Introduction: Why Thermal Management Matters for the VQ37VHR

The Nissan 370Z’s VQ37VHR engine is a high-revving, naturally aspirated V6 that thrives under hard driving. Yet even this robust powerplant has its limits when it comes to heat dissipation. On a warm track day or during aggressive canyon runs, oil and coolant temperatures can spike quickly, leading to power loss, knock, and long-term engine wear. Supporting modifications like an upgraded radiator, oil cooler, and intercooler (for forced induction builds) are not just “nice-to-haves”—they are essential for maintaining consistent performance and protecting your investment. This guide dives deep into each component, explaining why the stock parts fall short, what aftermarket options deliver, and how to choose the right setup for your driving style.

Upgraded Radiator: Keeping Coolant Temperatures in Check

The stock 370Z radiator is designed for everyday commuting and occasional spirited driving. It uses a plastic-end-tank design with a moderate core size that can become heat-soaked during sustained high-rpm operation. When coolant temperatures exceed 220°F, the ECU begins to pull timing and reduce throttle response to protect the engine. For drivers who push their cars at autocross, road courses, or simply live in hot climates, a performance radiator is a first-line upgrade.

How an Upgraded Radiator Works

Aftermarket radiators typically replace the plastic tanks with full aluminum construction and increase core volume. Many feature a dual-pass or cross-flow design that improves the coolant-to-air contact time. A larger surface area with denser fin pack allows more heat to be rejected to the atmosphere. Some radiators also include built-in oil coolers (heat exchangers) for the transmission or engine oil, though these are less common on the 370Z due to the separate oil cooler options.

Key Features to Look For

  • Core thickness: Stock is around 1.25 inches; performance radiators range from 1.5 to 2.5 inches. Thicker cores hold more coolant but may require fan shroud modifications.
  • Material: 6061 aluminum with TIG-welded tanks offers the best strength-to-weight ratio. Avoid epoxy-sealed tanks.
  • Fitment: Direct-fit radiators (like CSF and Mishimoto) bolt into factory mounts without cutting. Some “race” units require relocation of the coolant reservoir or trimming of the shroud.
  • Fans & Shroud: The stock electric fans can be reused with most radiators, but upgrading to a higher-flow fan kit (e.g., Spal) can reduce coolant temps by an additional 5–10°F.

Top Radiator Options for the 370Z

  • CSF Racing Radiator: 7180 series with 2-row, 1.5-inch core. Known for excellent build quality and direct fitment. Often used in Super Taikyu race cars.
  • Mishimoto Performance Radiator: 2.0-inch dual-pass core with machined fill neck and drain plug. Includes a lifetime warranty. Works well for daily-track dual use.
  • Koyo Radiator: High-flow brazed core with 1.5-inch thickness (VH series). Lighter than OEM and offers consistent cooling without overkill.
  • DeatschWerks Radiator: Large 2.5-inch core for extreme track use—requires minor modification to the lower radiator mount.

For a detailed comparison of radiator dimensions and pricing, check out this Z1 Motorsports radiator guide.

Oil Cooler: Vital Lubrication Management

Oil is the lifeblood of any engine, and the VQ37VHR is particularly sensitive to oil temperature. The stock oil cooler—a small water-to-oil heat exchanger built into the oil filter housing—does little to keep temperatures below 250°F during sustained hard driving. At those temperatures, oil viscosity drops, film strength weakens, and additives break down, increasing wear on bearings and camshaft journals.

How Oil Coolers Help

An aftermarket oil cooler uses a remote-mounted air-to-oil radiator (commonly called a “cooler core”) plumbed into the oil system via a sandwich plate or relocation kit. The cooler core is placed in front of the radiator or behind the bumper where airflow is greatest. A thermostatic sandwich plate ensures oil flows through the cooler only when it reaches a preset temperature (typically 180–200°F), allowing the engine to warm up quickly on cold starts.

Installation Considerations

  • Lines: Braided stainless steel or push-lock AN lines are preferred over rubber hoses to resist heat and abrasion. Use fire sleeve or heat wrap near exhaust components.
  • Core Size: Choose a 13-row to 19-row core depending on climate and driving intensity. Street-driven cars in mild climates can use 13 rows; track-only builds should go with 19 rows or a dual-core setup.
  • Mounting: Common locations include the lower grille opening, behind the front bumper support, or in the driver-side fender well if you relocate the power steering cooler.
  • Oil Capacity: Adding a cooler increases total oil volume by 0.5–1.5 quarts. Always re-check oil level after installation.
  • Setrab Oil Cooler Kit (via Z1 Motorsports): Uses a genuine Swedish-made 19-row core with AN-10 fittings. Proven in professional drifting and time attack.
  • Mishimoto Oil Cooler Kit: 13-row aluminum core with a billet sandwich plate and pre-cut lines. Affordable and includes a lifetime warranty.
  • Greddy Oil Cooler Kit: 13-row core with an integrated thermostat. Slim design fits behind the bumper without extensive modification.
  • Earl’s Cooler Kit: Modular design allows you to add a fan or second core. Popular among DIY builders who want to customize their setup.

