If your car uses a 15 amp fuse for the fuel pump, buying a drop in fuel pump upgrade is probably not the best choice unless you choose a Walbro GSS340/1/2
What the fuel pump upgrade manufacturers don’t tell you, is that to get their pumps to flow more fuel than the standard pump they simply increase the current that their pump can consume over the standard fuel pump.
For the background data, check this article
Basically most 45 PSI fuel systems use a fuel pump that uses around 7-8 amps of current in 99% of operating conditions.
The fuse for the fuel pump is probably 10-15 amps & the cables running power to the fuel pump are rated to this amperage.
However the so called “drop in” fuel pump upgrade pumps use 13/14/15/16 amps in normal operation.
So while these 320lph and 255lph pumps may indeed be a drop in upgrade ie they fit in the same basket as the car’s original fuel pump, there is a good chance your fuel pump wiring is going to be at the limit. In fact to get the most power from these pumps, I think I would also be upgrading the cables and not just the fuel pump.
And here is the crux of the matter.
If I am going to upgrade my fuel pump and that upgrade involves me running new, thicker cables, I am not going to be installing a drop in fuel pump. I am going to go the extra yard and rig a fuel surge tank as well which utilises a Bosch 044 fuel pump & get the ultimate fuel setup.
Having said all that there is one exception. And that is the Walbro GSS340/1/2 series of pumps.
Walbro seem to be doing something more intelligent that the other firms. The GSS fuel pump flows much more fuel than the stock fuel pumps in this test, and yet the current draw is around the same.
That seems like the uses of technology to me by Walbro instead of the brute force approach of the other fuel pump manufacturers
So in summary
For a fuel pump upgrade, either I am going to use a Walbro GSS fuel pump which does not require me to rewire my fuel pump.
Or I am going to fit a Bosch 044 in an external swirl tank with upgraded wiring and have the total solution. Big power and track ready.
I am not going to rewire a pump that goes in the tank, which does not give me the power handling of a Bosch 044 and does not give me a track ready fuel system.