Every time a turbocharged WRX or STI accelerates hard or shifts, the engine and transmission rock slightly against their mounts. The factory pitch mount is built from a plastic composite tuned for…
A turbo inlet upgrade often gets sold on the promise of better throttle response, and it is easy to see why that claim spreads. A bigger opening sounds like it should mean…
The factory turbo inlet on a 2015-2021 Subaru WRX is made of hardened plastic, and after years of heat cycling, that plastic becomes prone to cracking. A cracked inlet or a failed…
Adding an external fuel pump to a WRX or STI build solves a flow problem, but it introduces a wiring problem most people do not think about until the pump is already…
Shift feel on a 2002 to 2007 Subaru WRX is one of the more noticeable places where factory parts leave a gap. The stock shifter has a long throw with some slop…
Turbo upgrades and boost numbers get most of the attention in a WRX or STI build, but the fuel system is usually what actually decides how far a car can go. Every…
Most WRX and STI fuel system upgrades start with an in-tank pump, and for good reason, they are simpler to install and cover a wide range of power goals. The AEM 380LPH…
A stock Subaru STI fuel system was built around stock power. Add bigger injectors, a flex fuel setup, or a serious tune, and the factory rails, lines, and pressure regulator start showing…
More boost sounds simple on paper. Push the number up, make more power, done. Reality works differently. Every EJ or FA engine has a point where cylinder pressure outpaces what the internals,…
The EJ257 and FA24 are the two turbocharged Subaru engines most WRX and STI owners encounter when researching builds or considering a platform change. The EJ257 powers the Subaru STI through its…
The Subaru STI is one of the most capable performance cars available at its price point, but the EJ257 engine that powers it has well-documented limits under sustained high boost. Understanding where…
The factory turbocharger on the Subaru STI is a capable unit for stock and mildly modified builds, but it has a ceiling. As boost targets increase and power goals climb past what…
The EJ207 and EJ257 are both flat-four turbocharged engines from Subaru’s EJ engine family, and both power versions of the Subaru STI. However, they are not the same engine, and the differences…
Most Subaru WRX and Subaru STI builds run internal wastegates from the factory. The stock turbo manages boost pressure through an integrated valve inside the turbine housing, which works adequately at factory…
The 2015 to 2021 Subaru WRX runs a plastic end tank radiator from the factory. Under normal driving conditions it keeps coolant temperatures within range, but its thermal capacity becomes a limiting…