Upgrading the fuel system in a 2015 Chevrolet Camaro is a critical step for enthusiasts chasing higher horsepower, forced induction, or E85 conversions. The stock fuel system, while adequate for factory power levels, quickly becomes a bottleneck when you increase engine output. The Aeromotive Phantom Regulator is a top-tier choice for these builds because it integrates seamlessly with the factory fuel module and provides precise return-style fuel pressure control. This guide will walk you through every phase of the installation—from preparation and component selection to final calibration and leak testing.

Why Upgrade Your Fuel System on a 2015 Camaro?

The 2015 Camaro (fifth generation, gen5) uses a returnless fuel system from the factory. In a returnless system, the fuel pressure regulator is located inside the tank on the pump module, and the engine computer (ECU) controls pump speed to maintain pressure. While this works well for stock power levels, it lacks the flexibility needed for modified engines:

  • Increased fuel flow demand: Adding a supercharger, turbocharger, or nitrous oxide requires significantly more fuel volume—often exceeding the stock pump’s capacity.
  • Pressure stability under boost: Returnless systems can lose pressure as injector duty cycles rise, causing lean conditions and detonation.
  • Fuel type flexibility: Many tuners run E85 ethanol, which demands 25–30% more flow than gasoline; a return-style system with a bypass regulator handles this easily.

The Aeromotive Phantom Regulator converts the Camaro’s returnless fuel system to a return-style setup. This gives you a fixed base pressure (typically 58 psi for Gen V LT engines) and allows the regulator to bypass excess fuel back to the tank, maintaining constant pressure even at high flow rates. It also simplifies upgrading to larger injectors and pumps.

Understanding the Aeromotive Phantom Regulator

The Phantom Regulator is designed specifically for in-tank fuel pump modules like the one in the 2015 Camaro. It replaces the factory regulator cap on top of the module and adds a return port. Key features include:

  • Billet aluminum construction for corrosion resistance and durability.
  • Adjustable base pressure via an Allen key (40–70 psi range).
  • Integrated check valve to maintain system pressure after shutdown.
  • Compatible with gasoline, E85, and methanol blends.

This regulator is ideal for builds that need up to 1,000 crankshaft horsepower on gasoline, or around 850 on E85, depending on pump selection. It works with the factory fuel pump module, so you can retain the factory fuel level sender and pump wiring harness.

Tools and Materials Needed

Before starting, gather all necessary tools and components. You will need the Aeromotive Phantom Regulator Kit (PN 18533 for the Camaro), along with additional fuel system parts.

  • Aeromotive Phantom Regulator Kit (includes regulator, O-rings, spring, and gasket)
  • Socket set (metric and SAE) – 10mm, 13mm, 15mm, 7/16", and 1/2" sockets
  • Combination wrenches (10mm, 13mm, 15mm)
  • Torx bit set (T25, T30 for interior panel removal)
  • Fuel line disconnect tool (3/8" and 5/16" plastic or metal)
  • Fuel pressure gauge (for calibration)
  • Safety glasses and nitrile gloves
  • Shop towels and a fire extinguisher (rated for fuel)
  • Fuel line cutter or sharp utility knife
  • Wire strippers, crimpers, and heat shrink tubing
  • Multimeter
  • Optional: new fuel pump (e.g., Walbro 525 or AEM 340 LPH) if upgrading flow
  • Optional: fuel line and AN fittings for return line if not reusing stock

Pre-Installation Safety Precautions

Fuel system work carries inherent risks. Always work in a well-ventilated area away from open flames, sparks, or pilot lights. Disconnect the battery negative terminal before any electrical work. Depressurize the factory fuel system by removing the fuel pump fuse and running the engine until it stalls, then cranking for a few seconds. Wear safety glasses and gloves. Have absorbent materials ready for spills.

Step-by-Step Installation Process

Step 1: Access the Fuel Pump Module

The 2015 Camaro’s fuel pump module is located under the rear seat on the driver’s side. Remove the rear seat cushion by pulling up on the front edge and sliding it out. You will see a metal access cover with a rubber gasket. Remove the four 10mm bolts and lift the cover. Disconnect the fuel line quick-connect fittings using the appropriate disconnect tool. Use a shop towel to catch any fuel. Disconnect the electrical connector on top of the module. Carefully remove the retaining ring (usually a plastic locking ring) using a large pry tool or a spanner wrench designed for fuel modules. Lift the module out of the tank, being careful not to bend the float arm. Place the module on a clean work surface.

