Why the A90 Supra Is a Prime Candidate for Big Power

The A90 Toyota Supra, powered by the BMW B58 inline-six engine, has quickly become a darling of the aftermarket world. Its closed-deck block, robust cranktrain, and advanced variable valve timing provide a solid foundation for serious power gains. While the factory turbocharger delivers respectable performance, swapping to a larger unit like the BorgWarner EFR 8374 unlocks a whole new level of acceleration and top-end pull. A 620 wheel horsepower (WHP) target is a sweet spot: it’s enough to embarrass supercars yet still maintains daily-driver manners when tuned correctly. This article details the exact parts, installation steps, and tuning considerations needed to hit that number safely and repeatably.

Inside the BorgWarner EFR 8374 Turbocharger

Design Philosophy and Key Specs

The BorgWarner EFR (Engineered For Reliability) series is renowned for its use of advanced metallurgy and clever engineering. The EFR 8374 features a 74mm compressor wheel and a 62mm turbine wheel, both utilizing a billet design for maximum strength and airflow efficiency. Its twin-scroll housing helps scavenge exhaust pulses for faster spool, while the integrated recirculating wastegate eliminates boost creep and simplifies installation. Key specifications include:

  • Compressor inducer: 74mm / exducer: 100mm
  • Turbine inducer: 62mm / exducer: 55mm
  • Maximum power rating: up to 800 WHP (with appropriate supporting mods)
  • Bearing system: Dual ceramic ball bearings with oil and coolant circuits
  • Turbine wheel material: Gamma titanium aluminide (reduces rotational inertia for lightning-quick spool)

These features make the EFR 8374 an excellent choice for the B58 because it flows enough air to reach 620 WHP without pushing the compressor to its efficiency limits. The quick spool characteristics mean you get meaningful boost well before 4000 RPM, preserving low-end torque while allowing strong mid-range and top-end power. For more technical data and compressor maps, visit the official BorgWarner EFR page.

How It Compares to Other Turbo Options

Other popular upgrades for the A90 Supra include the Pure Stage 2 and Precision 6266. The EFR 8374 offers a balance of spool speed and top-end flow that many tuners prefer for 600–700 WHP builds. It responds well to ethanol blends and produces consistent power even in warm conditions thanks to its integrated recirculation valve. When paired with a quality boost controller, boost response is crisp and predictable.

Essential Parts and Supporting Modifications

Hitting 620 WHP requires more than just the turbo – every supporting system must be upgraded to handle the increased fuel demand, heat, and airflow. Below is a comprehensive parts list broken down by system.

Fuel System Upgrades

  • High-pressure fuel pump (HPFP): The factory HPFP runs out of capacity around 550 WHP. Options from Dorch Engineering or Spool are proven to support over 700 WHP on E85.
  • Fuel injectors: 1000cc or larger direct-injection injectors (e.g., Bosch Motorsport or upgraded OE-style units). Ensure compatibility with your chosen tuning solution.
  • Low-pressure fuel system: A larger in-tank pump and possibly a boost-a-pump or secondary fuel rail injection are recommended if you plan to run full E85. For 620 WHP on a blend, a single upgraded LPFP may suffice.

Air Intake and Induction

  • Intake system: A high-flow silicone intake tube and larger cone filter (e.g., Eventuri, MST, or Dinan) reduces restriction upstream of the turbo.
  • Charge piping: Upgrade to aluminum or silicone piping with robust couplers to prevent blow-offs under high boost.
  • Intercooler: A larger bar-and-plate unit (Wagner Tuning, CSF, or AMS) is mandatory – the factory intercooler heat soaks quickly. Aim for core volumes of 600+ cubic inches with cast end tanks.

Exhaust System

  • Downpipe: A catted or catless downpipe (3–3.5 inch diameter) frees up exhaust flow. The EFR 8374 benefits from a twin-scroll downpipe adapter to maintain pulse separation.
  • Mid-pipe and rear exhaust: A full 3-inch catback system reduces backpressure. Choose a valved exhaust if noise is a concern.
  • Wastegate venting: If using the integrated wastegate, ensure a proper dump tube or recirculation path to avoid boost oscillations.

