Why Air-to-Water Cooling Dominates the R35 Platform

The Nissan GT-R R35's factory intercooler setup is a compromise—adequate for stock power but quickly becomes a bottleneck as boost and horsepower climb. Air-to-water (A2W) intercoolers have become the gold standard for R35 owners chasing 150+ hp gains because they offer denser charge air, more consistent intake temperatures, and less pressure drop than traditional air-to-air systems. By using a separate water circuit and heat exchanger, A2W intercoolers can maintain near-ambient intake temps even during repeated pulls, making them ideal for drag racing, road course work, and high-speed highway driving.

When you upgrade to a quality A2W system, you're not just adding cooling capacity—you're enabling your tuner to add more timing and boost safely. The Nissan GT-R R35 responds exceptionally well to cooler intake air, and a well-designed intercooler is the foundation for a 150+ horsepower gain. Below we examine five top-tier A2W intercooler installations, each with unique engineering approaches, real-world power results, and the supporting hardware you'll need to maximize your investment.

What to Look for in an A2W Intercooler Upgrade

Before diving into specific kits, understand the key metrics: core volume, internal fin density, water flow path, and heat exchanger size. A larger core isn't always better if water flow is restricted or if the heat exchanger can't shed heat fast enough. The best systems balance these factors while offering a direct-fit installation that minimizes custom fabrication. All five options below have proven track records on R35s making over 700 wheel horsepower.

1. AMS Performance Alpha Intercooler

AMS Performance is synonymous with high-horsepower GT-R builds. Their Alpha Intercooler is a complete air-to-water replacement system designed for the R35's tight engine bay. The core measures 24” x 12” x 4” and uses a low-restriction bar-and-plate design to maximize heat transfer without choking airflow.

  • Core Size: 24” x 12” x 4” – optimized for maximum cooling surface area within factory constraints
  • Power Gains: 150+ wheel horsepower with supporting modifications and ECU tuning
  • Construction: TIG-welded aluminum with CNC-machined end tanks for leak-free performance
  • Water Pump: High-flow Bosch pump included; recirculates coolant through the front-mounted heat exchanger
  • Heat Exchanger: 13” x 24” dual-pass unit fits behind the lower grille

AMS claims their Alpha system reduces intake air temperatures by over 50°F during back-to-back dyno pulls compared to stock. The kit includes all silicone hoses, hose clamps, brackets, and an aluminum overflow tank. Installation requires removing the front bumper and bumper beam, but the kit is a direct bolt-on for 2009-2017 R35s. For later models (2018+), minor trimming of the crash bar may be necessary. Tuning is essential; without a proper ECU calibration, you won't realize the 150+ hp potential. Many owners pair this intercooler with AMS’s own downpipes and intake system for a complete power package. Visit AMS Performance

2. Mishimoto Air to Water Intercooler Kit

Mishimoto has built a reputation for race-proven cooling solutions. Their R35 A2W kit is engineered for enthusiasts who want a robust, all-in-one solution without breaking the bank. The core is slightly larger at 26” x 12” x 4” and uses a high-density internal fin pack to shed heat rapidly.

  • Core Size: 26” x 12” x 4” – enhanced frontal area for improved flow
  • Power Gains: Reliably achieves 150+ hp with a Stage 2+ tune (requires fuel upgrades)
  • Features: Direct-fit aluminum tanks with O-ring seals; no welding required for installation
  • Included Components: 10” x 22” dual-pass heat exchanger, high-flow water pump, CNC-machined thermostat housing
  • Warranty: Mishimoto's lifetime warranty on materials and craftsmanship

What sets Mishimoto apart is their focus on thermal recovery. The system includes a large coolant reservoir and an integrated bleed valve to eliminate air pockets, ensuring consistent cooling during repeated runs. On the dyno, Mishimoto reports a 45-50°F drop in intake air temperature at 25 psi boost. The kit is designed for 2009-2019 R35 models and includes detailed installation instructions. The only potential challenge is routing the coolant lines around the factory intercooler brackets, but most mechanically inclined owners can complete the install in a weekend. Pair with a full exhaust and a custom tune for the advertised gains. Browse Mishimoto's R35 products

3. HKS GT-R Intercooler Kit

HKS is a Japanese aftermarket giant known for motorsports-grade engineering. Their GT-R Intercooler Kit is designed for high-boost applications, with a focus on durability and airflow consistency. The core measures 25” x 12” x 4” and features a unique staggered fin design that reduces flow restriction while maximizing heat transfer.

  • Core Size: 25” x 12” x 4” – optimizes pressure drop vs. heat rejection
  • Power Gains: Over 150 hp with supporting mods (upgraded turbos recommended for full potential)
  • Benefits: Extremely robust construction with cast aluminum end tanks; resistant to cracking under high boost
  • Includes: High-capacity water pump, aluminum reservoir, silicone hoses, and thermostat
  • Heat Exchanger: 12” x 24” dual-pass with integral fan shroud for low-speed cooling

HKS's system is particularly popular among track-day enthusiasts because of its ability to maintain consistent power output lap after lap. The heat exchanger includes an electric fan that activates via a temperature switch, keeping coolant temps in check when the car is stationary or in slow corners. Installation is straightforward but requires removal of the factory intercooler system and some minor plastic trimming. The kit is compatible with 2009-2020 R35s. For maximum gains, HKS recommends their Flash Editor ECU tuning software. Find HKS dealers near you

4. Greddy Air to Water Intercooler System

Greddy (Trust) is another legendary name in Japanese performance. Their R35 A2W system prioritizes a compact footprint while delivering massive cooling capacity. The core is 24” x 12” x 4” but uses a higher fin density than most competitors, allowing it to punch above its size.