Note: On some models, the module is accessed from under the car by removing the fuel tank. However, on the gen5 Camaro, the under-seat method is standard and far less invasive.

Step 2: Remove the Factory Fuel Pressure Regulator

The factory regulator is built into the top of the fuel pump module. It is a black plastic unit with the fuel outlet and return line fittings. Using a small flathead screwdriver or a pick, carefully pry off the retaining clip. Remove the regulator cap and the internal spring and diaphragm. The Aeromotive kit comes with a new gasket that seals against the module body. Clean the mating surface thoroughly with a lint-free cloth. Do not use any solvents that could contaminate the fuel.

Step 3: Install the Aeromotive Phantom Regulator

Place the supplied O-ring into the groove on the module. Set the regulator body onto the module, aligning the fuel outlet port. The regulator should seat flush. Install the new retaining clip (included) to secure the regulator. Tighten the Allen head screws on the clip to the specified torque (typically 15–20 in-lbs, or as per kit instructions). Do not overtighten. Connect the fuel outlet line from the module to the regulator’s outlet. Use the provided adapter if needed. The regulator also has a return port. You will need to run a return line from this port back to the tank. The kit includes a 90-degree AN fitting; attach a PTFE-lined hose or a steel braided line using the appropriate fittings.

If you are also upgrading the fuel pump, install the new pump in the module at this point, following the pump manufacturer’s instructions. The Phantom regulator works with most aftermarket pumps.

Step 4: Install the Return Line (if not already present)

Factory returnless Camaros do not have a return line from the engine bay. You can either use the stock fuel line as the return and run a new supply line, or route a dedicated return line. The simplest approach is to use the existing fuel supply line as the return and install a new -6 AN supply line. If you prefer to keep the factory supply line, you must add a new return line from the regulator back to the tank. Route the return line along the frame rail, avoiding heat sources and moving parts. Use rubber grommets wherever the line passes through the floor or chassis. Connect the return line to the regulator’s return port and to a new bulkhead fitting on the fuel pump module top (drill and tap if needed, or use a pre-drilled module).

Alternatively, some aftermarket fuel modules have a dedicated return port. If you purchase a complete module (e.g., from Roto-Fab or DSX), the return line is already integrated. For this guide, we assume using the Phantom regulator on the stock module, so you will need to create a return port. The kit includes a drill template and a bulkhead fitting for this purpose. Follow the template carefully to avoid damaging the fuel level sensor.

Step 5: Install the Fuel Pump Controller (Optional)

The stock fuel pump control module (FPCM) may need to be retained or bypassed depending on your pump choice. For a basic configuration, you can wire the new pump directly to the factory harness, but you must ensure the pump is rated for the voltage and current. Many aftermarket pumps draw more current than the factory wiring can handle. Install a relay kit with 10-gauge wire from the battery, triggered by the factory pump signal. Connect a 40-amp relay and an inline fuse holder. The Phantom regulator does not require any electrical connections—it is purely mechanical—but the pump wiring is critical.

If you are using a brushless pump (e.g., Aeromotive Fuel Command Center), follow the manufacturer’s wiring diagram.

Step 6: Reinstall the Fuel Module

Carefully lower the module back into the fuel tank, ensuring the float arm is correctly positioned and the O-ring seals are in place. Install the locking ring and tighten it evenly with a spanner wrench. Reconnect the factory electrical connector and fuel lines. For the supply side, use a new quick-connect fitting if the original is damaged. For the return line, use a push-lock or AN fitting as per your setup. Reinstall the access cover and rear seat cushion.

Step 7: Connect the Engine Bay Fuel Lines

In the engine bay, connect the new fuel supply line to the fuel rail. If you are running a return-style system, you must also connect a return line from the fuel rail back to the tank. However, on a return-style setup, the regulator is at the tank, not the engine. The fuel rail should have a simple feed and return fitting. The return line goes back to the Phantom regulator’s return port. This is the standard configuration for return-style systems: fuel is pumped up to the rail, passes through the injectors, and unused fuel returns to the tank via the regulator. The Phantom regulates pressure by bypassing excess fuel inside the tank.

Note: If your engine is a Gen V LT1 (2016+ Camaro), you may need different fuel rail adapters. The 2015 Camaro is typically an LS3 (if SS) or L99 (if automatic), which use standard 3/8" quick-connect fittings.

