fuel return to the tank

[chevyart]

i have a stock gas tank in my 75 vega and had a fuel sump put in it and had a 3/8NPT bung put in in the upper drivers side(towards the front of car) for a fuel return for my mallory 250 electric fuel pump. the return runs right from pump to the tank and i am concerned that the returning gas from pump will maybe shoot into the tank too hard and maybe foam the gas up in the tank. does anyone know of a way i can put some sort of thing in the bung to slow the gas down (or fogging it up a little). the return line will be #8 russell line. maybe some sort of fuel filter?. maybe some sort of valve? any suggestions will be appreciated; thanks Art in NY

[chevyart]

PS the bung in the tank is on the side of tank, not the top, so the returning fuel will shoot across the tank, front to back and not straight down Art

[chevyart]

PS the bung in the tank is on the side of tank, not the top, so the returning fuel will shoot across the tank, front to back and not straight down Art

[Roundybout]

You want the return to below fuel level. Can you run a tube/hose making a 90 degree turn to discharge the returned fuel towards the bottom of the tank?

[url][http://www.youtube.com/watch?v=dP6Pogm6Ts0/url]

[Geoff2]

I have my return coming in the top of the tank. Why would 'foaming' be any more of an issue, if there is any, than foaming caused by the car movement??
Certainly do not think it is a good idea to have the return coming into the bottom of the tank; fuel has to 'push' it's way past the weight of fuel on top, might cause pressure variation in the system.

[motormonkey]

I've found on low pressure returns to blow fuel as close to tank wall up high as possible at 90° so the stream runs down the wall. I found by doing this it won't aerate fuel from the dreaded splash effect and from driveing.
Just want to add, make sure your tanks or cells have a good ground on them.

[dannobee]

Maybe follow what the oems have done for decades. The fuel pump is mounted in a 4" or so diameter plastic can with the return going right down the middle of it from the top. This keeps fuel around the pump during cornering and launching, and the return fuel helps keep it full.

[Racer71]

Having the fuel return from the bottom or top but with a tube that runs down into tank is the proper way. There is no foaming that way it just enters and circulates which also helps with cooling for fuel that runs back from engine in those type installs. Much like a water hose at bottom of a bucket.

[chevyart]

my idea would be to install something that would change the steady fuel stream back into my tank to a mild stream like a shower nozzle does going from hard steady stream to a light shower type of stream. is there a fuel filter or some other device i could use to accomplish this. thanks art

[Alaskaracer]

Won't matter either way...I've returned to the top, bottom, and zero change in performance.....And I'm running a substantially bigger pump than the Mallory 250...........

[allencr267]

my idea would be to install something that would change the steady fuel stream back into my tank to a mild stream like a shower nozzle does going from hard steady stream to a light shower type of stream. is there a fuel filter or some other device i could use to accomplish this. thanks art

An/A restriction.

[stealth]

Won't matter either way...I've returned to the top, bottom, and zero change in performance.....And I'm running a substantially bigger pump than the Mallory 250...........

I agree.. wont make a lick of difference.

I know it's been talked about and the only thing that kind of makes sense is that the returning full MIGHT beat the "lights" out of the fuel. The part of the mix that wants to evaporate by design when fuel is formulated. So if your drive 500 miles on a tank of gas it might be harder to get started on a cold winter day. Unlikely, this will impact you in any way.

Have you ever seen the videos of how the fuel foams up in a carburetor bowl.... now that's impressive!

[Alaskaracer]

Have you ever seen the videos of how the fuel foams up in a carburetor bowl.... now that's impressive!

I think it was Braswell that did a video like that, then showed another with very low pressure (2lbs) and a special needle and seat...foaming was gone...it's crazy how turbulent the inside of the float bowls are when an engine is running!

[chimpvalet]

In my amateur opinion there's not much cause for concern in this, as long as the rate of return is sensible. Though perhaps better than deadhead, a return system should be restricted on flow to avoid excess circulation by which heat and/or frothing is gained. So put a "pill" or restrictor at the appropriate point and then return through a comparatively large line to the tank.

Steve

[hoodeng]

Chimp, you have just added another jet to the system. Return should be unrestricted in any form with carburetors.
The only time i have heard of this working was in a Rolls Royce Merlin fitted with a Miss Shilling [Tilly]orifice.

The only time we see jets in a return is in mechanical fuel injection.

Many years ago some guys were running a methanol turbo drag bike, they were running into a high speed richness condition no matter what they did. Eventually it was discovered that the fuel return bung welded on the tank had a small diameter hole drilled through it into the tank, this now became the high speed jet.

Motormonkey and Dannobbe have given good advice here.

Cheers.