The 2012 Subaru Impreza G4 represents a specific era of Japanese domestic market and export compact sedans, built around a low-slung boxer engine and permanent symmetrical all-wheel drive. If you're looking at buying a used fourth-generation Impreza or trying to understand what the 2.0-liter FB20 engine actually delivers on the road, you need clear data rather than marketing fluff.
Unlike the North American hatchback and sedan variants that often came with slight trim variations, the Impreza G4 designation typically points to the four-door sedan body style popular in global markets. This car isn't a factory powerhouse or a hidden track monster; it's a dependable commuter car with rally-bred mechanical roots. Let's break down the exact specifications, real-world engine output, and what it takes to live with one.
2012 Subaru Impreza G4 Engine Specifications
Under the hood, the standard power plant for the global G4 sedan is the FB20 2.0-liter naturally aspirated flat-four boxer engine, replacing the older EJ series found in previous generations. It features a chain-driven double overhead camshaft layout with four valves per cylinder.
- Displacement: 1,995 cc (2.0 liters)
- Bore x Stroke: 84.0 mm x 90.0 mm
- Compression Ratio: 10.5:1
- Maximum Horsepower: 148 hp (110 kW) at 6,200 rpm
- Maximum Torque: 145 lb-ft (196 Nm) at 4,200 rpm
(Note: The competitor article incorrectly attributes a 2.5-liter engine and 170 horsepower to the standard 2012 Impreza G4 sedan, which actually belonged to the heavier North American outback/legacy variants or the sportier WRX trims of that era. The standard G4 runs on the 2.0L FB20 engine). Related coverage on this trend has been provided by BBC.
Power routes through either a five-speed manual transmission or Subaru's Lineartronic CVT (Continuously Variable Transmission). Fuel economy sits around 27 mpg city and 36 mpg highway under older EPA testing cycles, or roughly 7.0 L/100km in mixed driving conditions.
Dimensions and Curb Weight
The fourth-generation Impreza grew slightly in wheelbase compared to the third generation, translating to better rear legroom without turning the car into a boat.
- Wheelbase: 104.1 inches (2,645 mm)
- Overall Length: 180.3 inches (4,580 mm)
- Width: 68.5 inches (1,740 mm)
- Height: 56.5 inches (1,435 mm)
- Curb Weight: 2,900 to 3,100 lbs (depending on transmission and trim level)
- Ground Clearance: 5.1 inches (130 mm)
Cargo capacity in the G4 trunk is 12.3 cubic feet, which expands when you drop the 60/40 split-folding rear seats. It's a practical layout for daily groceries, luggage, or golf clubs, though the trunk opening is smaller than a hatchback's tailgate.
Performance and Handling Realities
You won't break any speed records in a stock 2012 Impreza G4. The 0-60 mph sprint takes roughly 9.8 seconds with the CVT automatic, while the five-speed manual drops that slightly to around 9.2 seconds if you shift aggressively.
Where the car shines is traction. Subaru's active torque split all-wheel-drive system continuously monitors wheel slippage, steering angle, and lateral G-forces, shifting power proactively to the wheels with the best grip. On wet pavement, gravel, or packed snow, the G4 feels planted and predictable.
Body roll is present due to the soft, comfort-oriented suspension tuning. MacPherson struts up front and a double-wishbone setup in the rear absorb potholes well, but they aren't built for aggressive track days.
Unlocking Performance: Myth vs. Reality
Car forums are packed with threads about unlocking "hidden horsepower" in naturally aspirated Subarus. Let's be direct: you cannot pull massive horsepower gains out of an FB20 engine without forced induction.
Because the engine lacks a turbocharger, bolt-on parts yield modest results:
- Cold Air Intakes: These change the under-hood sound and throttle resonance, but cheap hot-air intakes often lose low-end torque. Stick to quality panel filters unless you are getting a proper dyno tune.
- Cat-Back Exhaust Systems: An aftermarket exhaust gives the car a deeper boxer rumble, but horsepower gains are usually under 3 to 5 horsepower.
- ECU Tuning: A custom ECU flash can optimize ignition timing and throttle response, removing the sluggish dead pedal feel in the stock CVT models, but peak output won't jump dramatically.
If you want serious speed, buying a WRX or STI is far cheaper and more reliable than trying to turbocharge a G4 engine.
Common Maintenance Issues to Watch
Before buying or modifying a 2012 Impreza G4, check for these well-documented mechanical trouble spots:
- Oil Consumption: Early FB20 engines (2012–2014) are notorious for burning oil past the piston rings. Subaru issued service bulletins and extended warranties for affected vehicles. Check the oil level every fuel fill-up.
- CVT Reliability: The early Lineartronic CVTs can suffer from valve body failure or shuddering during low-speed acceleration. Listen for whining noises during test drives.
- Suspension Bushings: Control arm bushings and strut mounts wear out around 100,000 miles, leading to clunking over bumps and loose steering feedback.
For deeper technical service data, consult the Subaru Global Official Site.
Frequently Asked Questions
Is the 2012 Subaru Impreza G4 good in deep snow?
Yes. Combined with proper winter tires, the Symmetrical All-Wheel Drive system handles heavy snow and slush better than almost any front-wheel-drive compact sedan from the same year.
Can I swap a WRX engine into a G4 sedan?
Anything is possible with enough custom fabrication, wiring harnesses, and money, but a direct engine swap is extremely difficult due to differences in chassis reinforcement, transmission mounts, and computer systems. It's cheaper to buy a turbo model outright.
How often should I change the CVT fluid?
While Subaru once claimed the fluid was "lifetime," mechanics strongly recommend changing the CVT fluid every 60,000 miles to prevent premature transmission failure.
Does the G4 come with a manual transmission?
Yes, base and mid-tier trims offered a five-speed manual transmission, though finding one in clean condition is harder than finding the more common CVT models.
