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-8 or -10 return fuel line?

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Old Oct 31, 2013 | 11:10 AM
  #1  
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Default -8 or -10 return fuel line?

I bought the New Holley 12-1800 fuel pump.
Holly recommends on their website running – 10 for the pressure and the return.
The only problem with that is the Holley FPR they recommend and even the magna fuel regulator only have – 8 return ports! Lol
So if I'm going to do a -10 return I would Have to buy the ultra expensive fuel lab FPR and I would also have to cut the –8 bung off my fuel-cell and weld on a -10 bung.

Is all that worth it for 85 on the street with this pump?
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Old Oct 31, 2013 | 11:14 AM
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10 for supply and 8 for the return.
dont make the pump have to work to get the fuel to it
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Old Oct 31, 2013 | 12:29 PM
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Although you can easily change your ORB to flare fittings from an -8orb to -10 male an....I would do what 9sectruck said. Should be a 1x00rwhp capable setup on E85 no problem.
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Old Oct 31, 2013 | 12:29 PM
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Im running the same pump with an aeromotive regulator -10 supply and return..
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Old Oct 31, 2013 | 04:55 PM
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Originally Posted by knuts82
Im running the same pump with an aeromotive regulator -10 supply and return..
Same here areomotive regulator with an adaptor to -10 return line
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Old Oct 31, 2013 | 06:26 PM
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What's the big deal with a -10 return. If it is only feeding with a -10 then surely it doesn't need more than a -8 for the return. The majority of the fuel is going in the injectors...right? I feed with a -10 and return with -8 and haven't had any issues.
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Old Oct 31, 2013 | 06:50 PM
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Originally Posted by Wicked69
What's the big deal with a -10 return. If it is only feeding with a -10 then surely it doesn't need more than a -8 for the return. The majority of the fuel is going in the injectors...right? I feed with a -10 and return with -8 and haven't had any issues.
I did -10 return because my fuel cell had -10 ports and the line cost less than the fittings to adapt -8 to it..
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Old Nov 1, 2013 | 07:26 AM
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The -10 return helps to keep the fuel from getting hot when a vehicle with a high volume fuel pump is driven on long trips. Bob
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Old Nov 1, 2013 | 07:55 AM
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I have that pump on my engine dyno with -12 between the pump and tank, then 10 pump to engine, then 8 back. It works well although I only turn on one side when running NA engines or small boosted engines. At 900hp flywheel the fuel PSI will start dropping and I turn on the second side. Been good and fairly quiet pump.


Kurt
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Old Nov 1, 2013 | 01:57 PM
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Hooking -10 hose to any fpr with a -8 size return port means you can only flow what the ID of the -8 fitting is.

I have customers at work that run a 1/2" air hose to a machine and then connect it with a 1/4 quick connect and wonder why the machine is starving for air. Lol
The chain is as strong as the weakest link, or in this case the smallest id.
I think I will spend the extra $50 on the fuel lab fpr. It is the only fpr with a -10 return port
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Old Nov 1, 2013 | 02:11 PM
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I was going to say with a Dommy pump and its ability to run one motor at a time, is a -10 needed? I have the smaller Dommy pump 12-1400 and ran a -6 return.
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