Step 8: Prime the System and Check for Leaks

Reconnect the battery. Remove the fuel pump fuse and crank the engine for 5 seconds to prime the system without starting. Install the fuse and turn the key to the “on” position (do not start). Listen for the pump to run. Check all connections for leaks: at the regulator, at the fuel rails, and along the return line. Use a spray bottle with soapy water to detect bubbles around fittings. If you see leaks, tighten the fittings or replace O-rings. Do not proceed until all leaks are resolved.

Step 9: Set Base Fuel Pressure

The Aeromotive Phantom Regulator is adjustable. Connect a fuel pressure gauge at the fuel rail test port. With the engine off and pump running (key on, engine off), adjust the regulator using the Allen key on top. Turn clockwise to increase pressure, counterclockwise to decrease. Target base pressure depends on your injectors and fuel type. For LS3/L99 engines, 58 psi is standard. For E85, you may want 55–58 psi. For boosted applications, you will need to reference your tuner’s recommendation. Once set, lock the adjustment screw by tightening the jam nut.

After setting pressure, start the engine and let it idle. Monitor the gauge for fluctuations. The pressure should remain steady. If it drifts, you may have a restriction or a faulty regulator.

Final Calibration and Tuning

With the regulator installed and base pressure set, you are ready to tune the engine. The new fuel system will behave differently: the return line prevents pressure bleed-off, and the pump will run constantly at a fixed speed (unless you use a PWM controller). Work with a professional tuner to adjust the fuel map in the ECU. The tuner will need to know your base pressure, pump flow curve, and injector size. A return-style system simplifies tuning because fuel pressure is constant, eliminating the need for a pressure vs. pulse-width correction table.

Perform a road test under various conditions: low load, high load, and full throttle. Verify that the fuel pressure does not drop below base pressure under boost. If you see pressure drop, the pump may be undersized or there is a restriction.

Troubleshooting Common Issues

  • Engine won’t start or runs lean: Check for reversed fuel lines (supply and return swapped). Ensure the regulator is not stuck open. Verify pump wiring polarity.
  • Fuel pressure rises with boost: This is normal on a return-style system if the regulator is referenced to manifold vacuum/pressure. Ensure you have connected a vacuum reference line from the regulator to the intake manifold (if using a Boost Referenced Pressure Regulator). The Phantom regulator can be used with or without a boost reference; for forced induction, you typically want a 1:1 rise to maintain differential pressure across the injectors.
  • Fuel leaks from the regulator: Replace O-rings. Ensure the retaining clip is fully seated. Check the sealing surface on the module for cracks.
  • Fuel pressure too high or low: Adjust using the Allen key. If you cannot reach the desired pressure, the spring may be incorrect. Aeromotive offers different spring rates for different pressure ranges.
  • Fuel pump is noisy: Ensure the pump is properly insulated from the module. The Phantom regulator should not cause pump noise; check for cavitation (low fuel level) or a clogged inlet sock.

Additional Upgrades to Consider

While the Phantom regulator solves the pressure regulation problem, it works best with a matched pump and injectors. Consider these complementary upgrades:

  • High-flow fuel pump: Walbro 525, AEM 340 LPH, or a DC brushless pump for quiet operation.
  • Larger injectors: 60 lb/hr for gasoline up to 600 HP, 80–100 lb/hr for E85 and forced induction.
  • Fuel rail upgrades: Larger diameter rails prevent pressure drop at high flow.
  • E85 conversion kit: Replace all rubber lines with PTFE-lined hose and Viton O-rings.
  • Fuel pressure gauge: Permanent in-cabin gauge or a remote sensor for logging.

External Resources and References

For further reading and specifications, refer to the following:

Conclusion

Installing the Aeromotive Phantom Regulator in a 2015 Camaro is one of the most effective ways to unlock the full potential of a high-performance fuel system. By converting to a return-style setup, you gain precise pressure control, improved fuel flow, and the ability to run a variety of fuel blends. This guide has covered every step: from accessing the tank and removing the factory regulator, to installing the Phantom, routing the return line, and calibrating base pressure. With careful attention to detail and proper tuning, your Camaro will deliver reliable power for thousands of miles.

Remember that fuel system modifications are safety-critical. Always pressure-test your work and consult a professional tuning shop if you are unsure about any step. The Aeromotive Phantom Regulator, when installed correctly, will provide years of trouble-free service and make your Camaro a true high-performance machine.