Understanding the VQ37VHR Engine and Its 600 HP Potential

The Nissan 370Z’s VQ37VHR is a 3.7‑liter naturally aspirated V6 that delivers 332 horsepower and 270 lb‑ft of torque from the factory. With a 7500 RPM redline, dual‑intake Variable Valve Event and Lift Control (VVEL), and a forged steel crankshaft, the engine is a stout foundation. However, reaching 600+ wheel horsepower (whp) demands far more than bolt‑on intake and exhaust work — it requires serious forced induction and extensive supporting modifications. This guide walks through every essential upgrade, from air delivery to fuel delivery, so you can build a reliable and powerful VQ37VHR.

Why Intake and Exhaust Alone Won’t Hit 600 HP

A naturally aspirated VQ37VHR, even with ported heads, aggressive cams, and long‑tube headers, struggles to exceed 400 whp. The volumetric efficiency ceiling is low because the engine’s displacement and airflow characteristics limit peak power. To double the factory output, you must force more air into the combustion chambers — that means a supercharger or turbocharger system. Intake and exhaust upgrades then become critical to let that forced air flow freely into and out of the engine.

Forced Induction: The Path to 600+ HP

Every 600‑hp VQ37VHR build relies on a well‑designed forced induction kit. Two routes are common:

Supercharger Systems

Centrifugal superchargers (e.g., Stillen, Vortech, GTM) offer linear power delivery and easier installation. The Stillen supercharger kit, for example, includes an air‑to‑water intercooler, high‑flow intake, and custom tune. It reliably produces 480‑550 whp on 91 octane, and with E85 and larger injectors you can push past 600 whp. For more information, visit Stillen’s official site.

Turbocharger Systems

Twin‑turbo kits (e.g., GTM, Boosted Performance) can generate 600+ whp with lower boost levels than a supercharger. They offer greater top‑end potential but require more complex plumbing, oil lines, and intercooler routing. A well‑tuned twin‑turbo VQ37VHR can exceed 700 whp on pump gas with proper support.

Intake System Upgrades for Forced Induction

Once you add forced induction, the stock intake becomes a restriction. Upgrading the intake system ensures the compressor receives cool, dense air with minimal pressure drop. Key components include:

Cold Air Intakes (CAI)

Aftermarket CAI systems relocate the air filter outside the engine bay, reducing intake air temperature (IAT). For supercharged setups, a 3‑inch diameter intake tube is common. Brands like Z1 Motorsports and Injen offer VQ37VHR‑specific CAI kits. See Z1 Motorsports for options.

Intake Manifold and Throttle Body

At 600+ hp, the factory plastic intake manifold and 70‑mm throttle body become bottlenecks. Upgrading to a ported or aftermarket aluminum manifold (e.g., CJ Motorsports) and a 75‑80 mm throttle body improves airflow by 15‑20 %. For extreme builds, individual throttle bodies (ITBs) are possible but rarely used on street cars.

Exhaust System Upgrades for Maximum Flow

After the air is compressed and burned, the exhaust must exit quickly. Upgraded exhaust components reduce backpressure and prevent boost creep in turbo setups.

Long‑Tube Headers

Factory exhaust manifolds are restrictive. Long‑tube headers (e.g., PPE Engineering or Fast Intentions) with stepped primary tubes and a merge collector increase exhaust velocity. For turbo builds, some opt for equal‑length headers that spool turbos faster.

Cat‑Back Exhaust and High‑Flow Catalytic Converters

A 3‑inch cat‑back exhaust (single or dual) is mandatory. Look for systems with mandrel‑bent tubing and straight‑through mufflers. High‑flow catalytic converters (200‑300 cell) reduce restriction while keeping emissions legal. Skip the cats entirely for track‑only cars, but expect a loud exhaust note. Check Fast Intentions for quality cat‑back systems.

Fuel System Upgrades: Feeding the Beast

A 600‑hp VQ37VHR requires roughly 30 % more fuel than stock. The factory fuel pump and injectors max out around 450 whp. Essential upgrades include:

High‑Flow Fuel Injectors

Upgrade to 1000‑1300 cc/min injectors (or larger for E85). Return‑style fuel systems with a boost‑referenced regulator are common for turbo builds. Start with 1050 cc injectors for a conservative 600‑hp setup.

Fuel Pump and Fuel Rail

A single Walbro 450 or dual in‑tank pumps (e.g., Walbro 525) ensure adequate flow. A billet fuel rail with larger lines (−6 AN or −8 AN) prevents pressure drops. E85 users need even larger pumps due to its lower energy density.

Flex Fuel and Ethanol Blends

E85 is the cheapest way to gain 50‑80 whp. It also provides knock resistance, allowing higher boost. A flex‑fuel sensor and ECU calibration let you run any ethanol blend without retuning.

ECU Tuning and Engine Management

Without a proper tune, all the hardware in the world won’t make safe power. The VQ37VHR ECU is complex, but several options exist:

Standalone ECUs

Haltech, AEM Infinity, and Motec are popular for 600+ hp builds. They offer complete control over fuel, ignition, VVEL, and boost. Installation requires a full harness adapter, but the tuning flexibility is unmatched. Many high‑power shops recommend Haltech for VQ engines.

ECUTEK and Uprev Tuning

For less extreme setups, ECUTEK or Uprev reflash the factory ECU. They retain driveability features like cruise control and emissions readiness. With a talented tuner, these can handle up to 700 whp. For more on ECUTEK tuning, visit ECUTEK’s official site.

Supporting Modifications for Reliability

600+ hp stresses every part of the 370Z. These upgrades are not optional for a street‑driven car:

Cooling System

A high‑capacity radiator (e.g., Mishimoto or CSF) with an electric fan kit is essential. For forced induction, an oil cooler, power steering cooler, and transmission cooler (if automatic) prevent heat soak. Some kits include an auxiliary intercooler coolant pump.

Drivetrain Upgrades

The factory CD009 six‑speed transmission can handle 600 whp if driven smoothly, but clutch upgrades are mandatory. A twin‑disc clutch (e.g., ACT or Competition Clutch) with a lightweight flywheel is recommended. Differential bushings and an upgraded LSD (e.g., Quaife) improve traction.

Internal Engine Modifications

At 600‑650 whp, the stock VQ37VHR bottom end (forged crank, powder‑metal rods, cast pistons) is near its limit. For sustained 600+ hp, consider forged pistons (Wiseco or CP‑Carillo), stronger rods (Manley or Carrillo), and upgraded rod bearings. For 700+ hp, a sleeved block and billet main caps become necessary. A reputable shop like GT Motorsports can advise on engine prep.

Building a Balanced, Reliable 600‑HP 370Z

Achieving 600+ whp from a VQ37VHR is a rewarding but demanding project. The recipe is clear: forced induction, free‑flowing intake and exhaust, a robust fuel system, and expert tuning. Every component must be matched to the power goal, and supporting upgrades — cooling, drivetrain, and even internal engine work — cannot be skipped. Start with a quality supercharger or turbo kit, then methodically address each supporting system. With careful planning, your 370Z can deliver thrilling performance without sacrificing reliability. Always consult with experienced builders and tuners before making significant modifications.