The Nissan 370Z has long been a favorite among automotive enthusiasts seeking a balance of performance, style, and affordability. At the heart of this rear‑wheel‑drive sports car lies the VQ37VHR engine, a 3.7‑liter V6 known for its high‑revving nature and robust construction. While the stock 332 horsepower is respectable, many owners push the boundaries to achieve serious power outputs, with 500 wheel horsepower being a common and attainable goal. Reaching this level requires replacing critical internal components with forged parts, upgrading the forced induction system, and fine‑tuning the engine management. Below is an in‑depth cost breakdown and technical guide to building a 370Z with forged internals for 500 hp, covering every major expense, potential pitfalls, and real‑world considerations.

Why Forge the VQ37VHR?

The stock VQ37VHR uses cast pistons and rods that are adequate for factory boost levels (when equipped in the Infiniti G37 and Nissan 370Z). However, raising boost pressure on a turbocharger or supercharger setup beyond around 8–10 psi quickly exceeds the fatigue limits of these components. Forged pistons and rods are made from stronger alloys such as 2618 or 4032 aluminum and are machined to tighter tolerances, allowing the engine to handle higher cylinder pressures without risk of cracking or bending. An upgraded crankshaft, while not always necessary for 500 hp, provides an extra safety margin and is often recommended when spinning the engine to higher RPMs. The foundation of a reliable 500‑hp build rests on properly selected forged internals.

Key Components and Their Costs

Forged Pistons

Custom or off‑the‑shelf forged pistons for the VQ37VHR range from $700 to $1,200 for a set of six. Brands like CP‑Carillo, JE Pistons, and Wiseco offer pistons with higher compression ratios suitable for forced induction (typically 9.0:1 to 9.5:1). Many piston kits include high‑strength wrist pins and rings. The price varies based on coating options (e.g., thermal barrier, skirt coating) and exact material specifications.

Forged Connecting Rods

Quality forged rods, such as those from Carrillo, Manley, or K1 Technologies, typically cost $1,000 to $1,500 for a set. These rods are made from 4340 steel or similar alloys, capable of withstanding over 600 hp. Bushed rod ends allow for floating pins, reducing friction and improving durability at high RPM.

Upgraded Crankshaft

While the stock VQ37VHR crankshaft is forged from steel and can handle 500 hp in many cases, some builders opt for a billet or fully counterweighted unit to reduce stress and improve balance. A billet crankshaft from a company like Molnar Technologies or BC Performance can cost $1,200 to $2,000. For 500 hp, a high‑quality stock crank with proper balancing might suffice, but a billet crank offers room to grow beyond 600 hp.

Additional Internal Upgrades

Beyond pistons, rods, and crankshaft, a complete forged build often includes:

  • Main and rod bearings (e.g., ACL Race or King bearings) – $150–$250
  • Oil pump upgrade (e.g., Boundary Engineering or OEM replacement with high‑flow gears) – $200–$500
  • Head studs (ARP L19 or similar) – $200–$300
  • Valve springs and retainers (dual springs recommended for aggressive camshafts and higher RPM) – $400–$600

Performance Camshafts

Installing aftermarket camshafts improves volumetric efficiency, allowing the engine to breathe better at high RPM and boost levels. Stage 2 or Stage 3 camshafts from brands like Tomei, Brian Crower, or Kelford cost $900 to $1,400 for a set. They typically increase lift and duration without requiring major modifications to the VVEL (Variable Valve Event and Lift) system, though some tuning adjustments are necessary.

Fuel System Upgrades

Delivering enough fuel for 500 hp (approximately 60 lb/hr per injector at the crank) requires high‑flow injectors and often an upgraded fuel pump. Expect to spend:

  • High‑flow fuel injectors (e.g., 1000cc or 1300cc Injector Dynamics, Fuel Injector Clinic) – $500–$800
  • Fuel pump upgrade (e.g., AEM 340 lph, Walbro 525, or a dual pump setup) – $200–$600
  • Fuel pressure regulator and lines (if converting to return‑style) – $200–$400

Forced Induction System

To reach 500 hp, the VQ37VHR must be force‑fed with a turbocharger or supercharger. The cost of the forced induction kit is the single largest expense in the build.

Turbocharger Kits

Complete turbo systems for the 370Z range from $3,500 to $7,000 for a single turbo kit and $6,000 to $10,000 for a twin‑turbo setup. Popular options include:

  • Single turbo kit (e.g., Boosted6, Sound Performance) – $4,000–$6,000
  • Twin turbo kit (e.g., GTM, Fast Intentions, Spooler) – $7,000–$10,000
  • Custom fabricated manifold and turbo – often higher due to labor and materials

These kits typically include the turbocharger(s), exhaust manifolds, downpipes, wastegate(s), blow‑off valve, and all necessary piping. A turbo suitable for 500 hp might be a Garrett GT3076R, BorgWarner EFR 7670, or Precision 6266. Larger turbos offer room to grow but may introduce more lag.

Supercharger Kits

Supercharger systems, while less common for 500 hp targets, provide immediate throttle response and avoid the plumbing complexity of a turbo. Kits such as the Vortech V3 or A&A Corvette/V8‑based conversions cost $4,000 to $6,500. For the VQ37VHR, the Stillen and Vortech supercharger kits are the most popular, though they typically max out around 450‑480 whp with stock internals. With forged internals and higher boost (using an intercooled system and a larger head unit), reaching 500 whp is possible, but many tuners prefer turbos for high‑power builds.

