Fuel Cells And Surge Tanks

[Adz2332]

Hey all

Has anyone had any experience with fuel cells and also surge tanks?

Im looking at buying one of each for an e85 set up with twin external walbro pumps.

Do these both need to be baffled inside?

What is the difference between ones for a few hundred to thousands??

Any recommendations of brands?

Is there any difference id need for e85 over petrol?

Anyone actually have pics in your car?

Thanks

[Adz2332]

so twins plus a lift pump is needed?

[DCIEVE]

The expensive ones have bladders, internal baffles, internal pick-ups etc whereas the cheap ones are just an empty tank. If you run a surge as well you can get away with the empty tank (and some get away with a basic cell and no surge though I wouldn't risk it) - the only benefit of the expensive ones in that case is the safety of a bladder. The empty cells are typically filled with foam, just make sure it's e85 safe.

Keep in mind plastic cells will deform if you don't use a functioning breather and support them properly whereas ally tanks are a little heavier. They all have their place, just weigh up the pros and cons and decide which best suits your particular application keeping in mind legality for the street or your racing class.

[scotty nm35]

No foam is e85 safe in the long term, I couldn't find a brand willing to say their foam would last for more than a year or so for my setup.

[Adz2332]

thanks guys

what did you end up getting for e85 mate? like brand etc?

Pic?

[scotty nm35]

It was for my 19L poly surge tank, as long as the poly tank is completely full I won't need any foam or baffling. I just need to keep the twin Walbro's in the main tank for it to not empty, as the Fuelab is running 10an lines.

I ended up buying a Jaz brand tank.

[DCIEVE]

Interesting arrangement, your min fuel load is going to be 20 litres then (empty main tank, full 'surge'). You will also need a large return line to the main tank from the poly tank to minimise pressure or it will balloon when it gets warm. I'm curious why you didn't use a conventional surge tank?

[scotty nm35]

How long would a 2L surge tank last if the main tank pumps are sucking dry around corners? Not long was my theory. A surge tank needs to stay full, and my stupid saddlebag main fuel tank arrangement surges at 3/4 at the track.

19L would give me extra range on the road in a pinch also.

As for the return, I am using the 6an top breather fitting to take it back to the main tank. Should be enough considering the fuel rails return to the main tank. If it balloons I will make a sturdy alloy tank.

[DCIEVE]

No worries Scotty, you've obviously thought it through so this is mainly for the OP's benefit. If you return the rails to the surge you have a near enough to full surge after a corner assuming it was full beforehand (without arguing semantics about partial throttle). And at wot with 500odd kW you're using well under 8L/min, and never at wot for more than 30sec without braking = 4L. Not to mention on the gas typically means a flooded pickup at the rear of a drag cell. Anyway just just some numbers I pulled from memory, it's easy enough to work out your actual fuel demand and some likely scenarios in a great deal more detail (circuit, 1000m drags and in car vids with telemetry etc) to design the surge tank around, in my case I ended up with 4L. Another point worth mentioning is surge tanks are typically tall relative to diameter/width (high aspect) so they can run down without the main pumps drawing air.