Under Car Surge Tanks - Anything Available?

[MBS206]

Nice Setup.

Which brings me to a question - what is the general thought on mounting the pump or pumps in-surge-tank. ie in the surge tank immersed in the fuel?

I have a 044 in tank (main tank) and it runs almost silently, I assume it stays relatively cool and free from corrosion being in fuel. Certainly when you take the 15 yr old stock pump out it looks brand new, as does all the wiring/fittings etc.

Any reason people don't do this other that it being (maybe) more complex?

And also, rather than running duel 044's, is no one running big single pumps like Fuelab, Weldon etc?

I'm looking to do E85 setup soon and so looking at all these options.

If you look at the pump, you would see that the inlet is normally in the middle of the pump, that means you need to keep that much fuel over the pump, in a large area, meaning fuel can slosh/move around, and you can end up with surge.

The larger your surge tank becomes, the less of a true surge tank that it is...

The idea of a surge tank is to keep enough fuel at the pump, while you're cornering/launching and fuel in the main tank can't be picked up... If your surge tank gets bigger and bigger, then suddenly it can come prone to surge...

Also, most people don't require a surge tank, as they don't run fuel low enough in the tank. If it's just a weekender/occasional track day car, just keep the main tank over 1/2 full.

If you're going for ten tenths, then put a surge tank in, and run only 15 litres in the main tank...

[DCIEVE]

^ that's why internal pumps are mounted vertically.

A lot of these under car surge tanks have pretty ugly aspect ratios, if you can't fit something relatively tall compared to it's width what's the point? You'd want to be doing the numbers on max time at WOT, engine fuel demand and lift pump flow pretty carefully to ensure it stays full.

[Risking]

Alot of it falls onto the tanks desgin.

The ones I've been making for years upon years now have a fairly short height. They do however have a lower chamber that's designed for the pumps to feed from and internally baffled with a float type trap door.

I don't recommend running more than 2 044's from them though.

I've got a GTR using a Weldon pump that actually fills it's own surge tank via a -12 hose into the main tank.

The pump draws from the surge using -12. The surge draws from the main tank via -12 and has a trick pick up system that covers most of the tank floor.

With the return also feeding the surge there is always fuel overflowing back to the main tank.

The way we test how well a surge tank is working before selling them is to fit a clear hose between the surge tank and the main tanks return port for a track day or dyno session

Put a camera on the hose and film it for a few sessions.

Obviously if the tank is working properly it should always be returning fuel to the main tank through your clear hose.

If the tank is not working properly or is poorly designed the fuel in the return line will either become airated or non existent if the main pumps are too demanding.

Obviously there are variables like fuel consumption so they need to be tested and rated accordingly.