70z Turbo Kit Power Gains: from Stock to 400+ Hp with a 64mm Garrett Turbo

The Nissan 350Z and 370Z have long been revered as affordable, rear-wheel-drive platforms that respond exceptionally well to forced induction. Among the most popular turbocharger kits for these cars is the 70Z Turbo Kit, a complete system engineered around a 64mm Garrett turbocharger. This kit enables owners to push a stock engine well past the 400-horsepower mark, delivering a transformative increase in acceleration and top-end power. Whether you're building a weekend track car or a street-driven monster, understanding what the 70Z Turbo Kit offers—and what it takes to install and tune it—is essential before making the investment.

Understanding the 70Z Turbo Kit

The 70Z Turbo Kit is a dedicated turbocharging system designed specifically for the Nissan 350Z (Z33) and 370Z (Z34) chassis. Unlike universal turbo kits that require extensive fabrication, the 70Z kit is a bolt-on solution that integrates seamlessly with the factory engine bay layout. The heart of the system is a 64mm Garrett GTX or G-series turbocharger, known for its responsive spool characteristics and high-flow turbine housing. With a proper tune, this turbo can comfortably support 400 to 500 horsepower on pump gas while maintaining drivability.

It is important to note that the 70Z kit is not just a turbo bolted to the exhaust manifold. It includes a complete set of supporting components: a custom-cast exhaust manifold, a front-mount intercooler with mandrel-bent piping, a blow-off valve, wastegate, oil feed and drain lines, and all necessary hardware. This comprehensive approach reduces installation time and minimizes the risk of leaks or fitment issues.

Stock vs. Turbocharged: The Power Gap

To appreciate the gains from the 70Z Turbo Kit, we must first establish a baseline. Factory output for the VQ35DE engine in the 350Z ranges from 287 to 306 horsepower depending on the model year, while the VQ37VHR in the 370Z produces around 332 horsepower. These numbers are measured at the crank—wheel horsepower is typically 10–15 percent lower. A single turbocharger of this size completely changes the power curve.

Stock 350Z and 370Z Performance Numbers

• 2003–2005 Nissan 350Z (VQ35DE): 287 hp @ 6,200 rpm / 274 lb-ft torque
• 2006–2008 Nissan 350Z (VQ35HR): 306 hp @ 6,800 rpm / 268 lb-ft torque
• 2009+ Nissan 370Z (VQ37VHR): 332 hp @ 7,000 rpm / 270 lb-ft torque

All figures are SAE net at the crank. In stock form, both engines feel linear but lack the punch that forced induction provides. The 70Z Turbo Kit changes that dramatically.

Dyno Results: Measured Gains

Real-world dyno testing on a bone-stock 350Z with the 70Z kit and a conservative tune yields approximately 380–400 wheel horsepower (450+ at the crank) on 93 octane pump gas. On the 370Z, results are similar or slightly higher due to the larger displacement and improved cylinder heads. With higher boost and ethanol blends (E85), the same hardware can exceed 500 wheel horsepower.

• Stock 350Z (wheel): ~240–260 whp
• 350Z + 70Z Kit (91–93 octane): ~380–420 whp
• Stock 370Z (wheel): ~280–300 whp
• 370Z + 70Z Kit (91–93 octane): ~400–440 whp

These gains are not just peak numbers; the torque curve sees a massive uplift across the entire mid-range, making the car dramatically faster from any speed.

Key Components of the 70Z Turbo Kit

The 70Z kit’s strength lies in its component selection. Every part is chosen to work in harmony, eliminating guesswork and compatibility headaches.

The 64mm Garrett Turbocharger

The centerpiece is a Garrett 64mm turbo, typically a GTX2867R, GTX3071R, or a G-series equivalent. Garrett turbochargers are known for their dual-ball-bearing cartridge, billet compressor wheels, and high-efficiency turbine housings. A 64mm inducer provides excellent flow capacity while still spooling early—on a 3.5-liter V6, boost onset can begin as low as 2,800 rpm with full boost by 3,500 rpm. This makes the car extremely responsive on the street, unlike large turbos that lag until high rpm. Garrett Motion offers detailed specifications for each turbo model.

Supporting Components

• Cast exhaust manifold: Equal-length runners optimize exhaust gas flow to the turbine inlet. Stainless steel or cast iron ensures durability under high heat.
• Front-mount intercooler (FMIC): A large core with 2.5-inch or 3-inch piping reduces intake air temperatures for consistent power.
• Tial wastegate and blow-off valve: High-quality boost control and surge protection are essential for safe operation.
• Fuel system upgrades: The kit includes higher-flow fuel injectors (typically 550cc–750cc) and a compatible fuel pressure regulator. A fuel pump upgrade (Walbro 255 or AEM 340) is strongly recommended.
• Oil and coolant lines: Pre-bent stainless steel braided lines with AN fittings simplify installation and prevent leaks.

Many vendors such as Z1 Motorsports and Concept Z Performance offer the 70Z kit as a complete package with these components, often including a base tune.

Installation Overview

While the 70Z kit is designed to be bolt-on, it still requires a solid mechanical understanding of turbocharging. Expect a full install (including tuning) to take 20–30 hours for an experienced home mechanic.

