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Introduction to the BorgWarner EFR 7163 Turbo Upgrade for Subaru WRX

The BorgWarner EFR 7163 turbocharger has earned a strong reputation among Subaru WRX owners who demand responsive, high-horsepower builds without sacrificing spool characteristics. This turbo features a titanium-aluminide turbine wheel, a supercore bearing system, and an integrated wastegate designed to minimize lag while supporting up to approximately 550-600 wheel horsepower on pump gas with proper supporting modifications. Installing the EFR 7163 on your WRX requires careful attention to detail, from preparing the engine bay to tuning the ECU for the new flow characteristics. This guide provides a complete, step-by-step process to ensure a safe and effective installation.

Important: The EFR 7163 is not a direct bolt-on for all WRX models. You will need a specific turbo kit or custom fabrication for the exhaust manifold, downpipe, and charge pipe connections. Verify compatibility with your year and engine version before beginning.

Tools and Materials Required

Having the right tools on hand prevents unnecessary delays and ensures each fastener is tightened correctly. Use the list below as a checklist before you start.

Hand Tools

  • 3/8-inch and 1/2-inch socket sets with deep sockets (metric: 10mm, 12mm, 14mm, 17mm, 19mm)
  • Combination wrench set (10mm – 19mm)
  • Torque wrench capable of 20-80 ft-lb range
  • Flathead and Phillips screwdrivers
  • Gasket scraper or razor blade
  • Pick set for removing O-rings and hoses
  • Breaker bar for stubborn bolts
  • Socket extensions (3-inch and 6-inch)
  • Universal joint for hard-to-reach bolts

Specialty Items & Fluids

  • BorgWarner EFR 7163 turbocharger (with integrated wastegate actuator)
  • BorgWarner EFR install kit (includes oil feed line, oil drain line, coolant lines, gaskets, and hardware) – verify specific to your WRX model
  • New OEM Subaru exhaust manifold gasket and turbo-to-downpipe gasket
  • Oil feed restrictor (if required by your engine oil pressure – consult turbo specifications)
  • High-temperature silicone sealant for drain flange
  • Engine coolant (Subaru Super Coolant or equivalent)
  • High-quality engine oil (5W-30 or 5W-40 per builder recommendations)
  • Penetrating oil (for rusty fasteners – e.g., PB Blaster)
  • A boost controller (manual or electronic – optional but recommended for fine-tuning)
  • Safety glasses and mechanic's gloves

Optional but Helpful

  • Fluid catch pan / drain pan
  • Shop towels and brake cleaner
  • Digital caliper or micrometer (for checking gasket thickness)
  • Camera or phone for taking reference photos before disassembly

Preparation Steps Before You Begin

Proper preparation reduces the risk of mistakes and makes the removal process smoother.

1. Disconnect the Battery

Disconnect the negative terminal of the battery and wrap the cable end with a cloth or zip tie to prevent accidental contact with the chassis. This eliminates electrical shorts while working near sensors and wiring.

2. Relieve Fuel Pressure & Drain Fluids

Remove the fuel pump fuse or relay, then crank the engine a few times to relieve fuel pressure (be sure to disable spark by disconnecting coil packs if needed). After that, drain the engine oil and coolant. Drain the oil from the oil pan; drain the coolant from the radiator petcock. Dispose of fluids properly.

3. Remove the Engine Cover and Air Intake

If your WRX is equipped with an engine cover, remove it. Then remove the entire factory air intake system – air box, intake tube, and mass air flow sensor – to gain access to the turbo area. Label the MAF sensor connector and store it safely.

4. Clear Surrounding Area

Remove any hoses, wire looms, or brackets that might obstruct access to the turbo. Take photos of the routing before disconnecting anything.

Removing the Stock Turbocharger

This is the most labor-intensive part of the installation. Work methodically to avoid breaking fasteners or damaging nearby components.

1. Disconnect the Downpipe

Unbolt the downpipe from the turbo and from the exhaust system. You may need to remove the downpipe completely to access the lower turbo bolts. On most WRX models, the downpipe is held by four bolts at the turbo flange and two or three at the mid-pipe connection.

2. Remove the Exhaust Manifold Heat Shield

Use a flathead screwdriver or a socket to remove the bolts holding the heat shield on the exhaust manifold. If the shield is severely rusty, apply penetrating oil and work the bolts free slowly.

3. Unbolt the Turbo from the Exhaust Manifold

The stock turbo is attached to the exhaust manifold with a set of nuts/studs. Spray the studs with penetrating oil and let them soak for 10 minutes. Use a socket and breaker bar to loosen them. Once all nuts are removed, gently wiggle the turbo to break the gasket bond.

