Why Upgrade the Fuel System on Your Challenger Redeye?

The Dodge Challenger Redeye already leaves the factory with a capable fuel system, but when you start chasing higher horsepower numbers—especially in the 800+ hp range—the stock setup quickly becomes a bottleneck. A high-performance fuel system delivers the volume and pressure required to support forced induction upgrades, larger supercharger pulleys, or even a switch to E85. In Nashville, where the car scene is thriving and track days at places like Music City Raceway are common, reliable fuel delivery separates a weekend warrior from a trailer queen. Upgrading also improves throttle response and gives your tuner the headroom needed to dial in the perfect air-fuel ratio without leaning out at high RPM.

Key Components: What You’ll Actually Need

Building a proper fuel system for a Redeye isn’t just about throwing in bigger parts. Each component must work together to maintain stable pressure from idle to redline. Here’s a breakdown of what matters.

High-Flow Fuel Injectors

Stock injectors on the Redeye flow around 70 lb/hr. For builds targeting 900–1000 wheel horsepower, you’ll want 130–165 lb/hr injectors. These provide better fuel atomization, which helps with combustion efficiency and reduces the chance of misfires under boost. Look for units that are E85-compatible if you plan to run ethanol blends.

Upgraded Fuel Pump(s)

The factory in-tank pump can’t maintain pressure when demand spikes. Many Redeye owners go with a dual-pump setup (e.g., two 525 LPH pumps) or a brushless pump like the Aeromotive 340. In Nashville’s summer heat, fuel pump efficiency can drop, so over-speccing slightly is smart. For extreme horsepower, an external fuel system with a surge tank may be necessary.

Fuel Pressure Regulator

A boost-referenced regulator, such as the Holley Hydramat or Fuelab, keeps fuel pressure constant relative to boost pressure. Without it, your injectors could run out of headroom at 15+ psi. Set static pressure to around 58 psi for port-injected setups.

Reinforced Fuel Lines

Stock nylon lines may swell or burst under high pressure. Replace them with PTFE-lined stainless steel braided hoses or equivalent. This is especially important for E85, which is more corrosive and can degrade rubber hoses over time. In Nashville, where ethanol blends are available at many stations, switching to E85 is a popular power adder, but it requires a dedicated flex fuel system.

If you plan to mix fuels, adding a flex fuel sensor allows your ECU (via a custom tune) to adjust timing and fueling automatically. This gives you the best of both worlds: pump gas for daily driving and E85 for the track.

Preparation: Tools, Safety, and Workflow

Before you crack open the fuel system, preparation prevents frustration and fire. Here’s what you need.

Essential Tools

  • Fuel pressure gauge (to relieve pressure and verify after install)
  • Safety glasses and nitrile gloves—gasoline and E85 are harsh on skin
  • Line disconnect tools for factory quick-connect fittings
  • Torque wrench (fuel rail bolts and line fittings have specific torque specs)
  • Pry tools and trim removal kit (on the Redeye, the fuel pump access is under the trunk carpet)
  • Helping hands or a second person—some steps require holding parts while tightening

Safety First

Relieve fuel system pressure by running the engine with the fuel pump fuse removed until it stalls. Then disconnect the battery and work in a well-ventilated area. Keep a fire extinguisher nearby. Nashville’s heat can make fuel vapor more flammable, so avoid any open flames or sparks.

Step-by-Step Installation Guide

These instructions assume a Redeye with the 6.2L Hemi. Always consult your specific component manuals for torque values and wiring diagrams.

Step 1: Remove the Trunk Liner and Access Fuel Pump

Pop the trunk, pull the carpet, and remove the access panel. The fuel pump module is held by a locking ring. Use a hammer and punch (or a dedicated spanner tool) to rotate it counterclockwise. Disconnect the electrical connector and supply/return lines. Carefully lift the module out to avoid bending the float arm. Have a rag ready to catch residual fuel.

Step 2: Install the Upgraded Pump(s)

If using a dual-pump setup, the module basket may need modification. Some aftermarket kits include a replacement module. Ensure the pump(s) sit properly in the bottom of the tank and that the fuel sock doesn’t touch the tank floor (this can cause pickup issues on low fuel). Install a new gasket or O-ring on the locking ring. Torque the locking ring to spec (typically 25–30 ft-lbs).

Step 3: Replace Fuel Lines

Disconnect the factory lines at the fuel rail and the firewall connection. Route new PTFE lines along the same path, using nylon wire ties to secure them away from exhaust heat. If you’re adding a flex fuel sensor, place it in the return line after the regulator for best accuracy.

