Fuel System Layout............512 Stroker Tricks/Tips/Advise?

[Propwash]

Alright Fella's......I appreciate all the advice and idea's given on the build layout for my 512, got that pretty much nailed down. Thanks again! So, on to the next adventure, the Fuel System.

I spent a half an hour on the horn with George at Clay Smith Cams yesterday...Heck of a guy with quite a racing pedigree. Really enjoyed the stories about his aluminum '64 mopar back in the day, pretty much a priceless car now days. Anywho, I came to the decision to run their high volume mechanical fuel pump on the 512 (14-19 PSI @140GPH), being it's way more than adequate for my motor and I really don't want to play with the electric's.

So...Here's what George recommended for the fuel system..at least 3/8" but preferably 1/2" line coming from the tank to an inline fuel filter. 1/2" from the fuel filter into the pump. 1/2" From the pump into another filter and then into a fuel log. Fuel log obviously has an arms going to each edelbrock carb (dual quad 1405). At the end of the log a Bypass regulator (preset at 7PSI). Inlet hooked to log, outlet plugged and a 3/8" line running as a return back to the tank.

Here's my questions....

Where the heck do I find a fuel log that has the arms coming out to match the hook up spacing on the bowls for a dual quad? Seems all of them are for dual feed single 4 BBL holley's or Demon's. Right now my D/Q setup has the edelbrock dual line/log, but there is no rear port for any type of regulator. I do not want to run the regulator before the log and have a deadhead system. Do I go with more of a Fuel block system? If so, where and how does a guy mount something like that? I don't want to end up with a pile of spaghetti draping all over the engine bay and would like to keep the plumping as narrowed down and efficient as possible.

As far as my return line to the tank....My 3/8" sending unit doesn't have a return port, but there is (2) 5/16" vent ports on the tank itself. Can I use one of them for the return and will it be adequate for the 3/8" return line?

Another question...What is with all the hype with AN fittings? I'm quite use to them from the military, but never thought they were that great. Why pay $5-10 bucks per fitting, when I can buy standard NPT for a quarter of the price? Is it just the easibility of using the AN with flex hosing instead of hard plumbing?

Sorry about all the questions, this 512 is outside the normal box I play in. Just trying to gather as much info as possible from you fella's that have played with these scenario's in the past and what's worked and what didn't and where to go from here.

Thanks guys!

 

[RustyRatRod]

No need for a "log". Simply use female inverted flare "tees" and plumb to each carb and then to the regulator, then install the return line to the regulator and back to the tank. I hate fuel logs anyway. Using tees will sorta harken back to the 426 Hemi and Max Wedge.

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Like this. Crude, I know, but you get the point.

 

[Propwash]

No need for a "log". Simply use female inverted flare "tees" and plumb to each carb and then to the regulator, then install the return line to the regulator and back to the tank. I hate fuel logs anyway. Using tees will sorta harken back to the 426 Hemi and Max Wedge.

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Like this. Crude, I know, but you get the point.

LOL....Crapplebrock's. Gotta respect a guy that calls it like he see's it...appreciate it. If I had the clams to cough up for a more "premier" system up top, I sure would. Don't be too harsh on your sketch, now a days that would qualify for a modern art masterpiece in one of those swanky ritz ridden yuppy galleries. Besides, I see exactly where you're coming from. Thanks for taking the time to draw it out.

So keep it old school...Good train of thought. Drop the bells and whistles, keep it simple and save some cash. Thanks RRR! You gotta good source for those T's or they pretty common if I just search around a bit? Recommend 1/2" plumbing from the pump up?

 

[RustyRatRod]

I think 3/8 will handle whatever you're gonna put under the hood and from the tank all the way up. I sent you a PM about the carppelbrocks and why I feel that way. They are great carbs......just not so much for engines with big cams and low vacuum signals. We have a big local Ace Hardware that has tons of brass. Here's some cheap tees.

http://www.ebay.com/itm/Edelmann-Fi...Parts_Accessories&hash=item564e7f27f2&vxp=mtr

 

[67 coronet]

all the brass tee's and fitting you could need are readly available through summit or jeg's.its a lot easyer to see what they have for that stuff in the paper catalog rather then trying to see it online.

 

[benno440]

sounds very similiar to mine, i will tell you how i ran it.

i was told 1/2" is a must on anything 500 and bigger.

so i used a 1/2" pickup/sender in tank (does not have return as it does not need a return line)
1/2" line from sender to engine bay which then i put a 1/2" filter.
from 1/2" filter i ran a 1/2" line to the mechanical fuel pump which is a "Race Pump" http://www.summitracing.com/search/.../make/dodge/engine-size/7-2l-440?autoview=SKU
because i also did not wnt to run the electrics.
on the pump it has a 1/2" or 5/8" inlet i used the 1/2" from my filter to the inlet.
on the outlet of the pump is a 1/2" i ran a 1/2" line from outlet on pump up to my regulator which is a must for these pumps (7-15psi) the regulator has 2 outlets which i ran 3/8" lines to the dual quads.

if need anymore help with htis let me know.

i know all you guys say 1/2" is too big but the justification is that if you ever want to go bigger or more hp it is easier to change the line once engine and everything is out, plus the carbs dont eat more fuel if line is bigger just means the fuel is more readily available.

also takes about $40.00 to fill just the 1/2" fuel line HAHA just tricken

 

[RustyRatRod]

also takes about $40.00 to fill just the 1/2" fuel line HAHA just tricken

That was funny. I never said 1/2 was too big. I said that 3/8 would do all he will ever need. And it will.

