[65 Lamnas]

I've pretty much figured out a new fuel system for the '65 Lamnas. I'm going with a replacement tank with in-tank pump and I'm wavering on the size of the plumbing.
It's going to be a street-driven car (with an occasional rip at the dragstrip) n/a 461...should be in the 525-540hp range, and I'll be running a Q-jet....so lots of fuel volume at an appropriate psi will be critical for high-perf driving. Engine is about to be sent off for build.
So far, I've got the tank (and pump) picked out, filter, regulator.... I just don't know if I should step up to -8 hose and fittings everywhere or if -6 will be MORE than adequate.

[4zpeed]

Rule of thumb I use...

350-450 hp 3/8 in. -6

450-650 hp 1/2 in. -8



Frank

[Schurkey]

Originally Posted by 65 Lamnas

I just don't know if I should step up to -8 hose and fittings everywhere or if -6 will be MORE than adequate.

You aren't thinking of running hose from the tank to the carb...are you?

Using hose when metal (or hard plastic) tubing will work is crazy. Tubing is cheaper, lighter, has longer service life, and is less porous than rubber hose. Teflon- (PTFE-) liner hose isn't porous, but it's even more expensive.

Keep the hose length to the minimum--a foot or eighteen inches to allow for engine shake, for example, use tubing where you can.

[steve25]

Once you get on the increased HP highway most of us get power hungry so go with 1/2” tubing and line and don’t look back.

[72projectbird]

Originally Posted by Schurkey

You aren't thinking of running hose from the tank to the carb...are you?

Using hose when metal (or hard plastic) tubing will work is crazy. Tubing is cheaper, lighter, has longer service life, and is less porous than rubber hose. Teflon- (PTFE-) liner hose isn't porous, but it's even more expensive.

Keep the hose length to the minimum--a foot or eighteen inches to allow for engine shake, for example, use tubing where you can.

I've been running AN line at 58psi the full length of my 71 for years now, with no issues.

[4dblnkldude]

I recently did PTFE for some trans lines, wow what a connection! Very strong! I, too, Would do -8 AN all the way. I vaguely remember some company making factory lines in half inch?

[Skip Fix]

My 78 TA has had 1/2 AN frrm the external pump forward , switched to PTFE line after going back to pump gas and "regular SS rubber leaked. 3/8 hard line was not cutting supply to the Qjet at 450 hp. Camaro/IA has -8 feed and -10 return line PTFE the entire length .
Camaro has -6 PTFE to hard lines near the headers to and from the cooler.

[78w72]

Another vote for -8 or 1/2". I run a similar power engine with a q-jet and decided to go with 1/2" based on cliffs suggestion of using the biggest line possible for lower psi carb'd engines, EFI can get away with smaller -6 due to higher psi.

Braided hose does have a recommended life span, but from my experience & many friends that use it, it lasts 2-3 times longer than the 5-7 years some companies say. I have about 6-8' of summit brand non PTFE braided -8 hose from about mid door area to pump & pump to carb on a 2nd gen firebird, have pre bent 1/2" stainless from tank to there from right stuff detail. Been in use for about 10 years with no signs of any seepage or fuel smell issues.

A friend with a dedicated drag car SBC 72 nova that runs low 10s on motor & low 9s on NOS uses the same braided hose, -10 from fuel cell to pump & -8 from pump to carb & return line... been in use for almost 20 years with no issues, he wants to replace it but with little use these days & no signs of issues it gets put off each year. Other friend with a strip/street car been using braided line for 15+ years. Also braided line is much easier to run than bending metal lines if you cant or dont want to do that.

I dont doubt braided line has a limited lifetime, its usually not anywhere near as short as some claim... kinda like tires, some say you absolutely must replace tires at 5 years old regardless of miles or tread depth or condition.... way overkill if they are in good condition & within the rated mileage, theres probably multi millions of tires way older than 5 years on the road doing perfectly fine, but then again a 1 year old tire can fail depending on all kinds of different variables.

