Introduction: Why Upgrade Your G70 3.3T with HKS Components

The Genesis G70 3.3T is already a formidable performance sedan, but its twin-turbocharged V6 engine leaves significant headroom for improvement. Upgrading to an HKS intercooler and turbocharger represents one of the most impactful modifications you can make. HKS has earned a reputation for precision engineering and race-proven performance, and their components for the Lambda II engine platform are no exception.

By replacing the factory intercooler, you reduce intake air temperatures (IATs), which directly translates to more consistent power delivery and reduced risk of heat soak during aggressive driving. A larger, more efficient HKS turbocharger then capitalizes on that denser, cooler air to produce substantial horsepower and torque gains. Together, these upgrades transform the G70 from a quick grand tourer into a true performance contender.

This guide provides a detailed, step-by-step installation walkthrough for the HKS intercooler and turbocharger upgrade on your G70 3.3T. We cover everything from tool preparation and safety precautions to final testing, tuning, and long-term maintenance. Whether you are a seasoned DIY enthusiast or having a professional shop perform the work, understanding every phase of the process will ensure a successful outcome and years of reliable performance.

For reference on the factory engine specifications and the potential of the 3.3T platform, see the official Genesis G70 specifications page. For detailed product information on the components used in this guide, visit the HKS global website.

Tools and Materials: What You Will Need

Having the correct tools and materials on hand before you begin will save hours of frustration. The following list covers everything required for a complete intercooler and turbocharger swap.

Essential Hand Tools

  • Metric socket set: 8mm, 10mm, 12mm, 14mm, 17mm, and 19mm sockets (deep and shallow). A 1/4-inch and 3/8-inch drive set will cover most fasteners.
  • Wrench set: Combination wrenches in the same metric sizes, plus a 22mm wrench for certain turbo oil line fittings.
  • Screwdrivers: Flathead and Phillips head in multiple sizes for hose clamps and trim clips.
  • Torque wrench: A 3/8-inch drive torque wrench (5-80 Nm range) and a 1/2-inch drive torque wrench (20-200 Nm range) for critical fasteners.
  • Pliers: Standard and needle-nose pliers, plus a set of hose clamp pliers for spring-type clamps.
  • Hex and Torx bits: Set of allen keys and Torx bits (T25, T30, T40, T45 are common on the G70).
  • Trim removal tools: Plastic pry tools to remove bumper clips and interior panels without damaging paint.
  • Pick set: For removing stubborn O-rings and gaskets.

HKS Component Kits

  • HKS intercooler kit: Includes the bar-and-plate intercooler core, CNC-machined end tanks, silicone couplers, T-bolt clamps, and all mounting brackets and hardware. Verify the kit part number matches your G70 3.3T model year.
  • HKS turbocharger kit: Includes the GT-series or S-series turbocharger cartridge, wastegate actuator, oil and water lines, gaskets, and fasteners. Confirm the specific HKS turbo model recommended for your target power level.
  • Additional silicone hoses: While the kits include necessary hoses, having spare 2.5-inch and 3-inch silicone couplers and vacuum line is prudent.
  • High-quality clamps: T-bolt clamps provide more consistent clamping force than standard worm-gear clamps and are less likely to damage silicone hoses.

Fluids and Consumables

  • Engine oil: 5W-30 or 0W-40 synthetic oil meeting API SP or ILSAC GF-6 standards. You will need approximately 6-7 quarts for a full oil change after turbo installation.
  • Coolant: Pre-mixed ethylene-glycol-based coolant meeting Genesis specifications (typically phosphate-free). You will need approximately 2-3 gallons to refill the system.
  • Thread locker: Medium-strength (blue) Loctite for turbo mounting bolts and other vibration-prone fasteners.
  • Anti-seize compound: Copper-based or nickel-based anti-seize for exhaust manifold bolts and O2 sensor threads.
  • Silicone spray: For easing hose connections onto intercooler and turbo inlets.
  • Shop towels and degreaser: For cleaning mating surfaces and removing oil residue.
  • Jack and jack stands: A low-profile floor jack and four jack stands to safely lift and support the vehicle.
  • Engine support bar: If you need to remove the engine mount bracket for turbo access, this bar supports the engine from above.
  • Boost leak tester: A DIY or commercial boost leak tester allows you to pressurize the intake system and find leaks before the first drive.
  • Scan tool: A diagnostic tool capable of reading live data (IAT, boost pressure, fuel trims) helps verify proper operation after installation.

