Can someone tell me how a fuel reg works?

[The Pikey]

I have a Sard fuel regulator and I decided to test it but I can't see how it works. Take a look at this pic.here

 

Theres two blue fittings, one on the bottom, one on the side and theres a smaller one on the top. I thought that the one on the bottom was the fuel in, the other blue one was the fuel out and the little silver one was the return. I tried putting 7 bar of air through it but nothing happens until I screw the silver fitting all the way out and then the same pressure comes out as what goes in and wont regulate it at all. Nothing ever comes out the silver fitting at the top.

 

Is this thing not working or is it me not knowing what I am doing? (most likely)

 

thanks in advance

 

jason

 

Currently, I am qualified to plead ignorance.

 

Edited by - jason fletcher on 24 Feb 2008 21:45:12

[Stationary M25 Traveller]

That certainly sounds how a regulator would operate - we use hydraulic flow regulators, and they have a feed, a regulated output and a return to tank - all labelled on the body of the device - often P for pressure supply, R for regulated output and T for return to tank. Surely you have instructions for it ????

 

Are you working within the specified limits of 200 - 800 kPa ?

 

7 related photos

 

Edited by - Stationary M25 Traveller on 24 Feb 2008 22:05:04

[Stationary M25 Traveller]

Note on a website about these regulators:-

They increase fuel pressure when engine air demands are high, acting in response to a low vacuum in the inlet manifold.

Does this mean the little silver connector is not a fuel return, but a connection to the inlet manifold ?

 

I did a Google search on 'SARD Fuel Pressure Regulator', and got loads of websites .... time you went looking !

 

7 related photos

[campfreddy]

I do not know this particular regulator but experience with similar would lead me to believe that the supply (end of fuel rail) would be the side fitting and return would be the bottom fitting. The top silver fitting would be for sensing pressure in the inlet plenum to allow the regulator to correct for this pressure and thus injection would be at a more or less constant pressure above manifold pressure.

Hope this helps.

Ian

[The Pikey]

Thanks guys, most helpfull. I now know I bought the wrong one ☹️ as I thought the fitting on the top was the return but now I know it's for a manifold tap and theres no return.

 

Ebay here it comes.

 

 

Jason

 

Currently, I am qualified to plead ignorance.

 

[The Pikey]

right, I am now getting somewhere. I think the K series regulator must fit on the end of the fuel rail which is why it only has two fittings, one in and one out. But my Busa's fuel rail has no fitting for the return because the pump had its own regulator. Can anyone recommend a quality adjustable regulator that has a return on it?

 

Jason

 

Currently, I am qualified to plead ignorance.

 

[Andy A]

 

I'm confused by wanting to have a return on the regulator. Is there such a thing? Normally you would have a return line that goes back to the tank (or swirl pot in the unlikely event you are using one). Why would you connect back to the regulator?

 

The small inlet is indeed likely to be for connection to inlet manifold, but may be OK just left to atmosphere (particualrly when no turbo). If I were you I'd check first with the manufacturer before sticking it on e-bay.

 

[Peter Carmichael]

SM25T got the description a bit wrong.

 

The inlet to the regulator is the bit that is held at steady pressure - it is your fuel rail. The outlet is just a return line. The pump is running at full whack the whole time. The only way to control pressure is to "spill" excess flow back to the tank.

 

If this regulator is a "power boost" type, which senses inlet pressure and has anything other than a 1:1 gain on the pressure difference, this part of its functionality will be redundant in a mapped injection setup - the base map will just end up set up compensating for this behaviour - all I'm really saying is that mapped injection is *better* than fuel pressure fixes; however, the two can run perfectly happily together.