Author Topic: 6an ptfe fuel line big enough?  (Read 2367 times)

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Saltshaker

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6an ptfe fuel line big enough?
« on: October 07, 2020, 11:51:30 AM »
my tank has a 3/8 pick up and the motor is around 500 hp ... is 6an ptfe big enough? it measures .32
which isn’t 3/8...
Jon

GerryP

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Re: 6an ptfe fuel line big enough?
« Reply #1 on: October 07, 2020, 12:18:38 PM »
Depends upon how much horsepressure you're going to make.  Under 500HP?  Plenty good.  In AN, every - or "dash" equals 1/16"

cammerfe

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Re: 6an ptfe fuel line big enough?
« Reply #2 on: October 07, 2020, 10:10:45 PM »
Although nominally each 'dash' is a 16th, in reality, it seems to depend on the manufacturer. I believe you'd want to go to 'Dash 8' to feed 500 HP. More than necessary won't hurt anything but a bit in your pocketbook, but too small is asking for trouble. Unless you are using 'beaucoup' pressure.

KS

BattlestarGalactic

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Re: 6an ptfe fuel line big enough?
« Reply #3 on: October 08, 2020, 07:11:09 AM »
For a street toy, likely survive just fine as you won't be seeing high RPM for extended time.  If you plan on racing it regularly then something a bit bigger would be better.
Larry

Falcon67

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Re: 6an ptfe fuel line big enough?
« Reply #4 on: October 08, 2020, 08:22:22 AM »
I'd run -8, personally.  -6 is good from the fuel log to the carb. 

cjshaker

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Re: 6an ptfe fuel line big enough?
« Reply #5 on: October 08, 2020, 08:51:13 AM »
The 427 in my Mach dynoed at 497hp and I still use the entire stock 3/8" fuel system. The only 'upgrade' I have is an Edelbrock fuel pump. I haven't had any issues or seen any signs of running out of fuel on the strip. That's with a dual 4 intake, which likely uses more fuel than a single 4 during a run. Before spending a bunch of money on upgrading the fuel pick-up and feed, I think I'd try the stock system and see if it works. Worst case scenario is you find out you need to go bigger, but it might save you several hundred dollars if you find it works okay.
Doug Smith


'69 R-code Mach 1, 427 MR, 2x4, Jerico, 4.30 Locker
'70 F-350 390
'55 Ford Customline 2dr
'37 Ford Coupe

fryedaddy

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Re: 6an ptfe fuel line big enough?
« Reply #6 on: October 08, 2020, 10:28:00 AM »
i dont know about the track,but i was using the stock lines with 6an fittings on my fuel cell.i run my car on the street.i noticed it was starving for fuel on a long high rpm road race.i went bigger on the lines and fittings.runs great now at high rpms.
1966 comet caliente 428 4 speed owned since 1983                                                 1973 f250 ranger xlt 360 4 speed papaw bought new

Saltshaker

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Re: 6an ptfe fuel line big enough?
« Reply #7 on: October 08, 2020, 04:53:52 PM »
thnx every one...will try 6an and see how it works
jon

John67427

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Re: 6an ptfe fuel line big enough?
« Reply #8 on: October 08, 2020, 07:11:46 PM »
I would certainly try it first. I went thru the same process with my car. Read quite a few articles and visited webs sites that had answered about the fuel line size debate. My car is 750 hp with 2 750’s and didn’t want to spend money on all the -8 lines and fittings. What finally convinced me to try the stock 3/8” line to the front of the car and -6 to the regulator and fuel log was an article by Don Carlton with his pro stock car. Now I realize pro stock in that era is like S/S today. The jist of the article was Don used a stock fuel line and not a huge electric fuel pump. All his competitors told him he was not getting the full potential out of his engine due to fuel supply. Don finally gave in and spent quite a sum of money to Replace his full system with the large lines and humongous fuel pump. The end result for Don was zero difference...
 My fuel pump is a Holley black past a Fram canister fuel filter thru 3/8 stock fuel line to -6 to fuel regulator -6 to fuel log and - 6 to carbs.  Car in good weather runs 9.70’s @ 138mph. Someday I may try all the big lines just to prove the point. All cars are different so your results may differ- lol

djburton

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Re: 6an ptfe fuel line big enough?
« Reply #9 on: October 10, 2020, 06:59:11 AM »
It's not necessarily the ID of the -6 line itself but the fittings are a big restriction,especially on the suction side of the pump.I would think the stock original 3/8 tubing,or a replacement type 3/8 hard line and fittings, would flow better.