Upgraded Fuel System


Wish I had another Buick!
Jan 10, 2004
Just wanted to get some opinions if this set up will work on the street and what the max HP it could handle.
Guess I would have to take out the intank pump and put in say the tank sender from a 79 Regal or something. ANyway
Inline Fuel Pump
Outlet Presure Flow 45psi/80GPH (45 psi 460PPH) @12v
Max Pressure 90 psi
Current Draw 12.5 amps @ 45 psi
running 55# injectors and adjustable FPR

This is just to know what the limits of this system would be and if it will work on my 87 GN.

55# injectors won't make enough HP to need to modify the stock system, if the in-tank pump is a 340 and it's hot wired.

If you are going to make more HP, then the tank could be sumped and a bigger external pump used.
Let us know where you plan to go w/ the HP, and a better answer can be made.
Maybe I am mis-reading the question, but it sounds like alot of work for nothing. Why not just use the walbro 340 in the tank and be done? It will carry you into the 10's.
soory for the lack of info. I got the injectors new very cheap from a buddy and he has vthe other pump new too for the same price as the walbro 340 so I just was wondering if I should buy it. I will be looking for low 11's high 10's
In order to really figure out what the max that particular combo can support, more info is needed about the pump, like the pump's curve of flow vs pressure.

But, you've given us 2 data points, 80@45 and 0@90. BTW, that 80gph@45psi is a hell of some flow at that point, compared to single in-tank pumps (the XP+ will do that but at 15 volts instead of only 12). However, it falls off very quick at high pressure (most don't quit till well over 100 psi).

Using a straight line from the 2 points, and plotting that on the curve of the injector's flow vs pressure, I get about 50 gph or 600 hp @ 60 psi. That's assuming 6 injectors, 100% DC, and 20-25 psi boost.

Again using a straight line since we don't have any other info, if you could get 150 psi max out of it (by fooling around with the bypass valve), eyeballing the chart looks like 750 hp or so is available.
I dont have any other info, thats all that the paper says that he gave me that comes with the pump. Wish I had more. Its made by SX Performance
a single 340 and 55's will work to the high 10's(on a full weight car)......a double pumper (2 340's) will give you more room

be wary of any pump that doesn't function well above 65+ lbs....you will be running 43+25 = 68 lbs of pressure at least