MBC Racing

iTrader: (3)

I just got my new motor in the car and now have a FP gage. Only have ~115 miles on it so I have not hammered it yet.
I noticed that my FP is 60 PSI at idle and will drop to ~56 psi at 3/4 throttle. Is this normal or is something messed up? The car has ~25k on it.
If I buy a new bigger pump will it still do the same thing?

Thanks
Brad

jimmyblue

iTrader: (11)

In the Nitrous section there were remarks
from some guy who had beefed up the wiring
to his fuel pump, and was getting a lot
better (higher, and more stable) fuel
pressure. If the fuel pressure up front
is limited by the pump's RPM, this
might be worth looking at. Plus, on older
cars connectors and relay contacts can get
a little crusty. Might want to put the DVM
to the pump terminals and see whether you
have any voltage sag when you're accelerating
(more fuel delivery means more pump work)
or whether it's all just fuel line flow
resistance (pressure drop at higher injector
flow) and rearward g-force on the fuel
column.

This last is something that would show up
different on the dyno than on the road, as
the body doesn't move on the dyno.

Colonel

As long as it's holding 50-52 or better at WOT I wouldn't worry with it.

The more pump you put to it, the less it'll drop.

2MCHPWR

iTrader: (10)

you should be fine. keep an eye on KR though.
mine dropped way into the 40's so i got a new stock one. here's a graph of the old pump:
<img src="http://207.127.219.37/images/dyno11.jpg" alt=" - " />