23 replies to this topic

[ls2lxhatch]

The suction side of a pump is the weakest so it usually has a larger diameter hose than the pressure side.

 

I doubt you would get any benefit from the 3/8" fuel line if the pump is sucking through a 5/16" pickup. The Brown Davis tanks have an optional 1/2" pickup. 

 

Have a look at the Aeromotive fuel system diagrams.

http://aeromotiveinc...etedsystems.pdf

[ls2lxhatch]

Yes the maximum flow rate in any system is determined by the component in the fuel system with the lowest flow rate. If the engine does not require more fuel than the amount of fuel that can be delivered by a 5/16 fuel line then you are wasting your time going bigger.

 

The amount of fuel that flow through a fuel line is dictated by the size of the line and the fuel pressure or vacuum.

 

The mechanical factory pump is able to generate considerably more vacuum on the pickup side than the typical delivery pressure. If both the pickup and delivery fuel line are the same size then at a delivery rate of 6 psi the delivery fuel line will usually be the restriction.

 

A typical electric pump is able to generate more pressure on the delivery side than it is able to generate vacuum on the pickup side. If both the pickup and delivery side are the same size then at a delivery rate of 6 psi the pickup side will usually be the restriction.

Edited by ls2lxhatch, 19 July 2014 - 11:45 AM.

[ls2lxhatch]

The best way to check your fuel system is to plumb it up out of the car and measure the fuel flow produced at your delivery pressure. Make sure the pump height to fuel height is the same as it will be in the car.

 

3/8" hose is the equivalent of -6 hose. It has an ID of 3/8"

3/8" tube is the equivalent of -6 tube. It has an OD of 3/8" the ID is determined by the wall thickness of the tube. It will always be less than the hose ID.

 

You can get a guide to hose sizes by looking at the sizes used by fuel system manufacturers.

http://aeromotiveinc...etedsystems.pdf

 

Or you can can use the the Ryco Chart.

 

The red line shows the hose size required for a low suction line to deliver 1 US Gal / min (60 US GPH)

It is drawn from a flow rate of 1 Gal/Min (60 GPH) to a flow velocity of 2 ft/sec (low suction line). It crosses below -8.

 

The blue line shows the flow rate produced by a -6 line at low suction.

The blue line is drawn from a flow velocity of 2 ft/sec through -6. It crosses at a flow rate of around 0.7 US Gal / min ( 42 US GPH)

 

The yellow line shows the flow rate required to delivery 1 Us Gal / min using -6.

The yellow line is drawn from 1 US Gal / min through -6. It crosses with a low flow rate of around 3.75 ft/sec.

 

 

Edited by ls2lxhatch, 19 July 2014 - 03:04 PM.

[N/A-PWR]

also allow for Ethanol Fuels (316 S/S tube lines) etc, like Corrosion and Double the Flow.

never gave the pick-up a thought, till you made this thread Ryan

[ls2lxhatch]

400 hp naturally aspirated with take around 27-34 US GPH. If using nitrous then 34-41 US GPH.

 

See this document.

Aeromotive Techinical Bulliten #501

Edited by ls2lxhatch, 19 July 2014 - 05:22 PM.

[ls2lxhatch]

The only way to know for sure is to test the fuel system in your car.

 

Disconnect the fuel line from the carby and run it into a 20 lt fuel container for one minute then measure the amount of fuel in the container.

[N/A-PWR]

good measure ^

[LS1LX]

I would run a minimum 3/8 the whole way with no connections or fittings any smaller.