The V8 Owners Forum -

I am about to replace the factory fitted 3.5 on twin SU's in my Land Rover 110 with a 3.9 EFI what is the best approach to the fuel pump problem in order to achieve the different fuel supply pressure.

The 110 currently has an in tank pump which I understand supplies about 5 psi.

Gerald

Usually an external high pressure pump below the tank so gravity fed. You'll also need a return.

I did this on my Sherpa:

The large silver thing is a high pressure filter, the pump is behind it. I forget what the pump is off, but it is the kind of thing that was readily available from the likes of Demon Tweeks. In the 80's, some fuel injected cars had the pumps outside the tank, and that was what you needed.

Note the pump is above the tank. Worked absolutely fine.

Chris.

EDIT- the filter might be low pressure looking at it....., can't remember now.

Looks like a HP filter to me.
I was told you are not supposed to use jublie clips on HP fuel pipe - as it cuts into it. But must admit those smooth clamps dont seem to hold as well.

Eliot wrote:Looks like a HP filter to me.
I was told you are not supposed to use jublie clips on HP fuel pipe - as it cuts into it. But must admit those smooth clamps dont seem to hold as well.

That's a new version. I was told the correct clamps provide a better seal due to being narrower, so give a higher psi figure. But have used jubilee clips everywhere with no problems.

I would never use worm drive clamps in any small diameter hose. At least not for any flammable liquid or high pressure.

The smooth clips you refer to are the correct design and clamp perfectly.

Dont forget too though, carb tanks will rarely be designed internally for efi usage. ie a little bit of fuel slosh on a carb car isnt the end of the world as there is a reservoir of fuel in the carb.

Fuel slosh on an efi car will result in immediate effect on the engines running if the pump sees air, and reduced lifespan of the pump.

And in general, electric fuel pumps typically used on modern cars do not suck well, so should always either be gravity fed, or fuel pumped to them via a swirl tank or similar.

stevieturbo wrote:I would never use worm drive clamps in any small diameter hose. At least not for any flammable liquid or high pressure.

The smooth clips you refer to are the correct design and clamp perfectly.

Dont forget too though, carb tanks will rarely be designed internally for efi usage. ie a little bit of fuel slosh on a carb car isnt the end of the world as there is a reservoir of fuel in the carb.

Fuel slosh on an efi car will result in immediate effect on the engines running if the pump sees air, and reduced lifespan of the pump.

And in general, electric fuel pumps typically used on modern cars do not suck well, so should always either be gravity fed, or fuel pumped to them via a swirl tank or similar.

a fuel tank with no swirl pot fitted is a pain in the arse for EFI on both acceleration and cornering especially although can be kept to a minimum if tanked up but who wants to keep filling up just because the gauge as hit 1/2 tank ? easier to get an EFI fuel tank personally TVR used Jubilee clips on their RV8 cars as they left the factory but I don't like them on small bore hosing fuel line for example and certainly not under EFI pressures

The tank in that particular vehicle should have had Diesel in it, so I suspect it had an internal swirl pot of some sort. I certainly never had any problems with fuel starvation.

Chris.

ChrisJC wrote:The tank in that particular vehicle should have had Diesel in it, so I suspect it had an internal swirl pot of some sort. I certainly never had any problems with fuel starvation.

Chris.

If that so then a Diesel tank would work fine