Decent quality braided line is fine to use & the vast majority will live much longer than the claimed life, or get the PTFE... or bend your own metal line if you can.

[Formulajones]

I do -8 on setups like that on both feed and return.

[BILL BOWMAN1]

Does anyone still make 1/2 steel straight lengths? I can’t find anything. I want 1/2 line but not braided, and nothing that comes in a roll.

[b-man]

Originally Posted by BILL BOWMAN1

Does anyone still make 1/2 steel straight lengths? I can’t find anything. I want 1/2 line but not braided, and nothing that comes in a roll.

https://www.mcmaster.com/product/9220K361-9220K36

Comes in a 6’ length at the longest. The last time I bought some I used .049” wall, the .035” wall kinks easily white bending.

Also 1/2” .049” wall stainless steel tubing should be available in 20’ lengths. I used to work with this at one of my old jobs building semiconductor processing equipment (high-vacuum thin-film sputtering and electron beam coating systems) and man that .049” wall tubing sure wasn’t easy to bend.

[BILL BOWMAN1]

Thanks Bman

[JLMounce]

For a carbureted setup, I'd definitely do the -8 line. If you were EFI up to about 600ish hp you'd be fine with the -6 line. Remember a -6 line is equivalent to about 3/8 ID not 3/8 OD like hard line. There's a difference in flow capability there.

I like others have been running PTFE AN line for quite a while now. Since 2015 to be exact. Each time I think about going to replace it, I do inspections and it's all in great condition. I would not be afraid of it.

[Formulas]

Originally Posted by 65 Lamnas

I've pretty much figured out a new fuel system for the '65 Lamnas. I'm going with a replacement tank with in-tank pump and I'm wavering on the size of the plumbing.
It's going to be a street-driven car (with an occasional rip at the dragstrip) n/a 461...should be in the 525-540hp range, and I'll be running a Q-jet....so lots of fuel volume at an appropriate psi will be critical for high-perf driving. Engine is about to be sent off for build.
So far, I've got the tank (and pump) picked out, filter, regulator.... I just don't know if I should step up to -8 hose and fittings everywhere or if -6 will be MORE than adequate.

What pressure coming from tank?

[OCMDGTO]

Definitely 8an feed and return, do it right once

[Schurkey]

Originally Posted by steve25

Once you get on the increased HP highway most of us get power hungry so go with 1/2” tubing and line and don’t look back.

Originally Posted by OCMDGTO

Definitely 8an feed and return, do it right once

^^^ Yes.

Originally Posted by JLMounce

Remember a -6 line is equivalent to about 3/8 ID not 3/8 OD like hard line. There's a difference in flow capability there.

No.

Different brands/styles of hose have different internal dimensions. My experience with the hose I've actually worked with has been that most "Dash 6" hose is smaller than 3/8 ID, although some--the minority--actually was 3/8 ID. The same goes for the other sizes. "Dash 8" is rarely a true half-inch ID, Dash 12 is generally not 3/4" ID. MOST hose is approximately the same ID as tubing. There are some exceptions.

Some examples:

Aeroquip "AQP FCN06xx" has an ID of .380, slightly larger than 3/8".
https://www.summitracing.com/parts/aer-fcn0606

Summit house-brand Teflon-liner hose SUM-220985 has an ID of only .320.
https://www.summitracing.com/parts/sum-220985

Vibrant Performance -6 Teflon-liner hose also has an ID of only .320.
https://www.summitracing.com/parts/vpe-18976

Fragola -6 Teflon hose is only .312 ID.
https://www.summitracing.com/parts/fra-602026

Aeroquip "AQP FCA06xx" rubber-liner hose ID is .340.
https://www.summitracing.com/parts/aer-fca0620

In short...verify what you're buying, and make damned sure the hose ends you get match the hose.

And I still say it's nucking futs to use more hose than absolutely necessary. If it doesn't NEED to flex...you shouldn't be using hose in that application.

[65 Lamnas]

Originally Posted by Schurkey

^^^ Yes.


