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fuel pressure reg
theconrodkid - 6/11/06 at 08:19 AM

got an aftermarket adjustabuble pressure reg,ive been thinking about how to plumb it into the system,i have no return pipe from the fuel rail (gixer 750).
whats best,T peice into the "out" side with a re stricter in the return pipe or T into the "in" with said restricter ?

matt_claydon - 6/11/06 at 08:38 AM

There is no pressure in the fuel leaving the reg as the end of the pipe is open to atmosphere in the tank. It's the feed pipe that is at regulated pressure so take the tee off just before the reg.

HTH,
Matt.

theconrodkid - 6/11/06 at 04:03 PM

the reg regulates the amount of fuel going down said pipe,if i put the T before the reg,fuel will follow the easiest route,ie back to his mates in the tank,i believe the pump (seirra type) puts out about 60 psi,i need 43 at the injectors,would it harm the pump if i let it run and didn't use the return?

MikeRJ - 6/11/06 at 04:46 PM

quote:
Originally posted by theconrodkid
the reg regulates the amount of fuel going down said pipe,if i put the T before the reg,fuel will follow the easiest route,ie back to his mates in the tank,i believe the pump (seirra type) puts out about 60 psi,i need 43 at the injectors,would it harm the pump if i let it run and didn't use the return?


The pump may be capable of generating 60PSI, but it is the regulator that determines this. Think of the regulator as a variable restriction in the pipe that opens or closes to keep the pressure on its input constant as the flow rate changes.

In a normal system the fuel pump attaches directly to one end of the fuel rail (via a filter) and the other end of the fuel rail goes via the regulator back to the tank.

If your fuel rail has only one connection, then as matt said you need to Tee into the pump side of the regulator. If you tee into the return side you will have pretty much zero fuel pressure.

theconrodkid - 6/11/06 at 04:52 PM

ill give it a try,if you see a big black cloud over london............

matt_claydon - 6/11/06 at 05:16 PM

Think of the reg as your thumb over the end of a hose pipe. It's the water in the pipe that is under pressure (regulated by your thumb pressure). The water that has left the hose (like that in the return pipe) is under no pressure whatsoever.

Syd Bridge - 6/11/06 at 06:59 PM

Some regulators regulate the out pressure, some the in. ie, regulated pressure on the high side, and 0 on the out. Or V.High on the in, and regulated on the out.

Which type is it?

Cheers,
Syd.

theconrodkid - 6/11/06 at 11:59 PM

i assume its got the restrictor in the outlet,il let ya know when ive plubmbed it in and let the fuel have a quick whizz round

theconrodkid - 7/11/06 at 04:25 PM

went to get some more 8mm olives to finish off the T peice,asked spotty chav in plumbing shop,he said he had some 15mm ones in stock,will they fit i asked,he looked skywards and walked away

rusty nuts - 7/11/06 at 06:43 PM

We were all spotty kids once , just that some of us can't remember. But I do hope I had more between the ears than some do today

theconrodkid - 12/11/06 at 01:54 PM

piped it up today and got soaked in petrol,my type pressure reg goes on return