hows a fuel swirl pot made ?

Is it just a container with four conections or does it have pipe work inside it ?

Any one got any pics inside please ?

ive over spent on a new toy and need to finish the locost asap in a low cost fasion and was going to make one.



cheers

Hi Wasa,
No idea re te swirl pot internals but what's the new toy?
Matt

As far as I know there is nothing special inside. It's just a CAN. The inlet pipes go into it, at an angle so that the fuel swirls inside. Hence the name. Thereby making sure any air goes to the middle and can evecuate through the top centre mounted return tube.
I can take a few photo's over the weekend of mine (external only!) if you need.

Pieter

Thanks Pieter I was just wondering if there was anything elts in one.

Matt, mg zs 180

This any help:
http://www.rx7club.com/showthread.php?t=861608

Plus some additional info that somone may find useful:

"There seems to be a lot of debate regarding how big you should make a fuel surge tank. Everybody will give you a diffrent answer from no surge tank at all to 3L. Some people even claim you need a 5L one for drifting

So I'll try and clear it up for you (the way I see it, if you think I'm wrong please abuse me!)

The size of your fuel surge tank really depends on your engines fuel system. You can use maths to work out how big it needs to be:

Take for example my RB30/25. It runs 6 fuel injectors that flow 270cc (270ml) of fuel per minute at 43psi (2.96 bar) at 100% duty cycle

Therefore your total maximum fuel flow is 1.620L per minute. This figure is calcuted by multiplying your number of fuel injectors by the size of your injectors.

So in a surge condition in your fuel tank when your lift pump is sucking nothing but air a 1.620L fuel tank will give me a whole minute of surge "protection"

But really the sort of turn that would create a condition like that would have to be a big one. I mean how many places are there where you can pull a high G turn like that for over a minute (beside the donut pad!) I doubt that drifters can hold a high G drift without changeing direction for over a minute. So what I do is half that figure.

So now I'm down to a 810cc (.81L) surge tank. Its small and compact and gives me a whole 30 seconds.

Now before somebody shoots me down this only applies to a N/A EFI engine. To apply it to a boost engine (be it turbo or supercharger) you'll need to factor in how your fuel pressure regulator works.

To clear a few things up, the fuel pressure regulator changes the fuel pressure depending on the pressure conditions in the inlet manifold. For example on a N/A engine at full throttle you will get zero manifold vacume. For every PSI of inletmanifold air pressure you put into that the Regulator will add a extra PSI of fuel pressure to your injectors. This will increase your injector flow by a few CC a min.

Say if I was going to throw 10psi of boost into my N/A RB30/25. The fuel pressure regulator would "see" 10psi of manifold pressure and increase the fuel pressure by the same amount. My 270cc injectors are now 332.79cc injectors.

To get this figure you divide your injector size by its base fuel pressure (43psi for most Nissans) So my 270cc injector will flow a extra 6.279cc of fuel for every extra PSI of fuel rail pressure. So 10psi of boost will cause the regulator to add 10psi of rail pressure which adds a extra 62.79cc of injector flow.

Now we times this figure by the number of fuel injectors I have and then divide it by 2. We get a result of 188.37

Simply add 188.37 to our prevously calculated surge tank volume (810ml in this case) and we have our surge tank volume -- 998.37cc -- 998.37ml -- Almost a Litre in english!

See so simple As a example I'll work it out for a SR20DET that runs 7psi of boost pressure stock

370cc (injector size) x 4 (number of injectors/cylinders) = 1480cc <-- Fuel used at 100% cycle

1480cc / 2 = 740cc <-- divide by 2 to give you 30 seconds of "protection"

370cc (injector size) / 43psi (base fuel pressure) = 8.6 <-- Extra cc of fuel flowed from injector when another psi of fuel pressure is added to the rail

8.6cc (extra fue when adding 1psil) x 7psi (boost pressure) = 60.23cc <-- extra fuel flowed through 1 injector at 7psi of boost

60.23 (extra fuel when adding 7psi) x 4 (number of injectors/cylinders) = 240.93cc <-- Extra fuel flowed at 7psi of boost

240.93cc (extra fuel) / 2 = 120.465cc <-- 30 seconds of "protection"

120.465mm (extra fuel from 7psi of boost) + 740cc (calculated surge tank size) = 860ml

Now as you can see depending on how much boost you run, and how big your inectors are (not to mention fuel pressure) all play a part in saying how big your tank will need to be. I have not taken into account riseing rate fuel pressure regulators. They alter the rail pressure at a diffrent rate to your boost pressure eg 1:1.5 make sure you include this in your calculations.