Preparation and Safety: Setting Up for Success

Proper preparation is the difference between a clean, efficient installation and a frustrating weekend project. Begin by parking the vehicle on a level, well-ventilated surface. If working in a garage, keep the door open to avoid exhaust fume accumulation during the first start-up.

Vehicle Preparation

  • Allow the engine to cool completely. Exhaust components can exceed 400°F (200°C) and can cause severe burns even hours after shutdown.
  • Disconnect the negative terminal of the battery and isolate it from the post. This prevents accidental short circuits and resets the ECU adaptions, giving the new components a clean learning slate.
  • Relieve fuel system pressure if you are working near the fuel injectors or lines. The G70 uses a high-pressure direct injection system, so consult the service manual for the proper depressurization procedure.
  • Drain the coolant system by opening the radiator drain plug and removing the reservoir cap. Properly dispose of the old coolant at a recycling center.
  • Drain the engine oil if you are replacing the turbocharger. The new turbo will benefit from fresh oil immediately.

Safety Precautions

  • Eye protection: Wear ANSI Z87.1-rated safety glasses. Debris, coolant spray, and oil droplets are common during component removal.
  • Gloves: Mechanic-grade nitrile or latex gloves protect your hands from oil, coolant, and sharp edges. For heavy lifting, add a pair of leather work gloves.
  • Fire extinguisher: Keep a Class B/C or ABC-rated extinguisher within reach when working with fuel and electrical systems.
  • Ventilation: If using a parts washer or cleaning solvents, ensure adequate airflow. Avoid inhaling brake cleaner or carburetor cleaner fumes.
  • Lifting safety: Always use jack stands rated for the vehicle weight. Never rely solely on a jack. Chock the rear wheels before lifting the front.

Removing the Factory Intercooler and Turbocharger

This phase requires patience and careful attention. The G70's engine bay is tightly packaged, and many components must be moved or removed to access the intercooler and turbos. Work systematically and label all connectors and hoses as you disconnect them.

Front Bumper Removal for Intercooler Access

The factory intercooler sits behind the front bumper and low in the bumper beam. Removing the bumper provides unobstructed access.

  1. Remove the plastic push-clips and screws securing the under-tray to the bumper. There are typically four to six fasteners along the lower edge.
  2. Remove the screws at the top of the bumper cover inside the engine bay (usually four 10mm bolts).
  3. Unclip the fender liner attachments on both sides near the wheel arch. A trim removal tool prevents breaking the plastic retainers.
  4. Disconnect the fog light connectors (if equipped) and any parking sensor wiring harnesses.
  5. With an assistant, pull the bumper cover forward and off the guide pins. Set it aside on a soft surface to prevent scratching the paint.

Stock Intercooler Removal

  1. Disconnect the charge air pipes that connect the intercooler to the turbo compressor outlets and throttle body. Use a flathead screwdriver to loosen the T-bolt clamps, then twist and pull the hoses free.
  2. Unbolt the intercooler from its mounting points. There are typically three to four 12mm or 14mm bolts holding it to the bumper beam and lower radiator support.
  3. Carefully maneuver the intercooler out from the bottom of the bumper opening. It helps to tilt it at an angle to clear the crash bar.
  4. Inspect the stock intercooler for any signs of oil residue, which can indicate blow-by from the turbo seals or PCV system. Address any underlying issues before installing the new unit.

Stock Turbocharger Removal

Access to the turbochargers on the 3.3T engine is tight. The procedure below describes removal of one turbo; repeat for the second side if you are upgrading both (which HKS strongly recommends for balanced performance).

