Surge tank pump capacity
Turbo Mini Forums

Just a quickie. I'm thinking I might need a swirl pot now and was wondering what rating supply pump to use.

Pumps are rated in flow with a suggested bhp, I was thinking 20% to 50% over rated would be suitable. I don't want to waste energy, but I also don't want the pot to empty. As you will always get some return from the fuel rail could you run right on 100% rated?

Any thoughts?

If anyone has a cheap one for sale that would be good too.

Cheers

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

I was planning on using a Facet Red Top that is supposed to be able to supply up to 200hp to fill the swirl pot.

In the end we decided to just run braided teflon hoses through the car and just a single pump and filter in the boot.

Hence, used red top and new swirl pot are available if you are interested.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I use a redtop and swirl pot w/out problem.Even if you're on max fuel flow it's usually only for a few seconds,which the swirl pot volume can cope with.Mine's been ok both on the RR and at the strip.

'Where does the engine go?'

Steve, have you had any problem with the flow capacity of the standard .090 needle valve ?

I ask because I have a persistent lean out on high boost when it has been on WOT for more than a few seconds and I,m wondering if the needle valve can supply enough ?.

I have tried drilling one out to .125 but I get flooding problems, either from inadequate seating for the valve or too high a fuel level, I,m not sure.

Would a swirl pot maybe the answer, I wonder ?.

Hi David,no problem so far,still around 12:1 afr.Like you I have constant problems getting the needle valve to seal.I do now use a dab of loctite on the threads which seems to help.The swirl pot helps me because of the low fuel tank,so the high pressure pump always has a positive feed.

'Where does the engine go?'

Newb question, what is the pupose of a swirl pot in the fuel system and where about does it go? Between the pump and reg or between the reg and carb?

one day boost will be mine!

It acts like a resevior reserving fuel.

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


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Thanks Steve, I was not positive what setup you had -now it makes sense to me.
My pump as at the level of the lowest part of the tank so thats not an issue.
Do you mean you seal the needle valve body into the carb with Loctite ?
Burlen are sending me a new valve and body and I will re-set the fuel level and see where that gets me.

The frustrating thing is that it goes so well while it is going - 90+ down the M40 chasing another BMW yesterday -until an I/C pipe blew off !

The .90 needle valve should be fine. If your float bowl is emptying it's more likely a pump capacity problem than the size of your orifice.

We had the same problem for years, finally tested the pump and it was pumping 1/2 what was required.

swirl pot connections. You wouldn't generally need one with a carb, but if like Steve your tank is low then you need a pre pump to 'lift' the fuel from the tank first.

Edited by wil_h on 6th Jun, 2011.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

So iits only for injection set ups then, dont think thats something i'll ever venture into. Lol.

one day boost will be mine!

I have several injection cars and no swirl pots. The only time I did have one on an injected car all it did was keep the fuel nice and toasty warm under the bonnet rather than recirculating to the tank.

No it depends on where your tank pickup is. Injection pumps don't like to lift fuel, so this setup can make sure your system works well and the injection pump is supplied with fuel all the time. Injection pumps need fuel, run dry they will quickly fail.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

Thanks wil, I follow the theory, but the present Bosch pump can empty the tank in less than 10 mins - I,ve tried !!

The pump is within 12" of the tank and lower than the fuel level in the tank so I dont think the pump is the problem - but I am at a loss to know what is.

Lets see if ive got this then, so you would use a pump between the tank and swirl pot like the facet red top pump, then the injection pump between the swirl pot and the fuel rail meaning the injection pump always has fuel availible from the swirl pot which is being fed by a primary pump.
so for instance if you had a van/estate and a pump in the boot the tank would be lower so this would be a good set up for that?

one day boost will be mine!

Yes

If something is worth doing, it's worth doing half of.

David,the loctite was on the valve body threads,maybe co-incidence but it seals (so far!)
My swirl pot set up looks like this

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'Where does the engine go?'

I prefer the NOS tank to the swirl pot !

Your swirl pot seems to be identical to my oil catch tank