HKS 1599-SN001 Airflow Less Adapter for RB20 VG30 EJ Engines

The HKS 1599-SN001 Airflow Less Adapter is a precision-machined replacement pipe designed to eliminate the stock airflow meter (AFM/MAF) from the intake system. The factory air flow meter creates significant suction resistance in the intake path, and this adapter allows it to be removed entirely when switching to a speed-density (D-Jetro) fuel management setup—such as the HKS F-CON V Pro—where a mass airflow sensor is no longer required.

Constructed from polished aluminum casting, the adapter features a buffed finish that delivers a clean, show-quality appearance in the engine bay. The pipe includes a dedicated boss for an intake air temperature (IAT) sensor, allowing the sensor to be relocated after the AFM is removed. Note that IAT sensor installation may require minor modification.

Key Features:

• Replaces the restrictive stock airflow meter with a straight aluminum pipe
• Compatible with φ80mm flange AFM housings (Nissan RB/VG30 and Subaru EJ-series engines)
• Enables D-Jetro (speed-density / MAP sensor) fuel management tuning
• Polished buffed-finish aluminum cast construction
• Integrated boss for intake air temperature (IAT) sensor relocation
• Designed for use with HKS Racing Suction and Racing Suction Reloaded intake systems
• Compatible with HKS F-CON V Pro engine management

Performance gains are maximized when the Airflow Less Adapter is paired with an HKS Racing Suction Reloaded intake kit. Note that on SR20-equipped applications, an aftermarket intake kit is required for fitment—the adapter is not compatible with the standard factory intake system on those engines.