Cutting braided fuel hose + other fuel system q's

chodjinn · Post by **chodjinn** » Mon Jun 25, 2007 7:44 am

Bought a ton of this braided hose the other day, but for some reason I can't seem to cut it with any success. I've been using the tape and hacksaw trick and been very gentle but the metal stil frays very badly.

Is there a special technique to cutting it or do I need a special tool or something?!?

I will be running a Holley blue pump and Bosch 909 - what's the best way to wire them up (I was only using a Facet Red Top before)?

I also have a fuel swirl pot - how much straight hose should I leave between the swirl pot and HP pump?

cheers!

Alley Kat · Post by **Alley Kat** » Mon Jun 25, 2007 7:58 am

I've cut it with heavy-duty scissors, or a cutting disc in a grinder - the thin ones meant for stainless. Go gently or it curls a bit with the heat. Guess tin snips would do it too.

chodjinn · Post by **chodjinn** » Mon Jun 25, 2007 8:00 am

i tried tin snips but they didnt go throguh too well. Also tried cutting just the rubber bit, then the metal sheath and that didnt work either

ian.stewart · Post by **ian.stewart** » Mon Jun 25, 2007 8:50 am

I use 1mm cutting discs with tape wrapped around the cut, I also flush the pipes out before I use them to remove any residue from cutting.

Alley Kat · Post by **Alley Kat** » Mon Jun 25, 2007 9:38 am

Those cheap snips, tenner for 3 jobs, are crap. Just had a quick go with my pukka ones and they work excellently. Got to start in from the end, cutting one layer sort of thing, but does a very crisp clean cut.

chodjinn · Post by **chodjinn** » Mon Jun 25, 2007 10:03 am

Righto B&Q tonight it is then!

How about the wiring of the pumps?

Ian Anderson · Post by **Ian Anderson** » Mon Jun 25, 2007 12:23 pm

I've heard a dremil cutting disc workd well - again take it slow or the rubber and wires all snarl up together and fray up

Or a sharp cold chisel and hammer!

I was told that it is best to take 2 feeds through 2 relays - one for each pump. The pumps can spike on start up so presumably this is the reason (That said I have mine wired together on a single relay)

Swirl to HP pump I'd say as short as possible with the HP pump as near to the base level of the swirl as possible

Ian

chodjinn · Post by **chodjinn** » Mon Jun 25, 2007 4:37 pm

cheers Ian but most of that didnt make sense!

Dremel is out of the window - i bougth a good one and its the biggest piece of poop i've ever used. Sharp and chisel don't go in the same sentance in my garage!

Probably try the cutting disc - i need one for my aluminium

With the HP pump, can it be inside the car or does it and the HP filter have to be mounted outside?

stevieturbo · Post by **stevieturbo** » Mon Jun 25, 2007 5:29 pm

The very reason I rarely use braided hose !!! Its a right PITA.

If you can find something to slip up the inside of the pipe to support it, Ive used a normal pipe cutter on them before. Although it is quite sore on blades.

other than that, a junior hackaw really isnt that bad.

Ive used heavy duty cable shears before too, but it squishes the end making it harder to get the fittings on.

Ian Anderson · Post by **Ian Anderson** » Mon Jun 25, 2007 6:00 pm

Ok I'll try again.

Presuming you are running from a Lucas ECU - it has a single relay that operates when ignition is on(times for 3 seconds after engine stalls and then cuts power) This would normally power 1 pump in something like a range rover. So now you need to run 2 pumps

So from the Ecu take 2 triggers and 2 main feeds to 2 relays - each relay powering only 1 pump. - This is said t be the correct way to do it. - Each pump on initial start will draw more current than in normal running so hene the spike value of the current needs to be catered for in the fuse / fuses. 2 fumps on 1 power feed and you get a bigger "spike" hence the 2 relays are referred.

Now I did basically the first thing with a more powerful single relay powering the 2 pumps -not as good as the second one but it works!.

For a real basic system you could run both the pumps from the ignition switch - but this is not very good on safety features!!!!!

Now for safety I would also suggest a cut off switch to run on a couple of bits - this can "un hook" the relay / s.
1) An inertia switch so if you have a bump the fuel system is turned off automatically - remember how much fuel these pumps are rated at? This switch could be mounted on the floor of the passenger area and so you could reactivate it when seated.
2) On a low oil pressure switch so if your pressure drops to less than say 5psi it cuts the fuel - saves the engine if your oil system springs a leak.

Hopefully a bit clearer

Ian

chodjinn · Post by **chodjinn** » Tue Jun 26, 2007 7:23 am

thanks Ian. I have yet to get hold of an efi loom but should be sorting it this month.

I still dont know abotu the pump tho - do I have to mount them inside or outside the cockpit? The car must be road legal.

thanks

Alley Kat · Post by **Alley Kat** » Tue Jun 26, 2007 9:08 am

Not sure if it's an age-dependent thing, but got to be safer external - crash, split line, etc etc... Quieter too if it's all outside.

chodjinn · Post by **chodjinn** » Tue Jun 26, 2007 2:29 pm

that's a good point actually, i will chase that up. Mine is A '72 MG so might get away with it - i know I certainly do for noise and emissions.

Just that the pump would look so much better inside the car, all shiney and all that! PLus I wont have to faff around with holes in the body and those annoying rubber gromit things.

stevieturbo · Post by **stevieturbo** » Tue Jun 26, 2007 6:06 pm

If the entire system was stainless braided hose, the fuel system was totally vented to atmos, with no openings inside the cockpit, I guess it could be mounted inside the car.