Fitted to just 424 cars, the Subaru EJ22G is the rarest production EJ and the holy grail for rally purists—a closed-deck, big-bore, turbocharged boxer purpose-built for the 22B STi. Here’s how its engineering set a new standard for WRC street homologation, and why it stands apart from every other Subaru four-cylinder.
⬆️ The 2.2L Displacement Advantage
The standard EJ20G/EJ20K runs 92.0 mm bore × 75.0 mm stroke for 1,994 cc. The EJ22G keeps the 75.0 mm stroke but opens the bore to 96.9 mm, landing at 2,212 cc.
Bore-only growth was deliberate. Stroking the crank would have raised piston speed and rod angularity at an rpm range this engine needed to survive intact. Widening the bore adds displacement without disturbing rod ratio or deck height geometry.
The payoff shows up exactly where rally stages demand it. Peak torque arrives at 3,200 rpm, with a flat curve rather than a spike, so the driver gets usable output out of hairpins without waiting for the turbo to catch up.
🏗️ Closed-Deck Block vs Open-Deck
Standard EJ blocks are open or semi-closed deck — the cylinder liner is supported only at its base, with the water jacket left open around the top of the bore. Under sustained high cylinder pressure, the unsupported liner top flexes laterally. Bore distortion follows, ring seal degrades, and head gasket clamping loses integrity at the deck surface.
The EJ22G casts a genuine closed deck. The liner top ties directly into the outer block wall, with only narrow coolant transfer passages breaking the deck surface. That circumferential support at the point of maximum lateral load is what lets the block hold sealing and bore geometry under the boost curve delivered by the IHI VF23.
The VF23 is a compact, twin-scroll-fed unit, tuned for spool rather than peak flow. Small turbine mass gets meaningful boost by 2,500 rpm, and the closed-deck architecture is what allows the engine to hold that boost without walking the bores over a full rally stage.
⚡ The Underrated Power Output
Subaru rated the 22B at 280 PS. Nobody in the industry took that number at face value, and for good reason — it is the exact same figure stamped on the RB26DETT, the 2JZ-GTE, and the 13B-REW, a suspiciously round coincidence tracing back to the industry-wide JDM gentlemen's agreement that capped advertised output across Japanese manufacturers through the 1990s.
Independent dyno data on healthy stock 22Bs consistently lands closer to 300–310 hp at the crank. The hardware backs it up: forged pistons, sodium-filled exhaust valves, and a closed-deck casting are specified for loads well beyond a genuine 280 hp engine's needs.
💬 Join the Conversation!
If you were building a 90s dream project, would you choose the closed-deck EJ22G over an RB26 or 2JZ? Sound off in the comments below.
Comments
Post a Comment