[Shotimes] fuel pressure regulator and 255lph pump issue

[Zach Leahy]

I have a real time Fuel Pressure gauge, a 190 lph, and a stock regulator.
 The low load (high vacuum), low pressures are too high. I am only seeing
about 35-36 psi at 25 in Hg Vacuum (about 12.5 psi vacuum). Basically I am
seeing too high of pressure in high vacuum conditions, but seeing a nice
39psi at zero vacuum. Seems to me that the 190lph is being overrun. Unless
you are making upwards of 300hp at the crank, a 155lph should suffice. I
didn't know that I was having this effect until recently amd was very
intigued to find my car effected by it.
 Seems like both of the regulators you posted are around $90 with no
fittings. Why don't you just take the 255lph pump out and put a reasonably
sized one in instead for less money (by the time youadd fittings, hoses etc,
you wil be over the price of a new pump). Plus you won't have to figure out
new technology. Just my .02. If you really need the capacity of the 255lph
unit (blower, NO2 etc) you would need larger injectors, and just figure that
you will need a better regulator. I have cheated a bit for now and used the
tweecer to richen up the top end to compensate. WBO2 is showing about 13.5:1
at high RPM WOT.
 I am working on slowly turning my car into a blower car, and the next part
of the upgrade is the fuel system and I realize I will need to have the
rails machined, larger injectors, a new FPR, and a larger capacity pump. I
have been looking at these issues a lot in general.
  Z


On 9/10/05, Michael Tulloch <teach200513760@yahoo.com> wrote:
>
> Hello All:
>
> I have been reading more and more of what I should
> have done before replacing my fuel pump. I installed
> a 255lph walbro pump under the suggestion I thought
> from here that the stock pump (155lph) wasn't enough
> for WOT fuel rate. Now I'm reading more and more
> articles stating the stock fuel pressure regulator
> can't handle the increased pressure and will cause a
> lean-out at WOT through the ECU pulling injector pulse
> width. The exact opposite of what I wanted. I've
> read up on the SHONut fuel pressure regulator kit but
> not excited on buying a $250 kit to fix a mis-directed
> replacement pump. Has anyone tried a Holley
> (HLY-512-503-5) or Accel ( ACC-74560) regs from
> Summitracing.com <http://Summitracing.com>?
>
> Michael.
>
>
>
>
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