No.

Different brands/styles of hose have different internal dimensions. My experience with the hose I've actually worked with has been that most "Dash 6" hose is smaller than 3/8 ID, although some--the minority--actually was 3/8 ID. The same goes for the other sizes. "Dash 8" is rarely a true half-inch ID, Dash 12 is generally not 3/4" ID. MOST hose is approximately the same ID as tubing. There are some exceptions.

Some examples:

Aeroquip "AQP FCN06xx" has an ID of .380, slightly larger than 3/8".
https://www.summitracing.com/parts/aer-fcn0606

Summit house-brand Teflon-liner hose SUM-220985 has an ID of only .320.
https://www.summitracing.com/parts/sum-220985

Vibrant Performance -6 Teflon-liner hose also has an ID of only .320.
https://www.summitracing.com/parts/vpe-18976

Fragola -6 Teflon hose is only .312 ID.
https://www.summitracing.com/parts/fra-602026

Aeroquip "AQP FCA06xx" rubber-liner hose ID is .340.
https://www.summitracing.com/parts/aer-fca0620

In short...verify what you're buying, and make damned sure the hose ends you get match the hose.

And I still say it's nucking futs to use more hose than absolutely necessary. If it doesn't NEED to flex...you shouldn't be using hose in that application.

Good point about actual hose ID. All the more reason not to run the PTFE lined stuff...plus the bend radius is chit.

[Schurkey]

Teflon- (PTFE-) liner hose is sensitive to bend radius. But I don't see a problem with the ID since it's essentially the same as the tubing; and most cars get by with 5/16 tube, performance engines got 3/8, and both were using engine-driven fuel pumps that don't "suck" worth a crap.

Racers and wildmen move up to 1/2" nominal tube, Dash 8 hose. How much fuel can you push through needles 'n' seats spec'd at 0.130; especially if you have sense enough to use an electric pusher pump at 14+ psi with regulation down to whatever the carb wants somewhere in the engine compartment, AFTER all the bends in the fuel plumbing? Even Dash 6 hose and 3/8 tubing supports substantial horsepower when used with a pusher-pump at the rear.

The big benefits to the Teflon- (PTFE-) liner hose is that it's non-porous and lighter-weight than rubber-based hose, tends to have longer service life than rubber-based hose, and generally smaller diameter, too.

[65 Lamnas]

Wildman here. Thanks for the suggestions.

[HWYSTR455]

Like I've said for years, IF you are doing a new system, no matter what your power level, at least -8 or 1/2 for feed and return. That way you will never have to do it again.

Most aluminum 'fuel' hard line is .035 wall and handles 250psi. There used to be some vendors of AN stuff offer hard line in dash sizes, which ensured the inner diameter, not sure they still do, been a while since I looked.

.500 (1/2") - wall thickness of .035 = .465 . That will move considerable fuel, so should really be no concern of inside diameter.

Summit used to sell steel hard line, I know they sell aluminum and stainless still, but haven't looked for steel since aluminum is fine.

There use to be some concern over puncture risk for aluminum, from like rocks and stuff, but unless you're doing pikes peak, think it a non-issue. If there are areas you're concerned about that seem to be exposed, you can use the spiral line covers. (Rock guard)

AN tube sleeves and nuts are very inexpensive, and easy to use. A 37 degree flaring tool, maybe a debur tool, a nice cutter, and done.

If you're in a tight spot on the car and want to do it while on the car, you can use compression fittings, which work pretty well. But they are somewhat cost prohibitive.

The Eastwood deburring tool is worth the $35, deburs inside & outside of the line in seconds:

https://www.eastwood.com/eastwood-tu...ring-tool.html

Vinyl coated adel clamps are a nice way to go, just remember not to overtighten them, the line should be able to move slightly in the clamp:

https://www.amazon.com/Vinyl-Coated-...zcF9hdGY&psc=1

Try to use AN fittings instead of less expensive JIC stuff, those can be frustrating to thread at times and sometimes leak.


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