Step 4: Swap Injectors and Install Fuel Rail

Remove the upper intake manifold to access the fuel rail. Unbolt the rail and gently pry out the old injectors. Lubricate the new injector O-rings with fresh engine oil, then press them into the rail and intake ports. Reinstall the rail, tightening bolts evenly to prevent binding. Reinstall the intake manifold with a new gasket.

Step 5: Mount the Fuel Pressure Regulator

Install the regulator on the firewall or near the fuel rail. Connect the vacuum reference line to a manifold vacuum source. Set static pressure to 58 psi with the engine off (key on). Use a pressure gauge to confirm.

Step 6: Connect Electrical

Route power for the fuel pump(s) through a relay triggered by the factory pump control wire. Use 10-gauge wire and a 40-amp fuse. If you have a brushless pump, follow the manufacturer’s wiring diagram carefully—inverting polarity can damage the controller. Connect the flex fuel sensor to the ECU’s analog input (HP Tuners pins may vary).

Step 7: Test for Leaks and Prime the System

Reconnect the battery. Before cranking, cycle the key to the “ON” position a few times (without starting) to prime the system. Check all fittings for drips. If you see any, tighten them—do not over-torque on aluminum parts. Once leak-free, start the engine and let it idle. Monitor fuel pressure and listen for pump cavitation (abnormal whining).

Tuning: The Missing Piece

New fuel hardware won’t perform without calibration. Find a local Nashville tuner who specializes in the Hellcat platform. They will adjust fuel tables, injector latency, and MAF scaling to match your new injectors and pump. If you added a flex fuel sensor, your tune must include flex fuel logic (available through HP Tuners or DiabloSport). Expect to spend 2–4 hours on the dyno. Some reputable shops in the Nashville area include:

  • Redline Motorsports – Known for Hellcat and Demon builds, with a full chassis dyno.
  • Boosted Performance – Offers remote tuning if you have an HP Tuners RTD device.
  • Tuners Inn – Full-service performance shop with experience in forced induction.

Note: Always ask the tuner to provide a data log after the initial session. This confirms the fuel system is keeping up under wide-open throttle, especially on hot Nashville summer days when air density is lower and fuel demands change.

Nashville-Specific Considerations

Emissions and Law

Davidson County (Nashville) requires emissions testing for OBD-II vehicles. A modified fuel system itself rarely triggers a test failure unless it physically disables the EVAP system. However, if your tune causes a “Catalyst Efficiency” code, you may fail. Work with your tuner to keep the catalyst monitors ready. Some performance shops can also help with temporary “sneaker” passes if your build is primarily a track car, but street legality is your responsibility.

Fuel Availability

E85 is widely available in the Nashville metro area. Stations like the Mapco on Nolensville Pike and several Kangaroo stores carry it. However, ethanol content can vary from 60–85% depending on season. A flex fuel sensor is invaluable for adjusting to these swings. Regular 93 octane is also premium at most pumps, but for high-boost builds, consider using a fuel additive or blending with E85 for octane.

Climate Impact

Nashville’s hot, humid summers increase the risk of fuel boiling in the rails—especially on a car that sits in traffic after a hard pull. A good thermal barrier between the fuel lines and exhaust headers can help. Also, consider a heat shield for the fuel pump module to prevent vapor lock, which can cause hard hot starts. Some owners install a small radiator fan in the trunk area to cool the pump on days over 90°F.

Final Tips for a Flawless Build

  • Use genuine parts for the fuel pump hat gasket. Aftermarket O-rings often leak. Order from your local Dodge dealer or Mopar parts counter.
  • Don’t skip the fuel filter. Even with new lines, debris can enter during assembly. Place a high-flow inline filter after the pump.
  • Consider a fuel pressure gauge (mechanical or digital) inside the cabin. It can alert you to pump failure before the engine detonates.
  • Log fuel pressure during the first few pulls. If pressure drops more than 3 psi at 6000 RPM, your pump is undersized or the regulator is set wrong.
  • Inspect the fuel tank sock regularly. E85 can leave sediment that clogs the sock, starving the pump. Replace it every 10,000 miles if running ethanol.
  • Join the ChallengerTalk forum for local Nashville meetups and technical advice. Many owners have done this exact swap and can recommend trusted mechanics.

Upgrading your Redeye’s fuel system is not a simple bolt-on—it’s a careful integration of components, wiring, and tuning. But the reward is extraordinary: a muscle car that can pull hard all the way through the quarter mile, without hesitation. In Nashville’s vibrant car community, a properly fueled Redeye will turn heads on Broadway and dominate at the track. Take your time, use quality parts, and partner with a local expert to get the maximum return on your investment.