The Subaru BRZ, with its lightweight chassis and impeccable balance, is a natural candidate for forced induction. Installing a turbo kit transforms the driving experience, delivering the power that the naturally aspirated FA20 engine sometimes leaves enthusiasts wanting. However, this project is not for the faint of heart. A successful installation requires meticulous attention to detail, a solid understanding of your components, and a respect for the Subaru boxer engine's unique quirks. This guide provides actionable, BRZ-specific advice to help you avoid the most common and costly mistakes during your turbo system installation.

Understanding Your Turbo Kit Components

Beyond simply knowing the names of the parts, you must understand how each component interacts with the Subaru FA20 engine. A typical midsize BRZ turbo kit includes the following core elements, each with specific considerations for your build.

Turbocharger

The heart of the system. Common choices for the BRZ include Garrett, BorgWarner, and Precision units. Size matters: a 5858 or 6054 is typical for streetable power. Avoid oversized turbos (e.g., 6466) unless you have internal engine modifications and a high-revving fuel system to match. A correctly sized turbo spools quickly and avoids excessive lag.

Intercooler

Air-to-air intercoolers are standard. Pay attention to core thickness and end-tank design. A thicker core may require trimming the crash bar or relocating the hood latch. Bar-and-plate cores offer better heat dissipation than tube-and-fin designs but are heavier. Always route the piping with smooth bends to minimize pressure drop.

Exhaust Manifold

BRZ turbo manifolds are typically equal-length or unequal-length. Equal-length versions scavenge exhaust pulses more efficiently, improving spool and power. Unequal-length manifolds produce the classic Subaru rumble but can create uneven flow to the turbo. Choose based on your sound preference and tuning goals.

Wastegate

Boost control is critical. External wastegates are preferred for precise regulation. Common sizes are 38mm and 44mm. Ensure the wastegate spring pressure matches your target boost level. Plumb the reference line directly to the compressor housing or intake manifold for accurate sensing.

Blow-Off Valve (BOV)

Recirculating (venting back into the intake) is recommended for the BRZ to maintain mass airflow (MAF) signal integrity. An atmospheric BOV will cause rich condition on shifts and potential stalling unless you switch to a speed-density tuning strategy. If you choose atmospheric, plan accordingly with your tuner.

Fuel Injectors and Pump

The FA20 direct injection system has limitations. Most turbo kits require supplemental port fuel injection or upgraded high-pressure fuel pump (HPFP) internals. A fuel pressure regulator and additional injectors are often included. Ensure your injectors match the turbo's potential flow, and that your pump (in-tank or inline) can supply enough volume at boost.

ECU Tuning Software and Hardware

You cannot boost a BRZ without proper tuning. Platforms like ECUTek or COBB Accessport are industry standards. The kit should come with a base map, but expect custom dyno tuning fo fine adjustment. Be ready to datalog and send logs to your tuner during the break-in process.

Oil and Coolant Lines

The BRZ's boxer engine has an oil cooling system that must be integrated. Most kits include a sandwich plate adapter for oil supply and a dedicated return line to the oil pan. Coolant lines often tee into the heater hoses. Use AN fittings, not rubber push-on clamps, to avoid leaks.

Preparation Before Installation

Proper preparation saves hours of frustration. Follow these steps before you remove a single bolt.

Assess Engine Health

A compression and leak-down test is mandatory. Any internal issue (worn rings, valve guide wear, head gasket leak) will be magnified under boost. Address these before adding turbo hardware. Also check the oil control valve (OCV) screens and clean if necessary – they are known to clog on high-mileage FA20s.

Gather the Right Tools

Beyond basic socket sets, you need:

  • Torque wrench (both 3/8" and 1/2" – range from 5–150 ft-lb)
  • Pry bars and trim removal tools
  • Lines removal tools for A/C and power steering
  • Drill and step bits for potential sensor bung installation
  • Thread chasers and taps – the FA20 block is aluminum, and threads strip easily
  • Laser thermometer for post-install leak checks

Read the Kit Manual Thoroughly

Do not skimp on this. Each kit is different – piping routes vary, bracket mounting points differ. Note any required modifications (crash bar trimming, sound generator removal, hood latch relocation). Mark all parts before starting.

Check Compatibility

Confirm your kit is specifically for the 2013‑2020 BRZ/GR86 (ZND/ZC6 chassis). Some older kits designed for the FA20D may require additional brackets for the later engine variants. Verify the turbo manifold fits without contacting the frame rail or steering shaft.

Prepare Your Workspace

You will be working in the engine bay for several days. Remove the bumper, headlights, intercooler, and intake ducting. Bag and label all hardware. Have a clean workbench for assembling the turbo manifold and wastegate. Use a fender cover to prevent scratches.

Common Installation Pitfalls and How to Avoid Them

Experienced BRZ builders identify these recurring mistakes. Avoid them to keep your build on track.

Ignoring Vacuum Line Routing

Boost leaks are the most common issue. Use silicone vacuum lines and constant-tension clamps. Label every line during removal. Common mistakes: mixing up the wastegate reference line with the blowoff valve signal, or forgetting to plug the intake manifold's original boost reference nipple. Test all lines with a compressed air leak tester before first start.

Incorrect Torque Specifications

Fasteners on the exhaust manifold and turbine housing are subject to extreme heat and vibration. Use the manufacturer's torque values plus a small amount of anti-seize on stainless steel bolts. Over-torquing can warp the manifold flange; under-torquing causes exhaust leaks. Recheck torque after the first heat cycle.