  1. Remove the air intake duct and air filter box to access the intake side of the engine.
  2. Disconnect the exhaust downpipe from the turbo outlet. The downpipe bolts are typically 14mm and are often heat-seized. Apply penetrating oil and let it soak for 15 minutes before attempting removal.
  3. Disconnect the oil feed line from the top of the turbo cartridge. Use a 17mm or 19mm wrench on the banjo bolt, being careful not to lose the copper or aluminum crush washers.
  4. Disconnect the oil return line from the bottom of the turbo. This line is usually secured with a two-bolt flange and uses a metal gasket.
  5. Remove the water-coolant lines (if equipped) from the turbo housing. These lines will leak coolant, so have a drain pan ready.
  6. Unbolt the turbocharger from the exhaust manifold. The mounting nuts are typically 12mm and require a combination wrench with a swivel or universal joint for access.
  7. Lift the turbo assembly out of the engine bay. If it feels stuck, check for any remaining brackets or lines that are still attached.
  8. Clean the exhaust manifold mounting surface thoroughly. Any gasket residue left behind will cause exhaust leaks and poor turbo sealing.

For factory torque specifications and fastener locations, refer to the Genesis G70 technical forums where factory service manual excerpts are often shared.

Installing the HKS Intercooler

With the stock intercooler removed, you will immediately notice the difference in core size and fin density of the HKS unit. HKS uses a bar-and-plate core design that offers superior heat rejection compared to the factory tube-and-fin design.

Mounting the HKS Core

  1. Position the HKS intercooler into the factory location. The HKS kit is designed as a direct fit, so it should align with the factory mounting points without modification. If you encounter resistance, check for interference with the A/C condenser lines or power steering cooler.
  2. Secure the intercooler using the provided brackets and hardware. Torque the mounting bolts to 12-15 Nm (9-11 ft-lbs) to avoid crushing the aluminum core.
  3. Inspect the intercooler positioning. Ensure it sits squarely behind the bumper opening and has adequate airflow clearance. The core should not contact the bumper cover or crash bar directly.

Connecting the Silicone Hoses and Charge Pipes

  1. Apply a thin coat of silicone spray to the inside of each silicone coupler. This lubricates the rubber and allows the hose to slide onto the intercooler and charge pipe beads more easily.
  2. Slide the T-bolt clamps onto each hose before connecting them to the intercooler. Then, push the hose fully onto the intercooler outlet, ensuring it seats past the raised bead on the metal fitting.
  3. Tighten the T-bolt clamps evenly. A good rule of thumb is to tighten until the clamp compresses the hose firmly against the bead, then add one full turn. Over-tightening can distort the bead or damage the silicone hose.
  4. Connect the charge pipes to the throttle body and turbo compressor outlets using the same technique. The HKS kit typically includes step-up or step-down couplers to match factory pipe diameters.
  5. Reinstall the front bumper cover, taking care to align all clips and fasteners. Torque the bumper bolts to 8-10 Nm (6-7 ft-lbs).

Installing the HKS Turbocharger

The HKS turbocharger is the centerpiece of this upgrade. HKS uses a journal-bearing or ball-bearing cartridge depending on the model, with a billet compressor wheel and a high-flow turbine housing. Proper installation is critical for longevity and performance.

Pre-Installation Checks

  • Before mounting the turbo, pour approximately 50 mL (2 fl oz) of clean engine oil into the oil feed port and spin the turbine wheel by hand. This pre-lubricates the bearing assembly and prevents dry start damage.
  • Inspect the compressor and turbine wheels for any signs of shipping damage. The wheels should spin freely without contacting the housings.
  • Confirm that the wastegate actuator arm moves freely and that the gate fully seats against the turbine housing. A stuck wastegate will cause boost control issues.

