Steven Ressue

Can anyone give me what the fuel pressure is from a stock LS1 2004 fuel pump? I've researched the web with no answer. I'm using the 04 tanks and stock pump on a LS3 that requires 60psi. Before I upgrade to a new pump I was just curious what the pressure is of the one I have. Not hooked up and running yet so I have no idea what I have. Thanks.

crainholio

58psi at the rail is the specification.

PEERPSI

"Is the fuel pressure more than the specified value? 427 kPa (62 psi)"

Quote from the service manual.

lucky131969

Directly from the 2004 service manual : 380-427 kPa (55-62 psi)

Steven Ressue

What I need is a constant 400 kPa with the engine running with a minimum 40 gph @ 400 kPa. I was not sure if the stock pump will deliver that. If I install the tanks to test the pressure and it isn't what I need I have to remove the tanks to install a new pump. Just wanted info on CONSTANT pressure if that info is possible. Not sure if 58# is what I have. If it is, it's not enought.

PEERPSI

Run a test pumping into a container, measure your volume over time and you'll have your answer.

lucky131969

Great idea for evaluating the volume of your water faucet....very unsafe for gasoline.

LoneStarFRC

Or Aeromotive now offers their new "Stealth" 340 lph drop-in fuel pump module for late C5s and C6s as well. I'm sure it will give you all the volume you need, and probably pressure as well. If not, there's Kenne Bell Boost-A-Pumps too like 8VETTE7 said and it only kicks in at WOT.

TurboBerserker

Pressure has nothing to do with the fuel pump, but is governed by the fuel pressure regulator. The fuel pump generates volume at whatever pressure your FPR is set to (even for non-adjustible FPRs).

400 kpa = 58psi. (414kpa = 60psi)
40 gph = 151 lph.

Stock GM pumps are generally 170lph or 190lph for "higher powered" stock vehicles. Also, vettes are "4 bar" fuel systems -- which means they maintain around 58psi at idle (e.g. the FPR is set to 4 bar / 58psi). The vettes are 190lph, I believe, and as stated above, ring in 55 - 62 psi. Injector flow rate may drop (or increase) your rail pressure, e.g. you may change injectors and see your FPR drop from 58psi to 57psi, but its still a 4 bar fuel system running at 4 bar.

Even if you buy a replacement pump for a vette, unless it has an adjustable FPR, it limit pressure to 4 bars. You only need to increase your fuel pressure to "increase" the size of your injectors (e.g. I run 135 gph (510lph) at 400kpa (58psi) to stretch my injectors to 116 lb/hr from 96lb/hr (as rated at 43.5psi/3.5 bars), but I could also buy 116lb/hr injectors rated @43.5psi and turn down my FPR to 43.5psi and would have the same results -- I wouldn't even have to change my tune).

In any case, the stock pump and FPR both exceed or match the specifications you stated.

PEERPSI

With a proper dose of common sense there is no reason this needs to be unsafe. I've used this method several times to prove out fuel pumps. On occassion it has proven that while a pump makes the rated fuel pressure at the rail it does not flow at the required rate.

Or you could buy a new fuel pump and find out that's not the problem.

lucky131969

...and there in lies the problem. Common sense.........isn't common..

PEERPSI

I'm going to start calling you the Pesimator!

lucky131969