I'm trying to work out how best to run the fuel lines on the rally car (1985 Merkur XR4Ti) and would like some input. The plan is to ditch the stock plastic lines and reroute the fuel and brake lines through the car (lines under the floor get smooshed on a rally car).
My plan is currently to have AN fittings TIG welded to the fuel rail and tank outlets, and to use hard line in the interior, so the fuel lines would look like this from front to back:
Fuel rail > welded -6AN fitting > braided flex line > bulkhead fitting > hard line > bulkhead fitting > braided flex line > welded -6AN fitting > in tank pump assy
Thoughts? AN lines are the standard for this but they're pricy. Any reason to use flex line inside the car? Any reason not to weld AN fittings to the existing fuel stuff?
Make sure that the inside lines are sheilded in heavy wall tubing from entry to cabin to exit.
I got a long run of used Teflon braided -8 hose off ebay and ran them through a piece of solid metal conduit. Ebay is littered with the stuff, search: NASCAR hose. There's some very expensive-when-new hoses on there for pennies on the dollar, especially steel braided as they've all gone to Kevlar. Try to get a piece that you don't have to modify, as the fittings are quite spendy. You'll definitely wanted Teflon lined for fuel.
Ian F
MegaDork
11/30/16 2:18 p.m.
What does the rule book say? I've always wondered why hard lines aren't used more often, but I'm guessing there's a reason why just about every race car I've seen as braided hose running through the interior. Regardless of what any of us say, the ultimate decision will be by the tech inspector.
Define "pricey". I was curious and Summit sells 6AN braided fuel hose for about $4/ft. A 10' length of hose is about $40.
The fittings are the pricy part, not the line itself, so maybe I phrased that badly.
Rules state that the line must incorporate a metallic casing and can only have fittings at the firewall/bulkhead.
Ian F
MegaDork
11/30/16 2:31 p.m.
But you'll still need fittings at the hard lines to the bulkhead fittings. I guess I'm not seeing where you're saving much.
Hence why I'm asking, it doesn't HAVE to be AN, so if somebody went "hey check out these equally excellent JIS fittings that cost 20% as much, maybe plumb with those" I'd be open to planning around a whole different system.
EvanB
UltimaDork
11/30/16 2:46 p.m.
JIC is the industrial version of AN and can be sourced much cheaper. They will be steel instead of aluminum. You could also use a fiber braid cover truck fuel hose with the JIC steel fittings instead of the stainless braid teflon hose unless rules specify you need the stainless braid teflon.
EvanB
UltimaDork
11/30/16 2:52 p.m.
In reply to EvanB:
A hydraulics shop should have JIC stuff right? There's a shop near me, maybe I'll measure everything out and give them a call.
EvanB
UltimaDork
11/30/16 2:58 p.m.
¯\_(ツ)_/¯ wrote:
In reply to EvanB:
A hydraulics shop should have JIC stuff right? There's a shop near me, maybe I'll measure everything out and give them a call.
Yep, any hydraulics shop will be able to do it.
Looking into it more the 100R5 has a CPE inner tube which is good for diesel but not gasoline. You would want something with nitrile. Just tell the hydraulics shop what you are running through it (they should ask anyway) and they will get you something compatible.
If you just need short runs send me a PM and I can see what we have in the discarded hose bin at work.
Edit: Just noticed the rules say it must have a metallic casing so my examples don't work. You could probably still have a hydraulic shop assemble it cheaper than AN stuff.
