NB fuel pump, required?
 

Hey, I have a quick question. Do I need to upgrade the fuel pump in my '99, I plan on running 250whp on 550cc injectors, controlled by EMU. Or will my stock pump flow enough.

The stock pump in a '92 flows enough for ~200 WHP through 440s, so I imagine the stock pump in a '99 will suffice for ~250WHP through 550s.

The problem with stock fuel pumps in FI applications, and this covers both NA and NB, is not typically flow but rather pressure. This is principally a concern for those people running AFPRs with small injectors, where the pump is called upon to produce pressures in excess of 100 PSI, as compared to the 40 or 50 you see in a non-AFPR application.

At most, you might find that the increase in consumption through the rail necessitates a dual-feed arrangement, but I'd suggest that you try it as-is first and see how it responds.

I think people will tell you the stock pump is adequate. As it's a '99, it's still fairly new and should not be showing signs of slowing down. A Walbro 190hp in-tank is cheap insurance at $90.

If your stock pump is healthy it should be fine. If you're worried you could rig up something in the fuel line to measure fuel pressure. With our returnless style fuel system you should be around 60-65 psi constant. That fuel pressure is enough for 250 whp.

Sounds good boys, I will be doing a dual feed fuel rail, whenever FM gets some in. Sounds like it's not required but wouldn't hurt to put in a 255lph in there right?

I would do a 190 instead. The 255 is probably noisier and might over power the stock regulator. Either way, for only 250-300 you should be fine.

Well, it'll hurt your wallet for sure. And in the NAs at least it is rumored that the 255 can actually overpower the stock FPR and cause the fuel pressure to rise above stock while not in boost.

Wait... Can you even use a Walbro in a returnless system?

if i had an NB I'd get the 255. since it runs at 60psi static, no reason not to.

I've also heard that some NBs have trouble maintaining the pressure to redline, and the 255 acutally does so.

this is only if I had an NB and if I in fact needed a fuel pump.