Tomioka Racing TD06-20G JDM Twin Scroll Turbo Kit – 2002-2007 Subaru WRX / 2004-2021 STI

Tomioka Racing TD06-20G JDM Twin Scroll Turbocharger Kit — 2002-2007 Subaru WRX / 2004-2021 STI

The Tomioka Racing TD06-20G JDM Twin Scroll Turbo Kit for the 2002-2007 Subaru WRX and 2004-2021 STI is the complete twin scroll system — TD06-20G twin scroll turbocharger, TR-ES1002 twin scroll exhaust manifold with 3-bolt uppipe, and TR-ES1005 twin scroll downpipe. Rated to 500 HP. All components needed for the twin scroll conversion are included in one kit.

DETAILS

• Platform: 2002-2007 Subaru WRX EJ20/EJ255 and 2004-2021 STI EJ207/EJ257
• Complete kit: TD06-20G twin scroll turbo + twin scroll manifold + twin scroll downpipe
• Journal bearing construction
• JDM twin scroll 5-bolt flange
• Compressor: 51 mm inlet / 58 mm exducer
• Turbine: 68 mm inlet / 56 mm exducer
• Turbine housing: 8 cm²
• Actuator: 1.1 bar / 16 psi
• Max. power: 500 HP

Turbocharger Specifications

Bearing Type	Journal bearing
Flange Type	Subaru JDM Twin Scroll 5-bolt
Compressor Inlet	51 mm
Compressor Exducer	58 mm
Turbine Inlet	68 mm
Turbine Exducer	56 mm
Turbine Housing	8 cm²
Actuator / Gate Pressure	1.1 bar / 16 psi
Max. Power	500 HP

Turbocharger Design and Specifications

A journal bearing turbocharger uses a hydrodynamic oil film to support the rotating shaft. The oil film provides lubrication and a degree of compliance, requiring oil pressure to build before full-throttle use and a brief cool-down period after hard use before shutdown. Journal bearings are proven and durable — TR journal bearing turbos use the standard Subaru 5-bolt flange and include all oil and water connections for direct installation at the factory turbocharger location. A twin scroll turbocharger divides the exhaust pulse inputs from the engine into two separate scroll passages within the turbine housing. On a four-cylinder engine, the exhaust pulses from cylinders 1 and 4 enter one scroll while pulses from cylinders 2 and 3 enter the other. By keeping these paired cylinder pulses separated, each pulse arrives at the turbine wheel with higher energy and less interference from adjacent cylinder exhaust events. The result is improved exhaust scavenging efficiency, more consistent turbine wheel loading, and faster spool speed compared to an equivalent single-scroll design at the same turbocharger size.

Installation, Kit Contents, and Wastegate Spring Guide

Each Tomioka Racing turbocharger kit includes all hardware needed for the installation: the turbocharger unit, wastegate actuator, oil feed and return pipes, water cooling connections, all gaskets, and the hardware kit. All current production TR turbos include a billet wastegate actuator. Professional installation is recommended for turbocharger swaps — the oil feed and return line routing, water cooling connections, and boost line setup all require attention to detail for correct long-term function. For DCBB turbos, a Turbosmart TS-0811-0012 OPR V2 Turbo Oil Pressure Regulator is recommended to ensure correct oil pressure at the bearing unless otherwise noted.

Wastegate Spring Selection: 1.1 bar vs 1.3 bar

The actuator spring sets the gate pressure — the minimum boost the turbocharger will produce. You cannot run boost lower than the spring rating regardless of ECU or boost controller settings.

Choose 1.1 bar (16 psi) if your boost targets include values below approximately 22 psi, or if you run multiple boost maps including a low-boost street mode. The 1.1 bar spring provides good boost controller authority across a wide operating range.

Choose 1.3 bar (19 psi) if your minimum target boost is 19 psi or higher and your normal target is in the 22-28 psi range. The 1.3 bar spring provides better control stability at higher boost targets and better resistance to premature wastegate opening under high exhaust backpressure conditions.

As a general guideline, peak target boost should not exceed approximately 2x the gate pressure for stable boost control authority from the solenoid.

What’s in the Box

• TR-TS1015 twin scroll turbocharger
• TR-ES1002 twin scroll exhaust manifold with 3-bolt uppipe
• TR-ES1005 twin scroll catless downpipe
• Turbo mounting bracket
• All hardware kits

Why Choose Tomioka Racing (TR)

Tomioka Racing has been building direct-fit turbocharger upgrades for Subaru performance vehicles since the early 2000s. Every TR turbocharger is engineered around the factory connection points — oil feed, water cooling, mounting flange, and charge pipe inlet all match OEM positions — so installation is genuine bolt-on without custom fabrication. TR covers the full span of EJ-series and FA-series Subaru platforms, from the GC8 through the current VB WRX, and their turbochargers are proven in both street and motorsport use including rally racing. Each kit ships complete with turbocharger, actuator, oil pipe, water pipe, gaskets, and hardware — everything needed for the swap in one box. RallySport Direct stocks the full TR turbocharger catalog because their engineering quality and fitment accuracy are what our customers expect.

The RallySport Take

The TR TD06-20G JDM Twin Scroll Kit is the complete twin scroll conversion for GD WRX and STI — turbocharger, manifold, and downpipe together in one validated kit. The twin scroll architecture delivers spool speed dramatically faster than single-scroll setups at this power level — boost arrives noticeably earlier in the RPM range and power delivery through the mid-range is more linear.

Fitment

Year	Make	Model	Notes
2002-2007	Subaru	WRX	EJ20/EJ255 MT
2004-2021	Subaru	WRX STI	EJ207/EJ257 MT