Engine Breathing and Cooling

  • Oil cooler: Upgraded oil cooler (e.g., Setrab or Mishimoto) helps maintain oil temperatures below 240°F during sustained pulls.
  • Water cooling: An aftermarket radiator (e.g., CSF or PWR) with high-flow fans is recommended, especially for track use.
  • Catch can: A dual valve catch can removes blow-by vapors, reducing carbon buildup on intake valves.

Engine Management and Electronics

  • ECU tuning platform: Options include ECUtek, Bootmod3, and MHD. ECUtek is favored for its advanced features like multiport fuel injection control and flex fuel integration.
  • Boost control: A high-quality electronic boost controller (e.g., Turbosmart or CBR) allows precise adjustment of boost by RPM and gear.
  • Sensors: Wideband oxygen sensor (AEM or Innovate), boost gauge, and oil pressure gauge are essential for monitoring.

Installation Walkthrough

Installing the BorgWarner EFR 8374 turbo is an involved process best performed by an experienced technician. The job typically requires 8–12 hours of labor. Below is a general overview of the steps; always consult a factory service manual for torque specifications and safety procedures.

Step 1: Disconnect and Drain Fluids

Disconnect the battery, drain the engine coolant, and remove the underbelly pan. This provides access to the turbo and exhaust components.

Step 2: Remove Factory Turbo Assembly

  • Unbolt the exhaust manifold and downpipe.
  • Disconnect oil and coolant lines from the turbo.
  • Remove the factory intercooler and charge pipes.
  • Lift the factory turbo and manifold out as a unit. You may need to loosen the engine mounts slightly for clearance.

Step 3: Prepare the Engine Bay for the EFR 8374

  • Inspect the turbo mounting surface for flatness. Clean all gasket surfaces.
  • Install the new oil drain line (use a -10AN or larger to prevent oil pooling).
  • Pre-fit the new intercooler and charge piping to ensure no interference with the frame rails or radiator.

Step 4: Mount the BorgWarner EFR 8374

  • Bolt the turbo to the exhaust manifold using new gaskets and hardware. Torque to manufacturer specs (typically 45–50 lb-ft for manifold nuts).
  • Attach the coolant feed and return lines. Use high-quality hose clamps.
  • Connect the oil feed line (often a -4AN stainless line). Ensure the restrictor (if required) is installed – the EFR uses a built-in restrictor, so no external one is needed.
  • Secure the wastegate actuator and adjust the preload per BorgWarner’s instructions (typically 0.5–1mm of preload).

Step 5: Install Supporting Components

  • Mount the upgraded intercooler and secure all charge pipe couplers.
  • Install the downpipe and exhaust system. Check for leaks.
  • Wire the boost controller solenoid and vacuum lines per the controller’s manual.
  • If you’re also upgrading the HPFP and injectors, install them now. The HPFP bolts to the cylinder head and requires careful alignment.

Step 6: Final Checks

  • Reconnect the battery and refill coolant, engine oil.
  • Prime the oil system by cranking the engine with the fuel pump relay disabled until oil pressure registers on the gauge.
  • Inspect all connections for boost leaks using a smoke tester or pressure tester.

Tuning for 620 WHP – Getting the Calibration Right

A proper tune is the difference between a reliable 620 WHP build and a blown engine. The B58’s direct injection system and variable valve timing require careful mapping of fuel, timing, and boost throughout the RPM range.

Choosing a Tuning Platform

The most common platforms for the A90 Supra are ECUtek and Bootmod3. ECUtek offers raw code-level access and supports flex fuel, multi-map switching, and advanced knock control. Bootmod3 is user-friendly and popular for remote tuning. Both require a locked ECU (Bootmod3 can be DIY unlocked). For a build at this power level, custom dyno tuning by a reputable shop is strongly recommended over canned maps. A skilled tuner can adjust fuel trims, cam timing, and boost response to suit your specific parts and fuel quality.

