Fuel line plan?

[KMcCullah]

I'm not familiar with drag racing rules. I've just heard in the past that only so much hose was allowed in fuel systems at drag strips. Maybe black rubber hose? Obviously AN line isn't considered hose by the sanctioning groups if a complete fuel system can be built with it.

[65er]

I really appreciate everyone's input on this. Seems to be overly complicated for simply transferring fuel from one end of the car to the other but welcome to my world!  I'm not trying to be retarded, honest..

So let's get this thing done once and done right.  I already have all the stuff ordered up to do -6AN steel braided teflon hose from end to end but I can send it and the fuel pump back to Summit if that's not going to work.  Drilling the fittings out will be no problem, I'll plan on doing that unless I go with a different pump.

Let's look first at the requirement.  Daily driver with occasional blasts around town or out in the country, probably the occasional trip to the local 1/8 mile dragstrip to see what she'll do, and maybe will get on a 1/4 mile strip one day.   The engine will be a 458" FE with a 3X2 carb setup and should be capable of right around 500 horses and 600 ft-lb of torque at relatively low RPM.  I think the HP peak will be under 5000 RPM.  Since the max HP use will be for recreational use and not competition, I'm not concerned about a losing a bit of HP potential.  What I am concerned about is possibly hurting the engine from fuel starvation possibly leading to a damaging lean condition.  If I'm not going to hurt the motor by running too small of a line, then I won't worry too much about it.  On the other hand if there's a danger, I definitely want to address that.

[65er]

Alright, well some of my stuff showed up today and it looks like I'll be sending most of it back.  The AN hose ends are pretty dang small inside, down to .220 diameter and even I know that isn't going to be good.   At least dealing with Summit is easy.  UPS guy will ding me but that's to be expected...

[ScotiaFE]

Fittings. Not all fittings have a standard bore.
A 3/8 NPT can have a smaller bore than a 1/4" NPT.
Just depends on which bin you get the fitting from.
Here is a pic of a handful of fittings I scrounged up to take a pic.
The 3/8 NPT elbow has a smaller bore than the 1/4 NPT quick connect and so on.
The Swage is a really odd one. 3/8" pipe to 1" NPT. Ok



The 1967 Fairlane 427 8V ran pretty good on a 3/8" line and Carter type pump with 1/4 NPT fittings.

[65er]

  I appreciate your ingenuity always, but I find that you often try to make something simpler by making it 100times more complicated than it needs to be....   but that's what we love bout ya.

Believe me, I can see the trainwreck coming and I just can't seem to be able to do anything about it.  Be glad you're on the other side of the fence   Appreciate the love anyway!

[Drew Pojedinec]

yeah, the -6 is small.  you have to look at the inside diameter.  In the case of Summit Hose:
-6  0.343 in
-8 0.438 in

This is why I went with -8. 

To KMcCullah:
It was my understanding that SS braided hose does not count as hose in the eyes of the drag racing rule makers.....  Thus why I felt safe going that direction.  I currently have SS braided hose from the fuel pickup to the carb.

[drdano]

Somebody here posted an upgrade to larger fittings in a mechanical fuel pump a while ago, where he took the 1/4" pipe threads and bored them out to a larger size to eliminate that as a restriction. 

I'm that somebody: http://fepower.net/simplemachinesforum/index.php?topic=1735  I've yet to run this car with the modified pump, so I can't give any data if the modifications made an improvement.  In theory, they should.

[65er]

Good job Doc, and thanks for that link. I was thinking about drilling out my Carter pump for 3/8 NPT but after seeing the complications on that project, I'll return that pump and get the Edelbrock pump that already has the 3/8 NPT threads.  I looked for the RobbMC pump but it looks like it's no longer available?   Could put in a phone call I guess, or just get the Ed...

Looks like I've got it pretty well figured out now, and will be more or less following Drew's example.  It'll be stainless braided -8 PTFE up to the carbs, then I'll fab a fuel log and short little stainless braided-6 AN PTFE hoses from the log to the carbs.  I'm thinking I'll fab mounting brackets from the air cleaner base to the fuel log to keep it from bouncing around too much and hopefully transfer as little heat as possible into my fuel.

[drdano]

Good job Doc, and thanks for that link. I was thinking about drilling out my Carter pump for 3/8 NPT but after seeing the complications on that project, I'll return that pump and get the Edelbrock pump that already has the 3/8 NPT threads.

Take care when drilling out the lower inlet housing, I broke through and had to sleeve mine.  Had I drilled just a tad smaller hole, that wouldn't have happened.  It will be interesting to see if it has an effect on my car, surely it has to.  I still question how people are feeding 500HP with this pump in it's unmodified form when the inlet housing is only 1/4" diameter...

I plan to run -8 all the way tank to carb with a RobbMc fuel pump pre-filter and RobbMc carb pre-filter with braided PTFE lines and Summit/Fragola steel fittings whenever possible.