split bus fuel tank

[splitfan]

I need to fit a submergible pump into my fuel tank , I have a good idea on cost to build a ally tank but can also mod my existing tank.
Now I have no idea how much a split tank is worth or if there is any demand for em , I would like offers on the tank please (tank was redone a couple of years ago with anti rust coating inside and comes with cap and fuel sender)
Thanks

[Tony Z]

Why do you need to fit it into the tank? Going FI?
Why not get a surge tank and fit it to the outlet of this tank? Put in an inline pump like a Bosch 044.
Gotta be easier and cheaper than making a new tank

[splitfan]

Hi Tony , been there done that space with the turbo motor/oil cooler/rad pipes ect is just too tight and every joint is a potential leak and fire , im fitting a 6bar vr6 pump with sender as fuel starvation has been a issue since day 1 , the motor is out now and the plan is to try and work smarter not harder

[Tony Z]

Holley blue into a surge tank nearer to the engine which has the built in pump...
Feed the holley blue with a 12mm line via a 12mm bulkhead fitting in the tank like I originally did on my bug.
I know... I am not helping, am I?

[splitfan]

ha ha no not really I know the answer I just don't like the question ... I could only enlarge the std fuel outlet to around 9mm on the tank ,then ran a inline filter and pump to my fuel container , from there 13mm feed to main pump and rail , returning to the container and from the container a return line to the top of the tank again all of this in a space where you would have trouble fitting a KFC box meal I just need to find a simpler solution ...

[Tony Z]

Unless I am mistaken the original fuel line is about 4mm ID. Do you actually realize that 9mm is 5x larger (by volume and flow) than 4mm?
If you have 6mm ID then you are 2.25x larger than stock. Yes, 225% more flow with the same head/pressure.
There is no problem getting over 100hp out of a stock fuel line.
just some food for thought...
this is me still not helping

[Tony Z]

another thought... is your tank breather working? Maybe you are having starvation problems from not letting air into the tank (thus no fuel is leaving)?
Maybe you need to increase the diameter of the hole in that plastic fitting or add another breather? I think my beetles breather plastic thingy had a hole which was 1mm dia, I opened this up to 3mm just in case.

[Tony Z]

Also, without knowing anything about your surge tank... the fuel returning from the engine needs to enter the tank near the top and the fuel heading back to the main fuel tank needs to also leave from the top - this keeps hot fuel at the top and allows air to be pushed into the main tank to be vented out of the system.
Fuel going into the surge tank should enter fairly low down, and the fuel going to the engine should exit fairly low down too - this keeps it cooler and ensures there is no air getting sucked into your lines.
If you get this wrong, then your fuel starvation might be fuel getting too hot and flashing off, thus causing temporary air locks???

[splitfan]

Thanks for the help Tony I will check my setup ...

[german]

With the size of the pipes and the pressures you mention it sounds if those motors are thirsty

[splitfan]

With the size of the pipes and the pressures you mention it sounds if those motors are thirsty

This is part of the problem the motor is a big bore turbo charged waterboxer

[Dawie]

You could drill that hole in the aluminium nut much larger. Enlarge steel fuel-exit hole in tank as well. Think i went 10mm but 12mm should be possible. That's about the size of a late beetle tank's steel exit hole. (It's that large to accommodate the factory strainer, and twin pipes from early "reserve tap" designs.

I used a short piece of metal pipe and a normal brass or copper ferrule. Aluminium nut just squeezes the ferrule tight and seals. End of short pipe gets chamfered to provide smooth entry. It does not stick up in tank much further than end of the ferrule. (To help prevent a vortex from forming inside when tank is near empty).

Problem with kombi tank is that it's wide and draws fuel from one side. Doing a long, fast right turn caused fuel starvation, as fuel rushed away from outlet. So i cut the (similar) fuel outlet from an old beetle tank and welded it to the baywindow tank on the other side. Now it has an outlet on each side, going straight down to a tee-fitting mounted at lowest point below torsion bars. Centre outlet of tee fitting is 16mm, same as fuel pump's inlet. Return line for fuel injection welded into fuel filler tube, as high as possible. So that fuel would not be running out there when disconnecting hoses.

By the way it is common practise to fit the larger tank from a baywindow for use in a split. (Minor mods required). So you could use a bay tank instead of making a new one.