Fuel return line for a carb? ie Carb to tank?

[Rileys68Camaro]

In talking to some local guys and other sources, I'm being told having a fuel return to the tank from a carb will help its drivability and performance. Basically so there is always fuel pressure and flow at the carb and the excess is returned to the tank to allow for sudden changes in throttle without stumble or leaning out.

Is this a good idea? I think this is how FI works, so I'm thinking now would be a good time to do it as I will have FI at some point not to far in the future. How would I do that with a stock tank?

[Hugger67RSSS]

You can buy sending units for your stock tank that have a return line built in them but you will not use the same tank once you go FI more than likely. I am also interested in this. I am running a carb'd LS and dont know if I need to add a return? Anyone have any input?

[Rileys68Camaro]

I don't think you NEED one, it was recommended to me so as to always have fuel pressure and flow to help prevent issues.

[johnny68]

i seem to recall one of the spike hotrrod saterday shows doing the same thing they ran the main fuel line to a regualtor like normal and had a fuel rail at the carb one end was fuel in, than a fitting going to float bowl in middle of rail and the other end was fuel out back to tank so the bowl was tee'd off the rail if that makes sense , it seems some people are putting the regulator after the carb on the return line i dont understand that unless the have 2 regulators? http://www.brokenboltgarage.net/E85.htm
john

[LUACE]

What carb are you running? what kind of fuel pump are you using? Are you running a regulator? what size fuel line?

[Hugger67RSSS]

Aeromotive 11213 pump and regulator. Going to run braided lines but have not purchased yet. 750 Holley hp carb. Have a stainless tank and may run E85 if I switch the carb. Any suggestions? Thanks

[johnny68]

check the link i put it has an e85 kit for holley
john

[Rileys68Camaro]

Myself, I'll be using the stock 3/8" hard line, Holley 670CFM carb, mechanical pump probably. That can be changed, haven't bought it all yet.

As an aside, I highly suggest against any form of Ethanol fuel, but that's just my opinion.

[campindog]

I've been toying with this idea but I'm not sure. It seems like it would benifit have having fresh COOL fuel available for the carb with a stable pressure. But I'm no expert.

[Chevelle598bb]

To the OP, if you are just going to use the stock fuel line and mechanical pump then you would not need to run a return line back to the tank. You can just use a dead head style regulator and be fine. If you are going to be running a higher fuel pressure and high volume mechanical pump then a bypass style regulator could be used to help stabilize pressure at the fuel bowls.

To Hugger67RSSS, with the aeromotive pump you are going to run, a bypass regulator such as aeromotive 13204 would work great and help the pump last longer. One tip with using this style regulator is to use atleast the same size return line as your feed line. I like to use one size bigger line for the return than the feed line. It just makes the fuel easier to return to the tank. With this system you run the feed line to the carb inlet line (fuel log) and on the other side of the fuel log is the inlet of the regulator. Then the return comes out of the regulator and back to the tank. So the regulator is actually on the return side of the fuel log. It works very well and your pressure will be dead steady at all engine speeds. Here is a pic of my old big block in my chevelle. The feed line goes to the rear of the fuel log next to the firewall. The regulator is mounted on the front side of the fuel log which is the exit side. From there the pressure is adjusted and the return then comes out of the bottom of the regulator and back to the tank.