Unlock the Godzilla Within: The Road to 700+ WHP

The Nissan GT-R (R35) has earned its "Godzilla" nickname through a blend of cutting-edge all-wheel drive, a twin-turbocharged V6, and an almost legendary ability to respond to modifications. While the stock car delivers spine-compressing performance, the true potential of the VR38DETT engine lies dormant, waiting for the right combination of bolt-on parts to wake it up. Crossing the 700-wheel-horsepower (whp) threshold is a well-traveled path for GT-R owners, and it does not require a fully built engine or exotic internal components. With a carefully selected set of bolt-on upgrades and a professional tune, this power level is not just achievable but also surprisingly reliable.

This guide expands on the ten essential upgrades that form the foundation of a high-horsepower GT-R build. We will move beyond simple part names and explore why each component matters, how it interacts with the rest of the system, and what you can realistically expect from a well-executed build. Whether you are planning a weekend track car or a street-dominating daily driver, these modifications are the proven building blocks for turning your GT-R into a true 700+ horsepower machine.

1. High-Flow Air Intake System

The VR38DETT engine breathes through a pair of turbochargers hungry for air. The stock air intake system, while adequate for factory power levels, creates a significant restriction as you begin to increase boost. A high-flow air intake system is the first logical step in any GT-R build.

Why It Matters

Upgrading to a high-flow intake reduces the restriction on the intake side of the turbos. The stock air box and intake tubes are designed for noise reduction and packaging efficiency, not maximum airflow. Aftermarket systems use larger, smoother tubes and high-flow filters to reduce turbulence and allow the turbos to spool more freely. This directly translates to improved throttle response and a measurable increase in horsepower, typically in the range of 15 to 25 whp on an otherwise stock car.

What to Look For

Look for kits that include heat shielding to protect the intake charge from engine bay heat. Materials such as carbon fiber or aluminum with thermal barrier coatings are preferred. A quality intake kit will also maintain proper MAF sensor positioning to ensure accurate air-fuel ratio readings. Popular options from brands like AMS Performance or Stillen offer proven designs that support higher horsepower levels without introducing tuning complications.

2. Upgraded Intercooler System

As you force more air into the engine, the temperature of that air becomes critical. Compressing air generates significant heat, and hot air is less dense, meaning it contains less oxygen for combustion. The stock intercooler system on the GT-R is effective up to a point, but it struggles to maintain low intake air temperatures once you increase boost pressure beyond stock levels.

The Cooling Advantage

A larger, more efficient intercooler reduces the temperature of the air entering the engine. Cooler, denser air packs more oxygen molecules, allowing for more fuel to be burned and more power to be produced. An upgraded intercooler can reduce intake temperatures by 30 to 50 degrees Fahrenheit under sustained boost, which not only adds power but also protects the engine from detonation. This is especially important when targeting 700+ whp, as the stock intercooler quickly becomes a bottleneck.

Core Design Considerations

When selecting an intercooler, consider the core volume, fin density, and pressure drop. A bar-and-plate design is generally preferred over tube-and-fin for its superior heat dissipation. Some kits include upgraded piping and charge pipe connections to eliminate boost leaks, which are a common issue at higher boost levels. A properly designed intercooler system can provide a power gain of 15 to 30 whp on a modified car, primarily by allowing the engine to maintain optimal ignition timing and air-fuel ratios.

3. Full Turbo-Back Exhaust System

Exhaust flow is the other half of the air equation. The stock exhaust system, with its restrictive catalytic converters, mufflers, and resonators, restricts the engine's ability to expel spent gases quickly. A full turbo-back exhaust system removes these restrictions, allowing the turbos to spin more freely and reducing back pressure.

Components of a Proper System

A turbo-back exhaust includes downpipes (the section directly after the turbos), mid-pipe, and a cat-back section. For a 700+ whp build, a 3-inch or larger diameter system is necessary. Removing the stock catalytic converters (or replacing them with high-flow units) is a key step, as the stock cats are a major restriction at high power levels. The result is faster turbo spool, reduced exhaust gas temperatures, and a significant power gain, typically between 40 and 60 whp when combined with an ECU tune.

Be aware that a full turbo-back exhaust will dramatically change the character of the GT-R's exhaust note. It becomes louder and more aggressive. Some aftermarket systems include optional resonators or mufflers to manage noise levels for street use. Additionally, removing catalytic converters may affect emissions compliance in certain regions. A quality system from a reputable manufacturer like Fast Intentions or Akrapovic provides a balance of flow, sound quality, and durability.