 

[benno440]

agreed. sorry i worded it wrong.

 

[fatecaptured]

Hey Rusty, why would the regulator be plumbed after the carbs? So would vapor canister be too restrictive? I've also been told that no return line is needed, what gives?


Not being a smart *** here, just learning.

 

[Propwash]

The regulator after the carbs acts like a waste gate does with a turbo system or similar to a lot of fuel injection systems....Regulates pressure at the end of the system instead of creating deadheads. Helps with eliminating spikes in fuel pressure as well as general performance in the fuel system around idle. Also, a return line can help eliminate vapor lock issue's.

 

[RustyRatRod]

The regulator is positioned where it is, because it not only regulates the fuel pressure, but also controls the return flow. I've never seen a fual system that did not benefit from a return. Whether it is designed for one or not, it is always a good idea.

 

[fatecaptured]

So if you have a 3/8 line coming from pump and then a vapor can which is 5/16, will this be a bad set up? Ditch the vapor separator?

 

[RustyRatRod]

I would ditch it only if it was not a stock setup. Having a return line eliminates any need for vapor return. You are returning everything. Vapor liquid and all. You do need a vented gas cap though running a return line.

 

[lewtot184]

i think i'd call the clay smith guy back and ask if he's selling the old large diaphragm 6 valve nascar type pump. if so they need a clearance notch cut into the block or some grinding on the pump, maybe both. i've heard of guys notching the block for the big pumps and getting into water. asking some detailed questions from the supplier will make the install easier.

on another note, i did some mechanical pump testing some time back. i found a carter high pressure pump, 9psi, that had very good volume in a free flow test and didn't need any block work. you'll need .5lbs of fuel per horsepower per hour at WOT at the carbs.. simple math will tell you what you need.

 

[benno440]

like rusty told me a few weeks back when i asked, if it didnt have a return line it doesnt need it as my tank is vented through the cap.
rusty i bought that fuel pump above all i can say is WOW, exactly like a brake master cylinder and it self regulates to the amount of fuel i need, bit pricey but worth it i reckon.

 

[Moparmatt72]

A return is always a good thing keep fuel cooler they say plus get more out of it. There are some regs that have multi ports can plumb the pump to it and off each side go straight to the carbs duel inlets and also run arreturn line off the regulator. Placement all depends on what you like best I've heard both pre and post have some advantages. Carb I've always done pre but on my neon SRT4 with a big turbo I had it post fuel log.

 

[Propwash]

A venting gas cap would be an issue on a '69 roadrunner, being the tank filler tube and cap is is located behind the license plate. Needless to say, the petro guzzling Big block under the hood wouldn't be the only thing draining the tank. The tank has two vent ports. One that comes up through the trunk floor and ends by turning back into the passenger side rear frame rail. The other takes a horse shoe shape and tucks up in the rear shock crossmember. Will these vent's suffice?

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i think i'd call the clay smith guy back and ask if he's selling the old large diaphragm 6 valve nascar type pump. if so they need a clearance notch cut into the block or some grinding on the pump, maybe both. i've heard of guys notching the block for the big pumps and getting into water. asking some detailed questions from the supplier will make the install easier.

on another note, i did some mechanical pump testing some time back. i found a carter high pressure pump, 9psi, that had very good volume in a free flow test and didn't need any block work. you'll need .5lbs of fuel per horsepower per hour at WOT at the carbs.. simple math will tell you what you need.

Well worth bringing up lewtot184. George over at Clay Smith did bring this up. This pump is the 6 valve design and there will need to be clearance grinding done. According to them, the grinding can be confined to the pump and by all means avoid grinding on the block. They're 100% positive clearance is possible just by light grind work on the pump and if I can get it to fit without block modification, to send it back for a full refund. Good to hear about the carter running so strong. Nice to know for down the road...thanks

 

[Malicious]

Return with post fuel outlet regulator is the only way to go.

Thing you need to remember is yes at the top of the pump you may get say 5psi, but that 5 psi (and more importantly the lbs flow) ends up getting split between the carbs. Having the regulator after the carbs ensures that all the outlets (carbs, injectors) see the same pressure and get the same potential fuel flow.

And for the regulator to work correctly, you need a return line. Plus as already said, return line gets you cooler fuel, less stress on the pump etc. The other benifit of the regulater is smooth consistent fuel, no spikes or starvation, no mater what the car is doing.

I'd run a system like RustyRatRod suggested but I'd use a fuel block instead of T'ing a fuel hose, cleaner and easier to mount. You could just make one if you don't like what commercially available. Pretty easy job.

As for the AN fittings, its half wank, half genuine need. On a high pressure system it ensures that you don't pop a hose, but on a low pressure carb setup I think you can go without no problems.

I've got a twin turbo 6, that runs twin in-tank electric pumps, AN-10 from the tank to the fuel rail, -10 from rail to regulator, -8 regulator back to the tank. That's with 680cc injectors, estimated 40+psi fuel pressure and 4-450rwkw. So for that, AN is a worth while investment.

HTH

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That race pump looks nice, but $320 is a bit rich for my mild build! Think I'll stick with the edelbrock I was originally looking at...

 

[Propwash]

Thanks Malicious, appreciate it. Real good points. I ended up getting the pump off their ebay site for $155 + $12 shipping. I can imagine shipping to the land down under would throw a lot larger dent in the total cost.

 

[Malicious]

$12 shipping... bastard. ;)

I've been using Summit where possible, they have iparcel or some BS but it works out nearly reasonable. I got a Fan shroud shipped for $21 which is great for us!