Fuel Line Diameter

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josekh7

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Guys please help i am being torn here by choosing the right fuel set up. I have a 440 with 10.23 compression,
-Edelbrock RPM performer heads port and polished,
-gasket matched torket intake-from intake to runners.
-850 cfm carb with mechanical secondaries,
-TTI headers with 2 inch primaries 3.5 collector.
-The gear ratio is 3.55 26 tall tires in a 1970 dart.
-Stall converter is at 2800 flash stall.

I have no clue what fuel line diameter to use. Will be a weekend driver maybe some strip usage once a quarter. Please help!!! :(
 
josekh7 said:
Guys please help i am being torn here by choosing the right fuel set up. I have a 440 with 10.23 compression,
-Edelbrock RPM performer heads port and polished,
-gasket matched torket intake-from intake to runners.
-850 cfm carb with mechanical secondaries,
-TTI headers with 2 inch primaries 3.5 collector.
-The gear ratio is 3.55 26 tall tires in a 1970 dart.
-Stall converter is at 2800 flash stall.

I have no clue what fuel line diameter to use. Will be a weekend driver maybe some strip usage once a quarter. Please help!!! :(
Click to expand...


A 1/2 alum line or #8 will be plenty if you`re running something like a Holley blue/black pump, bigger if you step it up.............
 
a few months ago i bought a holley blue fuel pump yet i just was its a 3/8 npt inlet would that cause a bottleneck?
 
josekh7 said:
a few months ago i bought a holley blue fuel pump yet i just was its a 3/8 npt inlet would that cause a bottleneck?
Click to expand...

It can, but I don't think for your application you need to go full race fuel system. Lots of cars can handle high 11s with 3/8 line if done properly. If you feel it fall off in the top end it is likely a fuel supply issue though. A fuel pressure gauge mounted on the cowl will tell you if it is an issue or not. EFI cars can definitely work with 3/8 but they run at higher pressure.
 
What kind of (honest) hp you anticipate? I bet 3/8 would be PLENTY
 
What kind of HP can stock 5/16 line support? Any of you guys run fast with 5/16. I think I read Dwayne Porter ran 5/16 fuel line with an 11 sec car?
 
The only reason for large fuel line is for drag cars needing to overcome the inertia from launch. Unless you look carefully, you'll wind up with a pump with 1/4" npt fittings anyway. 3/8 is more than enough but the whole system flows only as good as its smallest diameter. Do yourself a favor and purchase a plain steel pre bent line from one of the tubing companies. Few things look worse than hand bent line.
 
GMachineDartGT said:
The only reason for large fuel line is for drag cars needing to overcome the inertia from launch. Unless you look carefully, you'll wind up with a pump with 1/4" npt fittings anyway. 3/8 is more than enough but the whole system flows only as good as its smallest diameter. Do yourself a favor and purchase a plain steel pre bent line from one of the tubing companies. Few things look worse than hand bent line.
Click to expand...

Actually it's the other way around. A really really big line creates MORE fuel inertia at launch.
 
67Dart273 said:
Actually it's the other way around. A really really big line creates MORE fuel inertia at launch.
Click to expand...

3/.8" is big enough till you get in to alcohol, monster motors, or extremely high rpm motors. I had a 600 horse sbc w/ 3/8" dead end lines. everyone told me to go bigger w/ the lines, I tried it and "no" improvement ! you can drill out 1/4"fittings, and use 45`s instead of 90`s w/ the right fuel pressure, and it will work !
 
To the OP...

I'm running 3/8 deadheaded lines and go 11's. It does fall off on top a bit. I'll be swapping to an Aero A1000 pump this season which requires 5/8" inlet and 1/2" return.

If I were you I'd build it based on the pump you have. In other words it's only as good as the smallest restriction.

but a simple answer to your original question is I wouldn't build anything with less than 1/2".
 
i think with practicality and with what i have now i will go with the 3/8 and install a fuel gauge to keep an eye of fuel starvation at the top end. Just to be clear the fuel gauge will mark low pressure if the engine is starving correct?
 
3/8 or 6an will flow a Lot of fuel at 7psi. 600hp all day long with a good pump.
 
Can someone explain how to read a fuel gauge aside from pressure does a drop in pressure mean a drop in volume?
 
Pretty much yes. No different than water pressure. More pressure through a given pipe is more volume. You do want the gauge tap "right at" the carb or as close as you can get
 
I run a 160 GPH 16 PSI mechanical pump with a bypass regulator and a return line with 3/8 line for the feed and return on mine. About 575 hp and it runs low 11s@ 121. No problems at all. 3/8 is fine.
 
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