What will happen when the fuel pump in the tank will suck air instead of fuel?
This could happen when you are on the track or during heavy acceleration. The fuel is forced towards the side of the tank, away from the pump. Especially when the tank is not full.
The air will be pumped into the fuel line, onwards to the fuel rail and via the injectors into the engine.
Most of the time this will cause a noticeable decrease of power and it may also damage your engine.
To stop air entering the fuel system, a surge tank / swirl pot is a very good solution.
I have tested a couple of designs and found two really well working versions. Which one to use is mainly a question of available space. Some install it in the boot, others in the engine bay. I will put mine in the engine bay.
If it is installed in the boot, use Teflon hoses. They are more gas tight compared with ordinary steel braided hoses and will prevent the smell of fuel inside the car. They are also resistant against E85.
To connect the hoses to the surge tank / swirl pot, use AN-connections. Usual sizes like AN-6, AN-8 or AN-10.
The installation is fairly simple. Remember the high pressure pump need rather much power and should be connected over a fused relay. It is recommended to use the ordinary pump power feed as relay control signal.
Boot installation
Engine bay installation
Bosch inline pump (0580254044)
Installation Diagram
