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Cal-look/High Performance => Technical stuff => Topic started by: numbnuts on February 18, 2017, 10:23:46 am



Title: Fuel lines
Post by: numbnuts on February 18, 2017, 10:23:46 am
Can anyone show me how best to route new larger fuel lines? I am planning on using an6 fittings/lines as that is what is most commonly used but should I be running a hard line on the body or could I fix a braided line to the body and connect to that?
Inside in the passenger floor next to the trans tunnel or outside underneath?
Any help greatly appreciated

Thanks joel


Title: Re: Fuel lines
Post by: Garrick Clark on February 23, 2017, 22:22:55 pm
I run 2 x 8mm fuel lines inside the bug tunnel.
Its not that difficult to do really.


Title: Re: Fuel lines
Post by: UltraOrange67-2443 on February 25, 2017, 14:15:51 pm
I'm fitting aluminium hard lines in the tunnel with bulk head fittings at each end.

-8 feed and -6 return.


Title: Re: Fuel lines
Post by: hotstreetvw on February 25, 2017, 15:00:11 pm
I ran two 1/2" aluminum lines on my current pan.  The exit is opposite of the clutch cable and accelerator cable.  Flared ends with tube nuts.  Where they go through the pan there's a rubber bushing, I then covered it all in seam sealer to dampen vibrations and the chance it would ever wear through.  I had to drill out the spot welds on the sheet metal part right there in front of the trans, ran the lines, trimmed it, aluminum riveted back on for easy removable if there was an issue.  Lines are rubber clamped and riveted to the tunnel inside.  At the front, each line has a 90 degree bulkhead fitting that comes out right in front of the napoleons nose.  The line is straight with the exception of the light upward bend at the rear.  If the line is straight you can run it through the shifter passage holes at the front of the car.  I'd suggest putting in a couple access holes in the tunnel.  On near the pedals, so you can attach the line to the 90, also allows access if the clutch tube was to break at this point, which mine did last year at the Denver race.  Second near the shifter to make replacing the bushing easy, and a third around the seat belt mounting point.  Mine are 3" hole sawed, cleaned up so they don't cut your hands.  I made aluminum covers, similar to the covers found around the front for the steering box. My car is caged, so I wasn't worried about losing a little strength in the tunnel


Title: Re: Fuel lines
Post by: baz on February 25, 2017, 17:52:02 pm
I ran two 1/2" aluminum lines on my current pan.  The exit is opposite of the clutch cable and accelerator cable.  Flared ends with tube nuts.  Where they go through the pan there's a rubber bushing, I then covered it all in seam sealer to dampen vibrations and the chance it would ever wear through.  I had to drill out the spot welds on the sheet metal part right there in front of the trans, ran the lines, trimmed it, aluminum riveted back on for easy removable if there was an issue.  Lines are rubber clamped and riveted to the tunnel inside.  At the front, each line has a 90 degree bulkhead fitting that comes out right in front of the napoleons nose.  The line is straight with the exception of the light upward bend at the rear.  If the line is straight you can run it through the shifter passage holes at the front of the car.  I'd suggest putting in a couple access holes in the tunnel.  On near the pedals, so you can attach the line to the 90, also allows access if the clutch tube was to break at this point, which mine did last year at the Denver race.  Second near the shifter to make replacing the bushing easy, and a third around the seat belt mounting point.  Mine are 3" hole sawed, cleaned up so they don't cut your hands.  I made aluminum covers, similar to the covers found around the front for the steering box. My car is caged, so I wasn't worried about losing a little strength in the tunnel


This is pretty much what I'm aiming for with mine.  I don't want permanent access holes left in my tunnel, so any temporary holes made for ease of fitting the lines will be welded back up.

For this reason I want mine to last and not require maintenance or replacement. Would stainless lines be more durable than aluminium? 


Title: Re: Fuel lines
Post by: hotstreetvw on February 25, 2017, 18:03:54 pm
Stainless would be more durable. However, your pretty much limited to 3/8".  I couldn't find any 1/2, except from the aircraft suppliers, and the length was limited. I think the aluminum is more than strong enough if you get the 250psi rated; hold it down well to limit vibration and abrasion.  You will be fine for the lifetime of the car.

Access panels are good. Here is how I did mine.  I still need to weld up a couple holes.

[attachment=1]


Title: Re: Fuel lines
Post by: baz on February 25, 2017, 18:21:04 pm
I think 3/8 inch would be enough for my car. I'd be concerned about leaving access holes in the tunnel as it's a street car without full cage. Though if I ever crash heavy enough to bend the tunnel I'll have more problems than a few holes in the tunnel to worry about.


Title: Re: Fuel lines
Post by: hotstreetvw on February 25, 2017, 18:56:48 pm
Weld your floor pans in all the way around the perimeter.  It will add rigidity to make up for the access holes.  Makes replacing the shift bushing easy.  And like I said, if the clutch tube breaks from the bracket at the front, it's easy enough to fix.  I had it break last year in Denver after the first round.  I had to drill into the bottom of the tunnel and zip tie to the pan near the shifter, I was able to get it tight enough to keep racing.


Title: Re: Fuel lines
Post by: neil68 on February 26, 2017, 06:52:21 am
Could I fix a braided line to the body and connect to that?
outside underneath?
Any help greatly appreciated

Thanks joel

I added -6 (9.5 mm) braided steel lines under the floor pan, because I did not want to modify the stock tunnel, lines, etc.  I capped the stock line at both ends, so that I can re-use again some day, after I've had my fill of racing.  I even used two stock holes to mount firewall adapters at the front and rear.

I routed the braided lines down the middle, underneath the pan, alongside the inner ridge.  This is obviously not as good as running solid lines through the tunnel, however, that's a more permanent solution.

I'll see if I can find some old photos.


Title: Re: Fuel lines
Post by: Neil Davies on February 26, 2017, 09:50:56 am
I ran a 10mm copper microbore central heating pipe under the heater channel of my race car. Been told recently that modern fuels can attack copper so might not be the best solution for you.