Well, I found out my return line back to my tank is well too restrictive for the fuel pump I am running. (Walbro 255lph) I have the Mallory 4309 regulator and a holley DP carb. The pressure would not drop below 10-11 psi so I am going to route a larger return line and while I'm in there run a larger supply line for future... I want to use 1/2" steel lines for both the return and supply from the engine bay back to the stock pickup. What is the easiest way to go about this? I've really never attempted anything like this before and I want to do it right. (I'm not going to use braided line, AN fitting) How do the connections work when i need to make a break in the lines? What fittings do I use? How do I get the lines in the stock pickup?

Any help is greatly appreciated. I can't get my car running before I do this and I'm on a tight budget.

Thanks.

 

Running 1/2" line is going to do much good when it goes back into the stock size fitting at the factory pickup. But, on my car I used 1/2" aluminum line from Summit. You can also get the fittings from them.

http://www.summitracing.com/parts/SUM-G2512/ - the fuel line
http://www.summitracing.com/parts/RUS-639220/ - the first fitting you need
http://www.summitracing.com/parts/SUM-220757/ - the fitting you would need to go to 1/2" rubber hose

 

I wanted to run steel lines for durability. Plus I don't have close to the coin to afford bradied hose. When the line goes back into the stock pickup, can't i just removed the stock return and supply and drill out the holes at the top? Run the steel 1/2" lines into the tank? I wanted to use all cheap fittings from plumbing warehouses. Can I use all compression style fittings and such? Why do I need the first fitting?

 

The first fitting is what actually connects to the hard line. You can then attach a barbed fitting to the first fitting. The first one I posted is a compression fitting you could go to a hardware store and get a brass one if you wanted to.

There is nothing wrong with the aluminum line. I dont know if youd be able to bend 1/2" steel line or where you would even get it. Not sure about drilling out the stock lines. I'm running a sumped tank with my pump mounted outside the tank. For my return line, I have 1/2" going into one of these fittings mounted close to the top of the tank.

http://www.summitracing.com/parts/RUS-670860/

Heres my feed line. The return line you cant really see but it is at the top of the back of the tank. Right where the hump in the tank is at.

 

I already have my new walbro in-tank 255 lph pump inside the gas tank already. I'm really wanting to run the 1/2" supply and return into the stock location. Not to sure what I'm getting myself into. I already had the pump in and it works so i can't get a different pump and mount it outside the tank. Also, I'm afraid I might kink the aluminum line. I have access to the steel line.

 

Ok, so i have a pretty good idea of what I'm going to do. What's your guys' opinions on this? Can I run all 1/2" steel line w/ compression fittings? Will they leak? I'm going to have my dad's buddy make two 90's to go to the top of the pick-up. from there I'm just going to mock the stock line routing up to the engine bay. Can I just pick up thin wall 1/2" tube steel? What psi is the steel line good to? And I want to make sure the compression fittings don't leak.

Thanks for the input.

 

Compression fittings will work just fine. I agree with what was mentioned earlier about the fittings going into the tank. You really want to have 1/2" fitting on the tank. I don't see why you couldn't drill out the stock connections to 1/2" then carefully weld new fittings to the pickup on the top of the tank. Some 1/2" hose to the lines you're going to run and you should be fine. Just make sure you use the same 1/2" pipe inside the tank from the pump to the fittings outside. You'll still have the stock 3/8" regulator inlet and outlet connections to deal with as a restriction, but it shouldn't be much of a problem. You should be able to find a 1/2" compression to 3/8" MIP fitting at the local plumbing supply store for your connections at the regulator.

 

Thanks for the reply. So you don't think the compression fittings wont leak? I'm going to have to have a connection where the lines meet the lines going to the tank (behind the seat) and in the engine bay i might have two connections per line. I'm still kind of confused by the fitting in the tank? Why can't i run my 1/2" steel lines into the tank and clamp a 1/2" rubber line to the steel line and run the rubber line to the pump? What fittings should i use for the top of the pick-up?

 

No, as long as you don't overtighten them and strip the threads compression fittings will work just fine. I've been running them on my Camaro and my truck both for over a year now with no problems. Fuel line repair kits sold at Advance Auto Parts and Autozone both include them to connect to the original lines.

