Ford Focus ST & RS Tuning Guide (2013-2018)
The Ford Focus ST and RS are among the most tunable hot hatches ever made. With their EcoBoost turbocharged engines, these cars respond incredibly well to ECU calibration, making them favorites in the tuning community.
Focus ST Overview (2013-2018)
Engine Specifications
- 2.0L EcoBoost (Ford Ecoboost I4)
- 252 HP / 270 lb-ft stock
- BorgWarner K03 turbocharger
- Direct injection
- 6-speed manual transmission
Tuning Potential
The Focus ST is known for being conservatively tuned from the factory. A Stage 1 tune on a stock car typically yields:
- 280-300 HP with 91 octane
- 300-320 HP with 93 octane
- 340+ HP with E30 blend
- Significantly improved torque curve
Focus RS Overview (2016-2018)
Engine Specifications
- 2.3L EcoBoost (derived from Mustang EcoBoost)
- 350 HP / 350 lb-ft stock
- Twin-scroll turbocharger
- All-wheel drive with drift mode
- 6-speed manual transmission
Tuning Potential
The RS has more headroom due to its larger displacement and better cooling:
- 380-400 HP with 91/93 octane tune
- 420-450 HP with E30 tune
- 500+ HP possible with turbo upgrade
Recommended Tuning Platforms
Stratified Automotive (Top Choice for ST/RS)
Stratified is the gold standard for Focus ST and RS tuning:
- Custom dyno-quality remote tunes
- Extensive data logging and revision process
- Excellent flex fuel support
- Works with COBB Accessport
- Known for reliability-focused calibrations
COBB Tuning
COBB developed the Accessport platform that most Focus ST/RS tuners use:
- Accessport V3 provides flashing and data logging
- Off-the-shelf maps available
- Protuning support through dealer network
- Excellent parts integration (intake, exhaust, intercooler)
HP Tuners
HP Tuners offers an alternative for shops doing custom calibration:
- More granular table access
- Lower ongoing costs (no license per vehicle)
- Preferred by some professional tuners
Focus ST Tuning Stages
Stage 1 (Tune Only)
- No hardware required
- 280-300 WHP on 93 octane
- Improved throttle response
- Reduced turbo lag
- Rev hang eliminated
Stage 2 (Bolt-Ons)
- Intercooler upgrade (essential)
- Downpipe (catted recommended)
- High-flow air filter or intake
- 300-330 WHP on 93 octane
- E30 capable of 350+ WHP
Stage 3 (Big Turbo)
- Upgraded turbocharger (Borg Warner EFR, GTX series)
- Larger injectors
- Upgraded fuel pump (Autotech HPFP)
- Forged internals recommended above 400 WHP
- 400-500+ WHP possible
Focus RS Tuning Stages
Stage 1
- 370-390 WHP on 93 octane
- Better boost response
- Improved AWD calibration
- Flat torque curve
Stage 2
- Intercooler upgrade
- Catless/high-flow downpipe
- 400-420 WHP on 93 octane
- 450+ WHP on E30
Stage 3+ (Big Turbo)
- Turbo upgrade (Pure Turbos, Garrett GTX)
- Built engine recommended
- 500-600+ WHP achievable
- AWD system handles power well
Critical Supporting Modifications
Intercooler (Both Platforms)
The stock intercooler is inadequate for any serious power increase:
- Heat soaks quickly, causing power loss
- Upgraded FMIC essential for Stage 2+
- Popular options: Depo Racing, CP-e, Mishimoto
High-Pressure Fuel Pump (ST)
The Focus ST fuel system is a limitation for high-power builds:
- Stock pump limits E85 usage
- Autotech internals most popular upgrade
- Required for E30+ on Stage 2
Motor Mounts
The soft stock mounts allow excessive engine movement:
- RMM (Rear Motor Mount) most important
- Reduces wheel hop and torque steer
- Improves shift feel
Head Gasket Concern (RS)
The Focus RS has a known head gasket weakness:
- Some early cars had coolant intrusion issues
- Ford issued revised gasket (part of a TSB)
- Upgraded gaskets available from Mountune
- Consider upgrade before aggressive tuning