4. Disconnect Oil Feed and Drain Lines

Locate the oil feed line (typically a metal braided hose coming from the block) and the oil drain line (larger diameter, often rubber hose). The drain line may drip oil, so have a catch pan ready. Disconnect both lines. For the drain line, you may need to remove a clamp and pry the hose off the turbo drain pipe.

5. Disconnect Coolant Lines (If Equipped)

Some WRX models have coolant lines running to the turbo for cooling. Depending on your year, you may have two small coolant hoses. Disconnect them and plug the ends to prevent coolant from draining onto sensors.

6. Remove the Turbo Assembly

Once all lines are disconnected, lift the stock turbo straight up and out of the engine bay. It can be heavy (around 25-30 lbs). Place it on a clean workbench. Inspect the exhaust manifold flange for any gasket residue or carbon buildup.

Preparing the BorgWarner EFR 7163 Turbo for Installation

Before mounting the new turbo, perform these critical checks and assembly steps.

1. Inspect the Turbo

Rotate the turbine wheel by hand. It should spin freely with no binding or excessive play. Axial play (in/out) should be minimal; radial play (side-to-side) should be very slight. If you notice any marks on the compressor wheel or turbine blades, contact the vendor immediately.

2. Mount the Oil Feed Line

Install the oil feed line onto the turbo using the supplied fitting. Use thread tape or thread sealant on the fitting threads (avoid blocking the oil passage). Tighten securely with a wrench. Many aftermarket kits include a braided steel line with an integrated restrictor – if yours does not, verify whether your engine needs an inline restrictor to avoid overfeeding oil into the turbo.

3. Attach the Oil Drain Line

The drain line typically uses a flanged fitting that bolts to the turbo. Apply a thin layer of high-temperature silicone gasket maker to the flange surface. Bolt the drain fitting to the turbo per the manufacturer’s torque specification (usually 8-10 ft-lb). Do not overtighten, as the aluminium housing can strip.

4. Connect Coolant Lines (If Applicable)

If your EFR 7163 kit includes coolant lines, attach them to the turbo housing now. Use new crush washers at each banjo fitting if supplied. Tighten banjo bolts to the spec provided (typically 15-20 ft-lb). Ensure the outlet fitting is oriented correctly so the hose will not kink.

5. Install the Turbo-to-Exhaust Manifold Gasket

Place the new gasket onto the turbo inlet flange. Most EFR kits use a multi-layer steel (MLS) gasket. Make sure it is perfectly aligned with the bolt holes. Do not use additional sealant on MLS gaskets unless instructed.

Installing the EFR 7163 Turbocharger onto the Engine

With the turbo prepared, you can now mount it to the exhaust manifold. This step requires careful positioning to avoid damaging the gasket or the turbo.

1. Position the Turbo on the Manifold

Lift the EFR 7163 and align its inlet flange with the exhaust manifold studs. The turbo is often heavier than the stock unit, so have an assistant support it or use a jack stand. Gently slide it onto the studs. Do not force it – if it does not seat fully, check for interference with a coolant line or the engine block.

2. Tighten Mounting Nuts

Hand-thread the nuts onto the studs. Use a torque wrench to tighten them in a crisscross pattern to the manufacturer’s specification (typically 30-35 ft-lb for studs, but confirm with your kit’s instructions). Over-tightening can distort the gasket and cause exhaust leaks.

3. Connect Oil Feed and Drain Lines

Route the oil feed line from the turbo to the engine block oil supply port. Many Subarus have a dedicated turbo feed port on the passenger side of the block. Use new crush washers and tighten to spec. For the drain line, connect the hose to the turbo outlet and route it to the oil pan return fitting or the oil filler neck (depending on your kit). Secure with a quality hose clamp. Ensure the hose slopes downward without any loops where oil could pool.

4. Reconnect Coolant Lines (If Equipped)

Attach the coolant hoses to the turbo banjo fittings and route them to the engine cooling circuit. Some kits tee into the heater core hoses; others use dedicated ports on the water crossover pipe. Secure all clamps and double-check for kinks.

5. Install the Downpipe and Intake Components

Bolt the downpipe to the turbo exhaust outlet using a new gasket. Hand-tighten the bolts first, then torque them to spec (usually 25-30 ft-lb). Reinstall the downpipe bracket and any supports. Next, reconnect the intake pipe from the air filter to the turbo compressor inlet. Use a good quality silicone coupler and T-bolt clamps. Ensure the MAF sensor is correctly oriented and the wiring connector is clicked in.

6. Actuator and Wastegate Adjustment

If your EFR 7163 uses an integrated wastegate, check that the actuator arm is properly connected to the wastegate flapper. Adjust the length of the arm if necessary to achieve correct preload (refer to BorgWarner documentation). Incorrect preload can cause boost spikes or creeping.

