Seperate Swirl Pot

[gjkrv8]

Hi everyone.

I am after some opinions and advice on an external fuel swirl pot etc.

My tank is a custom aluminium job that doesnt have baffles and has an external fuel pump - very noisy Bosch job.

I have a bit of a problem with fuel starvation when the tank is getting down to about half full and you go up a hill or accellerate hardish.

I reckon I need a low pressure pump and swirl pot prior to my high pressure pump.

I have seen a couple of posts on this, just wanted to get the latest advice.

Also any good sources/recommednations for where to get one (also made) and suggestions for low pressure pump (and a quieter high pressure one)?

Thanks

Rgds

Gregg

[Philm]

HI Gregg,
I have used a Carter Lift Pump to fill the swirl pot and they do the job nicely.
http://www.rocketindustries.com.au/d...partno=FMP4070

If you find a quite replacement for the Bosch 044 I would be interested as well.

Phil

[Mac VABCH]

Gregg,
I struggled with this for a couple of years. I had the exact same conditions that you are having. For pumps I used Mallory from Summit Racing, they are quiet and don't drawl much current. For the high pressure pump I used a Mallory 4060EFI pump it has a max pressure of 55 psi, flows 60 gallons per hour (227 liters per hour) and only draws 7.5 amps. For the low pressure pump I used Mallory 4070M w/a max pressure of 6 psi, flows 70 gph (264 lph) and only draws 2.5 amps. I am very happy with theses pumps as them a quiet, I mounted them on rubber grommets. They are being used on a 590 HP engine up to 7000RPM with no fuel starvation problems. With the low current draw I ran them on the same circuit in parallel with a 12 amp fuse. Hope this helps.... Mac

[Mando]

Hi Gregg, Im not sure what others have done but Im using the commodore tank with the standard in tank pump which pumps fuel under constant pressure into a swirl pot located under the rear guard. It then goes through an aeroquip fuel pump up to the fuel rails. Any unused fuel is then returned to the fuel tank.

Hope it works!

Regards.

[Mac VABCH]

Gregg,
I forgot to include the fuel system flow. From the main tank, to the low pressure pump, to to the swirl pot, to the high pressure pump, to the engine, return fuel goes to the surge tank and over low goes back to the main tank. The swirl pot has 4 fitting. Also the Mallory 4060EFI pump has a air bleed fitting the needs to be tied into the fuel return line. I used two fuel filters from Earls that I put them after both pumps. Hope this helps..Mac

[sambo]

Gregg, I'm using the VZ Commodore Crewman pump which has a single fuel line to the engine, internal reg and swirl pot and sits in tank - couldn't be any simpler. Since the L98 injectors flow around 39lb/hr and a stock LS1 only 26lb/hr, I assume this pump would give you a bit of headroom if you needed to increase fueling later. More info on injector flow/pressure rates here.

Sambo

[gjkrv8]

Thanks everyone for you great advice.

Sambo I wish I had of thought about this sooner and done the "all-in-one" VZ option you have. Saves a lot of external plumbing.

Phil - I think my noisy pump is made worse by the fact that it is attached to a mounting bracket on the Fuel tank - nice speaker box effect I think
I think I will put some rubber around it and see if that helps.

Carter lift pump sounds like the go.

I think I read Shaun Mellish does Swirl Pots (I got my Water Header Tank and Radiator pipes from him he did a good job), I'll have to have a chat to him.

From a Fuel flow perspective I have a single line going from the rear to the engine fuel rail so I am thinking the following:

- Fuel tank to low pressure lift pump
- lift pump to swirl pot
- swirl pot to high pressure pump
- high pressure pump return (after regulator) to Swirl pot (currently goes back to Fuel tank)
- swirl pot overflow to Fuel Tank.

I think that what Mac VABCH mentioned.

Rgds

Gregg

[boxhead]

My set up is very similar to Mando, I have factory commodore tank fitted with a factory V8 (VN I think) lift pump, this feeds to the back of the L/H rear guard where I have a factory VT fuel pump in a swirl pot (supplied by Aussie Mike). The lift pump supplies fuel to the swirl pot, the main pump is connected just as it would be in a VT commodore (even has all the factory hoses with push on connections), So like the commodore it only runs a single line to the front of the car (although when building my car I did install a return line for use later when a larger motor is fitted).
And with the factory hoses at the back and VT pump as main feed, this is all built with inbuilt regulator and inbuilt return line that feeds back into the swirl pot.

