The Subaru WRX STI (VA, 2019–2021) is rated 310 hp (SAE · US market) at 6,000 rpm and weighs 3,448 lb (US curb, WRX STI (Series.Gray 3,463 lb, Limited 3,514 lb)), or 11.1 lb/hp. On enthusiast estimates its stock internals are taken to about ~380–470 hp, the fuel system to around ~360 hp, and the stock turbo(s) are taken to about ~350–371 hp. Below: the sourced spec sheet, the limit sheet carbuildcheck analyzes against, and the platform's community-documented weak points.
Units
01 Spec sheet sourced
EngineEJ257 · 2,457 cc · flat-4
Bore × stroke99.6 × 79 mm
Compression8.1:1
Inductionsingle turbo, cross-flow intercooler, 16.2 psi max boost
Fuel systemport (sequential multi-port)
Rated power310 hp · SAE · US market @ 6,000 rpm
Torque290 lb-ft @ 4,000–5,200 rpm
Redlinenot sourced in this audit
Stock boost1.12 bar (16.2 psi), gauge
Transmission6MT only (DCCD)
DrivetrainAWD
Curb weight3,448 lb · US curb, WRX STI (Series.Gray 3,463 lb, Limited 3,514 lb) · 11.1 lb/hp
GenerationVA, final years (310 hp, 16.2 psi, 8.1:1) · 2019–2021 · facelift (applied model (Subaru letters), Subaru’s term)
rotating assembly ceiling · fails first: ringlands, then liners · 93 AKI / E85 · source: 8020 Automotive, FA20DIT vs EJ257 · same EJ257 short block as the 2015–2018 car; same band
Induction ceiling~350–371 hp
stock turbo / supercharger ceiling · fails first: stock turbo out of efficiency · E85 · source: DSPORT, Test & Tune 2017 WRX STI part 3 · same turbo family; the factory already runs 16.2 psi
Fuel system~360 hp
stock fuel-system ceiling · fails first: stock injectors and pump on E85 · 93 AKI · no named source: site planning estimate · site planning figure; no named source in this audit
thermal ceiling for sustained load · fails first: oil temperature and starvation on track · no named source: site planning estimate · site planning figure; no named source in this audit
⚑Ringland failure is the EJ257's signature move (IAG: failure-prone ringlands). The 2019 tune already runs more boost and less compression; margins are thinner, not wider.
⚑EJ oil starvation in long corners is community-documented; baffled pan or accusump before serious track use.
04 The typical path
Stage 1 tune → intake → downpipe → intercooler → Stage 2 tune. Fueling before E85; the clutch before sticky tires.
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