Plumbing a fuel system

Old 03-07-2010, 02:38 PM
  #1  
BEAST477
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Default Plumbing a fuel system

I need some input or links on various ways to plumb a system.

Right now I'm running a BG400 pump to a BG 4 port regulator. I do have a return line back to the fuel cell right after the pump but after a seminar I went to this weekend I was told I am running out of fuel at the finish line because I'm dead heading at the regulator. Do I need to run a return from the regulator to the fuel cell also?
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Old 03-07-2010, 03:40 PM
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TopspeedLowet
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Default Not really

I don't know what they could have in mind when you were told that. You do not want a return line from your regulator with a bg400 electric pump mounted in the rear of the car. The only time a return line is advisable on the regulator is when you are using a mechanical belt driven high capacity pump. I recommend mounting the regulator in front of the carb so that the fuel in the line's on the secondary side is forced in the needle and seat under acceleration and not artificially spiking the pressure that the regulator sees when the demand for fuel is at its highest which can cause a drop in fuel level and a bog in some cases. When you are at the finish line your fuel system is flowing at your engines max fuel requirement at that moment. When you slam the throttle closed the demand nearly stops and the fuel tries to continue to flow in the needle and seat's, then a bypass at the regulator would be helpful, possibly until the one on the fuel pump can regulate the sudden demand change. Otherwise, a return line at the regulator with your set up will take from what the pump would have for the engine's sudden demand at launch.
You are all set the way you are Mike, in my opinion
Bruce
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Old 03-07-2010, 05:03 PM
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chrisr
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What I was told by the tech at bg was if I ran their regulator I would have to use the bypass at the pump due to their regulator not having one. I am running a Mallory 4 port with a return and they suggested capping off the one at the pump and using the one on the regulator. The only thing I thought was odd was that they told me to use the same size return as supply which is a #10. I hooked it up that way and have not had any problems. They did by the way tell me to jack the pressure coming out of the pump all the way.
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Old 03-07-2010, 10:25 PM
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gnsrule
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Hey Beast,
Check you fuel psi at the pump and the reg. You should have 25 or so at the pump and 7-7.5 @ the reg. Make sure to check with the engine running as the regulator will not respond to changes without fuel flowing thru it. I run a # 12 to the pump,10 to the reg and 8 to the carb. If your running a BG fuel filter before the pump, i sugest you plumb it backwards from what BG says. You want to filter the fuel from the outside of the ellement to the inside. More surface area allows more flow. Ill prolly get slammed by someone for this but common sence says to do it this way, just like a oil filter filters, from the outside in.
If this is a new reg, throw a lockwasher on the allens that hold the reg together. You will find that the screws are just a tick too long and bottom out before they squish the diaphram tight.

Craig
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Old 03-08-2010, 04:54 AM
  #5  
hammertime
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Default Re: Plumbing a fuel system

Originally Posted by BEAST477
I need some input or links on various ways to plumb a system.

Right now I'm running a BG400 pump to a BG 4 port regulator. I do have a return line back to the fuel cell right after the pump but after a seminar I went to this weekend I was told I am running out of fuel at the finish line because I'm dead heading at the regulator. Do I need to run a return from the regulator to the fuel cell also?
5 yrs ago that was the ticket everyone did it right after the pump, a few yrs ago all these fuel pump/carb shops started saying put the regulator after the fuel log and then return back. It makes sense to have all the fuel volume up there then return back, for sure will not run out of fuel then but on the other hand I've seen people replumb and there is no difference in et.
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Old 03-09-2010, 04:07 PM
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BEAST477
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Thanks for the suggestions guys. I'm pretty sure my problem was pointed out. Now just a little plumbing and wait till the track opens. Thanks again.
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