Step-by-Step Install

1. Disassembly: Remove the OEM intake manifold, exhaust manifolds, catalytic converters, and the accessory belts.
2. Oil pan modifications: Drill and weld an oil return bung into the oil pan (or use a pre-drilled replacement pan). This is critical for turbo oil drainage.
3. Install turbo manifold: Bolt the custom exhaust manifold to the cylinder heads using new gaskets and hardware.
4. Mount the turbocharger: Secure the Garrett 64mm turbo to the manifold using the supplied gaskets and studs.
5. Intercooler and piping: Position the front-mount intercooler behind the bumper and route the charge pipes to the throttle body. Use silicone couplers and T-bolt clamps.
6. Wastegate and blow-off valve: Install the wastegate on the manifold or downpipe, and mount the blow-off valve on the hot-side charge pipe.
7. Fuel system: Upgrade injectors and install the fuel pressure regulator. Wire the fuel pump if necessary.
8. Oil and coolant lines: Connect the feed line from the engine’s oil pressure port, and the return line to the oil pan. Run coolant lines from the engine’s cooling system to the turbo’s water ports.
9. Exhaust: Attach the downpipe and connect to the existing cat-back exhaust. A 3-inch exhaust is recommended for allowing the turbo to breathe.
10. Interior wiring: Install a boost controller, wideband O2 sensor, and any electronic gauges (boost, oil pressure, air/fuel ratio).

Professional vs. DIY

Given the complexity of this installation, many owners choose to have a reputable shop perform the work. Professional installation often includes custom tuning on a dyno, which is the only way to guarantee safe and optimal power. A DIY install is possible if you have fabrication skills and an understanding of turbo systems, but mistakes in oil routing or boost control can lead to engine failure. Forums like My350Z.com have extensive threads documenting the 70Z install process, which are invaluable resources for the DIY community.

Tuning for Maximum Performance

No turbo kit can reach its potential without proper tuning. The 70Z kit requires an ECU remap to adjust fuel tables, ignition timing, and boost control.

ECU Tuning Options

• Uprev or ECUtek reflash: These are the most common solutions for Nissan ECUs. They allow remote or dyno-based tuning. Many 70Z kit vendors offer base maps that get you close, but a custom tune is recommended.
• Standalone ECU: For high-horsepower builds (500+ whp), a Haltech, Link, or AEM Infinity ECU gives full control over boost, fuel, and knock prevention.
• Piggyback systems: Not recommended for the 70Z kit because the factory ECU can’t handle larger injectors without a reflash.

Boost Levels and Safety

On stock internals (pistons, rods, and compression), the VQ engines can handle around 8–10 psi reliably with a good tune. The 70Z kit with its 64mm turbo will easily produce 400 hp at this boost level. Pushing beyond 12 psi without upgrading the fuel system or adding water/methanol injection is risky. Builders aiming for 500+ hp should invest in forged pistons and rods, as well as a larger intercooler and dual oil coolers. Always use a wideband air/fuel gauge and a boost gauge during tuning to monitor engine health.

Real-World Performance and Reliability

Thousands of 350Z and 370Z owners have made the jump to turbocharging with the 70Z kit. Feedback consistently highlights the drivability and predictable power delivery of the Garrett 64mm turbo.

Customer Testimonials

“My 2005 350Z went from feeling sluggish to downright violent. The torque hits hard from 3,500 rpm and pulls all the way to redline. I haven’t had any mechanical issues in 20,000 miles.”

“The 70Z kit transformed my 370Z into a car that keeps up with C6 Corvettes and E92 M3s. The power difference from the factory supercharger I had before is night and day.”

Track and Street Impressions

On the street, the 70Z kit offers strong acceleration from a roll and more than enough passing power. The turbo spools quickly, meaning you don’t have to wind the engine to high rpm to feel the boost. On track, the kit’s heat management is adequate for 20-minute sessions, but owners who do HPDE or drag racing often add an oil cooler and a larger radiator. The Garrett turbo’s internal wastegate is reliable for moderate boost levels (up to 12 psi), but for consistent track use, an external wastegate setup is preferable.

Cost and Value Considerations

The 70Z Turbo Kit is not the cheapest forced induction option—typically ranging from $4,500 to $6,000 for the complete hardware. When you add injectors, fuel pump, gauges, tuning, and labor, total cost can exceed $8,000. However, compared to supercharger kits that often cap out at 380 whp, the 70Z provides a clear path to 400+ whp with room to grow. The Garrett turbo’s rebuildability and reputation for longevity also add long-term value. For enthusiasts who demand high horsepower without sacrificing reliability, the 70Z kit remains one of the best investments for the Z platform.

Conclusion

The 70Z Turbo Kit with its 64mm Garrett turbocharger delivers on its promise of over 400 horsepower from a nearly stock engine. Its bolt-on nature, quality componentry, and proven results make it a top choice for Nissan Z owners seeking a dramatic power upgrade. Proper installation and tuning are essential to unlock the full potential and ensure reliability. With careful setup, the 70Z kit transforms the 350Z or 370Z into a force to be reckoned with—whether on the drag strip, road course, or daily commute.