Can I Use Flexible Fuel Lines Throughout For Injection

[Guest david_l_perry]

As part of my new engine fit I am replacing the original fuel lines on my 2B

 

Original fuel lines had a number of separate pipe connections and I would rather have as few connections as possible.

 

Routing the pipes through the tunnel and rear setup to the fuel pump will be far easer if I use high pressure flexible fuel lines rather than copper pipe and I Can use a single feed and return so little or no junctions.

 

I was looking through a Dax Rush build on kit car magazine and that's exactly what was done for that.

 

I can't see any issues using flexible pipe for injection fuel lines as long as it's high pressure stuff.

 

Has anybody come up with issues that I can't see ?

 

Dave

[Shaft]

i can't advise professionally but to copy your common sense approach i'd just add to your pressure suitability...

• Temperature resistance
  
• Suitability of your chosen clamping method
  
• Routing as to ensure no abbrasion or puncture risk
  

HTH,

 

Nick.

[fry61]

Add to Nick's points --- the cost -- copper pipe is pence per metre & easy to fix -- flexipipe will need to be in some sort of ducting to ensure its out of harms way though-out the run.

[alanrichey]

The Superspec (fuel injected engine) fuel lines are all flexible pipe throughout and I don't think any of us have had many problems except the pipes degrading over time because they were not of good enough quality.

[steve in stockport]

If you're going to use flexible pipe throughout make sure you get the right grade. You'll want at least R9 spec as any other will degrade, harden and smell with modern unleaded fuel

[brumster]

Just echo that as well; use high grade proper injection hose and you won't have problems. You could also use PTFE-lined braided hose if you didn't trust the rubber stuff, would give you *some* flexibility at a cost, although for pushing through a tunnel I wouldn't recommend it as the braid could get damaged/snagged during the process. Not really worth it in this application.

[Guest mdav1970]

I've replaced many older injection BMWs with front to back flexi fuel lines after the metal lines have corroded. Never had any issues so long as you use the correct spec and secure it enough under car, and don't allow it to touch rub any where it shouldn't. Makes the job a whole lot easier than trying to bend and thread copped piping around body and suspension parts.

[Dave R]

wouldnt risk flexistuff, unless your dead certain its the right stuff... have seen pipes that are stamped correctly for unleaded degrade very soon after instalation

run copper/knuifer, where you cant see it and keep an eye on it

[philshelton]

I ran copper lines on the top of the tunnel after having a accident and the prop-shaft cutting both fuel lines and scuffing the insulation on part of the wiring loom, I dont want to be stuck in a 4 point harness with flames licking round my feet.

[theduck]

wouldnt risk flexistuff, unless your dead certain its the right stuff... have seen pipes that are stamped correctly for unleaded degrade very soon after instalation

run copper/knuifer, where you cant see it and keep an eye on it

Not all. Injection flexi line is born equal. There is a new standard that copes with the ethanol content that kills the old stuff.

[Al Milton]

There are pros and cons for both styles, rigid vs flexi, so go with what you want and can afford.

 

What I would say is though, buy your hose/pipe from a reputable dealer, not a cheap as chips e-bay deal.

I had flexi connecting the tank to copper pipe via the pump and pipe to injectors manifold, that came from a 'special' deal a few years ago and was sopposed to be 'future proof' & suitable for modern petrol.

This soon became porous resulting in a petrol smell in the garage with no obvious leak.

 

I spent a bit more and got replacement flexi hose from CBS - no more petrol fumes. This is R9 (ethanol) grade and the change was instant - money well spent.

[fry61]

If you are worried about the copper tube/flexi joint ---- solder a same size olive onto the copper just short of the tube end -- with the flexi pushed over the olive & clamped by a correct size worm screw hose clip before the olive how can it possibly come adrift with the low pressures we are using -- even injection is only 45/50psi

[Guest david_l_perry]

Cheers for the comment guys. R9 high pressure hose ordered and on its way.

 

Just makes so much more sense to me to minimise the numbers of junctions and will certainly make routing the pipe far simpler through the existing rear end.

 

The original stuff fitted was a flexible plastic/nylon sort of material that had become a little brittle so replacing it all is certainly the right choice whilst I am on with the engine refit

 

Dave

Edited April 14, 2015 by david_l_perry