You also have to realise that not many EFI tuners like to run injectors at 100% duty cycle. And its very rare to run a motors injectors at 100% duty cycle. The fuel surge tank takes care of a "worst case" scenario.

Some people also like to over size their tanks to accomadate more boost etc. Thats fine the problem is you can go tooooo big and have the same problems with your fuel pickup like in your stock tanks. The tank should be tall and narrow, to get as little fuel "slosh" as possible. It *must* be mounted vertically. "

[Edited on 26/11/09 by Confused but excited.]

cheers thats great ^^

Soooo....
My Malpassi Filter King (V8 size) will give me about 250ml + whats in the fuel bowls of the 4 Mikunies however when the fuel pump sucks air even though i have a bit over 250ml still available, i will get air, probably, as i hit a few hundred meters of straight.
The swirl pot ( and yes i do have one, not fitted yet) will remove any air and the volume (about 1.5L) will give me plenty of time for the lift pump to catch up.

Now i gather that the lowest bottom pipe is the feed to the carbs/fuel injectors.
The very top pipe is the return to the fuel tank.
The next highest return from the fuel injection rail.
and the lowest but not the fuel to the carbs/injection is the feed from the tank lift pump.

Or are they....

As i run carbs with no return, can I .....

Lowest pipe fuel to carbs.
highest pipe vent to air
Next highest return to tank
next lowest feed from tank

Am i somewhere close

I don't think it would work like that with carbs,with injection there is a low pressure pump feeding the swirl pot and then the high pressure pump is fed from the swirl pot.The top pipe returns fuel and vapor continuously to the fuel tank .
There is nothing internally in the swirl pot.
Paul

quote:

---

Originally posted by snapper
Soooo....
My Malpassi Filter King (V8 size) will give me about 250ml + whats in the fuel bowls of the 4 Mikunies however when the fuel pump sucks air even though i have a bit over 250ml still available, i will get air, probably, as i hit a few hundred meters of straight.
The swirl pot ( and yes i do have one, not fitted yet) will remove any air and the volume (about 1.5L) will give me plenty of time for the lift pump to catch up.

Now i gather that the lowest bottom pipe is the feed to the carbs/fuel injectors.
The very top pipe is the return to the fuel tank.
The next highest return from the fuel injection rail.
and the lowest but not the fuel to the carbs/injection is the feed from the tank lift pump.

Or are they....

As i run carbs with no return, can I .....

Lowest pipe fuel to carbs.
highest pipe vent to air
Next highest return to tank
next lowest feed from tank

Am i somewhere close

---

pre injector pump all you need is a tall narrow can.if your supply pump can keep it overflowing to tank i seriously wouldn't worry.swirl pot tho,if you are seriously thirsty should have the supply coming in at an angle to the side of the can causing a swirl.like the sink does when you take the plug out causing a swirl,feed to engine from the base of a cone at the bottom.in reality unless its seriously thirsty and grips like nothing else a coke can with 2 holes in the top and 1 in the bottom you'll not starve of fuel....

On my old Audi with 450 bhp I had a 1.4 L tank.
Worked great.
3" in diameter.
5-6" high.
Fuel in in the top.
Outlet to pump in the buttom.
A plate in the middle if you are hardcore.

No NASA tech here.

Soren S2
Rescued attachment c.JPG

Don,t know about being hard core but mines a bit of ali scaffold capped at each end fuel in and return at an angle, bleed back to the tank at the top and feed out to efi pump at the bottom.

Took an hour to make and cost nowt, seems to work ok.

Its 12" high 2" wide so holds maybe a pint??
Rescued attachment Swirl_pot.JPG

Cheers all,

I was thinking a pint would be plenty for my set up.

Hi Confused but Excited.

Correct me if I'm wrong ...

But by your calcs I'll be needing a Surge Tank of at least 5L.

Car EVO6 - Running E85 - 4G63
Injectors 1650 @ 43PSI
Max Boost = 25 PSI
Not sure if I'll be holding that in and out of a corner, but we are calculating worst case here.

1650cc x 4 = 6600

6600/2 = 3300 for 30sec of protection.

1650 / 43psi = 38.37
38.37 x 25psi = 959.3 of extra fuel per injector.

959.3 x 4 = 3837.2

3837.2/2 = 1918.6 for 30 secs of protection.

3300 + 1918.6 = 5.2L rounding it down.

Wow 5.2L Surge Tank .... thats huge !!!

is this correct ????
Please help having Fuel issue currently, and trying to figure out what is going wrong.

Pic of Surge, Pre-Filter, Pump, Post Filter setup.
Surge tank is approx 2L
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