Why Upgrade to the BorgWarner EFR 7670 on Your GT-R?

If you own a Nissan GT-R (R35 or earlier generation with VR38DETT or RB26DETT), you already know the platform responds exceptionally well to turbo upgrades. The BorgWarner EFR 7670 stands out for its advanced technology—featuring a forged-machined compressor wheel, Gamma-Ti turbine wheel, dual ceramic ball bearings, and an integrated boost control solenoid. This turbo delivers quick spool, broad torque, and the ability to support 600–700 wheel horsepower on pump gas, or more with race fuel and aggressive tuning.

Upgrading to the EFR 7670 transforms your GT-R from a potent street machine into a serious performance weapon. However, a successful install requires careful planning, proper tools, and attention to detail. This guide walks you through every step, from gathering parts to testing your new setup.

Tools and Materials Needed

Before starting, gather all necessary items. Missing a critical tool mid-install can waste hours.

Turbo and Installation Kit

  • BorgWarner EFR 7670 Turbo — confirm orientation (clockwise rotation for GT-R).
  • Turbo installation kit — includes gaskets, bolts, washers, and oil/coolant line adapters. Many kits are vehicle-specific.
  • Upgraded oil feed and drain lines — use -4AN or -6AN stainless braided lines to match EFR fittings.
  • Coolant lines — silicone or stainless lines with proper quick-connect or banjo fittings.

Hand Tools

  • Socket set (metric, 8mm–22mm with extensions and swivels)
  • Combination wrenches (10mm–19mm)
  • Torque wrench — in-lb and ft-lb ranges
  • Screwdrivers (flathead and Phillips)
  • Pliers (regular, snap-ring, and hose-clamp)
  • Allen keys and Torx bits
  • Gasket scraper and razor blades
  • Heat-resistant gloves and safety glasses

Consumables and Misc

  • New gaskets (manifold to turbo, turbo to downpipe, downpipe gaskets)
  • Anti-seize compound for bolts
  • Threadlocker (medium strength)
  • High-temp RTV silicone
  • Brake cleaner for degreasing surfaces
  • Shop towels and drain pan
  • Coolant and engine oil (for refill after drain)

Preparation: Work Area and Safety

Park your GT-R on a level surface with the engine cold. Disconnect the battery negative terminal—this prevents accidental fuel pump activation or spark from tools. Allow the engine to cool completely; exhaust manifolds and turbo housings stay hot for hours after shutdown.

If possible, raise the vehicle on jack stands or a lift to access the underbody components. Remove the engine cover and any plastic shielding blocking access to the turbo area. Clean the work area of debris, oil, and coolant to avoid contamination during reassembly.

Removing the Stock Turbocharger

Carefully removing the factory turbo is half the battle. Take your time and label everything.

Step 1: Drain Fluids

Drain the engine oil and coolant to the appropriate levels (or completely if performing other services). Removing the turbo will spill residual fluids—drain them into a clean pan from the oil pan drain plug and coolant drain plug on the block. Dispose of fluids properly.

Step 2: Disconnect Intake and Exhaust

  • Remove the intake duct from the air filter to the stock compressor inlet. Unclip the MAF sensor harness.
  • Disconnect the charge pipe from the turbo outlet—typically a rubber coupler with hose clamps.
  • Unbolt the downpipe from the turbine outlet. On GT-Rs, this can be tight; use penetrating oil on rusted nuts.
  • Remove the oxygen sensor from the downpipe if necessary (use a dedicated O2 sensor socket).

Step 3: Remove Oil and Coolant Lines

The stock turbo uses banjo fittings for oil feed and return. Place a rag underneath to catch drips. Loosen the feed line from the block and the return line from the oil pan. Disconnect coolant lines at the turbo and at the engine block or water pump. Cap all open ports with clean plugs or tape.

Step 4: Unbolt the Turbo from the Manifold

Support the turbo from below with a jack and a block of wood. Use a 12mm or 14mm socket to remove the retaining nuts. The fasteners are often heat-seized. Apply penetrating oil and let it soak. When all nuts are removed, carefully lower the turbo out of the engine bay. On some GT-R variants, you may need to loosen the exhaust manifold to tilt the turbo out.

Step 5: Inspect and Clean

With the stock turbo out, inspect the manifold for cracks or warping. Clean the manifold mounting surface with a gasket scraper and brake cleaner. Check the oil drain port in the block for sludge. This is a great time to replace the manifold gaskets and studs if they are damaged.

Installing the BorgWarner EFR 7670 Turbo

The EFR 7670 uses a unique T4 or T3 twin-scroll flange depending on your setup. Ensure you have the correct manifold adapter or manifold. Many GT-R applications use a T4 divided manifold with a 1.05 A/R or 0.85 A/R twin-scroll housing. Confirm the flange matches before proceeding.

Step 1: Prepare the Turbo

  • Remove the compressor cover from the EFR if you need to clock the orientation for your charge piping (not usually required with proper kit).
  • Install the oil feed and drain fittings using Teflon tape or sealant on the threads (not on the crush washer seats).
  • Attach the coolant fittings if using a water-cooled version (some EFR turbos are oil-cooled only).
  • Install the wastegate actuator arm—EFR turbos come with a pre-set actuator; adjust only if using an external boost controller.

Step 2: Install Gaskets and Position the Turbo

Place a new manifold-to-turbo gasket. Apply a thin film of anti-seize to the studs. Carefully lift the EFR 7670 into position. It is heavy; use a helper or transmission jack. Align the oil drain port vertically with the block drain hole. Hand-thread the nuts onto the studs. Tighten them in a crisscross pattern with a torque wrench to the manufacturer specification (typically 30–35 ft-lb for M8 studs, check your manifold).

