I have had some questions lately on why I run 2 fuel pumps, one on each side of the tank. The short answer is, as those who track 86’s or BRZ’s already know, is Fuel Surge.
Sustained high G cornering to the left causes the fuel to slosh away from the pump pickup, causing loss of fuel pressure to the engine. Turbo or supercharged cars, or cars running on E85 suffer even more from this phenomenon. E85 consumption in an NA car is approx. 40% higher than normal fuel. Below is a video where I simulate this by un-plugging the OEM fuel pump while the car is at idle. Watch the gauges and see the second fuel pump turn on and take over.
What you just watched is a simulation only. In reality the system operates a little differently. The second pump is only turned off by the control unit I made when the car is at idle. When on the track both pumps would be running at the same time. When one loses pressure, the other is already running and keeps the engine supplied. It works well.