Running brake and fuel lines through the cabin

I am planning a long term rallycross project and I could use some help with brake and fuel lines.  The car I am looking at uses unprotected hard lines underneath the floor pan.  That is not good for rallycross but I am not sure the best way to fix the problem.  I am mulling over these options.

Option A: Keep them, where they are and build a metal/plastic shield around each line
Option B: Route them through the exhaust tunnel (FWD car)
Option C: Route them through the interior

I am leaning towards some combination of options B and C.  I am having trouble finding information about how to do this safely.  If there is a book that answers these questions, I would love to know about it.

If I run the lines in the exhaust tunnel, underneath the car, is it going to be too hot for the fuel/brake fluid?  If I run fuel lines here, will flexible lines work as well as hard lines?

All the rally guys run a single piece solid line through the cabin but everyone else suggests it is nearly guaranteed death.  Is there a reasonably safe solution for interior fuel lines with enough room for two people sit in the car?  How far should an interior fuel line be from the battery cable on a car with a rear mounted battery?

If you route a large enough hard line from the rear firewall to the front firewall, you can run flexible fuel/brake lines trhu the cabin and still have it enclosed in a fireproof structure.

Think about something like exhaust tubing running thru the interior of the cabin with stainless braided lines run thru it. The ends of the large tubing would be sealed at the front firewall and behind the cabin.

Maybe look for NASCAR fule line routing pictures...

There are regulations about how to run fuel lines through the cockpit, I believe. I'd have a look to see if Staniforth's Race and Rally Car Sourcebook has anything inside. Great reference to have on the bookshelf. Mine's still packed up after a move so I can't check for you.

My Saab 96 had the lines inside the car.

Of course that was years before the safety people took over.

I've run fuel lines through the cockpit in a variety of types of racing cars.  As Keith pointed out the rule book for your sanctioning body will tell you what you need to do to make it legal. 

If the rules alow it I prefer to use a Nicopp line run along the passenger side of the tunnel with a bulkhead fitting on each end.  If there's a passenger seat I put a steel shield over it where the passenger might kick it.  I like to pain the line red and label it fuel line.  If you have enough room the safest way to do it is to run it inside a steel tube that runs from firewall to firewall with no openings into the passenger compartment painted red and labeled.

Brake lines I just run wherever they're not in the way and won't get dragged on the ground.  They're pretty rugged so you're not likely to damage them and if they get hurt in a crash then you're probably past the point where brakes are going to do you any good anyway.

I wouldn't run either inside the exhaust tunnel since heat is really not good for them.

Whole lotta Hondas had lines through the cockpit.  They quit that somewhere in the early 90's, I think.

Brake lines inside would be fine, as long as there was a nice soft opening through the firewall, so they don't rub through.  Fuel lines can be run inside, but I wouldn't want to put up with the tech guys, even if the job is done to the rules.  I have run them (in the above mentioned Honda products) above the exhaust in the tunnel, and have never had a fuel boiling issue in ministock cars. 

All Ford Fairmonts have the rear brake line nestled in the corner between the passenger footwell and the rocker panel. It pops out through a grommet about a foot forward of the rear axle. 

BMW 2002s ran fuel line thru cockpit.

90s Subarus had fuel lines running through the cabin too. Installing a roll cage into those cars is an unnecessarily exciting exercise.

NASCAR runs fuel lines through the interior of stock cars. It’s a rather large diameter tube maybe 3/4 to 1 inch in diameter. Cannot tell you if it is a shield with an interior line or just the fuel line itself. Seems big to be just a fuel line. 

boxedfox said:

90s Subarus had fuel lines running through the cabin too. Installing a roll cage into those cars is an unnecessarily exciting exercise.

I am pretty sure that ALL Subarus run the brake and fuel lines through the cabin.

This is nice, because I have never had to replace a line rack on one.

Knurled. said:

I am pretty sure that ALL Subarus run the brake and fuel lines through the cabin.

 

This is nice, because I have never had to replace a line rack on one.

*Goes outside to pull up carpets on wife's Outback.

EDIT: Looks like you're right.

APEowner said:

If the rules alow it I prefer to use a Nicopp line run along the passenger side of the tunnel with a bulkhead fitting on each end.  If there's a passenger seat I put a steel shield over it where the passenger might kick it.  I like to pain the line red and label it fuel line.  If you have enough room the safest way to do it is to run it inside a steel tube that runs from firewall to firewall with no openings into the passenger compartment painted red and labeled.

For the fuel line, don't run lines with copper content due to fuel spoilage issues. 

Honestly, for rallycross there is absolutely no reason to. I don't know of anyone in our rallycross region with interior brake/fuel lines other than cars that came that way. We have a good dozen e30s running, and the brake/fuel lines run under the car along the frame rails.  I think in 8 years I've seen one e30 have a fuel leak, and that was actually at a flex line by the pump that just got pushed off the hard line because he didn't put ANYTHING to protect it and tried to drive over a giant rock (not on course) goofing around. 

Just get some UHMW/HDPE sheeting and put it across the floor pans. On my stage car I actually took a narrower piece of UHMW/HDPE and heated it into a 45-degree bend that protects my hard lines just fine, as well as flat sheeting attached to the rocker seams (with small angle iron and bolts) and through the floor. We broke all kinds of stuff under the car at the ultra-rocky NEFR (including my oil pan through a 3/16" stainless skidplate, giant dents in my gas tank, and bashed spare tire well) but had no issues with any lines being damaged. I've done a half-dozen stage rallies and 50+ rallycrosses and it's never been an issue.

HDPE is seriously strong stuff. Way stronger against impacts than anything you could bend out of steel or aluminum (which would also be entirely sufficient for rallycross)

example of my fuel line guard piece (you can see the lines there on either side of the frame rail)

and the big sheeting, which is overkill even for stage rally, in truth.

One other thought on this topic: A couple years ago at the Winter Rally in Wellsboro, between stages the Neon waiting behind us had a bad fuel smell. They had (by RA rules) routed fuel lines through the interior, but somehow something loosened up. The driver's rear floor pan had like half a gallon of gas sloshing around in it!

If a fuel line outside the car breaks or leaks, no big deal really. At worst you DNF the run or the day. If one inside the car does, it's a much bigger deal in terms of your personal safety. 

In reply to pirate :

There’s a braided line inside the tube.

Wally said:

In reply to pirate :

There’s a braided line inside the tube.

Thanks that make sense seeing how large the tube through the interior is. 

shuttlepilot said:

APEowner said:

If the rules alow it I prefer to use a Nicopp line run along the passenger side of the tunnel with a bulkhead fitting on each end.  If there's a passenger seat I put a steel shield over it where the passenger might kick it.  I like to pain the line red and label it fuel line.  If you have enough room the safest way to do it is to run it inside a steel tube that runs from firewall to firewall with no openings into the passenger compartment painted red and labeled.

For the fuel line, don't run lines with copper content due to fuel spoilage issues. 

That's only an issue with diesel fuel and then only if you plan on storing fuel in the line for months at a time.