Neglecting Oil Supply and Return Lines

Oil supply should be taken from a port with constant pressure, not from the oil pressure sending unit (which can cause starvation at idle). The return line must drain into the oil pan above the oil level, ideally with a -10 AN fitting or larger. A kinked or clogged return line will cause turbo seal failure. Use a restrictor if the turbo is a journal bearing type, but full flow for ball-bearing units.

Overlooking Electrical Connections

The ECU and sensors require stable power. Solder and heat-shrink all connections to the wideband O2 sensor, boost controller solenoid, and any extra injector drivers. Avoid using t-taps or scotchloks, which corrode over time. Route wiring away from exhaust heat and moving parts like the cooling fan.

Inadequate Fuel System Upgrade

The stock fuel system can handle only modest boost (around 6‑8 psi on pump gas). Above that, you need either larger injectors (with an auxiliary controller) or a return-style fuel system with a boost-referenced pressure regulator. Also consider upgrading the in-tank fuel pump – the stock pump is barely sufficient for naturally aspirated power.

Boost Creep and Uncontrolled Spool

If the wastegate is too small or the spring is too light, boost will continue to rise at high RPM. This can lead to detonation and engine damage. Use a 44mm wastegate for applications above 300 hp. Set the spring to your target boost (e.g., 7 psi for a conservative street tune) and let the boost controller add pressure later.

Routing the Intercooler Piping Improperly

If piping touches the radiator, it will transfer heat and may wear a hole over time. Use silicone couplers and T-bolt clamps. Avoid sharp 90° bends before or after the intercooler – they create turbulence and restrict flow. Keep the hot-side piping as short as possible to reduce lag.

Subaru-Specific Tips for the BRZ

The Subaru FA20 has distinct characteristics that differ from a traditional inline engine. Address these to ensure longevity.

Boxer Engine Oiling

The horizontal cylinders make oil return from the turbo challenging. The turbo's core should be mounted as high as possible relative to the oil pan. Use a scavenge pump if the turbo sits lower than the oil level (e.g., in a bottom-mount configuration). Always prime the turbo with oil before first start – turn the engine over with the fuel pump fuse removed until oil pressure registers.

Timing Chain and Thermal Management

The FA20's timing chain tensioner is oil-pressure-dependent. Prolonged idle after a cold start with a restrictive oil filter can cause chain rattle. Consider an oil cooler with a thermostat to maintain oil temperature between 190°F and 210°F. Also fit a high-flow oil filter that doesn't cause pressure drop.

Sound Generator Delete

Many turbo kits require removing the BRZ's intake sound generator (the pipe that routes intake noise into the cabin). Disconnect it and cap the firewall grommet – leaving it open will create a massive vacuum leak. Use a block-off plate on the throttle body.

Electronic Boost Control Integration

The stock BRZ ECU uses a wastegate duty cycle table in the tune. If you use an electronic boost controller, wire it to a switched 12V source and configure it in the ECU software (ECUTek or COBB). Do not simply tee into the vacuum reference – that will cause erratic boost control.

Coolant System Modifications

Turbo water lines often tap into the heater hose circuit. Ensure the coolant flow is not obstructed – a kinked hose can cause air pockets in the heater core. Use a coolant bleeder valve at the highest point of the cooling system to remove air after filling.

Upgrade Engine Mounts

The stock rubber mounts allow excessive engine movement under torque. This can cause the turbo manifold to contact the frame rail or the downpipe to hit the subframe. Upgrade to Group-N or polyurethane mounts after turbo installation. They also improve throttle response.

Post-Installation Checklist and Break-In Procedure

After completing the mechanical installation and before your first full-throttle pull, follow this critical process.

Check for Fluid Leaks

Pressurize the cooling system to 15 psi and inspect all hose clamps. Run the engine until warm, then shut off and check every oil line connection while the engine is hot. Common leak points include the turbo oil return flange, wastegate actuator, and intercooler couplers.

Verify Boost Levels and Wastegate Operation

With the engine idling, apply vacuum to the wastegate actuator to confirm it opens freely. Then, on a test drive at low RPM (under 3000), gently apply partial throttle and watch the boost gauge. It should rise smoothly without spiking. If you see boost above spring pressure before the wastegate opens, check for a plugged wastegate line.

Base Map and First Start

Load the tuner's base map. Crank the engine with the injectors disabled until oil pressure reads on the gauge. Then enable the injectors and start. Let the engine idle up to 200°F coolant temperature, checking for codes. Perform a throttle adaptation reset if required by the ECU software.

Datalog the First Few Miles

Record fuel trims, boost, intake air temperature, and knock correction. Send logs to your tuner. Any persistent knock events indicate a need for immediate map revision. Keep boost low (e.g., 5 psi) for the first 50 miles to allow the turbo seals to seat and the engine to adapt.

Retorque All Fasteners

After the first heat cycle (or after 500 miles), recheck torque on the exhaust manifold nuts, wastegate bolts, intercooler piping clamps, and oil line fittings. Use new gaskets if any show signs of leakage. This simple step prevents many later failures.

Conclusion

Turbocharging a Subaru BRZ is one of the most rewarding modifications you can make, but it demands respect for the engineering that goes into both the kit and the engine. By thoroughly understanding your components, preparing meticulously, avoiding the common pitfalls detailed above, and applying Subaru-specific knowledge regarding oiling, cooling, and mounting, you significantly increase your chances of a reliable, high-horsepower build. A professional tune is non-negotiable – partner with experienced tuners who understand the FA20 platform. With patience and attention to detail, your BRZ will deliver a thrilling, dependable power increase that transforms it from a momentum car into a true sports machine.