fuel hardlines

[Rich_h]

hi looking into fitting alloy lines in the tunnel of my Gasser racer project bug as the body is off at the moment (one of many projects  )

so my questions are what size id bore do i need for it
 
and also looking into fuel injection so thinking of fitting a return line as well does this need to be the same size ?

the engine planed to be a 2Lt screamer 

rich

[Fiatdude]

I used 5/8" aluminum thick wall supply and return with compression fittings to make the 90* and join sections together -- Do it once and never have to worry about having to do it again

[Frallan]

Aluminium can work if supported well but I will never take that chance again. Same as copper. No go for me.
Not for oil or fuel.
Water tubing and intake manifold tubing is OK.
Steel or stainless if it is a hardline and a critical liquid.

I know many will not agree but I am just voicing my preference from some own and learnings from others.

[MeXX]

Dear Rich H

I for myself prefere thin wall Aluminum with Aluminum sleeves and nuts for AN fittings.
They are soft and therefore easy to install look nice and there is no issue with corrosion.
As they are soft they are really safe and will never leak when installed properly.

You need bigger lines for carburatored engines than EFI (it's because of the pressure).

For a up to 250 Hp EFI  AN 4 would be enough (check out the OEM)
For a up to 250 Hp carb  AN 4 is on the edge I would prefer AN 6.

Be careful:

On E85 you need about 20% more fuel
On methanol you need about 2.2 times the fuel

Mount the fuel pump always near the fuel cell; try to keep the suction lines short and avoid bends and step one size up.
If you need a return line for EFI take always the same size to avoid pressure creep.

In my streetcar (238HP EFI+ 225 HP Nitrous  ) I use AN 6 feed and return line and AN 8 suction line.
In my racecar (293HP EFI + up to 250 HP Nitrous ) on methanol !! I use AN 8  feed and return line and AN 12 suction line.

I think there is no need for 5/8  as long as U stay below 1000 HP

MeXX

[BeetleBug]

In my streetcar (238HP EFI+ 225 HP Nitrous  ) I use AN 6 feed and return line and AN 8 suction line.

MeXX

Please tell us more about your street car, it SURE sounds interesting and I wonder what specs are able to hold a 225 shot of nitrous.

Best rgs
BB

[MeXX]

Please tell us more about your street car, it SURE sounds interesting and I wonder what specs are able to hold a 225 shot of nitrous.

Best rgs
BB

It's a 2595ccm (100 bore x 82,6 stroke) Oxyboxer (Wasser raus Luft rein).
But I think I should do a threat on this   

MeXX

[Erlend / bug66]

Please tell us more about your street car, it SURE sounds interesting and I wonder what specs are able to hold a 225 shot of nitrous.

Best rgs
BB

It's a 2595ccm (100 bore x 82,6 stroke) Oxyboxer (Wasser raus Luft rein).
But I think I should do a threat on this   

MeXX

Please do... 

[Shag55]

I'm doing the lines at this time for my Notch. -8 feed and return for efi -10 to the pump. My consern is the lines cracking when welded permenatly.

[Fiatdude]

I'm doing the lines at this time for my Notch. -8 feed and return for efi -10 to the pump. My consern is the lines cracking when welded permenatly.

That is why I used compression fittings from the Hose guy



the lines were thick wall -- and were a mother to bend --- not worried at all about damage to them -- accidently jacked the car up on one of the lines with no damage

[Shag55]

Harold you should really consider mounting your pump and filter below the tank or in the spare tire well.

[Fiatdude]

It draws from the bottom of the tank and with 1/4 tank of fuel it is OK -- that line you see on the top is the return

[Frallan]

Looks like we maybe should look at some rule books.
Normally it is good benchmarks for the safety of the streets too. I will for sure learn too, as I have not looked in to rulebooks since 1984.
Maybe I am being silly, maybe not.

[Fiatdude]

Rule books -- -- NHRA requires the lines outside the drivers compartment --- NASCAR requires the fuel line (thick wall) thru the compartment - passenger side --- 

[Shag55]

My consern is if you have a leak fuel will come through all the little holes in the dash and get inside.

[Airspeed]

I for myself prefere thin wall Aluminum with Aluminum sleeves and nuts for AN fittings.
They are soft and therefore easy to install look nice and there is no issue with corrosion.

Be careful:

On E85 you need about 20% more fuel
On methanol you need about 2.2 times the fuel

With either E85 and surely pure methanol, aluminium is not the preferred material for a fuel line exactly because of the corrosion risk?
Be carefull indeed.

