Overview of the HKS Super Turbo Kit for the GR Corolla G16E-GTS

The G16E-GTS engine in the Toyota GR Corolla is a high-performance three-cylinder turbocharged powerplant, factory-equipped with a compact turbocharger that delivers impressive output. However, enthusiasts seeking greater horsepower and torque often turn to aftermarket upgrade solutions. The HKS Super Turbo Kit is designed specifically for this engine, offering a significant performance increase through a larger, more efficient turbocharger and supporting components. This kit not only boosts peak power but also improves throttle response and overall drivability when properly tuned. In this guide, we walk through the complete installation process, from preparation to final testing, ensuring a professional-grade result.

Before diving into the installation, it is essential to understand that adding a larger turbocharger requires corresponding upgrades to the fueling system, intercooler, and engine management. HKS includes many necessary components, but you should also plan for a custom ECU tune (e.g., using an ECUTek device) and possibly higher-flow injectors. For reference, check the official HKS turbo lineup page for detailed specifications, and consult the GR Corolla Forum for community experiences.

What’s Included in the HKS Super Turbo Kit

The typical HKS Super Turbo Kit for the G16E-GTS includes:

  • HKS GTIII-4R or GTIII-5R turbocharger (depending on version)
  • Cast iron or stainless steel exhaust manifold
  • Downpipe / front pipe
  • Intake piping and high-flow air filter
  • Blow-off valve (HKS SSQV or similar)
  • Oil feed and drain lines
  • Gaskets, bolts, and necessary hardware
  • Instruction manual

Verify that your kit includes all parts before beginning work. Some versions may require separate purchase of a boost controller, intercooler upgrade, or reflash cable. The HKS website provides a detailed kit contents list for your specific model year.

Tools and Materials Needed

Having the right tools on hand makes the installation smoother and prevents unnecessary delays. Gather the following items:

  • Socket set (metric, 8mm to 22mm, including deep sockets)
  • Wrenches (combination and flare nut for oil lines)
  • Torque wrench (capable of 10-100 Nm)
  • Screwdrivers (flathead and Phillips)
  • Pliers (standard and snap-ring)
  • Jack and jack stands (minimum 2-ton capacity, four stands recommended)
  • Jack pads or adapters for pinch welds
  • Trim removal tools (plastic for bumper clips)
  • Safety glasses and gloves
  • Shop rags and cleaning solvent
  • Gasket scraper (for old gasket removal)
  • Thread locker (medium strength, e.g., Loctite 242)
  • Anti-seize compound (for exhaust fasteners)
  • Coolant and engine oil (for refilling after disconnections)
  • Digital multimeter (optional, for electrical checks)
  • Boost leak tester (recommended for final validation)

Additionally, have a clean work area with good lighting. If possible, use a lift instead of jack stands, but for DIY home garages, six-ton jack stands provide extra safety.

Preparation Steps

Vehicle Preparation

Proper vehicle preparation reduces the risk of damage and simplifies access to the turbocharger.

  1. Park on a level surface and engage the parking brake.
  2. Disconnect the battery (negative terminal first). Wait 5 minutes before proceeding to allow the ECU to fully power down.
  3. Drain the engine coolant (since the turbo water lines will be disconnected). Place a drain pan under the radiator petcock and remove the radiator cap to speed flow.
  4. Remove the engine undercover (plastic splash shield) if equipped.
  5. Lift the vehicle using a jack at the front center lift point, then place jack stands under the front pinch welds. Lower the vehicle onto the stands. Repeat for the rear if needed (or leave on wheels). Ensure the car is stable.
  6. Remove the front bumper by unclipping the top fasteners, pulling the sides out, and disconnecting any wiring (fog lights, parking sensors). Set the bumper aside on a soft surface.
  7. Remove the intercooler and charge pipes (factory intercooler is located in the front bumper area). This will provide clearance to reach the turbo.
  8. Disconnect the intake air box and intake tube leading to the turbo inlet.

Safety Precautions

Working with turbochargers and hot engine components carries risks. Follow these guidelines:

  • Allow the engine to cool completely if it has been running. Exhaust components can exceed 400°C and cause severe burns.
  • Wear safety glasses to protect against debris and fluid splashes.
  • Use jack stands rated for the vehicle weight; never rely solely on a jack.
  • Keep a fire extinguisher nearby when working near fuel lines and oily areas.
  • Work in a ventilated area if running the engine during testing.

Removing the Stock Turbo

Removing the factory turbocharger requires patience and careful disconnection of multiple systems. The G16E-GTS turbo sits behind the engine, close to the firewall, making access tight.

