DYNO TUNING / SUBARU
Subaru Tuning Melbourne
WRX and STI from GC through to the VB, Forester XT and Liberty GT — EJ and FA flatties are our speciality. Full standalone builds, ProEFI, Link ECU and OEM ECU tuning available.
— Subaru Dyno Results
Your Subaru Dyno Tuning Specialists.
— Models We Tune
Popular Subaru Models We Tune.
WRX and STI across every generation — EJ and FA flatties are platforms we know inside out, from mild Stage 1 OTS maps to full-build standalone tunes.
GET A QUOTE →— Platform Overview
Tuning the Subaru Platform.
Subaru's EJ-series flat-four was built for performance from the ground up. The EJ20T across the GC/GD/GE/GH WRX generations and the EJ25 family — EJ255 in the Liberty GT/Legacy, EJ257 in the STI — are closed-deck engines with decades of proven development behind them. The EJ257 in particular arrives from the factory with forged pistons, forged connecting rods, and a stronger block than the WRX EJ. Toyota's conservative TD05H turbocharger calibration leaves meaningful headroom on a stock engine, and the combination of a strong bottom end and a well-understood ECU makes the STI one of the most predictable tuning platforms available.
EJ tuning splits between off-the-shelf (OTS) maps and custom Mainline dyno work. OTS maps are calibrated for a theoretical standard car — correct fuel pressure, perfect injector flow, sea-level altitude, no wear. A car with any deviation from those conditions — even a slightly different intake, a worn O2 sensor, or local 98 RON — will benefit from a custom calibration developed on our dyno. We regularly see meaningful AFR and timing differences between OTS and custom-tuned EJs, and those differences matter for both reliability and power consistency.
The FA20DIT in the VA WRX (2015–2021) is a fundamentally different engine. Direct injection rather than port injection changes how the fuelling responds, and the FA doesn't develop the same low-end torque character the EJ is known for. It responds well to ECU calibration and gains are reliable on 98 RON, but the FA20 is more sensitive to fuel quality than the EJ — worn injector tips and variable pump fuel show up faster on a tuned FA20. For WRX owners wanting the full EJ character, a Blouch or similar turbo upgrade and supporting fuel system work unlocks the platform further.
— Typical At-Wheel Figures
Real Numbers. Mainline AWD.
At-wheel kW on 98 RON unless noted. Representative of results in our Epping workshop — your car may vary.
| Engine / Models | Factory | Stage 1 | Stage 2 |
|---|---|---|---|
EJ20T98 RON WRX GC/GD/GE, Forester SF/SG | ~145 kW | ~192 kW | ~240 kW |
Proven platform with massive aftermarket. OTS maps available, custom dyno tune recommended. | |||
EJ25598 RON Liberty GT BL/BP, Forester XT SH | ~165 kW | ~212 kW | ~258 kW |
Open-deck variant — Stage 2+ build should include head studs and head gaskets. | |||
EJ25798 RON / E85 STI GD/GR/GV/VA all generations | ~185 kW | ~235 kW | ~290 kW |
Closed-deck, forged internals. Strong bottom end handles Stage 2 safely. E85 Stage 2+ highly recommended. | |||
FA20DIT98 RON WRX VA 2015–2021 | ~175 kW | ~222 kW | ~265 kW |
Direct injection — very sensitive to fuel quality. Custom dyno tune strongly preferred over OTS. | |||
— Parts & Accessories
Subaru Tuning Parts & Accessories.
Subaru-specific performance hardware, sourced and fitted in-house.
Front Mounted Intercooler Throttle Adaptor Pipe (Suit PW FA24 Intake Manifold)
VB FA24 WRX Intake Manifold
VB FA24 WRX Intake Manifold (Port Injection)
G5 ECU Plug-In - Toyota GT86/Subaru BRZ/Scion FR-S
Bosch 980cc EV14 fuel injectors
Process West Front Mount Intercooler Kit (suits Subaru 15-21 VA WRX)
Process West Cold Air Intake W/ K&N Filter (suits Subaru 15+ WRX)
Xforce Subaru VA WRX FA20 Manual Downpipe Kit
— Subaru Tuning FAQs
Common Questions.
What's the difference between tuning an EJ257 STI and a FA20DIT WRX?
The EJ257 STI uses port injection and responds predictably to boost and ignition changes — it has a wide, flat torque curve and a strong low-end character that improves dramatically with a proper tune. The FA20DIT in the VA WRX uses direct injection, which makes it more sensitive to fuel quality and requires different fuelling strategies. The FA20 makes power higher in the rev range and gains are still strong, but it lacks the bottom-end grunt of a tuned EJ257. Most serious Subaru enthusiasts prefer the EJ257 platform for its character and tuning headroom.
Is an OTS map or a custom Mainline dyno tune better for a Subaru WRX?
An OTS map is calibrated for an idealised standard car — perfect injectors, standard fuel pressure, sea-level altitude, brand-new everything. Any deviation from those conditions means the OTS map isn't quite right for your car. A custom tune developed on our Mainline AWD dyno is built around your specific car, your actual injector data, your fuel, and your modifications. The power difference may only be 5–15kW, but the AFR accuracy and safe ignition timing across the full rev range is significantly better with a custom tune.
How much power can a stock EJ257 STI handle safely?
A stock EJ257 bottom end with head studs and a quality head gasket is generally considered safe to around 260–280kW at the wheels on a custom tune with 98 RON. Beyond that, the stock turbocharger becomes the limiting factor before the bottom end does. On E85 with a larger turbo (Blouch, Precision, etc.), 350kW+ at the wheels is achievable on a well-built EJ257. The STI's forged internals give it genuine headroom that the WRX open-deck EJ20 and EJ255 don't have.
What mods does Stage 2 on a Subaru STI require?
Stage 2 on an STI EJ257 typically requires: a high-flow up-pipe, a catback exhaust (or at minimum a catless or high-flow cat downpipe), an upgraded intercooler, a high-flow air intake, and head studs with a quality head gasket replacement. These allow safe, sustained higher boost levels. A custom ECU tune developed on our dyno with these mods in place is then required — a Stage 2 tune on a Stage 1 hardware setup will produce incorrect and potentially unsafe results.
Is E85 worth it on a Subaru EJ engine?
E85 (or a flex fuel setup) on an EJ platform is one of the best value performance upgrades available. The octane of E85 (~105 RON equivalent) allows significantly more ignition advance and higher boost pressure than 98 RON without knock risk. A properly tuned EJ257 STI on E85 with a good supporting build typically sees 30–50kW more at the wheels than the same car on 98 RON at Stage 2. You'll need upgraded fuel injectors and a higher-flow fuel pump to support the increased fuel consumption of E85.