fuel pump options

[northstar ninja]

So heres the deal- I have a 260Z that happens to have two fuel pumps- one mechanical and one electric. I'm wondering if the electric one (by the tank) is enough to run the car by itself. Does anyone know if the electric pump only turns on after the car is already running? (as opposed to priming the line) I was thinking about running a simple 12v power supply to the pump with an in cabin switch to prime the line for easier starting... I dont know if this will work, as I know very little about carberated cars.

part two- for an RB swap, do I have to swap out the whole tank with one out of a fuel injected car? or is it possible to simply use a sending unit out of a fuel injected car, and run a return line with a FPR? (after upgrading the external pump) I favor the idea of keeping the external pump, it makes it much easier to change as my goals for the car change...

[evildky]

lots to cover hereyou can should only have 1 pump, either mechanical or electric, nto both, pick one, if you run the electric you need a fuel pressure regulator, anything over 3psi will overpower the needles int he su carb's, and you shouldn't have to prime the fuel lines to start the car, the float bowls int he carbs should have enough fuel to get the car running as the pump begine to refill them

if you do a swap to the RB you'll need a high pressure electric ump, somethign capable of running 38-43 psi at idle and up to 90-100 psi at WOT, your FPR is boost referenced so the more boost you run the higher the fuel pressure, the size of the fuel pump will be determined by how much power you want to run, and of course ti has to be an external pump, the stokc 280Z n/a fuel pump is only good for 200 whp? the 280ZX Turbo pump is good for around 250 whp, I run an MSD pump wihich is good for around 500 hp

the stock tank is fine but the fuel lines are a bit small to feed a large aftermarket pump, I sumped my tank with a -8 a/n feed and added a -6 a/n return

[northstar ninja]

good info evilky- I think you know too much about these cars sometimes...

theres definitely 2 pumps- why I dont know. I had disconnected the fuel lune from the mechanical the first time trying to get it to run, off a separate fuel source- the line that runs to the tank kept spurting fuel while it started and ran, and it was under pressure. (I capped it with my thumb) I traced the line back to the tank, and there is an external pump visible through the passenger side wheel well. I was baffled by the presence of two pumps as well... Perhaps it was added due to the 260's having starting problems? Someone told me the 260s were wired for electric pumps from the factory, though didnt come with one...

I'm wondering if I should just disconnect the mechanical pump...

I know about the FPR being boost controlled wth the RB, just needed the info on the lines- and sumping the tank is an added bonus

[northstar ninja]

PS- Thanks!!!