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am i new to this i have had countless race/street cars that have had a electric fuel pump going to the carb, now my speed shop is telling me i need to run another hose from a bi pas all the way back to the cell. ive looked at alot of race cars and most people dont do this
 

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it all depends on the pump. we run one back. it keeps the pump cooler and it last longer.

off the regulator there is another port for "an" fitting, we run 1/2 line to carb, 3/8 from regulator to top of fuel cell. i also run dual 1/2 lines from sump too pump with a y block

everyone does theres different.
 

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what pump are you using??? ive ran elecric pumps for along time and never ran a return. but the pumps never called for one. i just recently went to a BG 400 pump and it has a return port on the pump. so now im running one but it only took 2 feet of hose instead of running another 15' from the reg back to the tank.
 

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The reason for the return is not to dead head the pump (pushing against itself). It prolongs the life of the pump, draws less amperage, etc. There's no downside to doing it, only upside. As one previous poster mentioned, some pumps come with a bypass built in so you can run a short return line to the tank/cell...otherwise it's running a line from the regulator back.
 

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On my Nova, for years I ran a Mallory 140 pump with an internal bypass. These pumps would die after 2 years. I switched to a Barry Grant 280 with an internal by-pass. Never a flow problem but always an inconsistent fuel pressure problem. One time it would be at 7 psi and the next time it would be over 10 psi. Even changing regulators would not cure the problem. My latest pump is a Magnafuel with an external by-pass. Pressure stays at 7 psi using the Magnafuel regulator. Pump runs quite and cool. Easy to plumb as long as you have an extra place to plumb it on your fuel cell.
 

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I ran Mallory 140s with a return line and they lasted since 1996 so far on my old Beretta. On this Nova I am now running a Aeromotive 2000 with a by pass line from the pump to the cell and I also run a return line from the carb as well. I am a big supporter of a return line in any higher rated pump.
 

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I ran Mallory 140s with a return line and they lasted since 1996 so far on my old Beretta. On this Nova I am now running a Aeromotive 2000 with a by pass line from the pump to the cell and I also run a return line from the carb as well. I am a big supporter of a return line in any higher rated pump.
You ran 2 140's together? How did you set it up. I was thinking of doing the same thing on my street strip nova. The smaller pumps seem to take the abuse of the street driving better than a big pump on the street.
 

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You don't have to run it back to the tank. Put a 'T' in the inlet line to the pump and run it back there. All it does is flow around in a circle. That's how my dragster is. Piece of cake. Dave
 

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You don't have to run it back to the tank. Put a 'T' in the inlet line to the pump and run it back there. All it does is flow around in a circle. That's how my dragster is. Piece of cake. Dave

I tried that and found in my application it reduced the flow to the carb so I went to the cell with it. Never knew for sure why it did that but I figured it created a turbulance in the supply line.
 

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You ran 2 140's together? How did you set it up. I was thinking of doing the same thing on my street strip nova. The smaller pumps seem to take the abuse of the street driving better than a big pump on the street.

Yes I had two pumps running to a single regulator close to the carb. I used a Y fitting at the regulator inlet with a single return line. As it turned out I only ran one pump and it did the job. The second pump ended up being insurance and seldom used. I personally like the Mallory 140 pumps. I was able to pump a gallon of fuel to the carb through a single 8 line in about 20 seconds which suppys most 700 hp single carb bracket engines fine.
 

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am i new to this i have had countless race/street cars that have had a electric fuel pump going to the carb, now my speed shop is telling me i need to run another hose from a bi pas all the way back to the cell. ive looked at alot of race cars and most people dont do this

There are now 2 types of systems.
Deadhead, most common and just what it says.
Tank to pump to Regulator(if required) to carb

Or a closed loop system
Tank to pump to regulator to carb to tank

The main design for the closed loop system was for fuel injection, this removes all air in the system and efficient fuel pressure control.

The requirement is based on the pump you use.
Some pump pressure valves are set by flow pressure, not dead head pressure.

A pump that is designed for closed loop and used on a deadhead will create too much pressure.


The rumor of keeping heat down by using a loop system is just that. RUMOR! The pressure valves are set the same and the pump is under the same pressure and amperage use.

Hope this helps.

A carburetor application does not require a closed loop system.

AL
 

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I think the fuel stays cooler on the loop systems. There is no fuel sitting in the lines close to heat sources if you are constantly circulating a couple gallons per minute. Another advantage is a more constant pressure. Many dead head systems have wide ranges in pressure. The loop systems don't seem to have that.
 

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Yes I had two pumps running to a single regulator close to the carb. I used a Y fitting at the regulator inlet with a single return line. As it turned out I only ran one pump and it did the job. The second pump ended up being insurance and seldom used. I personally like the Mallory 140 pumps. I was able to pump a gallon of fuel to the carb through a single 8 line in about 20 seconds which suppys most 700 hp single carb bracket engines fine.
Thanks McCoy.
 

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I think the fuel stays cooler on the loop systems. There is no fuel sitting in the lines close to heat sources if you are constantly circulating a couple gallons per minute.
never thought about that!

Good point.

I was only thinking of the pump.

Al
 

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never thought about that!

Good point.

I was only thinking of the pump.

Al
The thing is that the internal bypass may be set at the same pressure with or without a return,but you are not loading the pump with the back pressure from the reg, if you are loading the pump it increases the amp draw makes the pump bypass,all of that is creating more heat, Imo
 

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I run an Enderle injector pump on my CFM 1050 alky carb. It flows tight back to the inlet side of the pump. Real simple. I'll post pics if I can get some. Dave
 
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