APR 2.0T Low Pressure Fuel Pump System (LPFP) - EA113/EA888 Gen 1 (AWD)
The APR Low Pressure Fuel Pump (LPFP) Upgrade is designed to ensure the low pressure fueling system is capable of delivering the proper volume of fuel from the fuel tank to the high pressure fueling system under high demand situations.
Key Components and Benefits:
- APR LPFP ECU, harness & bracket
- APR 255 LPH high pressure inline fuel pump & bracket
- OEM quality fuel lines, crimp clamps & quick connectors
- Clean and simple solution to OEM low pressure fueling system
- Allows for higher output calibrations with select APR Stage 3/3+ Turbocharger Systems.
- Integrated into factory CAN bus
- Quiet and cool low power operation, only on when needed
- Quick fuel tank emptying mode for use with switching fuel grades or dry storage/transportation
- No unintended side effects common with other parts
- No ECU software required
- Only needed where specified by APR
OEM Fueling System Overview:
The OEM fueling system consists of several key components:
- Direct injection injectors
- Direct injection high-pressure fuel pump (HPFP)
- In tank PWM-controlled low-pressure fuel pump (LPFP)
- LPFP controller
- Engine control unit (ECU)
The high-pressure fuel pump (HPFP) needs to provide the injectors with a large volume of fuel to satisfy the desired air to fuel ratio. The injectors are only able to spray for a very small window of time, so the HPFP must provide the fuel at high pressures, upwards of 200 bar. In some instances, if the injectors are a limiting factor, they can be enlarged to reduce the time they need to spray. In other instances, the bore and or stroke of the HPFP can be increased to increase the volume of fuel displaced by the HPFP. By increasing the volume of fuel between the HPFP and the injectors, pressure behind the injectors increases and the amount of time the injectors need to spray decreases.
Unfortunately under some situations, the HPFP is capable of displacing a larger volume of fuel than it receives from the low pressure fueling system. As demand goes up, the low pressure fueling system needs to work harder to provide the volume of fuel necessary, but in some situations, the factory unit is unable to do so.
The APR LPFP increases the supply of fuel from the fuel tank to the HPFP to ensure the HPFP displaces the maximum volume of fuel possible during each stroke. This ensures the HPFP is capable of working at 100% capacity.
Challenges to upgrading the LPFP:
- Very little room for upgraded pump
- OEM Pump requires a PWM signal
- OEM pump controller overheats with high output pumps
- Upgraded OEM pump controller not fully compatible
- ECU modifications may be required
- Secondary controllers often rely on physical boost signals
The factory LPFP sits in a basket submerged in the vehicle’s gas tank. The pump operates off of a pulse-width modulated (PWM) signal sent from the pump’s control module, which is mapped in the ECU. As fueling demand increases and decrease, the PWM signal adjusts to send only the required amount of fuel through the pump.
Unfortunately upgrading the LPFP is not a simple drop in task. The pump’s factory enclosure presents some packaging constraints limiting clean expansion to a larger unit. Likewise, doing so often results in overheating and subsequent protective shut down of the factory control unit as it’s operating outside of its intended design. This is even true when installing larger and expensive factory units like those found on high output vehicles, such as the Audi TT RS and RS3. Furthermore, upgrading the LPFP control module with the matching expensive higher output control units present other issues as the controller receives CAN messages from integrated vehicle componentry not common on vehicles requiring an upgraded LPFP.
The APR Solution:
- Inline fuel pump
- Fuel pump controller with proper ECU CAN bus communication
- Clean mounting brackets included
- Direct bolt on with no software required
APR took a multi-step approach to solving the low pressure fueling system and is pleased to present a clean and accurately controlled solution for high horsepower applications.
The APR LPFP System features a 255 LPH high-pressure inline fuel pump that sits between the HPFP and the factory LPFP. The included APR Auxiliary ECU sits on the factory CAN bus and receives critical operating information from the factory ECU to accurately control the pump. As fueling demands increase and decrease, the APR Auxiliary ECU controls output of the pump to deliver the desired volume of fuel to the HPFP.
By connecting to the factory CAN bus, the APR Auxiliary ECU eliminate the need for less sophisticated and often problematic methods of controlling the upgraded pump. Because the pump only runs when needed, less power is consumed, fuel temperature is lower and noise, especially at idle, is essentially non-existent.
Finally, with the fuel line disconnected, with the click of a buttion the APR Auxiliary ECU allows the user to quickly and easily empty the vehicle’s fuel tank to make way for switching to higher octane fuels or for dry storage and transportation.