4. Upgraded Turbochargers

The stock turbochargers on the GT-R are efficient and responsive, but they reach their flow limits around the 600-650 whp mark. To consistently achieve and surpass 700 whp, a turbo upgrade is essential. This is the single most impactful modification for power output.

Options for Every Goal

There are several tiers of turbo upgrades for the R35. For a 700+ whp target, a set of upgraded stock-frame turbos or a mild hybrid upgrade works well. These turbos fit into the stock locations and use the factory manifold, making installation straightforward. Options from manufacturers like Turbo Lab of America or AMS offer billet compressor wheels and revised turbine housings that can support 700 to 800 whp while maintaining excellent response. Larger, high-mount turbo setups are available for power levels exceeding 1000 whp, but they require more extensive modifications and are not necessary for the 700 whp target.

Installation and Supporting Mods

Installing upgraded turbos is not a simple bolt-on job. It requires removing the engine or at least the front clip of the car. This is a major labor investment, so it is wise to plan for other upgrades at the same time. Supporting modifications like larger fuel injectors, a high-flow fuel pump, and an upgraded intercooler are mandatory. With properly sized turbos and a good tune, a 700+ whp GT-R retains strong low-end and mid-range torque, making it exceptionally fast on both the street and the track.

5. ECU Tuning and Calibration

All the hardware in the world is useless without proper calibration. The GT-R's engine management system is complex and must be reprogrammed to take advantage of increased airflow and fuel delivery. An ECU tune is not just a checkbox item; it is the single most critical factor for making safe, reliable power.

The Role of Professional Tuning

A professional tuner uses software like EcuTek or Cobb Accessport to adjust fuel maps, ignition timing, boost pressure targets, and throttle response. The GT-R has multiple fail-safes and torque management systems that must be recalibrated for higher power levels. A good tune will optimize power output while keeping air-fuel ratios and exhaust gas temperatures within safe limits. Pushing the engine too lean or too aggressive can lead to detonation and catastrophic engine failure.

Custom vs. Off-the-Shelf Tunes

While off-the-shelf (OTS) tunes are available from several vendors, a custom tune performed on a dynamometer is strongly recommended for a 700+ whp build. A custom tune accounts for variables like fuel quality, altitude, and the specific combination of parts on your car. It also allows the tuner to test for knock resistance and adjust parameters in real time. The cost of a custom tune is a small price to pay for the safety and performance it delivers.

6. High-Flow Fuel Injectors

Reaching 700 whp requires a significant increase in fuel volume. The stock fuel injectors, which flow around 550 cc/min, are not capable of supplying enough fuel for this power level. Upgraded injectors ensure the engine does not run lean, which is the fastest way to damage pistons and rings.

Sizing and Compatibility

For a 700+ whp target, injectors in the 800 to 1000 cc/min range are appropriate. These injectors are direct replacements for the stock units and fit into the factory fuel rail. It is crucial to select injectors that are compatible with your tuning software and have a proven spray pattern. Bosch or Injector Dynamics injectors are popular choices among GT-R builders for their reliability and linearity.

Installation and Tuning

Injector installation is a straightforward process, but it must be done carefully to avoid leaks. Once installed, the ECU tune must be updated with the new injector flow rates and latency values. A properly tuned fuel system with upgraded injectors will maintain safe air-fuel ratios even under the highest boost conditions, providing a crucial margin of safety.

7. High-Volume Fuel Pump System

Fuel injectors cannot do their job if they do not receive enough pressure and volume from the fuel pump. The stock fuel pump on the GT-R is designed for the factory power level and begins to lose pressure as fuel demand increases. A high-volume fuel pump system is necessary to maintain proper fuel pressure throughout the RPM range.

Drop-in vs. Surge Tank Systems

The simplest upgrade is a drop-in high-flow fuel pump, such as a Walbro 525 or AEM 320. These pumps fit directly into the factory fuel pump assembly and can support up to around 700-750 whp with proper wiring. For higher power levels or E85 fuel usage, a fuel system upgrade with a surge tank and external pump may be required. The surge tank setup prevents fuel starvation during hard cornering or low-fuel conditions.

Wiring and Voltage Considerations

Upgraded fuel pumps draw significantly more current than the stock pump. It is often necessary to install a relay and heavier gauge wiring to ensure the pump receives adequate voltage. A voltage drop to the fuel pump can result in reduced fuel pressure and a lean condition at high RPM. Proper installation is critical for reliability.

