The Nissan RB26DETT engine is legendary in the performance world. Found in the iconic R32, R33, and R34 Skyline GT-R, this 2.6-liter twin-turbo inline-six has powered countless builds to four-digit horsepower figures. For many enthusiasts, a 600 wheel-horsepower target represents the sweet spot—enough power to dominate street and track duties without sacrificing daily reliability. Reaching that number with a modern, responsive turbocharger like the BorgWarner EFR series requires careful planning and a well-allocated budget. This article provides a detailed cost breakdown and component guide for a 600 HP RB26 turbo upgrade centered on BorgWarner EFR turbochargers.

Understanding the RB26DETT Engine

Before diving into costs, it’s important to appreciate what makes the RB26 special. The engine features a cast-iron block, a forged steel crankshaft, and a 24-valve DOHC head with individual throttle bodies from the factory. Stock output was conservatively rated at 276 horsepower, but the internals can handle well over 400 HP without modification. However, to reach 600 HP safely, several components need upgrading. The stock twin-turbo setup becomes a bottleneck at higher power levels, which is why swapping to a modern single or twin-turbo solution like the BorgWarner EFR is a popular choice.

Why 600 Horsepower?

Choosing a 600 HP target offers a balance of performance and longevity. At this power level, the RB26’s stock rods and pistons can remain in place if the engine is well-maintained and tuned safely. The car becomes capable of high 10-second quarter-mile times while remaining streetable. It also allows the use of EFR turbochargers in their efficiency sweet spot, providing quick spool and broad torque curves. Going much higher would require upgraded internals, increasing the budget significantly.

Core Components of a 600 HP RB26 Upgrade

A reliable 600 HP build requires more than just turbochargers. The following sections cover each critical component and its estimated cost.

BorgWarner EFR Turbochargers

BorgWarner’s EFR (Engineered For Reliability) series is known for advanced features like dual ball bearings, Gamma-Ti titanium-aluminide turbine wheels, and integrated wastegates. For the RB26, two common approaches are a single EFR 6758 or twin EFR 6258 turbos. A single turbo simplifies the engine bay and lowers cost, while twin turbos retain the original layout and can provide faster spool. Prices for a pair of EFR turbochargers range from $2,800 to $3,500, depending on the specific models and sourcing. A single EFR 6758 kit costs approximately $2,200 to $2,800 plus manifold and downpipe adapter costs. We’ll base the breakdown on a twin-turbo setup, as it’s the most common path for high-street performance builds. BorgWarner’s official EFR page provides detailed specifications.

Supporting Air and Fuel Systems

Intercooler

A large, efficient intercooler is critical for keeping intake temperatures under control. Stock units quickly become restrictive at 600 HP. A quality front-mount intercooler core from brands like Garrett, PWR, or Vibrant costs $600 to $1,100. Expect additional piping costs of $200 to $400 for custom silicone and aluminum sections.

Intake and Exhaust Manifolds

The RB26’s individual throttle bodies are capable, but the intake manifold plenum needs to flow adequately. Aftermarket plenums (often billet aluminum) can cost $400 to $900. For the exhaust manifold, a twin-scroll or equal-length design is recommended to maximize EFR response. Custom stainless steel manifolds range from $800 to $1,500 depending on materials and fab work.

Fuel Injectors and Pump

To deliver enough fuel for 600 HP, high-flow injectors are mandatory. 1,000 cc/min injectors are a common choice. A set of six top-feed injectors from trusted brands like Injector Dynamics or Bosch costs $500 to $800. An upgraded fuel pump—typically a Walbro 450 or AEM 320—is required to maintain pressure. Budget $120 to $250 for a pump and $50 to $100 for a fuel pressure regulator, install kit, and rewire.

