Fuel Pressure ?

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Re: Fuel Pressure ?

Post  bigjohn2007 on April 7th 2014, 2:40 am

bbf-falcon wrote:Sorry,don't recollect at this time. Changing pushrods right now ,will get back later.
Thanks
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Re: Fuel Pressure ?

Post  kjett on April 8th 2014, 8:01 am

Do you have a gage back at the pump to see what the return pressure is? I had this problem on my Aeromotive pump and deadhead Aeromotive regulator up front. Like it was mentioned before, the bypass was adjusted too high. I pulled the pump apart and cleaned it as well as the regulator, then lowered the bypass pressure. All was good after that. There really should be no need to run a return style regulator when you have a bypass style pump as long as everything is clean/adjusted corretly.
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Re: Fuel Pressure ?

Post  kim on April 8th 2014, 8:28 am

kjett wrote:Do you have a gage back at the pump to see what the return pressure is? I had this problem on my Aeromotive pump and deadhead Aeromotive regulator up front. Like it was mentioned before, the bypass was adjusted too high. I pulled the pump apart and cleaned it as well as the regulator, then lowered the bypass pressure. All was good after that. There really should be no need to run a return style regulator when you have a bypass style pump as long as everything is clean/adjusted corretly.

I disagree, fuel cell to (rear of car) to regulator (front of car) pressure should be considerably higher than the pressure your regulating the fuel down to, to feed a carb. The reason most of the high end pumps operate at pressures of 15 to 30 psi is you have to have sufficient push to keep that large long column of fuel moving in the right direction against anything from 1/2 to 2.5g (s) depending on car. A rare few potentially even higher. Carb feed only need be somewhere around 6 to 8 psi.

25 feet of #10an at 2.5 g's is a wee bit oh weight...

Better fuel system for pump longevity as well as consistent fuel deliver is a bypass regulator for carb/n2o or whatever reduction, returning fuel to fuel cell. The continuous flow will keep pump cooler, lasting longer and ensure the fuel flow to the needy end of the system is always adequate.

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Re: Fuel Pressure ?

Post  maverick on April 8th 2014, 8:41 am

kim wrote:
kjett wrote:Do you have a gage back at the pump to see what the return pressure is? I had this problem on my Aeromotive pump and deadhead Aeromotive regulator up front. Like it was mentioned before, the bypass was adjusted too high. I pulled the pump apart and cleaned it as well as the regulator, then lowered the bypass pressure. All was good after that. There really should be no need to run a return style regulator when you have a bypass style pump as long as everything is clean/adjusted corretly.

I disagree, fuel cell to (rear of car) to regulator (front of car) pressure should be considerably higher than the pressure your regulating the fuel down to, to feed a carb.  The reason most of the high end pumps operate at pressures of 15 to 30 psi is you have to have sufficient push to keep that large long column of fuel moving in the right direction against anything from 1/2 to 2.5g (s) depending on car.  A rare few potentially even higher.  Carb feed only need be somewhere around 6 to 8 psi.  

25 feet of #10an at 2.5 g's is a wee bit oh weight...  

Better fuel system for pump longevity as well as consistent fuel deliver is a bypass regulator for carb/n2o or whatever reduction, returning fuel to fuel cell.  The continuous flow will keep pump cooler, lasting longer and ensure the fuel flow to the needy end of the system is always adequate.

Well said.
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Re: Fuel Pressure ?

Post  kjett on April 8th 2014, 9:15 am

kim wrote:I disagree, fuel cell to (rear of car) to regulator (front of car) pressure should be considerably higher than the pressure your regulating the fuel down to, to feed a carb.  The reason most of the high end pumps operate at pressures of 15 to 30 psi is you have to have sufficient push to keep that large long column of fuel moving in the right direction against anything from 1/2 to 2.5g (s) depending on car.  A rare few potentially even higher.  Carb feed only need be somewhere around 6 to 8 psi.  

25 feet of #10an at 2.5 g's is a wee bit oh weight...  

Better fuel system for pump longevity as well as consistent fuel deliver is a bypass regulator for carb/n2o or whatever reduction, returning fuel to fuel cell.  The continuous flow will keep pump cooler, lasting longer and ensure the fuel flow to the needy end of the system is always adequate.

I think you missed what I was saying. Your comment is a really a partially true statement and really only applies when using a non-bypass style pump with a dead head regulator. However he is using a BYPASS style pump. The BG400 is pretty much the same setup as the Aeromotive A2000 pump like I run and it says right in their instructions:

"If using a “dead head” style fuel system connect the AN-8 by-pass port to a return line that goes back
into the fuel cell. The return line must go into the top of the fuel cell and direct fuel away from the inlet
for your fuel pump. Attach suitable fuel pressure gauges to the fuel system pressure regulator and the
pressure gauge port on the Aeromotive pump."

The purpose of the bypass is to allow the pump to retun un-needed fuel back to the tank giving the continuous flow and keeps the pump running cooler. This allows the use of the deadhead style regulator to be run at the front of the car and as long as the bypass pressure is properly adjusted, the pressure at the regulator will be maintained and you don't get the sudden drop after the regulator like is often seen with at non bypass pump (i.e. Holley blue or black) and deadhead regulator. The key on making that bypass work is ensuring that you use the -8 return line back to the pump. I will agree that 25' of -10 fuel line adds some extra unneeded weight, when 1/2 of that is really all that is needed with a higher end bypass pump/deadhead reg combo. Here are the Aeromotive instructions for reference:

http://aeromotiveinc.com/wp-content/uploads/2009/12/11202.pdf
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Re: Fuel Pressure ?

Post  bigjohn2007 on April 8th 2014, 11:29 pm

Yes,have a gage at the pump to check line pressure.I have #8 return from pump to top of fuel cell and #10 run from pump from reg. then #8 from reg to carb.So what line pressure are you running from pump to reg?
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Re: Fuel Pressure ?

Post  kjett on April 11th 2014, 8:44 am

My bypass is set right at 18psi. I don't have a gauge between the pump and reg, so if things are right, and the bypass is at 18, then the line pressure to the reg should be close to 18psi before it opens the bypass.
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