Reassembly and Fluid Fill

After the turbo is physically installed, complete the rest of the reassembly.

1. Reinstall the Heat Shield

Put the exhaust manifold heat shield back in place. If the old shield is damaged, consider an aftermarket heat shield that fits the EFR turbo profile.

2. Refill Engine Oil and Coolant

Add fresh engine oil (use recommended viscosity for your climate and build). Prime the oil system by turning the engine over with the fuel pump fuse removed until the oil pressure gauge registers (about 10-15 seconds of cranking). Then install the fuse and fire the engine briefly. Top off the oil. Refill the cooling system with a 50/50 coolant mix. Bleed air from the system per the Subaru service manual.

3. Reconnect the Battery and Inspect

Reconnect the negative battery cable. Check all wire harness connectors, vacuum lines, and boost reference lines. Ensure nothing is pinched or touching the exhaust or turbo heat shield.

First Start and Leak Checks

Follow a disciplined procedure on the first startup to catch any issues early.

1. Start the Engine

Start the engine and let it idle. Listen for any unusual noises like a exhaust leak (ticking or hissing) or a screeching bearing. Look for oil drips under the car. Check the oil drain line connection and the oil feed line banjo bolts. Tighten if any weep appears.

2. Check for Coolant Leaks

Pressurize the cooling system by revving the engine briefly. Inspect all coolant hose connections. Any sign of coolant must be addressed immediately to prevent overheating.

3. Perform a Boost Leak Test

Using a boost leak tester (or a simple PVC cap setup), pressurize the intake system to 15 psi. Listen for hissing. Pay special attention to the charge pipe connections, intercooler couplers, and the turbo compressor outlet. Repair any leaks before road testing.

4. Verify Wastegate Operation

With the engine idling, verify that the wastegate actuator rod moves when vacuum is applied (if using an electronic boost controller, test with the controller disconnected for now). The flapper should open and close freely.

Tuning the ECU for the EFR 7163 Turbo

Installing a larger turbo without modifying the ECU’s fuel and timing maps is dangerous. You will need either an open-source reflash (like using Comma.ai or RomRaider) or a plug-in ECU like a Cobb AccessPort. Professional dyno tuning is strongly recommended.

1. Base Map Considerations

Start with a conservative base map intended for a 7163-sized turbo on a Subaru. Many tuners offer off-the-shelf maps. They should include reduced timing advance in the spool region and increased fuel enrichment to avoid detonation.

2. Boost Control Setup

If you installed an electronic boost controller, connect it to the wastegate pressure source and the ECU boost control solenoid (or use a standalone controller). Set initial boost to around 12-15 psi for break-in, then gradually increase. Do not exceed the turbo’s maximum boost rating (typically 30-32 psi) without verifying fuel system capacity.

3. Air-Fuel Ratio Monitoring

Install a wideband air-fuel ratio gauge. Target lambda 0.80-0.85 at full boost (approximately 11.5-12.0:1 AFR on gasoline). If AFRs lean out, you may need larger fuel injectors or a higher-flow fuel pump. The EFR 7163 can outflow the stock injectors above 20 psi.

4. Knock Detection

Monitor engine knock via the factory knock sensor or an aftermarket knock gauge. If you see timing pull or hear pinging, reduce boost or timing immediately. Subaru engines are sensitive to knock.

Performance Gains and Break-In Period

The EFR 7163 provides a significant increase in flow capability compared to the stock VF-series turbo. Expect earlier spool (full boost by 3500-3800 RPM with proper tuning) and a broad power band that extends well past 7000 RPM. With supporting mods (fuel, intercooler, exhaust), many WRX owners see 400-500 whp on pump gas. However, allow the turbo to break in over the first 500 miles. Avoid sustained hard pulls until the bearings and seals seat properly.

Maintenance and Long-Term Care

To keep your EFR 7163 performing optimally, follow these maintenance guidelines:

  • Change engine oil every 3,000 miles or 3 months – turbocharged Subarus run hot and tend to contaminate oil faster than naturally aspirated engines.
  • Inspect the oil drain line for any kinks or blockages every oil change.
  • Clean or replace the air filter regularly to prevent debris from damaging the compressor wheel.
  • Check the wastegate actuator rod for binding or corrosion.
  • Perform a boost leak test annually or after any front-end repair.

Conclusion

Installing the BorgWarner EFR 7163 turbocharger on your Subaru WRX demands time, mechanical skill, and careful tuning, but the rewards in power and drivability are substantial. By following this step-by-step guide, you can install the turbo correctly the first time, avoid common pitfalls, and enjoy a reliable, high-performance build. For additional resources, consult the official BorgWarner EFR documentation at BorgWarner Turbochargers and engage with the Subaru community on NASIOC for model-specific wiring diagrams and tuning advice.