related experience in the public is minimal and I doubt I'm competent enough with engine management to be the first.
- Rear disc brake conversion - rear discs were available on only a few '93-'01 Imprezas, but I collected all the parts and will have them installed soon.
