Is there a certain point in the fuel system on a petrol engine where the fuel pressure in the hosing/lines increases.

For example, the fuel pump draws the fuel from the tank in the rear to the front, into the filter. At this point i can't imagine a lot of pressure, it then goes to the fuel rails and fires out the injectors. When it enters the fuel rails how is there enough pressure to be firing the injectors at a pace fast enough for the engine to run?

I'm trying to understand if cheap teflon SS braided hose from the fuel filter back will be good enough as i can't see how the pressure will be that much.

Thanks

 

Static fuel pressure is 3bar, The pressure is increased with load/boost so if you are running 1.3bar of boost for example when the car hits that 1.3bar of boost this is then added to the static fuel pressure so your overall fuel pressure will be 4.3bar at full boost, Thats my understanding of it

 

cheap teflon ss braided hose ?

 

Its used in most wrc rally cars as its inpervious to smell the fuel pressur on the wrc cars is running around 8bar ,impreza static fuel pressure is 3 bar as above when added to full boost around 4-4.5bar

 

I've altered my original post, the grammer was terrible lol.

Okay i've had a read on fuel systems, so between the pump and the fuel pressure regulator is high pressure and before the pump and after the FPR is low pressure.

As you both say static is around 3 bar.

How does a FPR alter itself then when on boost?

I've been looking at braided hose and it seems to all be around £25+ per meter for the good quality hose.
I came across a company called MOCAL who make teflon braided hose for around £7 per meter and i'm sceptical that it can be any good, but if it can with stand the pressure that i'm asking about then there shouldn't be an issue should there?
Unless of course the quality of the teflon and braid is poor and it just expands.

The hose is sold here:

http://www.rallynuts.com/motorsport-...ided-hose.html

I've looked for the pressure rating but can't find any.

To be honest thought, if it can't stand 3 bar, then well... it's probably paper lol. I think the biggest issue would be a push fit with a clamp being a weak point in a pressured system, and they are most likely to pop of if there is maybe 10 bar?
But i just thought, the fuel lines as standard are clamped on anyway so...

Thanks

 

the fuel peessure reg doesnt really work on boost, it works on vacuum.

when engine vacuum is high the fuel pressure is lowered by spilling of to the tank. when vacuum is gone ( ie on boost ) the fuel pressure runs at whatever the pump delivers.

 

That hose has a max operating pressure of 3000 psi, I think it can cope with fuel pressure, it has a minimum burst pressure of 12,000 psi

 

That would explain about the vaccum on the FPR then.

Where did you find this figures out, i was on the MOCAL site and they weren't on there?

To what quality is my question now though. If you can buy that for £7 a meter and Goodridge hose for 25+, there must be some difference. Its not the fuel system so much i'm thinking about now, but the braking system, as i plan to braid them too, the ones which run through the cabin, but as there is more pressure on the braking system, i don't want to get a spungy pedal and want something that willl be as good or better as hard line, and for £7 i don't beleive this will be the best hose, i might have to splash out on the braking lines.

Thanks

 

You won't get anything "as good or better" than hard brake lines.
If you want to replace the flex hoses then get a specific kit for the job.
As for the fuel lines, if mocal are selling it then it'll be good quality I would suspect but mocal make oil coolers though.

 

It's the 2 hard line that run through the car i'm looking to replace due to getting a cage, but like i say i don't was to make the pedal spongy.

Maybe i should make new hard lines that route around the cage.

Thanks