Updated: Jun 18
The purpose of this post is to serve as a guide when choosing fuel system components. Due to vehicle to vehicle differences, as well as the large disparity in Dyno numbers circulated on the internet, we can't provide any absolutes or guarantees that these components will work with *Your* setup. The data provided here errors on the safe side, however, factors such as mechanical health, plumbing, pressure regulation, and boost pressure can lead to deviations from this guide.
Stock Fuel Delivery The 5th Generation Camaro SS comes equipped with a ~190lph in tank pump, regulated to 58psi in a returnless configuration. Fuel is delivered to the motor with injectors that flow 42lb/hr at their 58psi operating pressure. The 5th Gen ZL1 was equipped with a higher volume fuel pump, flowing around ~250lph at 58psi. The ZL1 is also running in a returnless configuration with 53lb/hr injectors, at 58psi of pressure. Both the SS and ZL1 have a Fuel Pressure Control Module (FPCM) that regulates pump voltage and sends fuel pressure data to the ECU over the vehicle's CAN bus.
The SS's stock fuel pump is the first component to reach a fuel delivery limit. The SS pump starts dropping pressure around 530whp on a factory 58psi returnless fuel system. Automatic cars, with more parasitic loss, will have trouble closer to 500whp. The ZL1 pump offers some additional headroom, delivering fuel into the low 600whp range. Injector Limits The 42lb/hr SS injectors are adequate for around 600whp NA. In a forced induction setup, however, they are often undersized. For example, when the same 42lb/hr injectors are pushing against 7psi of manifold pressure, they're only able to flow 39lb/hr, supporting around 480whp at the richer air fuel ratios you would see in a forced induction setup. The ZL1 fuel injectors also have problems working against boost pressure. At 10psi, the injectors are actually flowing around 48lb/hr against the pressure in the manifold. At 10psi, the stock injectors can support around 550whp worth of airflow. As boost increases, flow rate decreases. This is why injectors are usually required for a 10% pulley on a ZL1.
Pump Upgrades There are many drop-in solutions to augment the factory fuel pump. The pump is located under the back seat, and there is no access hatch. To remove the pump, you'll ether be dropping the exhaust, driveshaft, and front of the rear cradle, or you will need to cut and install an access hatch under the rear seat. Dropping and re-installing the tank is usually a 5-6 hour job.
With the many dual and triple pump sending units available you can size your in-tank fuel system for upwards of 1500hp using drop-in components. Triple pump kits exclusively rely on AN lines for fuel feed and return. On sub-1000hp setups, the hard factory fuel feed line can often be re-purposed as a return to save time and money. When upgrading to a multi-pump setup, or even when upgrading to a ZL1 pump, the FPCM will need reprogrammed to accommodate your changes. This is usually a $200 service at a qualified shop. If at all possible, it is ideal to retain the fuel pressure sensor from the factory feed line, so that your ECU can calculate your injector flow rate as fuel pressure varies. If you have converted to AN lines, you can accomplish this by purchasing a union fitting with an 1/8NPT or -4 port on the side to adapt to your existing sensor. These fittings are commonly available for this purpose.
Auxiliary Pumps An auxiliary pump, when installed properly, is the easiest way to add fuel flow to your existing fuel system. An off-the-shelf bolt-in kit from DSX Tuning is a quick way to add around 200lph more volume to your boosted 5th-Gen.
Kits similar to those provided by DSX Tuning tap into the bottom of the fuel tank, to feed an external pump. The external pump is triggered to come on when a certain manifold pressure is reached, and will push fuel into a Tee fitting, connected to the vehicle's feed line.
Since the 5th Gen FPCM has an input for a Fuel Pressure Sensor, the ECU is able to calculate the correct amount of fuel to inject, even if fuel pressure spikes or begins to fall. This assumes you have correct injector data.
Fuel Injector Upgrades While any injector with an EV6 connector, and a O-ring to O-ring height of 38mm will be a direct fit, it's important to find fuel injectors with actual data.
The ECU in the 5th Gen Camaro has an upper limit of just under 100lb/hr (rated at 58psi) for fuel injectors in a factory returnless configuration. In a return based application, with a boost and vacuum referenced fuel pressure regulator, you can run up to 127lb/hr with the factory ECU. Above these limits, the ECU will have to be re-scaled. Re-scaling is not difficult, but will complicate things if you're unfamiliar with the process.
Power is the driving factor for purchasing bigger injectors, however, it's important that the injectors are small enough to be able to idle well. For each injector, there is a minimum amount of time (pulse-width) that the internal valve can open. The opening time, as well as the amount of fluid that can flow through the injector while it is opening, will vary from injector to injector. Having correct data is key to being able to control idle fueling with large injectors.
On 5th-Gen Camaros, Injectors flowing more than 100lb/hr at 58psi have varied amounts of idle issues, depending on the quality of the injector data, the design / health of the actual injectors, and motor's fuel demand. It's important not to oversize, and to run quality injectors if your idle pulse-width is going to be around / under 1ms.
Flex Fuel The ECU in the 5th-Gen Camaro supports Flex Fuel. When properly equipped with a Flex Fuel sensor, it is able to calculate ethanol content, and add ignition timing to your calibration. This is a great option for those running Pump E85, which greatly varies in ethanol content as the seasons change. While ignition timing demands are typically identical from E50 all the way up to E100, the chemistry of the fuels is still different between blends. Roughly speaking, for each 10% increase in Ethanol content, there is a 4% increase in fuel demand. If you were tuned on E85, with actual 85% ethanol, and then were to fill up with a winter blend of E50 from the same "E85" pump, you would be running 14% richer than you were calibrated. This will cost power. To avoid this situation, and to fuel correctly, it's trivial to plumb a factory GM Flex Fuel sensor into your fuel system. These sensors can be found with two 3/8ths quick connect barbs, that can easily be adapted to 6AN. The Flex Fuel sensor ideally would be installed in the feed line, however, it can be successfully plumbed in a return line as well.
Electrically, the flex fuel sensor will need a switched 12v power source, a ground, and a connection to the ECU on Pin 40 of connector X1, using a Female Molex MX64 pin. The coil pack connector on either side of the motor is often an easy place to find 12v and Ground for the sensor. With a proper calibration, your 5th-Gen can dynamically change from a tame 91 octane commuter into an aggressively tuned E85 street car just by filling up with Ethanol. It should be noted that NA LS motors are typically not octane limited, and do not show the same power gains you would see in their boosted counterparts.