Mounting the Turbocharger

  1. Install a new exhaust manifold gasket onto the engine block. The HKS kit should include a high-quality multi-layer steel (MLS) gasket. Do not reuse the old gasket.
  2. Place the turbocharger onto the exhaust manifold studs or bolts. Ensure the oil return port faces downward and the oil feed port faces upward. Misalignment will cause oil drainage problems.
  3. Torque the turbo mounting nuts or bolts to the manufacturer's specification, typically 35-45 Nm (26-33 ft-lbs) for M8 fasteners. Use a crisscross pattern to evenly distribute the clamping force.
  4. Connect the oil feed line using new crush washers on both sides of the banjo fitting. Torque the banjo bolt to 20-25 Nm (15-18 ft-lbs). Over-tightening can crush the banjo fitting and restrict oil flow.
  5. Connect the oil return line with a new gasket. Torque the flange bolts to 10-12 Nm (7-9 ft-lbs). The return line must have a continuous downward slope to the oil pan without any low spots where oil can pool.
  6. Connect the water-coolant lines (if applicable) with new O-rings. Torque the fittings to 15-20 Nm (11-15 ft-lbs).
  7. Reconnect the intake and exhaust pipes. Use new gaskets on the exhaust downpipe flange. Torque the downpipe bolts to 40-50 Nm (30-37 ft-lbs).

Wastegate and Boost Control

If your HKS kit includes an external wastegate or upgraded boost control solenoid, follow these additional steps:

  • Mount the wastegate actuator using the provided bracket. The actuator rod length must be set to achieve the desired base boost pressure. Refer to the HKS tuning guide for the correct rod length for your target boost level.
  • Connect the vacuum line from the boost source (compressor housing or intake manifold) to the wastegate actuator. Use 4mm silicone vacuum line and secure it with small zip ties.
  • If using a boost controller (electronic or manual), install it in the pressure line between the boost source and the wastegate. This allows fine-tuning of boost response and peak pressure.

Fluid Fill and Initial Startup

After all components are installed and all fasteners are torqued, it is time to refill the fluids and start the engine.

Oil and Coolant Refill

  1. Refill the engine with the recommended synthetic oil. The 3.3T engine requires approximately 6.5 quarts (6.2 liters) with filter change. Use a high-quality 5W-30 or 0W-40 meeting API SP or ILSAC GF-6 specification.
  2. Install a new oil filter. Hand-tighten the filter, then give it another 3/4 turn. Do not use an oil filter wrench, as over-tightening can distort the seal.
  3. Refill the cooling system with the specified coolant mixture. Use a 50/50 mix of phosphate-free ethylene-glycol coolant and distilled water. Pour slowly to allow air to escape from the engine block.
  4. Bleed the cooling system by running the engine with the radiator cap off and the heater set to full hot. Add coolant as the level drops. When the thermostat opens (typically around 195°F / 90°C), the coolant level will drop noticeably. Continue adding until the level stabilizes.

First Start and Leak Inspection

  1. Reconnect the battery. Turn the key to the "ON" position but do not start the engine. Wait for the fuel pump to prime (you will hear a brief whirring sound). Repeat this ignition cycle two or three times to build fuel pressure.
  2. Start the engine and let it idle. The idle may be rough initially as the ECU adapts to the new airflow characteristics. Allow the engine to reach operating temperature.
  3. Listen for unusual noises, such as a whistling sound from a boost leak, a ticking sound from an exhaust leak, or a grinding sound from the turbo bearing. Any of these warrant immediate shutdown and inspection.
  4. Inspect all intercooler and turbo connections for leaks. Use a boost leak tester to pressurize the system to 10-15 psi (0.7-1.0 bar). Listen for air escaping and apply soapy water to suspect joints to identify bubbles.
  5. Check the oil level and coolant level after the first heat cycle. Top off as needed.

Testing, Tuning, and Performance Optimization

Installation is only half the battle. Achieving the full potential of the HKS components requires careful testing and, ideally, professional tuning.

Initial Test Drive

  • Drive the vehicle gently for the first 10-15 miles to allow the ECU to begin adapting to the new components. Avoid sustained boost during this period.
  • Monitor coolant temperature and oil pressure on the instrument cluster. The G70's factory gauges are adequate, but a dedicated aftermarket gauge or OBD2 scan tool provides more precise readings.
  • After the initial warm-up, perform a few moderate acceleration runs from 30-70 mph. Listen for any detonation (a metallic pinging sound) or abnormal spooling characteristics.

