Ptfe braided line for entire fuel supply?

I am scrapping my metal lines that are proven to be troublesome in making and installing. I've seen other guys run PTFE braided line for their entire feed and return line from their fuel cell to their engine compartment. Is there a reason I should not do this? Car is a tube frame race car fuel lines will be on the inside of the car under metal shielding.

You'll smell fuel vapors seeping through the lines, maybe.  Also, check the safety regs for anywhere you might want to enter the car, a lot of sanctioning bodies say metal lines in cabin only.

I ran nylon line in the ecotech swapped b210 for Lemons. It ran under the car in a piece of 1" conduit from the fuel cell to the regulator/filter. No issues with tech or fueling. And super easy to run. 

A 25' kit with fittings was $100 from the Stop Shop on Amazon.

In reply to Pete. (l33t FS) :

Not with ptfe lines will you have the normal fuel vapor smell.

You can build a channel/cover over flexible lines.

That's a really expensive way to run fuel lines.

I saw your other thread and I think you might be making life harder than it needs to be.  When I run fuel lines inside the car I use aluminum tubing like this -> Link to Speedway motors.  I use compression fittings like these -> another Speedway Motors link and, I use bulkhead fittings where I enter and exit the car.

I buy tubing in long enough rolls that I don't have any junctions inside the car and I plan my entry and exit points to minimize bends.

In reply to APEowner :

The aluminum hard line isn't recommended for EFI use; I don't think the tube nuts are meant for the high pressure.  I have used thicker wall aluminum tubing and welded AN fittings on the ends before, which was cheap and worked well.  If you're contemplating E-85 use at any time you'd better stick to PTFE or stainless.  
 

I've had great luck with Evil Energy stuff from the jungle website.  6AN Kit  This stuff was about 30% cheaper when I bought it a couple years ago but I prefer this to standard AN lines.  It's less compliant than rubber core AN, but no smell and the ferrule compression fitting on the PTFE liner forms a really good seal, I've never had a leak running at 70psi.

Summit Racing used to sell 6AN and larger kits with braided lines with enough to run the whole way, but I also recall them getting sued a few dozen times over it.  Race I think it's a known risk, but on the street, losing grandma to an inferno of gasoline didn't go over too well.

The thing about steel line is that it can take some pretty hard abuse and not rip or rupture too badly.  Once you crush or rip the PTFE liner in a braided line, it's a gusher.

What about NiCu?  Should be suitable for gas and super easy to bend

I have always considered braided lines to be wear items that will need replacing soon enough.  Grit gets in there and compromises the lines.

Ranger50 said:

In reply to Pete. (l33t FS) :

Not with ptfe lines will you have the normal fuel vapor smell.

You can build a channel/cover over flexible lines.

Maybe its brand dependent but I have never had ptfe lined hoses smell. The point is the hose interior is impermiable and protects the cheap rubber. 

So i guess more explanation is in order.

Car is an 80s Winston cup car. Originally, it had a single fuel line from the cell, through a pass through in the frame, through the floorpan into a tube up to the firewall along a cage tube, through the bulkhead in the firewall to the carb.

That cage tube and conduit are gone. In ots place is a seat for the passenger. 

Additionally, its efi and needs a return now. 

The ubderside of the car is not conducive to keeping the lines out of harms and heats way, so i decided to go through the interior, under the passenger seat, snaked between cage tubes at the kick panel, across the firewall to bulkhead fittings directly behind the fuel rails. 

I started with 3/8 steel lines, and mangled the job pretty bad with kinking the lines. Just couldn't get them where they needed to be. 

So i bought $100 worth of nicopp line. Then realized i couldn't get THAT where it needed to be without kinking. So i made it two pieces with compression fittings under the passengers floor heat shield. And kinked it anyway at the kick. Cut the kink out, added a 6 inch section of rubber line. Then kinked the over axle section in two places on each line. 

Then started this thread in frustration. 

It shouldn't be this berkeleying hard. Which means im trying to force it, instead of letting the car talk to me. Or asking for advice. Or looking for a different way. 

Im open to suggestions yall.

In reply to Dusterbd13-michael :

Seriously, this stuff worked very well. EFI rated and easy to run. I ran under the car through a piece of emt conduit, but through the car would also work. I would want a metal shield over it to keep it from getting damaged but it is extremely durable. The supply and the return will fit through a 1" conduit. 

The picture is the link. 

I don't see any issue using stainless braided hose for fuel line.  It's done a lot in race cars.   SCCA rules require fuel lines in the cockpit to be metal or metal braided so you're OK there, too.  It is more expensive than a metal line but I've done long runs of braided for the same reason you're looking at it: it's just really difficult to get a hard line in some locations.

That nylon stuff Toyman posted is going to go in the tunnel of my 914, now that I know it exists

In reply to Dusterbd13-michael :

3/8 is a pain even with a good bender unless you have developed the Finesse.  Which you get after many frustrating times.

I think the Nicopp is more prone to kinking because of how weak it is.  At least it squooshes roundish more easily.

In reply to Pete. (l33t FS) :

I generally have the finesse. Made many pretty runs, many perfect flares, many kink free bends.

I dont think my route is actually possible with a single segment of hard line. I think i made an impossible task, and didn't stop to think it through. 

Ptfe on order. 

Kendall Frederick said:

In reply to APEowner :

The aluminum hard line isn't recommended for EFI use; I don't think the tube nuts are meant for the high pressure.  I have used thicker wall aluminum tubing and welded AN fittings on the ends before, which was cheap and worked well.  If you're contemplating E-85 use at any time you'd better stick to PTFE or stainless.  
 

I didn't catch the EFI in this application, although the dual line should have been a clue.  I use 37 degree AN flares on 250 PSI rated aluminum line for EFI.

In reply to Toyman! :

I've seen this on many OEM applications but had no idea they sold kits with the line and tubing.  With the EMT conduit shield, that actually looks like a great solution for a lot of applications, including the OP's car.  A quick Google search shows tubing in at least up to 5/8" is available.  

Glad you mentioned it here!  

APEowner said:

Kendall Frederick said:

In reply to APEowner :

The aluminum hard line isn't recommended for EFI use; I don't think the tube nuts are meant for the high pressure.  I have used thicker wall aluminum tubing and welded AN fittings on the ends before, which was cheap and worked well.  If you're contemplating E-85 use at any time you'd better stick to PTFE or stainless.  
 

I didn't catch the EFI in this application, although the dual line should have been a clue.  I use 37 degree AN flares on 250 PSI rated aluminum line for EFI.

 

 

I bought some rotary parts from a GT racer who, while showing me his car (it is amazing how much a GT3 Miata has absolutely no Miata parts) and mentioned that he had a whole lot of carburetor issues that he found out from another racer were due to the aluminum fuel lines.  I forget the exact details other than marveling at the new and exciting problems that crop up when on a completely different level of motorsport than I'm used to.

Fires suck and burns hurt.  I would find a way to do steel hard line.  I would trust steel hard line with a proper union a lot more than braided line.  

In reply to Pete. (l33t FS) :

Anodize coating flakes off. Even "natural" look has a clear on it for oxidation purposes. Most people will size the line too small then jump the pressure up to compensate. This just puts them in the land of uncertainty with respect to Reynolds's number for fluid dynamics....

In reply to Ranger50 :

Sounds familiar.  Big flakes would cause problems like that.