Swirl pot - Do I really need one?
Steve Lovelock - 4/1/06 at 09:24 AM
I am building a '7' and intend to fit an Alfa V6 complete with the original fuel injection system. I also intend to reuse the original fuel
pump and fuel filter. My main obstacle is that nearly all the fuel tanks available are without a swirl pot. The only tanks with swirl pots are
expense and I am not the bank of England. I saw somewhere that because the fuel tank in a 7 is smaller than the original and complete with baffles it
does not need a swirl pot.
Is this the case?
If not can you suggest a cheap and simple solution?
Cheers
Chris_G - 4/1/06 at 10:00 AM
quote:
Originally posted by Steve Lovelock
I am building a '7' and intend to fit an Alfa V6 complete with the original fuel injection system. I also intend to reuse the original fuel
pump and fuel filter. My main obstacle is that nearly all the fuel tanks available are without a swirl pot. The only tanks with swirl pots are
expense and I am not the bank of England. I saw somewhere that because the fuel tank in a 7 is smaller than the original and complete with baffles it
does not need a swirl pot.
Is this the case?
If not can you suggest a cheap and simple solution?
Cheers
See the MkII Golf GTI fuel pump thread 
Chris
stevebubs - 4/1/06 at 10:20 AM
Risk of running without is that if the injection pump runs dry for a few seconds it will seize up....they don't like not being lubricated....
mookaloid - 4/1/06 at 11:00 AM
quote:
Originally posted by stevebubs
Risk of running without is that if the injection pump runs dry for a few seconds it will seize up....they don't like not being lubricated....
So what happens if you just run out of petrol? do you have to buy a new fuel pump every time?
NS Dev - 4/1/06 at 11:44 AM
they will run fine for a fair while without fuel in, that is scaremongering!!
I have run them for a min or so dry, they don't mind. Not good practise though.
In answer to the question, if using injection, yes you need some form of anti-surge unless you never go round corners or always have the tank at least
1/2 full.
With a bit of ingenuity though it should be possible to plumb a small canister into the fuel feed line, gravity feed in near the top, out to the pump
at the very bottom and a vent line from the very top of the canister into the very top of the fuel tank, should do the trick and not involve modding
the tank. Beware though that most injeciton pumps require a 1/2"/12mm inlet pipe dia or thereabouts!
Schrodinger - 4/1/06 at 12:47 PM
You can get a combined swirl pot and pump from a MkI/II Golf GTi from a scrapper although you may need to up the fuel pump or the MKIII has an
internal pump/swirl pot in the tank but would be a bit difficult to work with your own tank.
You will most likely need a low pressure pump to feed the injection pump certainly if you have to lift the petrol out of the tank as injection pumps
will not lift fuel.
Keith
Suffolk
MikeRJ - 4/1/06 at 01:57 PM
quote:
Originally posted by mookaloid
So what happens if you just run out of petrol? do you have to buy a new fuel pump every time?
If you look at the Walbro pump documentaion, running out of fuel does shorten their life expectancy.
Steve Lovelock - 4/1/06 at 05:35 PM
OK, so if buy a normal fuel pump and a Golf GTi pump then I should be ok? That sounds cheap and not overly expensive to me. Or have I missed
something?
stevebubs - 4/1/06 at 05:52 PM
quote:
Originally posted by Steve Lovelock
OK, so if buy a normal fuel pump and a Golf GTi pump then I should be ok? That sounds cheap and not overly expensive to me. Or have I missed
something?
Careful mounting of each is in order....and if you're going to do this, then surely a small swirl pot with 4 outlets isn't *that* much work
(if you hide it, it doesn't have to look as pretty as the ones you see for £60+)
stevebubs - 4/1/06 at 05:54 PM
quote:
Originally posted by NS Dev
they will run fine for a fair while without fuel in, that is scaremongering!!
Some will, some won't. mine seized after less than 10secs running dry. Thankfully I was quick in turning it off (was only testing the wiring -
had no fuel lines attached). It freed up again after it had been left a while (I'mguessing heat from friction was the problem)
Better safe than sorry - don't want to lose power in mid-corner!
zetec - 4/1/06 at 07:40 PM
I've got a baffled tank and because it is tall and slim I have not had any issues with with fuel serge, and therefore just run a feed via a
filter to the pump mounted below the bottom of the tank.
andytmc - 4/1/06 at 08:24 PM
My setup sounds very similar to Zetec's - no problems so far (hope I'm not tempting fate here!).
Fuel pump came off a Cavalier SRi.
Andy
Johnmor - 4/1/06 at 08:30 PM
If the fuel pump is from a 164 it may have the swirl pot included on the pump assembly, if it is check and see where it came out of the tank. I
removed a pump and there was no evidance of swirl pot within the tank , and baffles were not that evident. The pump assembly is about 150mm high and
about 140mm across.
May be wrong but just a thought!!
NS Dev - 4/1/06 at 09:40 PM
quote:
Originally posted by stevebubs
quote:
Originally posted by NS Dev
they will run fine for a fair while without fuel in, that is scaremongering!!
Some will, some won't. mine seized after less than 10secs running dry. Thankfully I was quick in turning it off (was only testing the wiring -
had no fuel lines attached). It freed up again after it had been left a while (I'mguessing heat from friction was the problem)
Better safe than sorry - don't want to lose power in mid-corner!
That's certainly right about the packing in mid-corner! Always worried me on the rally car, so that had a very carefully done swirl pot setup!
The only ones I have had seize did so because of dirt, often coinciding with running out of fuel because that swept the dirt out of the bottom of the
tank, that is the more likely cause. usually if they won't free up after a few secs then a few quick stabs of reverse polarity backs the dirt out
from behind the roller that it is jamming in the roller-cell inside the pump. Only ever had one refuse to start back up after a few polarity
reversals!
NS Dev - 4/1/06 at 09:42 PM
Ps, had one seize on me in the grasser mid corner, but there was plenty of runoff! Was a spot of mig splatter from inside the tank that somehow came
loose after 2 years racing and jammed the pump.........that was the one that wouldn't restart but luckily a very kind fellow racer (actually
visiting from another club!) responded to my plea on the tannoy and gave me his spare pump!
owelly - 4/1/06 at 10:02 PM
The 164 has a swirl pot built onto the outside of the pump which lives in the tank. I'm using the Golf pump/plastic swirl pot. Cost me a fiver
off Ebay.
I'm feeding the swirl pot with a Facet pump but once primed it seems to run without it (Swirl pot mounted lower than the tank).