8. Performance Camshafts

While not strictly necessary for a 700 whp build, performance camshafts can significantly enhance the engine's ability to make power at higher RPM. The stock camshafts are designed for a broad torque curve and emissions compliance. Aftermarket camshafts with more aggressive profiles can improve airflow through the cylinder head, resulting in higher peak horsepower.

Profile and Timing

Camshafts for the VR38DETT are available in various profiles, from mild street grinds to aggressive race specifications. For a 700+ whp car, a moderate performance camshaft with increased duration and lift is a good match. The key is to maintain a balance so that low-end driveability is not sacrificed for peak power. Proper cam timing is critical, and this is another area where a professional tuner's expertise is invaluable.

Spring and Retainer Upgrade

Installing more aggressive camshafts often requires upgrading the valve springs and retainers to prevent valve float at high RPM. This is a durability upgrade that becomes more important as the engine is pushed harder. While camshafts alone may only add 15 to 25 whp, they allow the engine to breathe more efficiently and can make the power curve broader and more responsive.

9. Lightweight Crank Pulley Kit

The GT-R's crankshaft pulley drives the accessory belts for the alternator, water pump, and air conditioning compressor. The stock pulley is a heavy rubber-damped unit designed to minimize vibrations. While this is fine for a production car, it also adds significant rotating mass that the engine must accelerate.

Reducing Rotational Inertia

A lightweight crank pulley replaces the heavy stock unit with a much lighter, often aluminum, pulley. This reduces rotational inertia, allowing the engine to rev more freely and accelerate faster. The result is a noticeable improvement in throttle response and a small but real power gain, typically 5 to 10 whp. This is one of the simplest and most cost-effective upgrades available for the GT-R.

Risks and Considerations

Some lightweight pulleys eliminate the harmonic damper built into the stock unit. This can potentially lead to increased crankshaft vibrations at certain RPM ranges, although this is rarely an issue on the robust VR38DETT engine. For street-driven cars, a quality lightweight pulley from a reputable brand is a safe and effective upgrade. It pairs well with other bolt-on modifications to make the engine feel more responsive.

10. High-Performance Tires and Drag Radial Options

Building 700 whp is one thing; getting that power to the ground is another entirely. The GT-R's all-wheel-drive system is legendary, but even it can be overwhelmed by the torque produced at this power level. Without proper tires, the car will spin its wheels under acceleration, wasting power and slowing lap times.

Traction as a Power Mod

Upgrading to a high-performance tire or drag radial is arguably the most important modification for actually using the power you have built. A tire like the Michelin Pilot Sport 4S provides excellent grip for street and light track use. For serious drag racing performance, a tire like the Hoosier DOT drag radial allows the GT-R to hook hard and deliver devastatingly fast 60-foot times. Remember, a car that can put its power down effectively is faster than a car with 50 more horsepower that cannot stop spinning.

Wheel and Suspension Considerations

Running wider tires may require aftermarket wheels with the correct offset to clear the brakes and suspension. Many GT-R owners move to 18-inch drag wheels for the softest sidewall compliance and maximum contact patch. Additionally, upgraded suspension components like adjustable coilovers and sway bars help control weight transfer and keep the tires planted during hard acceleration and cornering. Traction is the final link in the power delivery chain, and it should not be overlooked.

Bringing It All Together: The 700+ WHP Build

Building a Nissan GT-R to produce over 700 wheel horsepower is a rewarding project that transforms an already impressive car into a genuine supercar killer. The ten upgrades outlined in this guide form a comprehensive and proven path to this goal. The key is to plan the build carefully, purchase quality components from reputable manufacturers, and invest in professional installation and tuning.

Start with the basics: intake, exhaust, intercooler, and tune. This combination alone can push the car to the 600-650 whp range and give you a taste of the GT-R's potential. From there, add upgraded turbochargers and the supporting fuel system to break through the 700 whp barrier. Along the way, consider the smaller upgrades like lightweight pulleys and camshafts to refine the power delivery and responsiveness. Finally, ensure the car has the tires and suspension to handle the newfound power.

With proper maintenance and a sensible tune, a 700+ whp GT-R can be a reliable and astonishingly fast vehicle that performs flawlessly on the street, at the drag strip, or on the road course. The journey requires patience, investment, and expertise, but the result is a driving experience that few other cars can match. Godzilla, fully awakened, is a force to be reckoned with.