1987ZTPI

I just installed an AFPR i was running 40psi at idle and 45 when i disconnected the vacum line i'm told that stock pressure at idle should be 42-43 psi , i have a bunch of bolt on headers wires , pullies full exhaust , also msd 6a and coil as well as a programed E-PROM , tb air foil and port and polish on the upper plenum and runners . what is a good pressure to start off at i've been told that 46psi at idle will give you better performance even on a stock motor any input would help thanks

RYAN

DJP87Z28

Stock fuel pressure at Idle shpuld be 36/38 PSI. Why do you think increase pressure at "IDLE" is going to increase your performance??

Reid Fleming

iTrader: (2)

5 psi difference when pulling the vacumme line? Mine was 43 psi with line on or off. In fact it's never made a difference for my car whether the line was on or off.

I upped mine to 50 psi and it seemed to have better throttle response. Better midrange power.

Dyno Don

iTrader: (7)

Pressure at idle should be 42-43 psi with the vacuum line off. 37-38 w/it on.
Unless you do a custom chip, that is where it should be.

1987ZTPI

well not sure about everything i'm hearing cuz with the pressure at 49psi at wot and 44 at idle the car runs alot better it idles way smoother it idles at 650rpm and it just feels smoother it kind of feels the same or a tad slower than befor when accelerating but that mite be because it's 2 degrees outside but it feels alot better to me.

AND I DO HAVE A CUSTOM BURNED CHIP

Dyno Don

iTrader: (7)

Was it burned for 49 psi @ WOT?
It so, that's why it runs better there.

1987ZTPI

not sure if it was programed for that pressure , when i gave the guy my mods lisy he said i should put in a 165 degree thermostat and maybe an adjustable fuel pressure regulator to help tune it better .