Step 3: Connect Oil and Coolant Lines

  • Oil feed: Connect the -4AN line from the block (or head) to the top of the turbo center housing. Use a restrictor if recommended (EFR turbos have internal restrictors; verify with BorgWarner specs).
  • Oil drain: Attach the -10AN or -12AN drain line to the bottom of the turbo. Ensure it has a gentle slope to the oil pan adapter—no kinks. Tighten all fittings securely.
  • Coolant lines: If water-cooled, connect the supply and return using quick-connect fittings. Use new O-rings.

Step 4: Reconnect Intake and Exhaust

  • Install the downpipe with a new gasket. Tighten nuts to spec (usually 35–40 ft-lb). Use anti-seize on these threads too.
  • Reconnect the charge pipe with a high-quality silicone coupler and t-bolt clamps. Ensure the compressor outlet is aligned.
  • Reattach the intake duct, MAF sensor, and any breather hoses.

Step 5: Final Mechanical Checks

  • Rotate the compressor wheel by hand—it should spin freely without rubbing.
  • Check that all hose clamps are tight, wires are clear of hot surfaces, and no tools or rags remain in the engine bay.
  • Reinstall the engine cover and any heat shields. Consider adding titanium wrap or turbo blanket to the EFR to reduce underhood temps.

Finalizing the Installation: Fluids and Electrical

Refill Engine Oil and Coolant

Fill the engine with high-quality synthetic oil (5W-40 or 10W-50 recommended for turbo GT-Rs). Use a new oil filter. Fill the coolant system with a 50/50 mix of distilled water and ethylene-glycol coolant. Bleed the cooling system at the highest point to remove air pockets.

Reconnect the Battery and Prime the Turbo

  • Reconnect the battery negative terminal.
  • Critical: Before starting, prime the oil system. Disconnect the fuel pump relay (or remove the fuel pump fuse). Crank the engine for several 10-second intervals until the oil pressure gauge shows pressure (or you see oil returning to the tank). This prevents dry starts that can damage the new turbo bearings.
  • Reconnect the fuel pump relay. Start the engine and let it idle for 2–3 minutes. Check for oil, coolant, and boost leaks. Inspect all connections while the engine runs.

Testing Your New Turbo Setup

After installation, a careful break-in and test procedure ensures longevity and peak performance.

Initial Idle and Low-Load Drive

  • Let the engine reach operating temperature with moderate revs under 3,000 RPM.
  • Take a short drive on low boost—keep throttle openings gentle. Do not exceed 0.5 bar (7 psi) for the first 50–100 miles.
  • Listen for unusual whistles, scraping, or rattling. Check all oil drain connections for leaks—a common issue is the drain line weeping at the turbo or pan adapter.

Monitoring and Logging

Use a boost gauge, wideband oxygen sensor, and engine management software (like Cobb Accessport, ECUTek, or Syvecs) to log parameters. The EFR 7670 spools quickly; you should see positive boost around 2,800–3,200 RPM depending on your manifold and displacement. Watch the air-fuel ratio: under light boost it should be 11.5–12.0:1, tapering to 11.0:1 at peak power.

Potential Issues to Address

  • Boost creep: If boost rises uncontrollably, check the wastegate actuator preload and the wastegate port size. EFR turbos have a recirculating wastegate design; sometimes the port needs enlarging or an external wastegate is necessary.
  • Oil leaks at drain: Ensure the drain line is not kinked and uses a 1 inch ID hose. If the oil pan adapter is too high, oil will back up into the turbo center section causing smoke.
  • Surge: If you hear a fluttering sound on deceleration, the compressor may be surge-limited. A larger compressor map or blow-off valve may be required.

Tuning Considerations for the EFR 7670

Do not drive the car hard on a stock tune. The increased airflow demands recalibration of fuel, timing, and boost targets. Work with a reputable GT-R tuner. Typically, the EFR 7670 supports:

  • 550–600 whp on 91–93 octane (pump gas) with moderate timing.
  • 650–750 whp on E85 or race fuel with upgraded fuel system (injectors, pumps, and lines).
  • Spool: Full boost by 3,500 RPM on a 3.8L VR38 or ~3,800 RPM on an RB26.

Ensure your fuel system can deliver: 1,000cc minimum injectors (or ID1300x) and dual walbro 525 or AEM 340 pumps. Upgraded intercooler and intake plenum also help maximize the turbo's capability.

Maintenance and Long-Term Reliability

After installation and tune, adhere to a stricter maintenance schedule:

  • Change oil every 3,000 miles or annually with high-zinc synthetic.
  • Inspect the turbo oil feed and drain lines for cracking or leakage every oil change.
  • Check boost leaks and tighten all charge pipe clamps periodically.
  • Consider a turbo timer or idling for 30 seconds after hard driving to cool the bearings.

Conclusion

Installing the BorgWarner EFR 7670 Turbo on your Nissan GT-R is a rewarding upgrade that transforms the car’s character. By following this step-by-step guide—paying careful attention to preparation, line routing, torque specs, and tuning—you can achieve a reliable high-horsepower setup that remains streetable. Always double-check your work and consult a professional if you are unsure about any step.

For further reading, check out BorgWarner’s EFR technical page and GT-R Life forums for real-world experiences. Drive safely and enjoy the power.