EcoBoost · 2.0 turbo I4. What the stock hardware is estimated to support, where it breaks first, and the honest path to more.
Same family, other generations and variants:Focus RS (Mk3)
The Ford Focus ST (Mk3) is rated 247 hp (EU 250 PS / 184 kW; US rating 252 hp SAE · EU market) at 5,500 rpm and weighs 3,168 lb (lightest kerb weight incl. 75 kg driver and 90 % fuel, 5-door (wagon 1,461 kg)), or 12.8 lb/hp. On enthusiast estimates its stock internals are taken to about ~400 hp, the fuel system to around ~340 hp, and the stock turbo(s) are taken to about ~330 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
EngineEcoBoost · 2,000 cc · I4
Bore × stroke87.5 × 83.1 mm
Compression9.3:1
Inductiontwin-scroll turbo
Fuel systemdirect
Rated power247 hp · EU 250 PS / 184 kW; US rating 252 hp SAE · EU market @ 5,500 rpm
Torque266 lb-ft @ 2,000–4,500 rpm
Redlinenot sourced in this audit
Stock boostnot sourced in this audit
Transmission6MT
DrivetrainFWD
Curb weight3,168 lb · lightest kerb weight incl. 75 kg driver and 90 % fuel, 5-door (wagon 1,461 kg) · 12.8 lb/hp
GenerationMk3 (2012–2018; the 2015 facelift kept 250 PS); the Mk4 ST (2019+) uses the 2.3 · 2012–2018
rotating assembly ceiling · fails first: head studs and gasket on the big-turbo path · 98 RON · no named source: site planning estimate · site planning figure ~400 hp; no named Focus ST tuner source was fetched
Induction ceiling~330 hp
stock turbo / supercharger ceiling · fails first: stock turbo out of efficiency · 98 RON · no named source: site planning estimate · site planning figure ~330 hp
Fuel system~340 hp
stock fuel-system ceiling · fails first: HPFP · 98 RON · no named source: site planning estimate · site planning figure; no named source in this audit
Clutch (manual)~300 hp
stock clutch torque capacity · fails first: stock clutch slip · no named source: site planning estimate · site planning figure; no named source in this audit
Cooling (sustained)~350 hp
thermal ceiling for sustained load · fails first: charge-air heat soak · no named source: site planning estimate · site planning figure; no named source in this audit
Tuning limitsenthusiast estimates, crank hp on the stated fuel; sources: none named yet; method: the analyzer plans on the lower bound of each range
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