What the 22B Actually Is
The Subaru Impreza 22B STI was produced for exactly one model year, 1998, and only 424 units were built. It was the ultimate expression of Subaru's Group A homologation special. The engine was a 2.2-liter EJ22 flat-four, wider than the standard EJ20 by 15 millimeters, with a different bore spacing. It made roughly 280 horsepower in Japan due to the gentleman's agreement, though real-world numbers often ran higher. The widebody fenders weren't cosmetic addons - they were designed to accommodate the 18-inch BBS wheels that came standard, which required flaring just to clear the tires. Recreating or restoring one of these cars is a different proposition than working on a regular WRX. The parts are scarce, the wiring is fragile, and most importantly, the value curve punishes mistakes badly. A single incorrect repair can drop a car's worth by tens of thousands of dollars. That's why people who work on these tend to be methodical to a fault. The 22B used a set of IHI turbochargers, typically the RHB52 in later iterations. These are different from the TD04H turbos found on the standard 22B STi that came out around the same time. The RHB52 has a larger compressor wheel and a different internal wastegate design. One thing most people don't realize: the oil feed line from the pump to the turbo on these engines is aluminum, not steel. It's a known failure point. I had a car come through my shop with a cracked oil supply line that was starving the turbo at highway speeds. The turbo had actually ingested some oil from the crack but hadn't failed yet. The fix was replacing the aluminum line with an AN-8 braided stainless steel line and an adapted fitting. That modification alone is something I recommend on every 22B I touch, regardless of whether there's an existing leak. The original lines are nearly thirty years old and under thermal stress every time the engine runs.
The 22B used a five-speed manual transmission with a specific gear ratio setup that was different from the STi spec C. The rear differential is a viscous coupling unit from the factory, and these wear out. Not gradually - they either work or they don't. I've seen cars where the viscous fluid had degraded to the point where the rear wheels were getting almost no power in normal driving. The fix is rebuilding the center differential with an adjustable unit, but you have to be careful about what you choose. A full lock on a street car with 280 horsepower going through four-wheel drive is not a good idea. It makes the car unpredictable in wet conditions and puts enormous stress on the driveline. The front differential is a standard Subaru unit, but the pinion preload is different. When you're rebuilding these, use the factory specifications and don't guess at shim thickness. I once had a car with a whining noise that turned out to be a missed 0.05 millimeter shim during a previous rebuild. That small a difference creates enough play to cause premature bearing failure down the line.
Engine Management and Wiring Issues
The ECM on the 22B is the JDM-specific version with different mapping than the North American STi. If you're trying to swap an EJ20 motor into a 22B chassis or vice versa, the wiring harnesses are not interchangeable without significant modification. The sensor placement is different, the fuel injector connectors are the same but the pinout in the main harness differs between markets. I spent three weeks tracing a wiring diagram on a customer's car because someone had tried to mate a USDM STi harness to a JDM 22B engine bay. The check engine light was throwing codes for sensors that didn't exist on that engine. The solution was to cut and splice the harness at specific junction points, following the factory wiring diagram page by page. It took about twelve hours of work once I had the diagram in front of me. The ignition system uses individual coil packs on later models. These are another failure point. The primary coil on the number one cylinder tends to go first, and when it does, you get a misfire that's subtle enough at idle to be easily missed. Under load, the car will run rough and lose power. Replacement coils are available but they're expensive. A temporary workaround I've used is swapping the coil from cylinder one to cylinder four. If the misfire moves to cylinder four, you've confirmed the coil is bad. This lets you identify the problem without immediately buying a new part.
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Suspension and Chassis Components
The 22B suspension was tuned differently from the standard STi. The front struts have a different spring rate and damping curve. The rear multi-link setup uses specific bushing hardness that affects how the car handles over uneven surfaces. Most owners swap these out for aftermarket coilovers anyway. If you're keeping the stock suspension, inspect the control arm bushings and the rear lower control arm joints. These are rubber components that crack with age and heat. A cracked rear lower control arm bushing will make the car feel vague under hard acceleration and can cause unpredictable handling changes as the suspension compresses. The subframe mounting points are another area to check. The 22B had reinforced subframe mounts compared to the standard Impreza, but after twenty-five years, the metal fatigues. I found hairline cracks in the left front subframe mount on a car that had been sitting for about ten years before being revived. The cracks weren't visible without cleaning the area and using a bright light at an angle. Replacing the subframe is the proper fix, but in a pinch, reinforcing the existing mount with plates and welding has been done successfully. It's not ideal for a show car, but it keeps the car running.
Body and Rust Considerations
The widebody panels on the 22B are composite materials, not steel. This means they don't rust in the traditional sense, but they do degrade. The inner structure underneath the wide fenders can rust while the outer panel looks fine. Always lift the car and check the inner fender wells and the rocker panels before buying one. Rust in those areas is expensive to fix because the panels are difficult to source and even more difficult to fit properly. The doors and hood are aluminum on the 22B. This is lighter than steel but it dents differently. A dent in an aluminum hood won't pop out the same way a steel one would. Heat treatment or professional panel replacement is usually necessary. I've seen people try to use body filler on aluminum panels, which works temporarily but fails within a year as the filler contracts at a different rate than the metal underneath.
Value and Market Realities
A clean 22B in working condition currently sells for well over half a million dollars. There are clones and replicas on the market that look similar but are built on standard STi or WRX bases. The real differentiators are the VIN number, the engine block casting marks, the turbocharger part numbers, and the interior door jam labels. If you're buying one, bring someone who knows what they're looking at or plan to spend money on a pre-purchase inspection by a specialist. The cost of a thorough inspection is negligible compared to the risk of buying a fake. I've seen at least three confirmed replicas pass for real 22Bs at auction in the last five years. Parts availability is the main bottleneck for restoration. Engine internals are generally available through Subaru dealers and specialty suppliers, but exterior body panels, especially the wide fender flares and the front bumper assembly, are nearly impossible to find new. Most restorations rely on salvage yards or reproduction panels from companies like Venilla Works. The reproduction quality has improved significantly in recent years, but fitment still requires more work than genuine OEM parts.
Practical Ownership Advice
If you own a 22B, drive it. These cars are not meant to sit. The seals dry out, the fluid degrades, and the rubber components deteriorate. A car that has been stored for two years without being started will need significantly more work than one that's driven regularly. Change the fluids every six months if you're storing it. Rotate the tires. Run the HVAC system periodically to keep the compressor seals lubricated. Keep detailed records of everything you do. The provenance of the car matters enormously for resale value. A receipt for an OEM part is worth more than the part itself in some cases. Buyers want to know the history, and documented maintenance is the best proof you can provide.
