Swirl Pot Advice

Fri Jul 11, 2008 3:46 pm

I'm looking at getting a fuel swirl pot for my car as it seems to suffer from fuel starvation when there's about a thrid or less of the tank remaining. I've got a couple of questions though;

What pumps have people used?

What size outlets/inlets on the swirl pot should I get?

Is it worth going for threaded fittings (jic -6) or will normal push-on ones secured with a jubilee clip be ok?

If anyone has a setup for sale, i'd be interested.

Cheers,

Theo

Fri Jul 11, 2008 3:52 pm

Also noting my interest.. I seem to suffer the same thing, although only when its low on fuel, and I suspect the S50 when it eventually makes it way in will exacerbate the situation

Fri Jul 11, 2008 4:51 pm

all the stock pipes are fitted with jubilee clips. this is what I am going to use. Have you checked your in tank lifter pump? (if you have one)

I was also thinking of fitting a one way valve into the little pipe which connects the LH and RH half of the fuel tank.

Fri Jul 11, 2008 4:55 pm

Speak with Nigel at Carerra, he's got ones designed to fit in the spare wheel wheel and knows all the pipes sizes based on extensive testing in Essex :lol:

He is also able to supply an alloy disk to cover the wheel well

Pump wise on all Dave Kears cars he uses a bmw external fuel pump as fitted on early 320's and on 318's

Top quality as with all his stuff

Fri Jul 11, 2008 6:03 pm

Uwe, I don't think I have a lifter pump. The one way valve in the connecting pipe isn't a bad idea, but wouldn't the petrol need to be under pressure to pass through it?

Jimmy, did Dave use that pump as the low pressure pump feeding the swirl pot? My standard fuel pump can't be used in line as far I know, maybe earlier cars use different pumps?

Fri Jul 11, 2008 8:18 pm

Theo325 wrote:Uwe, I don't think I have a lifter pump. The one way valve in the connecting pipe isn't a bad idea, but wouldn't the petrol need to be under pressure to pass through it?

Jimmy, did Dave use that pump as the low pressure pump feeding the swirl pot? My standard fuel pump can't be used in line as far I know, maybe earlier cars use different pumps?

no pressure required, I just want to stop fuel running OUT of the right hand halve of the tank where the pic up is located. With the one way valve you only allow fuel to move back from the left hand half.
But to be honest, I don't think this will be a dramatic improvement

Longrun only a swirlpot is solving this. I just don't fancy having one in my boot. (and the pump)

Fri Jul 11, 2008 10:05 pm

This is a common problem.. here's what I did on my old E30 (now owned by Shorty)... it uses a fabricated swirlp pot from www.brise.co.uk, a facet red top to pump into the swirl pot and a Sytec race injection pump to send fuel to the engine. To be honest, the standard pumps are pretty good though so you'd probably get away with using them instead...

Fri Jul 11, 2008 10:15 pm

hi theo
ive just started making these for a few pbmw racers, dave kear uses the standard lift pump and the standard external pump on the swirl pots. if you dont have a lift pump in your tank, then you can use a facet red top lift pump, then the standard external pump as a feed from the pot to the fuel rail.
if you just had a lift pump in the tank then you can use that as feed to the swirl pot, then just get a standard bmw external pump or a cossie pump as the supply to the fuel rail.
i also can supply an alloy disc which acts as a cover so your boot can still be used and then theres no risk of the swirl pot and lines being knock about.
jubilee clips will be fine.
if your interested let me know either pm or call and i can sort you out a price, will put some pics up soon as well.
thanks jimmy c, is yours fitted yet? will sort some stickers out in time for snetterton on the 20th
regards nigel

Sat Jul 12, 2008 9:44 am

Alloy products

I bought one of your fuel cells a while back(car not finished yet), will i still have the same problem above or will the fuel cell stop this?

Sat Jul 12, 2008 11:04 am

Thanks for the input guys, I hadn't really considered how much space the setup will take up and that it will pretty much prevent the boot from being used. This is obviously a problem as I drive my car to trackdays/the 'Ring and take spare wheels/parts etc. I'd be using the OEM fuel tank so perhaps I could make an enclosure on the rear bench area which contains all these components, rather than using the spare wheel well?

Nigel, I think the BMW pumps you mention must be from a pre-facelift car? My facelift car has a single pump mounted in the tank which sends fuel directly to the engine. Having just checked my prefacelift 325i, it seems to have an inline pump behind the sill near the NSR wheel. Is there also a low pressure lift pump in the tank then?

Another question - how many filters do you use? On M3GTR's photo there is a filter before the facet pump, as well as a filter inside the pump - did you also use the oem filter?

Sat Jul 12, 2008 3:46 pm

Theo, the boot will only become unusable if you fit a fuel cell in the spare wheel space. The swirlpot can be fitted with the standard tank. You just need to find a way to fill the swirl pot out of the way.

you could:
use the BMW in tank pump to feed the swirl pot (even if that is too much fuel, it will go back in the tank via the overflow of the swirlpot as show on the picture above) and use an external pump from your other car to feed the pressurised fuel to the fuel rail.
You only need to overcome the issue that the return line (back from the engine) needs to end in the swirlpot aswell and wherever that swirlpot is located, some piping needs to be done properly. Don't forget the grommets!!!

Sat Jul 12, 2008 10:27 pm

i would agree with uwem3 on the pump set up. if you put the swirl pot in the spare wheel well then used an alloy cover, your boot would remain useable. will sort some pics out next week of the set up. or an enclosor should work just as well.
hi oldroydsr4 you shouldnt have this problem as the tank is foam filled and has a collector in it to prevent fuel surge.

Sun Jul 13, 2008 9:00 am

alloyproducts wrote:i would agree with uwem3 on the pump set up. if you put the swirl pot in the spare wheel well then used an alloy cover, your boot would remain useable. will sort some pics out next week of the set up. or an enclosor should work just as well.
hi oldroydsr4 you shouldnt have this problem as the tank is foam filled and has a collector in it to prevent fuel surge.

why does the swirl pot has to go in the spare wheel well? That makes the boot for me unusable! I still use the spare wheel well to carry my track day tyres when driving to an event. Three in the boot and one tyre in the cabin.

I will try to fabricate a pot to go in the corner of the boot along the suspension turret. (if I can't find a place somewhere outside)
I was even so mad to consider buying a new fuel tank and integrate one IN the tank.

Mon Jul 14, 2008 10:22 am

We stick them in the spare wheel wheels as its easy to seal off that area with a plate, if your racing the fuel tank and any other smaller tanks (ie the swirlpot) has to be sealed off from the drivers compartment.

A cover over the well is easier than trying to seal the bulkhead.

You can stick the pot anywhere as Uwe says, we only stick them there as its the simplest option

Nigel- haven't fitted mine yet, will be done post snetterton, i'm sending you 2 tickets over when I get them.

Tue Jul 15, 2008 12:55 pm

use the BMW in tank pump to feed the swirl pot (even if that is too much fuel, it will go back in the tank via the overflow of the swirlpot as show on the picture above) and use an external pump from your other car to feed the pressurised fuel to the fuel rail.
You only need to overcome the issue that the return line (back from the engine) needs to end in the swirlpot aswell and wherever that swirlpot is located, some piping needs to be done properly. Don't forget the grommets!!!

This sounds nice and simple, I have all the bits here - in-tank high pressure pump with 8mm tails, and an inline high pressure pump with a 12mm inlet and 8mm outlet. Is there not a risk of pressure accululation? On a lot of the swirl pots i've seen advertised the overflow/breather seems to be smaller than the inlets and outlet.