Best Intank Fuel Pickup design?

[260BC]

Thanks all for your help

Looking at locating a block of foam inside the tank to act as an absorbant baffle, and, installing a new pickup line coming out of the bottom of the tank, in place of the present which enters the tank about a third up and then slopes down inside.

These mods should reduce fuel side slosh and assist the pickup pump to operate more effectively.

[THE ASH]

Why not make your swirl pot larger?

I was going to ask this very question, easiest thing to change IMO, way less work & less chance of making things worse/causing other problems (eg: edo's don't cut the foam, don't ask statement)

[260BC]

Why not make the swirl pot larger?

Space and the concern that the pickup pump is running dry too much.

[Billzilla]

I'm assuming that the floorpan of a Zed is roughly the same as a Skyline, could perhaps an EFI fuel tank from one of those be retrofitted into the bulging arse of your chariot, Richard?

Factory is often the most simple and the best.

[80DGY]

So no-one has any feedback on that idea I posted?

[BigMuz]

What- a swirl pot.

Brilliant work :D

How is that any different from a conventional swirl pot- the problem isn't the high pressure pump running out of juice from the pot, it is about the pot running out of juice from the low pressure pump/ tank.

If the hp pump was running dry from your swirl pot due to lateral loads, then you have some pretty serious problems!

Muz

[hotgemini]

Talking to 260DET about this problem though it didn't quite add up (he acknowledges this) he's already got a tall surge tank (I think he said about 1.5 litres) which is fed by his low pressure pumps from the stock tank. His high pressure pump feeds off this and the return to the rail goes back into the surge tank. Now (again IIRC) he's complaining about starvation on the exit of turn six, which means he must be using a sufficient percentage of that 1.5 litres in under 10 seconds. The maths didn't add up and suggest something else is coming into play, but what?

[BigMuz]

Low voltage / high restriction to the low pressure pump.

Blocked pickup

Collapsed filter on low pressure side

Pump dying

Restrictive plumbing

Muz


edit: I am still wondering about the comment earlier that "even on the dyno the swirl pot stays at least half full"- that isn't right. I would do some trouble shooting to see if the pot is ever being filled while the car is running.

[80DGY]

Yeah fair enough muz, I was just wondering and didn't want to start another thread :D

I've just never seen anyone put the high oressure pump inside the swirl, was wondering if people did do it...

[hotgemini]

Muz: Rereadin that first comment in Richard's first post, I have to agree, something very wrong on the low pressure feed side.

[hotgemini]

Bodgy: You got your 'feed from main tank' and 'return to main tank' backwards, return should be at the top.

[260BC]

...............

I've just never seen anyone put the high oressure pump inside the swirl, was wondering if people did do it...

Can't see the point really. Might be an option for a factory production job but it gives no real practical benefit in my or similar diy situations.

[80DGY]

I was under the impression that there was a drama having fuel pumps inside the car? Then again I spose there's dramas with surge tanks too Maybe quieter?

[TRAV-KE55]

I may be wrong here but start with the basics, check Low pressure pump voltage supplies and low pressure pump flow rate, you may have a situation where as you have a lot of full throttle aplication before turn six and you are bleeding the swirl pot low and it just happens to rear it ugly head on that corner due to the lead up to it.
pick up from tank to LP pump
LP pump middle fitting in swirl pot
Bottom fitting on pot to efi pump
return from engine to one of the middle fittings in swirl pot
fitting at top of swirl pot delivers back to tank (pref in internal pot in tank with pick up)

This is just the way i think it should be set up , but feel free to shoot me down in flames guys!!!
even a lp pump that delivers 3lts a min from repco would prob do the job, i dont know of to many race cars that use 3lts fuel in a one min lap!! They are a crap pump though and would suggest something better.
Trav

[hotgemini]

Trav: Thats correct although it really shouldn't matter where the LP feed and return lines join the surge tank.

Exactly as you said though, if 260DETs LP pump is half up the scratch then that surge tank should be completely full 99% of the time.