As many of you know, the fuel system for the 2.0T FSI platform is composed of two separate systems: the high pressure system (50-130bar), and the low pressure system (3-5bar). While, the limitations of high pressure fuel delivery have been eliminated by products such as the APR upgraded rail pump, the low pressure system has been ignored.
Through our research and development here at USP Motorsports, we were able to determine that the low pressure fuel system is nearly maxed out when producing around 350whp, running an a/f ratio between 11.0:1 – 11.5:1. This limitation is a result of the in-tank fuel pump being maxed out. By replacing the factory in-tank fuel pump with an APR in-tank fuel pump, the low pressure fuel system sits on its limits at around 400whp, while still maintaining the same a/f ratio mentioned above.
Developing a low pressure fuel system to work properly with the complicated components and electronics of the 2.0T FSI was no easy task. The in-tank fuel pump that runs the FSI does not function like a traditional fuel pump. Meaning, the fuel pump does not always receive a full 12volt signal while the car is running like a traditional fuel pump does. Instead, the ECM controls the fuel pump through a Pulse-Width Modulated signal (PWM). This quickly ruled out the ability to add an inline fuel pump. Other options were explored but, adding a secondary in-tank fuel pump was the end result.
The main purpose of the USP Motorsports auxiliary fuel system is to provide enough fuel flow to the high pressure fuel pump to support 400+ horsepower safely. This was done by incorporating a secondary in-tank fuel pump that alone can support 600 horsepower. However, incorporating a secondary in-tank fuel pump by itself will not function properly as the FSI low pressure fuel system is return-less. To combat this issue USP Motorsports created a load-based fuel pump controller. The result is the secondary fuel pump only being turned on when it is needed.
This system is estimated to be good for around 700 wheel horsepower and is the same system used on our in-house MK5 GTI which produces 605whp
What is included:
- High flow in-tank fuel pump
- Load-based fuel pump controller
- Preassembled fuel lines and fittings
- Fuel distribution block w/check valve
- All wires, terminals, and connectors