how neccesary is a return line for a electric fuel pump?
- Thread starter mattchoy
- Start date
-
cudaspaz
Well-Known Member
Do a recent search on the post I basically asked the same question in air/fuel forum.
I posted a link that will answer all your questions.
Also email Holley tech and ask of they recommend it with your pump.
I posted a link that will answer all your questions.
Also email Holley tech and ask of they recommend it with your pump.
67Dart273
Well-Known Member
I say "with today's fuel" ANY carbureted engine can benefit with a vapor return system, even and especially mechanical pumps. First one of those I ever saw was on my old 70 RR sixpack car, AND IT WORKED.
Wix and other filter manufacturers make this easy to implement, they make a couple of sizes of throwaway filters with a built in vapor return port
Wix no. 33040/ 33041 are 5/16/ 3/8 fuel line with a built in 1/4" return port
You mount them either vertically as shown below, or horizontally, as long as the 1/4 port is UP
The other argument FOR a return on ANY motor drive pump is that the pump impeller sits back there on a "non return" system, and when the needles are closed, the impeller churns and generates foam and heat.
The higher volume and pressure your pump is rated for, the more you need a return.
Having said that, the Holley Red pumps don't need a regulator nor a return line. I just think they are beneficial
Bear in mind that the following destructions cover more than just the red pump:
http://www.holley.com/data/Products/Technical/199R7914-3rev3.pdf
http://www.holley.com/data/Products/Technical/Fuel Pump Tech Info.pdf
Wix and other filter manufacturers make this easy to implement, they make a couple of sizes of throwaway filters with a built in vapor return port
Wix no. 33040/ 33041 are 5/16/ 3/8 fuel line with a built in 1/4" return port
You mount them either vertically as shown below, or horizontally, as long as the 1/4 port is UP
The other argument FOR a return on ANY motor drive pump is that the pump impeller sits back there on a "non return" system, and when the needles are closed, the impeller churns and generates foam and heat.
The higher volume and pressure your pump is rated for, the more you need a return.
Having said that, the Holley Red pumps don't need a regulator nor a return line. I just think they are beneficial
Bear in mind that the following destructions cover more than just the red pump:
http://www.holley.com/data/Products/Technical/199R7914-3rev3.pdf
http://www.holley.com/data/Products/Technical/Fuel Pump Tech Info.pdf
AdamR
Big Member
Its not needed for a Holley red pump, You shouldnt even need a regulator for that pump. However with any electric fuel pump a regulator with a return line will keep the fuel cooler and put less stress on the pump.
stumper
Well-Known Member
Not "needed" for the Holley HP series pumps either as they have an internal bypass. With a bypass, you need to make sure you size your pump to give your motor all the fuel it needs at WOT plus enough recirc flow to keep a recirc flow - ideally a full line volume.
67Dart273
Well-Known Member
pettybludart
Well-Known Member
I agree,I tried a return line running a Holley blue pump.My car ran like crap(slower)so I removed the return line and all was back to normal(running high 10,s)
moparlee
64 Valiant
Killer info.......thanks.
stroked340
Well-Known Member
Been running a Holley black pump for 6 years no return..no issues either..
x2
I agree,I tried a return line running a Holley blue pump.My car ran like crap(slower)so I removed the return line and all was back to normal(running high 10,s)
that just proves your holley blue wasn't up to the job .
furyus2
Well-Known Member
Not sure if this applies, but I was reading an article by Ford, about fuel injection on their Fox bodied cars, and it said they don't recommend a return line due to it picking up heat. I know this contradicts what is said on this forum, but this was written by their tech guys.
You need to run a return type regulator in a return system instead of the dead head style regulator, as well as a pump that's capable of supporting a return.
Since a return is essentially a controlled "leak", this causes a pressure drop. The pump needs to be able to feed the fuel system and take the hit from the pressure drop of the return.
With a pump that's capable of supporting a return type fuel system and the proper return type regulator, there won't be any pressure variation.
A return, while not necessary, is certainly nice to have as it makes the fuel pump's life much easier. It keeps the fuel pump from fighting dead head pressure and that will make the pump ultimately last longer.
Also, especially with vacuum secondary carburetors, a return system helps keep the fuel in the rear bowl from stagnating and turning to varnish if you don't use the secondaries often. A return also helps keep cool, fresh fuel at the carburetor. With today's alcohol infected gas, that's a big plus.
Just remember a return and dead head type fuel system are totally different and need to be set up accordingly in order to work properly.
Either will work fine as long as all of the right parts are used for each system.
Since a return is essentially a controlled "leak", this causes a pressure drop. The pump needs to be able to feed the fuel system and take the hit from the pressure drop of the return.
With a pump that's capable of supporting a return type fuel system and the proper return type regulator, there won't be any pressure variation.
A return, while not necessary, is certainly nice to have as it makes the fuel pump's life much easier. It keeps the fuel pump from fighting dead head pressure and that will make the pump ultimately last longer.
Also, especially with vacuum secondary carburetors, a return system helps keep the fuel in the rear bowl from stagnating and turning to varnish if you don't use the secondaries often. A return also helps keep cool, fresh fuel at the carburetor. With today's alcohol infected gas, that's a big plus.
Just remember a return and dead head type fuel system are totally different and need to be set up accordingly in order to work properly.
Either will work fine as long as all of the right parts are used for each system.
dano
Evil Handy Man
Oddly, the 86-98 Mustangs do have a return. I think 99 was the first return less system.
I think the newer model Mustangs have a pump in the tank along with a regulator, the fuel from the regulator just returns inside the tank. They don't dead head the pump pressure I believe.
67Dart273
Well-Known Member
Corvettes have a variation on this as well. The return comes off in the rear of the car I I believe at least the regulator is external. So it's a return, but does not go clear to front of car.
There are advantages to both types
doogievlg
Well-Known Member
I just made a thread about this a few days ago and decided to do the whole better safe than sorry thing. I'm going to run one just to be safe.
Thumperdart
Well-Known Member
Not that pump as it doesn`t have much volume. You can`t just decide to bypass any old elec. pump just because.........
mguner
How many is too many?
Not to mention much QUIETER!
Dave1967
Cuda crazy
If you plan to drive the car with ethanol blend gas, in traffic, and pleasure driving? Absolutely yes you need a by pass. If your car is a drag only car? Then no. Dead head will be fine. I run a 340 sixpack in a 67 barracuda . Holley black pump. 3/8 fuel line to carbs. 3/8 fuel line back to the tank. Holds 6 1/2 pounds at all rpms. To 7000. Ask me why I did this? I had a Holley blue pump set up in a dead head system. In traffic I would get vapor lock and be dead on street until I could cool off pump. Remember ethanol blend gas starts to boil about 110 ish. With return system pump stays right around 80. Do what you want. I can only get ethanol blend gas where I live.
mguner
How many is too many?
When I was a 20 something around 1979 I had a Cadillac EFI pump supplying the 440-6 in my 69 Dart. I made an adjustable return out of a brass "T" with spring and check ball that dumped back into the filler neck. The pop off was at about 20 pounds or so and then the big Holley regulator cut it back to 7 at the engine. This was able to supply enough fuel through 5/16 line to run high 12s at 4000' ASL. If you tried to dead head that pump it would literally blow up the rubber fuel line segments.
-
