Stock ST/GT fuel pump limit, FYI - dont go beyond 12 psi on a stock pump Options

[scothaniel]

The stock fuel pump in my 96 ST finally reached it limits last week and chocked at around 16 / 17 PSI of boost. I thought I hit fuel cut at first, but I didn't get the usual warning light and was able to boost again without restarting the car. I'm using the stock ST205 fuel pressure regulator with a set of RC 550 injectors. Looking at the BGB's, the base fuel pressure for the ST205 appears to be 36 psi (or between 33-39), so it chocked around 52 psi (only estimating, I don't have a fuel pressure gauge in the cars cabin). Both the GT and ST use the same pump.

So for a year I was boosting around 12 -14 PSI without issues, even running rich due to the 10cc larger injectors (and the fact that the stock ECU runs rich) . I was probably pushing the limits at 14psi, so I wouldn't recommend anyone going over 10 or 12 psi on the stock pump.

This post has been edited by scothaniel: Jul 31, 2007 - 11:34 AM

[scothaniel]

You know, I never thought about that before. The only connections on the trans are the speedometer and neutral switch, no way for the ECU to know gearing. I read about the vsv limiting boost by gears a long time ago and never looked back. It just goes to show how much mis-information is on the net:

http://www.gtfours.co.uk/what/abbrev/abbrev.htm
http://k1ano.co.uk/boostcontrol/rvgt4specifics.htm
http://www.celicatech.com/forums/showthread.php?t=1161

I was confusing 'safe mode' with 'limp mode' - code 34 on the st185, where the ecu pulls timing after over boosting so you cant get any boost.