For installation tips and common pitfalls, refer to this detailed owner-written oil cooler guide on The370Z.com.

Intercooler: Essential for Turbo or Supercharged Builds

If you’ve added forced induction—whether a Stillen supercharger, Vortech centrifugal kit, or a full Garrett turbo system—the stock intercooler (if present) or the lack thereof becomes a bottleneck. Even mild boost levels of 6–8 psi can push intake air temperatures (IATs) beyond 140°F, robbing power and increasing the risk of detonation. A capable intercooler is the single most important supporting mod for any boosted 370Z.

Bar-and-Plate vs. Tube-and-Fin Cores

Aftermarket intercoolers come in two main core designs:

  • Bar-and-plate: Denser, more efficient, and more tolerant of high boost. Slightly heavier and more expensive. Preferred for track-heavy or high-horsepower builds.
  • Tube-and-fin: Lighter and cheaper, with less internal restriction. Adequate for street-driven cars running up to 500 wheel horsepower. Easier to fit behind a stock bumper.

Sizing and Pressure Drop

A common mistake is choosing an intercooler that is too large for the power level. Oversized cores increase the air volume the turbo must fill, raising spool time and adding pressure drop. A rule of thumb: for 400–500 whp, a core approximately 24″ x 6″ x 3″ (bar-and-plate) is ideal. For 600+ whp, step up to 28″ x 8″ x 4″ or a dual-core setup. Measure the area behind your front fascia—some intercoolers require trimming of the crash bar or bumper support.

Top Intercooler Options for the 370Z

  • AMS Performance Intercooler: Bar-and-plate with cast aluminum end tanks. Designed for their own supercharger kits but fits many custom setups. Excellent flow and heat rejection.
  • Stillen Intercooler Kit: Tube-and-fin core designed specifically for the Stillen supercharger. Direct-fit, includes all plumbing. Best for street-driven forced induction cars.
  • Greddy Intercooler Kit: Large bar-and-plate core with polished end tanks. Works with most turbo kits. Requires bumper modifications on some years.
  • Treadstone TR8 Series: Budget-friendly bar-and-plate option. Sold as a core only—you supply piping and couplers. Highly customizable.

For pressure drop and IAT testing data, see this CXRacing intercooler comparison study.

Creating a Cohesive Cooling Package

Installing a radiator, oil cooler, and intercooler individually helps, but their synergy is what transforms a 370Z into a reliable high-performance machine. When all three systems work together, coolant temps stay below 200°F, oil temps hover around 210–220°F, and IATs remain close to ambient. This thermal stability allows the ECU to run full timing, sustaining peak power lap after lap.

Placement and Airflow Planning

The key is to avoid stacking heat exchangers directly behind one another, which starves the rear unit of airflow. A typical layout from front to back is: intercooler (if boosted), then oil cooler, then radiator. If you have a supercharger, the intercooler may sit on top of the engine or in the driver-side bumper vent; in that case, the oil cooler can go in the passenger-side vent. Always use ducting to force air through the cores rather than around them. Aluminum duct tape or custom sheet metal shrouds make a measurable difference.

Additional Supporting Mods

  • High-flow thermostat: A 160°F or 170°F thermostat (e.g., Mishimoto, Nismo) keeps coolant flowing more freely, though it may delay warm-up in cold weather.
  • Electric fan controller: Programmable units (like Flex-a-lite or Spal) let you set lower trigger temperatures and run fans after key-off for cool-down.
  • Coolant additives: Water wetter or similar products reduce surface tension, improving heat transfer by 5–10°F. Use with distilled water and a proper antifreeze blend for street cars.
  • Oil temperature gauge: Essential for monitoring the effectiveness of your oil cooler. The factory gauge is notoriously inaccurate. Install a Defi or AEM digital gauge.

Conclusion: Prioritizing Your Supporting Mods

Every 370Z owner aiming for reliable performance should consider cooling upgrades before adding power. An upgraded radiator provides the foundation; an oil cooler protects the engine’s internals during sustained use; and if you run forced induction, a quality intercooler is non-negotiable. Start with a radiator and oil cooler—even naturally aspirated cars benefit greatly from these two mods. Then, as you move past basic bolt-ons toward supercharging or turbocharging, invest in a matching intercooler and re-evaluate your entire thermal management system.

Choosing the right products from reputable brands like CSF, Setrab, and AMS saves time and money in the long run. Remember that proper installation and thoughtful airflow planning are just as important as the components themselves. With a well-designed cooling package, your VQ37VHR will reward you with consistent power and longevity for many seasons of spirited driving.