  1. Remove the heat shields covering the turbo and exhaust manifold. Use a socket to unfasten the bolts; they may be stubborn due to heat cycling.
  2. Disconnect the oxygen sensors (O2 sensors) from the downpipe and turbo outlet. Unclip the wiring harness and remove the sensors with an O2 sensor socket or a 22mm wrench. Be careful not to damage the threads.
  3. Loosen the V-band clamp securing the downpipe to the turbo outlet. If there is a separate downpipe section, unbolt it from the catalytic converter as well.
  4. Remove the charge pipe connecting the turbo compressor outlet to the intercooler. This pipe is typically rubber with hose clamps.
  5. Disconnect the oil feed line from the top of the turbo. Use a flare nut wrench to avoid rounding the fitting. Have rags ready to catch residual oil.
  6. Disconnect the oil drain line from the bottom of the turbo. This is usually a metal tube with two bolts; expect some oil to drain.
  7. Disconnect the coolant lines (feed and return) from the turbo. They are clamped rubber hoses; slide the clamps off and pull the hoses. Cap the copper lines to prevent dripping.
  8. Remove the turbo-to-manifold bolts (typically four or five 12mm nuts). Reach from underneath or above using extensions and a swivel socket.
  9. Carefully lift the turbocharger out of the engine bay. It may require wiggling past the block and frame. Remove the exhaust manifold if the new kit includes a replacement manifold (most HKS kits do). Unbolt the manifold from the cylinder head.
  10. Clean the mounting surfaces on the cylinder head (for the manifold) and on the downpipe flange. Use a gasket scraper and solvent to remove old gasket material.

Inspect the removed turbo for any signs of failure (excessive shaft play, oil leaks) that could indicate underlying engine issues. This is also an opportune time to replace the turbo oil drain gasket and clean the oil pan return port.

Installing the HKS Super Turbo Kit

Manifold and Turbo Mounting

  1. Install the new HKS exhaust manifold using a new OEM or HKS gasket. Torque the manifold nuts to the manufacturer specification (typically 30-40 Nm) in a crisscross pattern. Apply anti-seize to the threads.
  2. Attach the HKS turbocharger to the manifold. Use the supplied gasket and bolts. Coat the bolt threads with anti-seize. Torque to spec (usually 35-45 Nm). Do not overtighten.
  3. Install the oil drain line from the turbo to the oil pan. Ensure the line is not kinked. Use a new gasket or o-ring.
  4. Connect the oil feed line from the engine block to the turbo. If your kit uses a braided stainless line, route it away from heat sources. Tighten the banjo bolt with new copper washers to 25 Nm.
  5. Attach the coolant lines. Slide the rubber hoses onto the turbo fittings and secure with constant-tension clamps. Make sure the hoses are oriented to avoid pinching.

Downpipe and Charge Piping

  1. Install the HKS downpipe or front pipe. Use the supplied gasket (often a multi-layer steel gasket). Torque the flange bolts evenly.
  2. Reconnect the O2 sensors. If the downpipe has a new bung, install the sensor with anti-seize. Route the wiring away from rotating parts.
  3. Mount the charge pipe from the turbo compressor outlet to the intercooler or throttle body (depending on kit). Tighten all silicone couplers using T-bolt clamps. Verify the pipe does not contact the frame or engine.
  4. Install the blow-off valve (HKS SSQV) on the charge pipe or intercooler piping. Use the supplied adapters and confirm proper orientation (flow direction marked on the valve). Tighten the set screws.

Intake System

The HKS kit typically includes a high-flow intake pipe and filter. Install these after the turbo is secured to avoid dislodging components.

  1. Attach the intake pipe to the turbo compressor inlet. Use the supplied silicone coupler. Ensure the MAF sensor (if retained) is correctly installed and sealed.
  2. Mount the air filter in a location that receives cool air. Some kits provide a heat shield.
  3. Secure all vacuum lines for the blow-off valve and boost reference. HKS provides line routing diagrams—follow them precisely.

Connecting the HKS Components

Blow-Off Valve Routing

The HKS Super Turbo Kit includes a blow-off valve (BOV) that must be properly plumbed. Connect the vacuum reference line from the BOV top port to a boost source (e.g., intake manifold or turbo compressor cover). Use a tee if you have a boost gauge. Ensure the line is free of leaks and secured with zip ties.

To safely control boost levels, install an electronic boost controller such as the HKS EVC-S. Mount the solenoid in the engine bay away from heat, run vacuum/pressure lines from the compressor outlet to the solenoid and from the solenoid to the wastegate actuator. Set initial boost pressure low (e.g., 0.8 bar) before tuning. For comprehensive tuning guidance, see the HKS EVC series product page.

