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

[lagos]

The turbo vsv limits boost in 1st and 2nd gear to 7 psi, and 3rd-5th gear get 9 psi normally. IIRC, safe mode on the st185 was no boost - but its been a long time since I ran the stock ECU in my st185.

no thats not correct at all. the only time the tvsv limits boost, is to put you into safe mode. when in safe mode, youll be limited to 7psi. the reason why you see less boost in 1st, 2nd gear is because those gears cant create enough load on the motor to fully spool the turbo. there are no gear specific limitations inside of the ecu.

This post has been edited by lagos: Aug 1, 2007 - 1:24 PM