Fuel and Octane Considerations

To safely reach 620 WHP, you’ll need at least 93 octane (98 RON). For best results, run an ethanol blend (E30–E50). E85 allows more aggressive timing and lower charge temperatures. If you’re running full E85, ensure the fuel system can supply enough volume (upgraded LPFP and HPFP). Many tuners target 22–24 psi of boost on 93 octane and 26–28 psi on ethanol mixes. Watch the HPFP fuel pressure – if it dips below 2000 psi on ethanol, reduce boost or add a second pump.

Boost Response and Spool Targets

The EFR 8374 should reach 18–20 psi by 3800–4000 RPM on the B58. A boost controller with gear-based ramping helps maintain traction in lower gears. Typical boost targets for 620 WHP:

  • 1st gear: 15–17 psi
  • 2nd gear: 20–22 psi
  • 3rd and above: 24–26 psi (depending on fuel)

Work with your tuner to avoid overboosting on shifts. Logging is essential – use a wideband O2 sensor to keep air/fuel ratios at 11.5–12.0 under full load on pump gas, and 11.0–11.5 on ethanol.

Ignition Timing and Knock Control

The B58 is sensitive to low-octane fuel. Keep ignition timing conservative until knock is not observed. On 93 octane, typical max timing is 12–15 degrees BTDC at peak torque, advancing to 18–20 near redline. On E85, you can push to 18–22 degrees BTDC. Each engine is different – a professional tuner will perform runs with knock sensors enabled.

Expected Performance and Dyno Results

With the setup described above, expect 615–630 WHP on a Dynojet or Mustang dyno (correction factor varies). The torque curve will be impressive – typically 550–600 lb-ft at the wheels. The car will pull hard from 3500 RPM to the 7000 RPM fuel cut. Quarter-mile times drop into the 10.5–11.0 second range at 130–135 mph, depending on traction and altitude. On a well-prepped drag strip, a 10.8 is achievable with proper tires and suspension.

Reliability Considerations

620 WHP is within the B58’s threshold for stock internals, but safety margins shrink. Here’s how to keep the engine happy:

  • Oil changes: Use high-quality 5W-40 full synthetic (e.g., Motul 300V or Liqui Moly) every 3000 miles. Send oil samples for analysis.
  • Cooling: Monitor coolant temps. If they exceed 225°F during pulls, consider a larger radiator or ducting upgrades.
  • Transmission: The ZF 8HP50 can hold 620 lb-ft for street use, but repeated drag launches may require a transmission tune or upgraded torque converter. Consider a transmission cooler if tracking.
  • Heat management: Wrap the downpipe and turbo blanket to reduce underhood temperatures. A vented hood also helps.
  • Regular inspections: Check for boost leaks, exhaust cracks, and fuel system weirdness every oil change.

Common Pitfalls to Avoid

  1. Fuel starvation on E85: Don’t assume a single HPFP can handle full E85 at 620 WHP – many require a PORT injection or secondary HPFP kit.
  2. Overlooking wastegate tubing: The EFR integrated wastegate can crack if the mounting bracket is not stress-relieved. Use a flexible braided line from the actuator to the turbine housing.
  3. Ignoring the intercooler: A stock intercooler will heat soak after one pull, causing knock. Invest in a quality unit from the start.
  4. Cheaping out on tuning: A $1500 custom dyno tune is cheaper than a new engine. Avoid “off-the-shelf” maps for a turbo swap.
  5. Not upgrading the intake:** The factory intake is restrictive above 500 WHP. A 4-inch intake with a high-flow filter is a must.

Final Thoughts

Reaching 620 WHP on your A90 Supra with the BorgWarner EFR 8374 is an attainable goal that will transform the car into a genuine high-performance machine. The combination of a robust engine, efficient turbo, and quality supporting parts delivers fast spool, strong power, and good reliability when the work is done properly. The key steps are selecting the right fuel system components, installing everything with care, and investing in a professional ECU calibration. With these elements in place, your Supra will not only hit the 620 WHP target but also provide consistent, thrilling performance for years to come. If you’re not comfortable performing the work yourself, partner with a reputable B58 specialist who has experience with EFR turbos. Research your parts thoroughly, and don’t cut corners – your engine’s longevity depends on it.