Engine Management and Tuning

Stock ECU will not control EFR turbos and larger injectors. A standalone ECU like a Haltech Elite 1500, Link Fury, or ECUTek (if using a modified stock ECU) is necessary. Standalone units cost $1,200 to $2,000 plus harness and sensor costs ($200 to $400). Professional dyno tuning by a reputable RB specialist will add $500 to $800. For more advanced features like flex-fuel or anti-lag, tuning costs may be higher. Haltech’s ECU range offers good options for RB engines.

Boost Control and Wastegates

EFR turbochargers feature an integrated wastegate, but for higher boost levels and better control, many builders opt for external wastegates. A pair of 38mm or 44mm wastegates from Tial or Turbosmart costs $300 to $600. An electronic boost controller—such as a GReddy Profec, AEM, or Turbosmart unit—adds $150 to $350. These devices ensure consistent boost pressure and prevent over-boost spikes.

Detailed Cost Breakdown

The following table breaks down each major component, including low and high estimated prices. Note that prices are for parts only and assume buying new or like-new used components. Exchange rates and regional variations apply.

  • BorgWarner EFR Turbochargers (pair) – $2,800 – $3,500
  • Front-mount Intercooler (core + piping) – $800 – $1,500
  • Exhaust Manifold (custom, twin-scroll) – $800 – $1,500
  • Intake Plenum – $400 – $900
  • Fuel Injectors (1,000 cc, set of 6) – $500 – $800
  • Fuel Pump + Regulator + Install Kit – $200 – $350
  • Standalone ECU (Haltech, Link, etc.) – $1,200 – $2,000
  • ECU Harness and Sensors – $200 – $400
  • Dyno Tuning – $500 – $800
  • External Wastegates (pair) – $300 – $600
  • Electronic Boost Controller – $150 – $350
  • Miscellaneous: gaskets, oil lines, coolant lines, clamps, couplers – $300 – $600

This parts list totals between $8,150 and $12,600. The variance depends on brand choices, whether you buy new or used, and the complexity of the fabrication required.

Additional Costs: Labor, Consumables, and Incidentals

Unless you are performing all work yourself, labor will be a significant cost. Removing the RB26 engine and transmission, installing the turbo kit, fabricating charge piping, wiring the ECU, and tuning can take 40 to 80 hours at a shop rate of $100–$150 per hour. Expect $4,000 to $10,000 for professional installation. If you are a competent DIY mechanic, you can save on labor but must invest in tools and possibly a dyno rental. Other consumables include fluids, coolant, oil, and fuel (for tuning). Budget $200 to $400 for these items.

Estimated Total Project Cost

Combining parts and labor, a complete 600 HP RB26 upgrade with BorgWarner EFR turbochargers typically lands between $12,000 and $22,000. The lower end assumes a well-sourced parts kit and self-installation; the upper end uses all new, top-tier components and professional fabrication and tuning. Keep in mind that this estimate does not include potential engine rebuild costs. If your engine has high mileage or you plan to strengthen the bottom end, add another $2,000–$5,000 for rods, pistons, bearings, and machine work.

Final Considerations

Reliability is the ultimate goal. Skimping on the ECU, tuning, or fuel system can lead to catastrophic failure. Invest in a quality tune from an RB specialist. Also, consider upgrading the clutch, transmission, and rear differential to handle 600 HP. A twin-plate clutch will cost $800–$1,500, and a stronger gearset or complete transmission swap (e.g., Tremec T56) could add $3,000–$6,000. For the best results, plan your budget with a safety margin of 15–20% for unexpected needs like new gaskets or broken bolts discovered during disassembly. Community forums like GTR.co.uk offer real-world experiences and vendor reviews that can guide part selection.

Conclusion

Building a 600 HP RB26 with BorgWarner EFR turbochargers is a rewarding project that transforms the Skyline GT-R into a serious performance machine. The total investment, including parts and professional labor, typically ranges from $12,000 to over $20,000. By understanding the costs involved and choosing components that complement each other, you can achieve a reliable, powerful build that delivers exceptional driving thrills. Plan thoroughly, research parts carefully, and trust a knowledgeable tuner to bring your RB26 build to life.