Fuel Line Swirl Pot?

[Jaye R]

Hi Guys

Anyone know whether the S3 is fitted with a fuel line swirl pot??

If it doesn't - which I'm presuming, as I can't spot one - anyone know whether one is available to fit & how easy is it.

The reason I ask is that when I'm taking part in sprints on tight/twisty circuits the car is occasionally fuel starving - as the fuel pump is sucking air when the petrol gets flung around the tank (& you tend to run low fuel loads when sprinting, which doesn't help) - and this does not help when you are trying to get the car to accelerate out of corners!!!

Many thanks in advance.

Cheers
Jaye

[ketvrin]

Could that be the purpose of that 90 degree fitting in the 16mm dia bore pipe between the tank and the pump?

does your have one of those Jaye ?

K

[Jaye R]

Kev

My tank just has a 16mm hose straight from the bottom of it to what I presume is the pump - then the line goes to another cylinder which I presumed was the filter - then the line goes along the chassis to the engine.

Looks like I may have to take some photos???

Cheers
Jaye

[Jaye R]

This is where the hose from the bottom of the tank connects to - I've always assumed that this is the fuel pump??



Am I right?

Cheers
Jaye

[ketvrin]

OK so my pipe goes from the tank to this 90 degree duberry and then onto the pump.

it looks like this (apologies for the manky pic)its the wee tin thing on the left of the drive shaft flange on both pics...

Hope that helps mate...

[ketvrin]

thats the "duberry" which turns the fuel through 90 degree to the pump... so you do have one...

so it cant be a missing duberry then ?

K :stumped:

[Jaye R]

Kev

That looks like the same on mine, however, I am led to believe that a swirl pot is quite a bit bigger and goes between the fuel pump and the engine??

It is designed to maintain the fuel pressure - even when the pump sucks air from the tank (causing the pressure to drop) - to the injection system. Apparently the injection engine is a lot more sensitive to drops in fuel pressure than a carb engine.

Any further ideas??

Cheers
Jaye

[magpies]

Hi Jaye

a swirl pot would be a cylinder of about 1/2 to 1 litre in capacity fitted before the main fuel pump (the return fuel line from the injector rail would be routed to this instead of returning fuel to the main tank. The cylinder would either be located slightly below the main tank or fed from the tank using another pump (high capacity low pressure) - something similar to the swirpot used in the engine cooling system.
This gives the fuel pum a small resevoir of fuel while hard cornering stops the feed from the main tank.

[ketvrin]

wow ... you live and learn... I'm out !

K

[Jaye R]

Mike

OK - that answers what one is - and the fact I ain't got one and probably need one.

So the next question is - where do I source one from for the S3 and how easy is it to fit (i.e. can a mechanically dumb person like me do it)?

Many thanks

Cheers
Jaye

[Wiz]

Try Burtons, Merlin Motor sport or even Demon Tweeks. Filter king is the item i think you want.

Alan

[Gerald-TVR]

ketvrin said:

thats the "duberry" which turns the fuel through 90 degree to the pump... so you do have one...

so it cant be a missing duberry then ?

K :stumped:

That "duberry" is the fuel damper, its almost free flowing but has a rubber cushion which I presume acts as the damper evening out the fuel pulses, see item 14 below

[Jaye R]

So - using Norman's diagram as a guide - where would I fit the fuel swirl pot?

Cheers
Jaye

[TonupS2]

I find it amazing that the fuel pump can suck air when the tank has any amount of fuel. Looking at the tank when its off the car there is a bottom lower sump which has a perforated cover plate and the main tank over has 2 baffles inside. You would think its very difficult to remove petrol from both the lower sump and the length of pipe leading to the pump. All credit to you, you must really be testing the car. Ive got to try that!

[Elfit]

Hi Jaye
The system I have follows Norm's diagram, although I have added an inline filter between the filter and the pump.

I would be suprised if your pump is sucking air, although I could be wrong. The feed is 5/8inch which is pretty large and there is a fair head of pressure from the tank. Your tank most probably has baffles in it to reduce 'sloshing' on corners
If you think there is fuel starvation I would check a few things first before putting something new in the system.

If your fuel tank is rusty/full of crap there could be a blockage in either the strainer ( 27 in diag) or in the thimble strainer in the pump inlet.( Just after the duberry) The fuel filter is situated after the pump ( which I always thought was odd) ~ have you changed that?
Are any of the fuel lines pinched /compressed ?
Are all connections to the fuel pump sound?
Is the pump itself OK? (not sure how you would check)

As well as a rusty fuel tank I also had another problem that I thought was fuel related that turned out to be electrical ~ a wire in the top of the fuel pump relay was not pushed fully home.

I have heard people refering to the 'pot' on the bottom of the fuel tank referred to as the swirl pot.

Just some things to think about, I'm sure others will have more ideas.

cheers
Tim

[Gerald-TVR]

Tims right about the swirl pot being part of the tank, at least according to Steve Heaths bible

[Jaye R]

Tim/Norman

Thanks for your thoughts - gives me some more options to explore - especially whether the 'pot' at the bottom of the tank is indeed meant to act as a 'swirl pot' for the fuel.

I have never changed the fuel filter in 7 years of ownership - so this could be a good place to start.

By the way - I was properly 'hooning' at the last sprint - the marshalls pulled me over for seeing fuel leaking from the car - turned out to be coming back up through the fuel cap when cornering !!!! Now have a new seal on the fuel cap - come on Norman, hurry up with those new caps

Cheers
Jaye

[GreenV8S]

If you need a swirl pot the usual way to do it is to have two fuel pumps - a low pressure lifter pump that just shoves fuel into the swirl tank, and a high pressure pump that feeds the engine - return from the engine goes back to the swirl tank, overflow from the swirl tank goes back to the main tank. It could be fitted anywhere there is physical space for it - and there's quite a lot of space beside the diff.

[Jaye R]

Chaps

Thanks for all your replies - looks like I'm going to do some research in to swirl pots, additional fuel pumps and in-line filters (as well as all the hoses required).

Looks like an 'add to the project list' item for the winter

Thanks again

Cheers
Jaye