efi question

[Semaphore]

Will a 1/4 return line be large enough as fuel return  line

Thank you

[cdr]

most need at least 5/16,but i would run a 3/8

[Rolling_Thunder]

Depends on the volume of the pump you're running -  3/8 feed and 5/16 return....     I ran a -8AN and a -6AN return on my old system

[fy469rtse]

I think it will be ok , remember its excess fuel from reg just being returned to tank,
As long as your feed line good size ,
That's the one that counts 

[BSB67]

I think it will be ok , remember its excess fuel from reg just being returned to tank,
As long as your feed line good size ,
That's the one that counts  

Right, and depending on the engine demand, the smaller return could cause overpressure (i.e. causing pressure higher than the regulated pressure)

[cdr]

so to answer your ?,,no to the 1/4 return . lol

[John_Kunkel]

Go by the manufacturer's recommendations. The MSD Atomic specifies 3/8".

[Semaphore]

The reason i asked is that there is a 1/4 return on the sender
I gather its for emissions

[beezee]

 Have the fuel tank sumped ,Instal efi rated hose to the external pump to the fuel regulator and use the original 5/16 or 3/8 fuel line to return to the fuel tank-sender.My stroker has yet to starve for fuel down to a near empty tank.
http://www.forbbodiesonly.com/moparforum/showthread.php?84185-Fuel-return-EFI&highlight=efi

[Semaphore]

I have purchase a Edelbrock sump that fits under the hood.

http://www.summitracing.com/int/parts/edl-3605

[Rolling_Thunder]

I've never used that Edelbrock piece but I believe you would send your return line back to that - it is basically a surge tank with an in tank pump for make the high pressure the EFI needs - but doesnt require a high pressure pump in the tank....   you will need a small pump to get the fuel from the tank to the new surge tank though ---  run pressure line from the surge to the fuel rails, then the regulator, which returns fuel to the surge

[Mike DC]

 
IMO the underhood mini-tank & electric pump deal is probably safer for old cars than the standard modern way of EFI conversions.  High-pressure electric fuel pumps are scary if they don't shut off at the right time.  But with an old mechanical pump still bringing fuel from the gas tank to the engine bay area, then the little electric pump runs dry in a few seconds once engine stops turning.   

[Semaphore]

Hello

I'm going to modify my Edelbock EFI sump and add a connection for a return line.

picture attached show someone has done it already

I would like your thoughts on this mod

Thank you
pete

[rt green]

exposed to a lot of heat?

[MechTech]

I have been running a 1/4" return line from my motor all the way back to my fuel cell for some time and it has never been a problem. I have a dash gage and run 55psi. The return line is technically a pressure line and will flow more than a suction line. My setup is supporting around 600hp. Having said that when it comes to fuel bigger can't hurt.