The CJM S1 Fuel System is a complete return-style fuel system upgrade for the VQ37VHR platform. It replaces the factory supply-side plumbing with upgraded -6AN PTFE plumbing from the fuel pump module to the engine bay while retaining the factory fuel rails.

Fuel flow improvements begin inside the tank. The factory integrated filter housing is bypassed, allowing fuel to exit the pump module directly out a -6AN bulkhead fitting. Returning fuel is properly integrated into the factory venturi jet-pump system using our billet regulator delete and return conversion hardware.

In the engine bay, the S1 system upgrades the fuel supply path with black PVC-coated stainless braided PTFE hose and crimped aluminum hose ends. An inline CJM 10-micron microglass fuel filter is mounted beneath the vehicle with an included bolt-in bracket. An adjustable 1:1 manifold-referenced regulator controls fuel pressure at the firewall.

The original factory feed pipe is repurposed as the return line. This keeps the underbody installation clean, avoids permanent modification, and allows the vehicle to be returned to stock if desired.

• 370Z: Includes fully chassis specific bolt-in regulator mount.
• G37: Includes universal mounting hardware.

In off-the-shelf configuration, the S1 system has been tested to support 700+ WHP on E85 when paired with a sufficient fuel pump.

This is a fully engineered return system designed for high power, clean installation, and long-term reliability.

Tech Info

To replicate the factory returnless behavior using your existing tune:
Set base fuel pressure to 52 PSI and leave the regulator reference port unconnected (no vacuum/boost line attached).

For proper return-style operation (recommended):
Connect a vacuum/boost reference line to the regulator for a 1:1 manifold-referenced pressure ratio. This allows fuel pressure to rise and fall with manifold pressure. Consult your tuner before making adjustments.