Checking Clearances and Fitment

Rotate the engine by hand (using a socket on the crankshaft bolt) to ensure the turbo compressor wheel does not contact any part of the housing or manifold. Check that all hoses and wires have at least 10mm clearance from exhaust heat. Use fire sleeve or heat wrap on lines that are too close.

Reassembling the Vehicle

Installation of the turbo is only half the job—reassembly must be done methodically to avoid rattles or damage.

  1. Reinstall the intercooler (if using the stock unit) or mount your upgraded intercooler. Connect all charge air hoses.
  2. Refill the coolant with the manufacturer-recommended fluid (Toyota SLLC or equivalent). Bleed the cooling system by running the engine with the radiator cap off and heater on full.
  3. Reattach the front bumper by lining up the clips and securing with screws. Plug in any electrical connectors for lights and sensors.
  4. Reinstall the undercover and any trim pieces removed earlier.
  5. Lower the vehicle from the jack stands. Tighten lug nuts to 103 Nm in a star pattern.
  6. Reconnect the battery (positive first, then negative).
  7. Check fluid levels: engine oil (top up if needed), coolant, and transmission fluid (if disturbed).

Testing the Installation

Static Checks Before Starting

  • Inspect all turbo oil and coolant fittings for drips.
  • Pressurize the intake system with a boost leak tester to 15 psi. Listen for hissing and repair any leaks.
  • Verify the blow-off valve operates freely (press the plunger manually to confirm no binding).
  • Check throttle cable and pedal for full travel.

Initial Start and Idle

  1. Start the engine and let it idle for 30 seconds. Listen for unusual noises from the turbo (scraping, whistling).
  2. Allow the engine to reach operating temperature. The turbo will begin to warm; check for smoke from exhaust (could be assembly oil burning off—this is normal for a few minutes).
  3. Visually inspect all oil and coolant connections for leaks. Tighten as necessary (use caution with hot components).
  4. Cycle the engine off and on several times to verify consistent idle.

Test Drive

Before driving, ensure the ECU has a base tune appropriate for the larger turbo. Running the engine without proper fuel and timing maps can cause detonation and severe damage. If you are not using a preloaded file from a tuner, schedule a professional dyno session. For driveability, a remote tuning service like GR Garage tuning solutions can provide a custom calibration.

  1. Take a short test drive under light throttle (below 3000 RPM). Monitor boost pressure and air-fuel ratio if you have gauges.
  2. Gradually increase load and RPM, staying below 0.5 bar boost until the tune is verified.
  3. Listen for boost leaks under load. If the car hesitates or has audible hissing, inspect all clamps.
  4. Check for any warning lights. If the check engine light illuminates, scan codes immediately.

Post-Installation Break-In

New turbochargers benefit from a break-in period to seat the bearings. Follow this procedure for the first 500 km (300 miles):

  • Vary engine speed; do not hold constant RPM for extended periods.
  • Avoid full-throttle operation above 5000 RPM.
  • Allow the turbo to cool by idling for 30 seconds before shutting off after a drive.
  • Change engine oil and filter at 500 km to remove any assembly debris.

After break-in, perform a final inspection of all turbo fasteners and connections. You can now enjoy the enhanced power and responsiveness of the HKS Super Turbo Kit on your GR Corolla.

Common Pitfalls and Troubleshooting

  • Boost creep: If boost continues to rise beyond the target, the wastegate may be undersized or the actuator spring rate is too low. Consider an external wastegate setup or a boost controller with higher duty cycle.
  • Oil leaks from turbo: Verify the oil drain line is not kinked and the turbo is sitting level. A sloped installation can cause oil to pool in the bearing housing.
  • CEL after installation: Common codes include P0031 (O2 heater circuit low) if the downpipe bung location changed wire length. Extend the sensor harness carefully.
  • Boost leaks: Use a smoke machine or pressurized spray bottle with soapy water to find leaks at couplers and BOV flanges.

For advanced troubleshooting, the Go Fast Tuning knowledge base offers detailed articles on turbo diagnostics.

Final Thoughts

Upgrading the GR Corolla G16E-GTS with an HKS Super Turbo Kit is a transformative modification that rewards careful installation with substantial horsepower gains. By following this comprehensive guide—and ensuring you have a proper calibration—you can achieve a reliable, high-performing vehicle. Remember that turbocharger upgrades push the engine to its limits; invest in supporting mods such as a larger intercooler, fuel system upgrades, and robust engine monitoring. With the right planning, your GR Corolla will become a streetable powerhouse ready for track days or spirited drives.