[Rebel1]

Here is a swirl tank available in Melbourne from EFI hardware. Sounds like it is not unlike that which boxhead had described.

http://www.efihardware.com/

Has a holden pump fitted and comes with the push on fittings, costs about $500.00.

[boxhead]

Yes that is same design as my setup.

[C0braed]

The only thing I would suggest is to not return your fuel to the surge tank but return it back to the tank. The reasons for this is that you are retuning hot unused fuel back to the surge tank and then sending it back to the engine for consumption or recirculating. If you think that your lift pump is not capable of maintaining a full surge tank either your tank is to small or your lift pump is to small. The advertised flow ratings for most pumps is in US gallons (3.75 litres) per hour at what ever restriction required to achieve a rated pressure, when you remove the restriction and the pump is in free flow the volume is greatly increased, Make sure that the surge tank has the same size return as supply.

[gjkrv8]

Originally Posted by C0braed

The only thing I would suggest is to not return your fuel to the surge tank but return it back to the tank. The reasons for this is that you are retuning hot unused fuel back to the surge tank and then sending it back to the engine for consumption or recirculating. If you think that your lift pump is not capable of maintaining a full surge tank either your tank is to small or your lift pump is to small. The advertised flow ratings for most pumps is in US gallons (3.75 litres) per hour at what ever restriction required to achieve a rated pressure, when you remove the restriction and the pump is in free flow the volume is greatly increased, Make sure that the surge tank has the same size return as supply.

Can you get non-return valves as I would want to plumb the high pressure return and the "low pressure" Surge Tank overflow back to a single outlet in the Fuel Tank?

[boxhead]

Originally Posted by C0braed

The only thing I would suggest is to not return your fuel to the surge tank but return it back to the tank. The reasons for this is that you are retuning hot unused fuel back to the surge tank and then sending it back to the engine for consumption or recirculating. If you think that your lift pump is not capable of maintaining a full surge tank either your tank is to small or your lift pump is to small. The advertised flow ratings for most pumps is in US gallons (3.75 litres) per hour at what ever restriction required to achieve a rated pressure, when you remove the restriction and the pump is in free flow the volume is greatly increased, Make sure that the surge tank has the same size return as supply.

I agree with you there, I initialy only set it up that way wanting to be able to get every last drop of fuel from the tank, and I have similar issues as Gregg is describing in hi speed cornering and accelerating when the tank is below about 1/4 full, I was thinking that by returning the fuel to the swirl pot then atleast it is not getting sloshed around in the tank and missing the intank pick up.
I figured I was not chassing every single last bit of HP so the small loss due to warm fuel did not bother me.

All feed and return lines to and from surge tank are the same size, being 8mm ID

[C0braed]

Originally Posted by boxhead

I agree with you there, I initialy only set it up that way wanting to be able to get every last drop of fuel from the tank, and I have similar issues as Gregg is describing in hi speed cornering and accelerating when the tank is below about 1/4 full, I was thinking that by returning the fuel to the swirl pot then atleast it is not getting sloshed around in the tank and missing the intank pick up.
I figured I was not chassing every single last bit of HP so the small loss due to warm fuel did not bother me.

All feed and return lines to and from surge tank are the same size, being 8mm ID

The thing with returning fuel to the surge tank is that under full throttle or anything apart from idle is that less fuel is returned to the tank so in effect you will get little gain from it, at idle the engine is using less fuel and the return volume is at its highest and the lift pump should not be having any troubl supply the tank. The problem I have found with most surge tanks I have seen is that they usually have a -6 or -8 supply into them from the lift pump and the same size -6 or -8 as the return to the tank and then the have a -6 or -8 return into the surge tank for the returned fuel, so in effect you have double the supply into the tank but only half the area for returning to the tank. This in effect especially at idle will create pressurization of the surge tank and will apply pressure to the back of the regulator which can cause a richer than normal idle.

[Aussie Mike]

I reckon a bit of pressure in the surge tank is a good thing. I would even reccomend putting a restrictor in the return line to create a few PSI of possitive pressure in the surge tank.