As for running the steel lines into the tank, I'm not sure on how you plan to keep the tank from leaking? Drilling out the OEM lines and running the 1/2" lines down through the holes is fine as long as the lines are sealed where they go into the tank to prevent gas/fumes from leaking out and contaminants from getting in.

Rubber line from the steel lines to the pump inside the tank is fine, but don't use more than a couple inches of rubber line. Rubber swells under pressure and will give you problems keeping a constant supply of fuel to the carb. It's also a good idea to use a small section of rubber line between the tank fittings/lines and the hard lines mounted to the car's chassis. Again, not more than a couple inches or you may have feed problems. I had issues with that when I first got my truck. The PO had replaced about 20" of steel fuel line with rubber hose and it would start fine and drive fine for about a 1/4 mile till the hose swelled from the pressure and then it would stumble and almost die on me. If it didn't die, it would be ok after that initial stumble, but had very poor throttle response and lacked power.

 

Thanks alot for the info! So your saying where the lines come out of the tank where they connect to the lines under the car, to use rubber fuel line? I was going to use compression fittings there as well. The only rubber I wanted to use was 2-3 inches in the tank connecting to the pump to my new 1/2" line. I was afraid if I used a couple inches of rubber between the lines under the cars chassis and the lines going up to the tank that they would leak? Not sure, I guess that's what's there now (factory). At the top ot the tank i'm going to have my dad's buddy at his fluid shop (very good welder) weld the lines to the pick up so it's sealed up properly. If I connect the lines with rubber under the car's chassis then i will only need to make one connection at the filter and maybe up towards the front of the car then?

Also, I'm thinking my best bet to go about this is to drop the tank first and mock my new lines to the factory configuration and get that done first, get the tank back in. From there take out the factory lines out of the car and bend my new 1/2" lines outside ther car? That's just what I was thinking but I'm up for any helpfull critisism.

Thanks.

 

Not looking to really hijack but did you sump a stock tank?? If so I'd be interested in hearing / seeing more via PM.

 

The OEM setup uses 6-8" or rubber line between the tank fittings and the lines under the car. What I did when I repaired the lines under my truck is this:

I left the rubber hoses attached to the fittings on the tanks. The other end of the rubber hoses where they went into the metal lines I cut the ends off. Then I took the replacement fuel line I was using and made a double flare on the end with a flaring tool. The flared end I pushed into the hose(which was a real PITA) and then used 2 hose clamps to secure the hose to the metal line.

NO leaks and all, and with the flare on the end of the metal line it helps keep the hose from slipping off just like the "bubbles" in the OEM metal lines.

Good luck removing the lines though if you use my method. I recently tried disconnecting them so I could remove the tank to change the fuel pump and couldn't pull them out. I had to leave them connected till I got the tank lowered enough to undo the flare fittings at the tank.

The easiest way I've found to run lines is to completely remove the one you are replacing, preferably in 1 piece and without bending it. Then you can use that as a template to bend the new line. Then you can put it into the car to make any necessary adjustments.

Best bet is to run 1 solid line from the fuel filter to the regulator, one line from the tank to the filter, and one line from the regulator's return to the tank. If you want to put a compression fitting in the middle of the feed and return lines for easy removal for repairs/chassis work/etc later, that wouldn't be a problem. Just locate it somewhere under the car out of the way. Where the lines run over the transmission crossmember would be an ideal spot.

 

how is the stock 3/8" size too small for u? lol... im running the walbro 255lph high pressure pump in the tank and its fine to support my 480hp HSR383. i have great pressure and no drops. i made my own line tho... i kept the stock line off the tank, i used new rubber line to connect to 3/8" steel line to the back of the engine, then ran 4"-6" of rubber line to the back of my HSR. the pressure line is 3/8" and i used a summit hard line adapter to -6AN fitting, then connected a russell -6AN to metric (stock fuel filter size) which plugged into the stock fuel filter and then the same on the opposite side which runs the 3/8" steel line to the back of the motor. return line i upgraded from 5/16" to 3/8" from the tank to the engine.

dont use aluminum line for fuel lines. its too brittle and will weaken more and more as it heats and cools. not to mention it has to be anchored every 6" or so where steel line can be anchored every 12-24". honestly 3/8" line is fine for over 500hp but i wouldnt upgrade to 1/2" untill your pushing 700hp ish.

