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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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FPR Questions
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Sat, 01 January 2005 08:33
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I've been thinking about fitting a rising rate regulator to my 3S-GTE mainly for ease of future plumbing. I have one concern though  The 3S-GTE has a base fuel rail pressure of 39psi, so if I fit a 1:1 RRFPR and then wind in say a max of 30psi of boost, thats 69psi of pressure in the rail! Or am i totally confused? If I am correct, will the injectors cope with this or with they explode into small pieces?
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Location:
Brisbane
Registered:
February 2003
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Re: FPR Questions
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Sat, 01 January 2005 14:18
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this is from www.msefi.com ... but i would assume application is pretty much universal for EFI cars:
Typical pressures needed in the neighborhood of ~45 psi for port fuel injection, ~10-20 psi for TBI injection. A port injection pump will work with TBI, but not vice-versa.
pumps:
The external pumps used in Ford F150 fuel injected trucks from the 89-93 model years areDelco EP286. At 12 volts, the operating pressure is 70-95 PSI with 36-40 gals per hour... The Carter pump#P70199 (the outlet is 7/16 standard pipe thread and the inlet is 15/32 clamped hose type fitting or 3/4 standard thread. The specs are 95-PSI max, 68-93 G/Hr wide open).
... VolksWagen models (87 VW Fox, for example). Part number is:Bosch 0 580 254 957 reportedly rated at 90 GPH@ 70PSI,
tubing:
... Unless you have a very unusual combination (or very high horsepower, well over 500+), you should be able to use 3/8" tubing for both the supply and return lines.
guages:
If you are using an aftermarket fuel pressure regulator, it is a good idea to also install a pressure gauge, since most of these are adjustable. For TBI, use a 0-30 psi gauge. For port injection use a 0-60 psi or 0-100 psi gauge.
all from http://www.megasquirt.info/manual/minj.htm#supply
SDS think that rising rate are a bad idea...http://www.sdsefi.com/techfpr.htm and point out that a lot of fuel is returned to the tank via the return line - hence the high static pressure ratings for the pumps compared to that actual rail pressure.
fwiw: i'm going to use a malpassi for the 18R turbo+efi as i don't want to run lean (e.g. repeat the red-hot manifold thing again). i bought i thru a local distributor for these folk: http://www.speed-technology.com (prepare to skip their annoying flash introduction). Their rising rate is 1.2 times manifold pressure (not 1.5 as i had previously thought). The unit can regulate up to 5 bar of pressure (anyone care to convert that?)
the upshot of all this should be that injectors should be designed to withstand common factory highest pressures - and quite likely a lot more. Failure points are more likely to be the o-rings at the fuel rail.
cheers,
cahrles.
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: FPR Questions
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Sat, 01 January 2005 14:52
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5 bar is 72.5psi.
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