Professional Tuning Considerations

The factory ECU is not designed to fully exploit the airflow capacity of an upgraded intercooler and turbocharger. To see the full power gains, you will need custom calibration. Several options exist:

  • ECU flash (bench or OBD): A reputable tuner can remap the factory ECU to adjust fuel tables, ignition timing, boost targets, and throttle mapping. This is the most comprehensive approach.
  • Piggyback ECU: A plug-and-play device like the JB4 or a dedicated HKS F-CON unit modifies sensor signals to alter boost and fueling without altering the factory ECU. This is easier to reverse and less invasive.
  • Standalone ECU: For maximum control, a full standalone engine management system (such as a Haltech or MoTeC) allows total authority over all engine parameters. This is the most expensive and complex option, typically reserved for race applications.

When selecting a tuner, look for experience specifically with the Genesis 3.3T engine and familiarity with HKS components. For more information on the importance of proper tuning after turbo upgrades, read this Driving Line article on turbo tuning fundamentals.

Performance Expectations

With a proper tune and supporting modifications (such as a freer-flowing exhaust and upgraded fuel system), a G70 3.3T equipped with an HKS intercooler and turbocharger can gain between 80-150 wheel horsepower and similar torque gains. The intercooler alone will reduce IATs by 30-50°F (15-25°C) during sustained boosting, which helps maintain power on hot days and during track sessions.

For a data-driven look at how intercooler upgrades affect IATs and power delivery, check out this EngineLabs intercooler testing article.

Long-Term Maintenance and Care

Upgraded components require consistent attention to maintain their performance and longevity.

Intercooler Maintenance

  • Inspect the core monthly: Look for bent fins, rock damage, and debris buildup in the core. Use a fin comb to straighten bent fins and increase airflow.
  • Clean the core annually: Remove the bumper and gently wash the intercooler core with a mild detergent and a low-pressure hose. Avoid using a pressure washer directly on the fins, as it can bend them.
  • Check hose clamps: After the first 500 miles, retighten all T-bolt clamps. The silicone hoses compress slightly after initial heat cycling, so re-torquing is essential to prevent boost leaks.

Turbocharger Maintenance

  • Oil changes every 3,000-5,000 miles: High-performance turbos place more thermal and mechanical stress on the oil. Shorten your oil change interval to protect the turbo bearings.
  • Use high-quality synthetic oil: The oil must maintain viscosity at high temperatures and resist shearing. Stick with a major brand that meets API SP or ILSAC GF-6 standards.
  • Allow the turbo to cool before shutdown: After a hard drive, let the engine idle for 60-90 seconds before turning the key. This allows the turbo to cool down gradually and prevents oil coking in the bearing housing.
  • Listen for bearing noise: A whining or grinding sound from the turbo at idle or during spooling indicates bearing wear. Address this immediately to avoid catastrophic failure.
  • Monitor boost levels: If you notice a sudden drop in boost or slower spooling, inspect the turbo for wastegate issues, boost leaks, or compressor wheel damage.

Cooling System Checks

  • The upgraded intercooler places a higher thermal load on the engine's cooling system. Check coolant level and condition monthly.
  • Consider upgrading to a higher-flow water pump or a larger radiator if you plan to track the car or live in a hot climate.

Conclusion

Installing an HKS intercooler and turbocharger on your Genesis G70 3.3T is a rewarding project that dramatically elevates the vehicle's performance potential. The bar-and-plate intercooler core delivers consistent intake temperatures, while the high-flow turbocharger unlocks significant horsepower gains. By following this guide methodically, you ensure a safe and reliable installation that delivers the driving experience you are after.

Remember that the hardware is only part of the equation. Proper tuning, careful break-in, and consistent maintenance are what transform a collection of aftermarket parts into a cohesive, high-performance system. Take the time to do each step correctly, and your G70 will reward you with thrilling performance for years to come.

For ongoing community support and shared experiences from other G70 owners who have performed this exact upgrade, the Genesis Owners forum is an invaluable resource. Happy building, and enjoy the boost.