So I intend to agree with Torben, stainless looks like the most inert, hence best, material for a hard line, unless you never will run either one of those alcohols 

Walter

[Andy Sykes]

I've been looking into this as my motor will be a meth motor, from what read and who I've spoken too who run meth aluminium isn't all that bad yes you don't want to leave it there for weeks but I think if you flush out with pump gas after you've done all should be well, and at the end of the day you won't be leaving the fuel in the car as it will absorb water. And it not much different to what the guys on race fuel do as most of them drain there tanks after a weekends racing and put in pump gas. I'm planing on having a small second tank with pump gas to start the car one as I will be using a mechanical pump for the efi

Cheers andy

[Frallan]

Rule books -- -- NHRA requires the lines outside the drivers compartment --- NASCAR requires the fuel line (thick wall) thru the compartment - passenger side --- 

Under the car and exposed....looks pretty risky to me.
Way back in 1985 I had a beetle with watercooled heads and it ran water pipes exposed below the pan like that. I know how that got me in trouble. Fuel, for sure not a better option.

Some rules in some book also said that if running through the drivers compartment, it had to be inside a larger tube/piping. Does it sound familiar?
Inside the tunnel must be an optimal place, if we just could fix the tubing in a nice way not to be moving around?

[danny gabbard]

Something I did on my car. One thing to think about with alum, The more rigid you mount it, the more the stress rise's the more chances of a cracks could happen. I saw a very high dollar race burn up at dan gurneys when I worked there, Because of a alum fitting crack on a high pressure fuel line. Just a idea, but stainless or steel lines/fittings are cheap insurance.

[AntLockyer]

Inside the tunnel must be an optimal place, if we just could fix the tubing in a nice way not to be moving around?

I have to say I want to be able to see my fuel pipe and know if there is a problem rather than wait for my tunnel to fill with fuel. It's not like it has to be really exposed under the pan either, it is small enough to be tucked up out of the way.

[Fiatdude]

Beautiful Work Danny

Shag -- I know what you are thinking but a leak under the hood anywhere will still put fumes into the car and fumes are more deadlier than fluid -- the Oval had the pump in the wheel well and I could smell fumes when a o-ring let go in the pre-filter. -- -- -- In this installation and first fire up of the system, I had several small leaks, the fluid flowed away from drivers compartment, but the smell/fumes were still there. I guess if you were using the stock tank and could "seal" out the fumes and liquid by having the pump and hoses mounted below the tank, there might be a lot benefit. But once you go to a fuel cell or aftermarket tank or in a severe accident where the top of the fuel tank is ruptured, you loost that integrity immediately .. .. .. .... On my buddies NASCAR COT car there is a full, solid Aluminum fire wall and then a second dash where all the gauges are mounted. But like most all VW's out there, I've got all my gauges and wiring mounted into/through the "firewall"/dash, loosing the fireproof integrity. .. .. It is something I want to address when I do a rebuild on the second time around.... I'm just wanting this piece running for now, I'll deal with some "issues" and pretty next time around.

[Pedalpusher]

Danny- Looks really good, is the tunnel bottom detachable in some way?

[Frallan]

Wow Danny! Detacahable bottom of the tunnel. LIKE! Grommets for the tubes, right on!

[danny gabbard]

Thanks guys, Ya I made it so it bolts back in.  Here are a couple shot of Roger crawfords pan I did for his 67 vert project about 7 years ago.

[NoBars]

That's a great idea.

[AntLockyer]

Lots of fasteners on that bottom one 

[Frallan]

Yeahh, but nice and countersunk. High tech, stylish and very functional.

[Rich_h]

Cheers people for your good and bad points / great pic of your work 
So my plan is to go down the stainless route and as I have lots of bits of braided line in the
workshop  leftover from a the bosses water cooled  vag circuit car just need to buy the ends 

Rich

[Neil Davies]

Aluminium can work if supported well but I will never take that chance again. Same as copper. No go for me.
Not for oil or fuel.
Water tubing and intake manifold tubing is OK.
Steel or stainless if it is a hardline and a critical liquid.

I know many will not agree but I am just voicing my preference from some own and learnings from others.

I use copper on most of my cars. I run it along the bottom of the heater channel, protected by the edge of the floorpan. I use plastic P clips but deliberately use bigger clips than the diameter of the copper - this allows for a rubber sleeve around the outside of the copper to give even more vibration absorbtion.
As for size, on the race car I used 10mm O.D. microbore central heating pipe...

[Shag55]

Very nice Danny!

[Rich_h]

i was contemplating running bradid lines front to back 
but like the look of the hard lines running in side the tunnel and popping out of the framehorns looking factory with a twist
then bradid lines between the tank / pump /regulator and carb's (fuelrail)