The V8 Owners Forum -

I always had the pump above the fuel tank, both on my Landie and on my Sherpa:


Never gave me any problems. Although I did wonder about commutator arcing whilst the pump was filling with petrol!!

Chris.

I'm surprised that works, and even more surprised if the pump isnt screaming like mad most of the time

scudderfish wrote:If it helps, my fuel system is basically two circuits linked at the swirl pot.

Circuit A is
Tank -> LP pump -> swirl pot -> tank

Circuit B is
Swirl pot -> HP pump -> fuel rail -> swirl pot

(with filters and regulators in there as well)

The LP circuit keeps the swirl pot full, the HP circuit feeds the engine.

Very similar to mine except I have two fuel tanks so one on each side and have a 6 way changeover valve in there too so I return fuel to the tank it is being drawn from. I.e draw from left tank to 6 way valve to LP pump filter swirl and back through 6 way valve to left tank

Basically as long as the inlet to the HP pump is full all the time there should be no problem

Ian

I reckon I would have to go similar to Scudderfish and Ian with it being:

Main & Reserve feeds >Reserve Tap> Facet > swirl pot > efi pump > fuel rail > return to tank.

Also with a return from swirl pot to tank?

However, how the flip I am going to get all this lot under the car I have no idea!

I may need to have the EFI pump situated up at the front, but would rather avoid this as almost everything is next to an exhaust manifold, and I would want to keep pipe joints in there to a minimum.

Guess that that the best way for the time being would be for me to look out for something cheap and second hand that I can use to offer up and figure it all out for real.

A P6 is a big car, I'm sure there is plenty of room somewhere.

Ah, you see I am more used to Landrovers, space is never usually a consideration!

Quagmire wrote:I reckon I would have to go similar to Scudderfish and Ian with it being:

Main & Reserve feeds >Reserve Tap> Facet > swirl pot > efi pump > fuel rail > return to tank.

Also with a return from swirl pot to tank?

However, how the flip I am going to get all this lot under the car I have no idea!

I may need to have the EFI pump situated up at the front, but would rather avoid this as almost everything is next to an exhaust manifold, and I would want to keep pipe joints in there to a minimum.


Guess that that the best way for the time being would be for me to look out for something cheap and second hand that I can use to offer up and figure it all out for real.

Sounds like a plan
But I would take the reserve outlet only to the Facit, as once the fuel level drops below the normal outlet all you will get is air!

That then leave the normal take off that could be used a the return inlet to the tank.

Yes you need a return from the swirl to the tank or if you manage to pump air or bubbles it will always gather in the swirl as it has nowhere to go!

I like to look at it as two systems

Tank, filter pump swirl, return from swirl to tank.

Then swirl to filter and HP pump to rail and return to swirl.

The pipe for feed from tank to swirl and swirl back to tank need to be able to flow the full rate of the pump ie have no restrictions.

Now depending on where you are driving this you may want to go to the breakers and get a fuel cooler off a small diesel van, and fit that in the return from the swirl to tank as beleive it or not the HP pump warms the fuel quite successfully!

Ian

I see Radium make a nice swirl tank type item where the pump goes inside.

http://www.youtube.com/watch?v=ACEriGn0PKw#t=67

stevieturbo wrote:I see Radium make a nice swirl tank type item where the pump goes inside.

http://www.youtube.com/watch?v=ACEriGn0PKw#t=67

Have you seen the price though?

Nope...but it is a nice piece.

If I fitted one of those and filled the tank up with fuel I would have probably doubled the value of the car!

For a road car, not a 400bhp racing machine that corners like a house fly, is it really necessary to fit a swirl tank?

I'm asking as I have just managed to pick up this tasty little morsel
and will be far.. erm.. fitting it sometime later in the year. My P6 isn't really a very big car and I didn't want to lose too much boot space. I have an in tank pump and was going to use that.

Any reason why I shouldn't?

Richard

Richard P6 wrote:For a road car, not a 400bhp racing machine that corners like a house fly, is it really necessary to fit a swirl tank?

The issue is nothing to do with power or performance.

It's simply the fact the original tank was never designed to supply a fuel injection pump

You must never allow an efi pump to suck air, and given the large volumes of fuel they flow, it needs a good unrestricted and clean fuel supply at all times.

None of those things are overly important with carbs, at least not as important

Richard P6 wrote:For a road car, not a 400bhp racing machine that corners like a house fly, is it really necessary to fit a swirl tank?

The issue is nothing to do with power or performance.

It's simply the fact the original tank was never designed to supply a fuel injection pump

You must never allow an efi pump to suck air, and given the large volumes of fuel they flow, it needs a good unrestricted and clean fuel supply at all times.

None of those things are overly important with carbs, at least not as important

Thanks Stevie

I was more concerned with it's cornering ability.

The lower 4" or so of the P6 tank is the reserve bit. If I were to fit the pump into the top of the tank and allow the actual 'pick up' to sit in the bottom of it, then it would always be sitting in 4" of petrol. As long as you take notice of the fuel gauge and don't let yourself run too low, that is.

Even driving as fast as possible around a roundabout shouldn't swoosh it enough to the left to allow it to uncover the pump intake.

Any thoughts?

P6s don't corner that well btw