Fuel line inside the car - Preference for installation...

I plan on replacing the fuel plumbing on my A1 Scirocco. Sticking with the stock pump/tank setup for now. Runs a high-pressure fuel pump, so I need to be careful if using rubber line.

Options:

A) Leave it how it is under the car, spend the time covering it to protect from rocks/gravel spray.
Downsides, big enough hit can still potentially crush the line; gravel could get in and slowly rub through a line; moisture/salt trapped between floor and underbody protection rots the lines.
Upsides... no time wasted with bulkheads and leaks inside the car. Cheapest route

rubber/braided lines outside the vehicle to bulkhead fittings, aluminum tube routed through the car, secured with rubber insulated mounts, and out of the way from kicking/stepping on. Requires the use of a 37° flare tool, which I have access to.
Downsides: fuel line in the car. Aluminum can work-harden and crack, potential leaks at fittings/bulkheads due to bad flares or overtightened fittings. Could be crushed by dropping something in the car. More expensive than Option A. If I ever switch to a fuel cell and pump in the car, lines would need to be replaced.
Upsides: No danger from outside the car, except where soft-lines exit, which would be covered anyways. Corrosion resistance. No leaky braided lines inside the car to be replaced or fuel smell permeating through the liner. Cheaper than Option C

C) Rubber/braided line outside the car to bulkhead fittings, braided line inside the car. Secured with rubber/insulated mounts.
Downsides: Fuel line in the car. Complaints of fuel smell due to lines being slightly porous. Lots of fittings to put together, more expensive than option A/B
Upsides: Easier to run through the car, no bending aluminum tube, less risk of crushing.

Thoughts?

I'd go with modified , steel line inside car with a nice full circle strain relief bent at each end, cheaper/stronger, available at CarQuest...

Cheers, Ted

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Pure mathematics is the enemy of every truly creative man -- Sir Alec

I like running hard lines inside the car, no braided stuff. I use stainless...more of a PITA to form and flare, and certainly more expensive. But it won't crush like aluminum, nor rust like steel. I've gotten mine from Inline Tube http://www.inlinetube.com/straight.htm, they're pretty reasonable.

Bob

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Opel is a 4-letter word...
http://www.flickr.com/photos/10498579@N07/sets/

What do you use for passing the lines through the bulkheads?

If you have hard lines, get rubber grommets.

I prefer braided soft lines inside the car. A rally car interior should have this strange mixed smell of sweat, oil, and race fuel. Just the thought of it makes me smile.

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Grant Hughes

dtompsett Wrote:
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> What do you use for passing the lines through the
> bulkheads?


I used to use purpose-made firewall pass-thru fittings, but now I just buy dry-seal electrical fittings. Two-piece metal fitting with a rubber center locks on to the fuel line sealing it, but allows for movement. And they're cheap and available at Home Depot.

Bob

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Opel is a 4-letter word...
http://www.flickr.com/photos/10498579@N07/sets/

McMaster-Carr has them for pretty cheap, page 797 of their online catalog shows 'Nylon Liquid-Tight Cord Grips' for about $2 each.


http://www.mcmaster.com/ctlg/DisplCtlgPage.aspx?ReqTyp=CATALOG&CtlgPgNbr=797&RelatedCtlgPgs=796,797,798,1309,2038,3342,3343,3608,3609,3610,3611,3612,3613,3621,3624,3625,3626,3627&term=Grommets&sesnextrep=831240790090957&ScreenWidth=1024&McMMainWidth=812&ToolsetID=ToolMultiPageNav&ToolsetAct=

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Opel is a 4-letter word...
http://www.flickr.com/photos/10498579@N07/sets/

I had thought about that... but hadn't gone anywhere with it. Is that considered CARS legal?

Don't use the AL lines; too risky for fatigue and cutting, and prone to fatigue at the connections.

If you want to not have smelly braided lines, use Teflon lined braided hose (with the appropriate fittings), not rubber lined.

Note that the incidence of crushed lines under the car is very low; it will happen from time to time, but not likely. Since you are prepping for a near term event, you're highly probable to be OK even if left unshielded. Take care of the changes later.

Good luck in getting prepped!

Mark B.

dtompsett Wrote:
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> I had thought about that... but hadn't gone
> anywhere with it. Is that considered CARS legal?


I honestly don't know. I prefer to use the metal electrical fittings because they're stronger. I figure if a plain rubber grommet is legal, then these things are far safer.

Bob

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Opel is a 4-letter word...
http://www.flickr.com/photos/10498579@N07/sets/

Ya... I've been thinking the money would be better spent elsewhere... and when I decide to do lines inside the car I'll go with a fuel cell as well.

One thing I always liked about my Audi... fuel tank in the trunk.

look at any subaru ever made.

The lines run under the car for about 3 feet, then enter the passangers compartment in the rear seat area, then exit out the fire wall.

Subaru themselves used nothing but a fancyish rubber gromet.

Clearly it meets DOT standards, and also Rally standards.

You can easily do the same thing with a spool of fuel line purchased from Napa/Carquest/crappy tire...costs about 20 bucks. Find some gromets somewhere (home depot) and you are done. You can buy a very cheap and effective line bender from Crappy Tire or Home Depot..i think it's about 20 bucks also.

i don't know what kind of pressure you are talking about, but Subaru also just has a bulge on the end of the hard line, and they attach High pressure fuel line with a fuel injection clamp. I have never heard of a problem unless the clamps are not tight.

Subaru does the exact same with the brake lines.

Only problem is that after about 15 Years, the lines will begin to rott out at the gromets.

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Chris

Thanks Chris... I was over to Napa today and saw some nice grommets. The other option are those cable-seals posted above. I didn't pick up the fuel line cause I couldn't remember what size it was in metric (or the imperial equivalent).

As for system pressure... the VW's/Audi's run ~90psi of fuel pressure on the CIS/CIS-E systems.

Do It Sidewayz Wrote:
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> Only problem is that after about 15 Years, the
> lines will begin to rott out at the gromets.

Yeah. Ever try pulling the tank out of an svx to replace the lines? Sucks!