budd

iTrader: (5)

I'm about to fit a swirl pot to my 99MY, I hav the fuel pump access cover off see pic

and I believe no 1(8mm) is the return return feed from the fuel rail , no 2 (10mm) is the rail supply feed, howv=ever I'm uncertain about the third hose, it's 10mm and has a plastic 'quick release?' type connector, I'm guessing it's a vent, if so is it the one that runs to the engine and ultimately the carbon can?
Secondly I've been told that std fuel hose leaks a very slight amount of vapour through it's walls, this is OK when the lines run outside the vehicle but will cause a petrol smell when housed in the boot, if this is true what spec hose is required ? Am I right in thinking Fluro coated silicone or Marine grade hose will do the job?

alcazar

iTrader: (2)

What does a swirl pot do?

budd

iTrader: (5)

basically a swirl pot prevents fuel starvation, only really necessary on the most highly tuned road cars but pretty much standard on most race cars.

In high load or track driving situations the fuel can be forced away the in-tank pumps pick up or the std pump simply can't supply enough fuel to feed a high power engine, this causes at best a misfire and at worst detonation and serious engine damage.

The swirl pot is simply a reserve tank mounted in the boot, usually holding between 1-3 litres, it is filled by the O/E in-tank pump and also recieves the excess rail fuel that is normally returned directly to the tank, this means there is always an ample reserve of fuel to draw from regardless of tank level or driving conditions.

The in-tank pump now only as to keep the swirl pot full as the job of supply the injectors now falls to a high power external pump also usually mounted in the boot, this system ensures the engine always as enough fuel in any situation, it also rises the rail pressure a little so even with the stock regulator it can be good for 5-7bhp which is a nice bonus.

hope this helps

alcazar

iTrader: (2)

Cheers mate

FB Tuning

iTrader: (30)

1 is breather to charcoal cannister
2 is Fuel return from regulator
3 is Fuel feed to rails.

Use PTFE lined braided hose and Earls (or similar) fittings, to prevent in cabin fuel smell

budd

iTrader: (5)

cheers mate, looks I guessed wrong on all the hoses, I'll have a look at the Earls kit, although I was sort of hoping to get away with miklor / clasp type clamps rather than 'proper' hose ends,
re no 1 pipe I should be able to pull that through and route it to air in the rear wheel arch ? at the moment it's running it's normal route then vented to air into the ns inner wing

budd

iTrader: (5)

I’ve done some more research on this and basically the hose layout stated above is incorrect, no 3 is indeed the delivery pipe to the rail, no 2 is the return pipe from the rail, but it’s no 1 hose that is incorrect, it’s not the breather to the carbon can, it is in fact called the ‘jet pump hose’ this is essentially another feed hose, in essence the fuel tank as 2 compartments this hose is the feed from the N/S compartment, there is a ‘jet pump’ integrated into the in tank fuel pump mounting bracket, this pump is driven by the fuel flow returning from the rail, the flow causes a siphon effect and lifts the fuel from the N/S tank compartment.
When fitting a swirl pot that return feed goes into the swirl pot rather than returning directly to the tank, the overflow from the swirl pot now returns the excess fuel to the tank, my concern is that the pressure from the overflow will differ from a direct return from the rail and be insufficient to correctly drive the ‘jet pump’ and scavenge the fuel from the N/S of the tank.

saiklon

T think you should be ok. The 'jet pump' is not an actual mechanical pump, it is an arrangement of the hoses such that the return feed causes a low pressure which sucks in fuel from the other side of the tank.

dunx

iTrader: (3)

You can use the "Pro-clamp" to fix decent hose to a metal pipe...

dunx

http://www.demon-tweeks.co.uk/Motors...hers/1988/2479

budd

iTrader: (5)

your probably right, if the difference in pressure between a direct return and the overflow return is not to great, otherwise it may not create the 'suction' required to draw the fuel up into the compartment with the lift pump.