LostCauseZ06

iTrader: (4)

exacly how it says.. id post it in fueling but noboby ever answers stuff in there.. what PSI does a LS1 system run at usually???

2000slpss

iTrader: (27)

when we tested mine it was a pretty steady 57 psi

LostCauseZ06

iTrader: (4)

k so i will definately need to upgrade my injectors on my 408 then hehe

RoyO

Mine measured a steady 60psi.

LostCauseZ06

iTrader: (4)

what kind of pressure tester do you use??

SlickVert

iTrader: (5)

Stock mine was 62 @ idle and would drop to 54 @ WOT
I installed a racetronix and it went up to 64 @ idle and drop to around 61 @ WOT

ArcticZ28

iTrader: (14)

No matter what, you need to upgrade the injectors. I'm running 42#'s (which most people run) to give me a bit of room to play. Also should upgrade the fuel pump with a walbro 255lph or something of the likes, nothing crazy.

aux_fast_cam

I mounted a gauge to the rail. Take out the shrader valve on driver's side rail. get a 4an to 4an coupling then 4an male to 1/8npt male and 1/8 npt to 1/8npt coupling then fuel pressure gauge 0-100psi with 1/8npt looks nice on rail too.

aram

iTrader: (7)

it's supposed to be a steady 58 psi at all times for what it's worth.

if it's dropping under load then there is a problem somewhere in the fuel system. If it reads a little high or low it's probably just the gauge you are using or a problem with the regulator built into the fuel pump unit (99+). On mine it actually reads about 60psi at all times but I think the gauge just read a little high.

LostCauseZ06

iTrader: (4)

so if i get 42 lb injectors is it going to force me to get a tune before i start it??? will an injector change mess things up really bad??? or will it work the exact same but just be able to flow more??

DrkPhx

iTrader: (15)

The GM spec calls for a constant 55-60 psi. This includes the Ignition in the ON position, idle, part throttle and WOT.

ArcticZ28

iTrader: (14)

It'll definitely need to be tuned, but it will still be able to run and such, just like doing a head/cam swap. It'll run, but not as well as it would tuned.

jt_2002_ta

iTrader: (3)

bringing up a way old thread!! anyways, is it not supposed to drop under load and read the same when ignition is on without running? mine with ignition on when i first hooked it on the rail and turned ignition on it read like around 30. running was around 55-58 and under load it dropped to 50-52 or maybe less. do i need to check my pump out? got a issue im tryin to track down and thought it may be fuel related

wildcamaro

iTrader: (15)

Bigger injectors won't increase fuel pressure only a new/better/booster pump will help with that...sometimes an old *** fuel filter that's clogged will reduce pressure as well...I def would upgrade the injectors for a 408 though no doubt...