I'm running a 300litre/hour Bosch external pump and need an intank pump to avoid caviatation. My garage recommended a 150litre/hour in tank pump but I preferred the 255litre/hour walbro to keep up with the external pump. His concern is there might be too much pressure in the flexible line between the two pumps and bust the line. My concern with the 150litre/hour pump is that it might become a bottleneck at WOT. Which one should I use assuming I'm not going to have a fuel reservoir / swirl pot between the two pumps? Also is it necesarry for me to upgrade the size of the fuel line leading to the fuel pressure regulator? I'm running OME primary and 1,300cc secondaries. many thanks.

Michael

 

I do not know the specifics of such high flow applications. I am making educated guesses. Listen to me at your own risk.

1. If there is concern about pressure in the line between the two pumps, set it up like a fuel rail. Use a regulator and a return line to maintain a constant pressure in the line.

2. Why are you not going to use a swirl pot? It is a devilishly simple system that ensures your main pump has enough fuel at all times and that your secondary pump is not strained or excessively over/underworked.

 

Ditch the external one, and just get the walbro for in tank. You don't need more than that for those injectors.