Bracket Talk
Changing fuel lines

This topic can be found at:
https://drr.infopop.cc/eve/forums/a/tpc/f/80760912/m/5397017196

September 25, 2019, 05:22 AM
blasttime
Changing fuel lines
Time for me to get rid of the stinky AN braided line and install return style regulator . This is pump gas motor should I be looking t PTFE hose and fittings ? If so whose do you recommend ? If I had -8 AN for feed line sizing what's required for return line sizing ?
September 30, 2019, 03:07 PM
blasttime
Receiving bad info is never desired so I will thank you all for not posting .
September 30, 2019, 03:12 PM
Dead On
if this is a race car I'd use -10 to the reg and -8 back with -8 to the carb bowls. If its just a mild street car you could get away with -6 every where or -8 to the reg and back with -6 to the carb


Ron Shields

https://uniim1.shutterfly.com/...e/1570815955/enhance
September 30, 2019, 08:28 PM
Ron Gusack
I just re-did mine and used Orme Brothers PTFE stuff. They give 30% off if you're a DRR member. I used -10 to the pump and -8 to the regulator and carb. I use a Magnafuel pump with a return and no return from the regulator. No problems with this set-up in a 3,000 pound car running 6.1X. I previously ran -10 to the regulator but decided to go smaller and there's zero difference.
October 01, 2019, 09:00 AM
FootbrakeJim
I think the advice Barry Grant gave on line sizing for a return regulator system is worth considering, (especially if your pump is capable of 280 GPH or greater). He recommended -10 from tank or cell to pump, -8 from pump to fuel log, -8 from log to Regulator, and then a -10 return line from reg to cell. The key part being the return line should be larger than the feed line. The logic is that a -8 feed with a good pump will provide more fuel than any single carb can demand, and that the return line should never become a restriction, or the regulator may not be able to control the pressure to the carb. If you use -10 from the pump to feed the log, and you are at idle or part throttle, (not using much fuel), a smaller return line (like a -8) will not be able to easily flow all of that excess fuel volume without building some back pressure, which would affect the regulated fuel pressure, and possibly push some of the excess fuel past your needle & seat assemblies. It made sense to me, I plumbed mine accordingly, and it works perfectly. Even running alcohol, with a rear-mounted pump, 14 feet of -8 from pump to log, and a 1050 Dominator with massive jets & squirters, I am able to run my fuel pressure at 5-3/4 pounds, and never experience any leaning out down track, or flooding.
Obviously there are many different systems that work, both dead-head and return-style, and lots of different pumps. I just wanted to share this piece of BG wisdom, since you are going to a return type setup. Smile
Ron Gusack, thank you for the tip on the Orme Bros discount! Wink


Dan "Jim" Moore
Much too young to feel this damn old!!
October 01, 2019, 09:37 AM
Tom R
quote:
Originally posted by FootbrakeJim:
I think the advice Barry Grant gave on line sizing for a return regulator system is worth considering, (especially if your pump is capable of 280 GPH or greater). He recommended -10 from tank or cell to pump, -8 from pump to fuel log, -8 from log to Regulator, and then a -10 return line from reg to cell. The key part being the return line should be larger than the feed line. The logic is that a -8 feed with a good pump will provide more fuel than any single carb can demand, and that the return line should never become a restriction, or the regulator may not be able to control the pressure to the carb. If you use -10 from the pump to feed the log, and you are at idle or part throttle, (not using much fuel), a smaller return line (like a -8) will not be able to easily flow all of that excess fuel volume without building some back pressure, which would affect the regulated fuel pressure, and possibly push some of the excess fuel past your needle & seat assemblies.


Was told the same thing from Magnafuel when we were setting up cars at Autofab. The return needs to be bigger than the feed for an alcohol system to work correctly with their electric pumps.


Disclaimer: The opinions expressed here are the views of the writer and do not reflect the views or opinions of any entity other than myself.

72 Nova 370 ci (Stealth Black)
October 01, 2019, 09:49 AM
Brktracer
I used -8 and 1/2" aluminum tubing for the entire system. Mine is not ptfe. Ideally use larger for the return line. Return regulator after the carb. Pressure blips about .1 psi at the hit and holds rock steady remainder of the run.


Matt Ward



October 01, 2019, 10:02 AM
FootbrakeJim
quote:
Originally posted by Brktracer:
Return regulator after the carb.

^^^ Yes. I didn't make that clear in my comment, but a return-style regulator should be plumbed after the carb feed lines or fuel log.


Dan "Jim" Moore
Much too young to feel this damn old!!