  • Core Size: 24” x 12” x 4” – tight tolerance design for easy fitment
  • Power Gains: 150+ hp with a comprehensive stage 2 package (intake, downpipes, exhaust, tune)
  • Installation: Complete bolt-on kit with all hardware; includes a water pump wiring harness
  • Construction: Aluminum core with cast tanks and rubber-bushed mounts to reduce vibration
  • Cooling: Separate 12” x 24” heat exchanger with a built-in fan

Greddy’s system excels in cars that see a mix of street and occasional track use. The water pump is quieter than some competitors, and the included instruction manual is detailed. One unique feature is the optional blow-off valve flange integrated into the intercooler outlet, simplifying installation of a BOV. The kit is designed for 2009-2018 models. Some owners report needing to notch the under-tray for heat exchanger clearance, but this is a simple modification. Tuning with a Cobb Accessport or ECUTek is mandatory to unlock the 150+ hp. Shop Greddy intercooler systems

5. Forge Motorsport Intercooler Kit

Forge Motorsport is known for high-pressure engineering and has strong ties to competitive motorsport. Their R35 intercooler kit is the largest of the group at 27” x 12” x 4”, designed to support extreme power levels well beyond 150 hp gains.

  • Core Size: 27” x 12” x 4” – largest core in this comparison
  • Power Gains: Capable of 150+ hp with a proper tune; supports up to 800+ wheel hp
  • Construction: High-quality cast aluminum end tanks with CNC-machined inlet/outlets
  • Included: All silicone hoses, T-bolt clamps, water pump, and a triple-pass heat exchanger
  • Durability: Tested to over 40 psi boost pressure without distortion

Forge's triple-pass heat exchanger stands out—it routes water through three distinct passes before returning to the intercooler core, significantly increasing heat rejection. The kit also includes a billet aluminum thermostat housing to maintain optimal water temperature. Installation is more involved than some competitors due to the larger core; minor modifications to the front bumper support may be needed. However, the cooling performance is unmatched. Many owners using Forge's system on built motors report intake temps within 10°F of ambient even after multiple high-speed passes. Explore Forge Motorsport's GT-R lineup

Installation Considerations for Air-to-Water Systems

Installing any of these A2W intercoolers requires careful planning. All five kits are essentially bolt-on, but you'll need to flush and refill the cooling system, which adds time. Common steps include:

  • Removing the front bumper, crash bar, and factory intercooler assembly
  • Mounting the new intercooler core in the engine bay (requires removing the factory intake manifold cover on some models)
  • Routing coolant lines from the front heat exchanger to the pump and back to the core
  • Bleeding air from the system to prevent cavitation
  • Reinstalling the bumper with possible modifications for heat exchanger clearance

If you're not comfortable with cooling system work, have a reputable shop perform the installation. Labor time ranges from 4-10 hours depending on the kit and the technician's experience. Also consider upgrading the radiator and oil cooler simultaneously, as the additional heat load from higher boost can push other systems to their limits.

Tuning for 150+ Horsepower Gains

An intercooler alone won't deliver 150 hp—it's an enabler. To realize the advertised gains, you must address fuel delivery, airflow, and exhaust flow. Most builds combine an A2W intercooler with:

  • High-flow intake system (cold air or ram air)
  • Aftermarket downpipes and cat-back exhaust
  • Upgraded fuel injectors (1,000cc or higher) and high-pressure fuel pump
  • ECU tuning via Cobb Accessport, ECUTek, or HKS Flash Editor
  • Boost controller (optional but recommended for precise tuning)

With these supporting mods, a proper tune should yield 150-200 wheel horsepower over stock. Many tuners target 650-700 wheel hp on 93 octane, which approaches the limits of stock internals. If you plan to exceed 700 whp, consider upgrading the turbos and fitting a larger heat exchanger or ice tank.

Comparing the Five Kits: Which Is Right for You?

All five intercoolers are excellent, but they cater to different budgets and use cases. Here's a quick guide:

  • Budget-minded enthusiast: Mishimoto offers the best value with lifetime warranty and balanced performance.
  • Hardcore track user: HKS or Forge stand out due to their robust construction and superior heat exchanger designs.
  • Proven high-horsepower builds: AMS Performance has a long history of 1000+ hp GT-Rs and their Alpha intercooler is a staple in record-holding cars.
  • Compact, streetable install: Greddy's kit is the easiest to fit and quieter than most, ideal for daily drivers who want occasional track fun.
  • Extreme power goals (800+ whp): Forge's larger core and triple-pass heat exchanger give it a slight edge in sustained cooling.

Don't forget to budget for installation and tuning—they can add $1,500-3,000 to the total cost. Also factor in the price of an upgraded heat exchanger (some kits include a good one, others offer optional upgrades).

Final Thoughts: The Path to 150+ HP

Upgrading to an air-to-water intercooler is one of the most impactful modifications for a Nissan GT-R R35. The five systems covered here—AMS, Mishimoto, HKS, Greddy, and Forge—each deliver the necessary cooling performance to safely support 150+ horsepower gains when paired with proper supporting modifications and tuning. The key is to choose a kit that matches your power goals, driving style, and budget.

Remember that the R35's engine management system is highly adaptive; even a modest increase in cooling efficiency can yield double-digit horsepower improvements. By selecting one of these proven intercooler systems and working with a skilled tuner, you'll transform your GT-R into a formidable performer capable of embarrassing much more expensive machinery. Join the NAGTROC community for owner feedback and independent dyno results.