The way I've got mine set up I have a #6 line from the in tank lift pump. This is a low pressure in tank pump from a VL commodore. I have a #6 return from the swirl pot but I've piece of brass in the line with a hole drilled in it to provide a bit of restriction. The feed from the swirl pot is a #8 line and it goes into the fuel filter and from the filter to the Bosch 044. There's a 1/2" line from the bosh 044 to the back of the left fuel rail and a crossover to the other rail. On the back of the right fuel rail there is a line to the regulator. The regulator bleeds off pressure to a #6 line back to the swirl pot.

There's also a check valve on the output of the 044 that stops fuel draining back trhu the pump when the car is sitting. It starts first turn of the key.

Here's a pic of the swirl pot looking from under the car (The pic is the wrong way round so it's a bit confusing)



The fuel lines running up the tunnel and you can see the reg on the firewall. the 3rd line is for the purge on the carbon canister.



Here's the fuel pump mounted on the underside of the boot floor. Not a position I would reccomend as the boot cavity makes the sound resonate even worse. You can see the check valve on the output.



Cheers

[sideshow]

the best setup is to have as minimal connecti0ns as possible
now the problem u have is half the guys that make these tanks do not ask enough questions
no one these days asks why where how or what
ive been doing conversions for 15 years and u have to look 50 steps forward
even though its just a fuel tank they should be asking u what enigne is it what is the std fuel system setup like
surge tanks are ok if u got a premade tank but in a cobra with minimal room best to go internal

now if u are getting custom tank made up why not get the thing made to exactly how need it
these fabricators should be asking what can we do to mak eit easy
anyway best setup is

std holden vt to vz fuel pump assembly directly into the tank then u will have the most minimal amount of connections and possible leaks
i have these neat fuel filters with a pressure reg already inside them
they work a tread
another need to know the fuel sender resistance to get a matching gauges
so i always tell people to ask many questions when getting things made up

if u can afford the cobra to be off the road for a week or so
get a std holden pump setup and drop the tank out and get it modded to suit the new pump

[WKB]

The Harrison cobras have a setup that utilises the fuel pump from a BA/BF Falcon(similar to the VT/VZ Commodore) straight into the fuel tank the way Sideshow discribed. Mine was one of the first few tanks they started to use this idea which used a commodore pump before they changed over to one from a falcon. I used a V8 ute pump which fitted a bit easier.

I would fit the falcon pump over the holden pump as the falcon unit is a lot easier to fit. The falcon uses five screws to hold it in position with a cork gasket and holden uses a large O ring and circlip.

In the picture of the swirl tank and pump that Rebel attached, the pump is a BA/Bf falcon unit.

Warren

[sambo]

Originally Posted by WKB

I would fit the falcon pump over the holden pump as the falcon unit is a lot easier to fit. The falcon uses five screws to hold it in position with a cork gasket and holden uses a large O ring and circlip.

Warren, here's a picture of my VZ Crewman pump. Sounds very similar to the Ford unit you're describing - certainly no O ring or circlip involved. More pics in my gallery.

[Plums]

Originally Posted by sambo

Warren, here's a picture of my VZ Crewman pump. Sounds very similar to the Ford unit you're describing - certainly no O ring or circlip involved. More pics in my gallery.

In the standard set-up, the LS pumps have a large o-ring that seals against the tank and it's all held in place by a big circlip. The Crewman pumps look a bit different because the return plumbing happens inside the unit, as opposed to other models that come out through the filter then return to the regulator inside the unit.

[boxhead]

Originally Posted by WKB

The Harrison cobras have a setup that utilises the fuel pump from a BA/BF Falcon(similar to the VT/VZ Commodore) straight into the fuel tank the way Sideshow discribed. Mine was one of the first few tanks they started to use this idea which used a commodore pump before they changed over to one from a falcon. I used a V8 ute pump which fitted a bit easier.

I would fit the falcon pump over the holden pump as the falcon unit is a lot easier to fit. The falcon uses five screws to hold it in position with a cork gasket and holden uses a large O ring and circlip.

In the picture of the swirl tank and pump that Rebel attached, the pump is a BA/Bf falcon unit.

Warren

My setup is definatly a VT V8 pump and when Mike made the swirl pot instead of using the factory circlip arangement he made it a sandwich plate system the same as the one pictured by Rebel.