The V8 Owners Forum -

I'd modify it for return lines personally! Shouldn't cost much to have a pair of hose barbs added to the dead end and route back to a FPR.

Absolutely no need to though.

Random wrote:I'd modify it for return lines personally! Shouldn't cost much to have a pair of hose barbs added to the dead end and route back to a FPR.

Ok - given that all this is exactly as LR built the system, why would you run return lines from the fuel rails?

Cheers

Garry

garrycol wrote:

Random wrote:I'd modify it for return lines personally! Shouldn't cost much to have a pair of hose barbs added to the dead end and route back to a FPR.

Ok - given that all this is exactly as LR built the system, why would you run return lines from the fuel rails?

Cheers

Garry

Im paranoid about any vapour in the fuel lines. Also temperature alters fuel density.

Its likely unecessary but its how I always set up my fuel systems!

Random wrote:

garrycol wrote:

Random wrote:I'd modify it for return lines personally! Shouldn't cost much to have a pair of hose barbs added to the dead end and route back to a FPR.

Ok - given that all this is exactly as LR built the system, why would you run return lines from the fuel rails?

Cheers

Garry

Im paranoid about any vapour in the fuel lines. Also temperature alters fuel density.

Its likely unecessary but its how I always set up my fuel systems!

And what temperature does your fuel normally run at, vs what temperature it will be here ?

And what problem do you perceive vapour will cause if it exists...that isnt affecting the millions of vehicles with dead end rails already out there ?

You're worrying over nothing. But by all means with a little work you could adapt the rails for full flow, or just make new rails.

I thought that vaporisation was almost entirely eliminated due to the fact that the pressure in the fuel.rail is what , 3 bar or something?

Same principal as having a pressurised cooling system.

I am not sure what the problem is even if vaporization does occur. It can only occur after the car has been parked with heat build up and as soon as the fuel pump fires up and the engine is cranked any vapour will be expelled through the injectors.

The hot fuel will help start.

Vaporization in a fuel system is only a problem when it occurs in a fuel line before the fuel pump and is sucked into the fuel pump causing it to cavitate and not pump fuel.

Garry

Quagmire wrote:I thought that vaporisation was almost entirely eliminated due to the fact that the pressure in the fuel.rail is what , 3 bar or something?

Same principal as having a pressurised cooling system.

My SD1 EFI has a factory designed mod to overcome fuel vaporisation on a hot restart. A valve fitted to the fuel return which shuts off, controlled by a thermostat on the rad. And a relay which bypasses the series resistor to the fuel pump. So when cranking, the fuel pressure goes up to the maximum the pump can do.