Re: Anyone using a RRFPR on a '99 9-3? - Saab Performance Bulletin Board - Saabnet.com
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Re: Anyone using a RRFPR on a '99 9-3?
Posted by Dean (more from Dean) on Wed, 19 Nov 2003 08:38:44
In Reply to: Anyone using a RRFPR on a '99 9-3?, Jeff in ATL, Wed, 19 Nov 2003 06:38:27
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I think that the FRP that you have is a rising rate FPR now. Not easily adjusted. That what the small VAC line is for. When on boost, the pressure via the VAC line acts on a diaphragm. The total force then acting on the FPR's valve seat is the air pressure plus the spring force. The fuel pressure builds up until the pressure of the fuel on the diaphagm balances the pressure of the spring and air pressure on the other side. If the fuel pressure exceeds that balance point a bit, the FPR valve will lift a bit off of its seat and release fuel to flow back to the fuel tank. In practice, there is always some flow back to the fuel tank. So the valve seat never closes, but creates variable restrictions that create the required pressure balance. The fuel pump is a fixed flow pump. There will be some drop of flow at higher pressures due to pump design, clearances and wear etc. Any of this 'fixed' flow that the injectors do not need, is released by the FPR back to the tank.
I hope I have the above right. If not, someone will correct me soon.
posted by 208.24.17...
Posts in this Thread:
- Anyone using a RRFPR on a '99 9-3?, Jeff in ATL, Wed, 19 Nov 2003 06:38:27
- i instaled PFPR to some Aero 9-5+, NGB, Thu, 20 Nov 2003 00:18:27
- No, ckpaden, Wed, 19 Nov 2003 14:33:40
- Re: Anyone using a RRFPR on a '99 9-3?, 900 Aero
, Wed, 19 Nov 2003 09:44:38 - Re: Anyone using a RRFPR on a '99 9-3?, Dean, Wed, 19 Nov 2003 08:38:44 <-- Viewing This Message
- and, Dean, Wed, 19 Nov 2003 08:42:21
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