Intercooler and Intake

An efficient intercooler is critical to maintain safe intake air temperatures. A high‑quality air‑to‑air intercooler core (e.g., Treadstone, Mishimoto, or Garrett) along with custom piping costs $600 to $1,200. Cold air intake upgrades add another $200–$400.

Exhaust System

A free‑flowing exhaust reduces backpressure and helps the engine make power efficiently. A complete cat‑back exhaust system for the 370Z (e.g., Fast Intentions, Motordyne, ARK) costs $800 to $1,500. Adding high‑flow catalytic converters or a straight‑through test pipe can add $200–$500. For turbo builds, a larger downpipe (3‑inch or larger) is essential.

Engine Management and Tuning

The stock ECU can be reflashed using software like ECUTek, which is the standard for Nissan VQ engines. A professional tune (dyno tuning or remote tuning) costs $500 to $1,000. This covers the initial calibration and street/dyno time to dial in fuel and timing maps. Many tuners charge an additional $200–$300 for a base file before dyno tuning. For more advanced control, a standalone ECU such as a Haltech Elite 2000 or AEM Infinity can be used, adding another $1,500–$2,500 to the budget.

Labor Costs

Building a forged VQ37VHR engine requires skilled labor. Labor rates vary by shop, but expect to pay:

  • Engine removal and reassembly – $1,500–$3,000 (depending on whether the engine is removed from the car and the extent of modifications)
  • Installation of forged internals (including machining, balancing, and assembly) – $1,500–$2,500
  • Turbo/supercharger installation – $800–$2,000 (if providing the kit, additional fabrication may increase cost)
  • Fuel system installation – $300–$600
  • Dyno tuning – $500–$1,000 (included in tuning cost above if provided by the same shop)

Total labor can run between $3,500 and $7,000 for a complete build. Choosing a shop experienced with the VQ37VHR is paramount to avoid costly mistakes.

Total Cost Estimate for 500 HP Forged Build

Below is a consolidated budget for a well‑equipped 500‑hp 370Z with forged internals and a turbo setup (likely the most common path):

CategoryLow EstimateHigh Estimate
Forged pistons & rods$1,700$2,700
Crankshaft (optional but recommended)$0–$2,000$1,500–$2,000
Supporting internals (bearings, studs, springs)$800$1,500
Camshafts$900$1,400
Fuel system (injectors, pump, regulator)$700$1,400
Turbo kit (single turbo, intercooler, piping)$4,000$6,500
Exhaust system$800$1,500
ECU tune & software$500$1,000
Labor (engine build & installation)$3,500$7,000
Total$13,900$24,000

Note: The low estimate relies on a single turbo kit with a stock crank and basic labor, while the high estimate includes a billet crankshaft, twin‑turbo setup, advanced standalone ECU, and shop rates in higher‑cost regions. Many builders spend $16,000–$20,000 for a reliable 500‑whp package with proper attention to detail.

Additional Considerations for the Build

Cooling System

Increased power generates more heat. Upgraded radiator (Koyo, CSF), oil cooler (Setrab, Mishimoto), and possibly a larger auxiliary fan may be needed. Budget $500–$1,200 for cooling upgrades.

Drivetrain Upgrades

The stock CD009 6‑speed manual transmission is strong but may require an upgraded clutch (twin‑disc, e.g., Southbend, Competition Clutch) costing $800–$1,500, and a lightweight flywheel ($400–$700). The differential may also need a limited‑slip upgrade or stronger axles if launching aggressively.

Suspension and Brakes

While not required for the power build, many owners upgrade coilovers and brake pads/rotors to handle increased speed and weight transfer. These are not included in the engine budget but should be considered for a complete package.

Reliability and Longevity

A forged engine built correctly can last tens of thousands of miles on 500 hp with proper maintenance. The key is a conservative tune, high‑quality oil, and regular checks of fuel pressure, boost leaks, and oil condition. Many enthusiasts report that a VQ37VHR with forged rods and pistons, a single turbo kit, and a good tune will remain daily‑drivable. The decision to use a billet crankshaft or not often depends on power ambitions beyond 500 hp. For those targeting 500–600 hp, the stock crank is usually sufficient, but adding a crank keyway fix (common on high‑hp VQ builds) is wise to prevent the harmonic balancer from slipping.

Real‑World Examples

Several shops and enthusiasts have documented their 500‑hp 370Z builds. For instance, a well‑known build from Sound Performance achieved 508 whp on a single turbo system with forged rods and pistons, stock crank, and ECUTek tuning. Another example from GT Motoring used a twin‑turbo kit and forged internals to hit 550 whp, with a total build cost around $18,000. These examples show that a 500‑hp goal is realistic with proper planning.

Where to Find Parts and Knowledge

High‑quality aftermarket parts for the VQ37VHR are widely available from vendors like Z1 Motorsports, CX Racing, and CJMoto. Forums such as The370Z.com and MyG37.com contain in‑depth build threads where owners share costs, dyno sheets, and lessons learned. It is highly recommended to research extensively before purchasing parts, as some budget kits may require additional fabrication or tuning effort.

Final Thoughts

Building a 370Z with forged internals for 500 hp is an ambitious but attainable project. The total cost, including parts and labor, typically falls between $14,000 and $24,000, with the median build landing near $18,000. This investment transforms the 370Z into a potent street and track weapon capable of challenging much more expensive machinery. The key to success is choosing quality components, working with a reputable builder, and allowing ample time for tuning. While the upfront cost is significant, the satisfaction of a custom‑built, high‑output VQ37VHR is unparalleled for Nissan enthusiasts.