 

My reasoning behind running 1/2" line is because I need to upgrade my stock 5/16" return to a larger line. I figured since I was tearing out all the old lines all the way back to the tank I might as well upgrade both the supply and return so i never have to do it again.

 

why cant you just what i am going to do and replace just the feed line and use the original feed line as the return?

 

Would 3/8" be enough for a return with the Walbro 255 lph pump? I would rather play it safe and only do this once.

 

should be plenty, considering people are using that pump with factory feed and return lines anyway

 

Even with a carb? I can't seem to get my pressure to drop below 10-12 PSI with the new walbro pump. With the TBI pump it was fine. I came to the conclusion my return line is too small. I wonder how some people can get away with using the factory return and mine just won't work.

 

well you gotta think, that pump is made for fuel injection, so you need a really good regulator and a good liquid filled gauge on your rail for exact measurment, when i had a carb i used the mallory 3 port return style, http://www.summitracing.com/parts/MAA-4309/

oops, i see you have that... my bad. maybe a bad regulator?

mine held steady at 7psi with my speed demon carb. it you put that in, and it still does it, then switching the lines, or troubleshooting will be needed.

does it stay that high with just the key on, or when the engine is idleing? does it fluctuate much?

let me know man, well figure this out dude.

 

a 3/8" line would be fine. on a 1/2" feed line u would use a 3/8" return line minimum... you gotta remember that the return line isnt full of fuel like the pressure line. it only sends watever the regulator regulates back to the tank. figure 100% going into the fuel rail and maybe 15% coming out. the regualtor basically just bleeds off fuel/pressure to keep the rails at a constant pressure that u set (if adjustable). rememeber also that this is with fuel injection. a carbs pressures are alot less.

as a rule of thumb your return line should be as big as your pressure line (says holley) i called them bc of questions with my HSR fuel lines. this is for a performance application, most cars can get away with a 3/8" line and a 5/16" return line, stock cars, and the stock lines can support enough fuel for 500hp without a hiccup. there must be something wrong with your return line, or your regulator.

dnt cheap out on a regulator, i never ran the holley adjustable regualtor that came with my HSR, i didnt bother bc of all the problems i hear with them. i went with a 100$ billet kirban unit that is amazing! no one ever has problems with them and its been running flawlessly. I say its your return line (blockage or a dented/crimped line) or your regulator.

a liquid fuel pressure gauge would help with needle vibrations, but really its not neccessary. i had a new summit 1 1/2" liquid filled 0-60psi gauge mounted on my fuel rail, 3months later it stopped working. i went with a non liquid filled auto gauge (autometer) and its been great for a few months, needle doesnt jump much.

 

Run a 1/2 inch feed, and a 1/2 return and be done with it.

 

Last time I tried it the pressure stayed high with the key on. Then I though. No big deal, so I tried starting the car it ran but was flooding out badly. The pressure was still high with the car half *** running and the regulator set for the lowest fuel pressure setting.

 

Where is your regulator? We had issues with fuel psi being all over the place until we moved the regulator closer to the carb. We used 1/2" soft copper to plumber our S-10, worked great, bends easier than aluminum and they had it at the hardware store so we didn't have to wait to get it. We use compresion fittings and we've never had a leak.

 

Oh, another thing. Don't know if posted this earlier but when I had the stock TBI pump in the tank with the mallory 4309 regulator, it worked flawlessly. It was after I switched to the Walbro 255 lph pump when I started having the pressure problems.

 

maybe you might need all new lines? idk, but my buddie swears by the aluminum type, uses it for all his high hp builds. just be sure to get those clamps big enough so you can mount the line back at the stock location muonting points to save trouble , instead of drilling new ones, you may have to actually add a couple drill points anyway, but try and reuse as many mounting locations as possible to avoid problems.

good luck man, i hope things work out for you bro!

adam

 

the walbro will flow double wat the stock pump puts out without a hicup... problem is that the walbro will flow more fuel at the same pressures as the stocker, this would be harder for the regulator to handle. upgrading the regulator for a quality peice would be my first mod, if it works then your golden, if it doesnt then its time to replace the lines or if you want to upgrade then do it. point being its either the lines or the regulator cant really be anything else.

as far as running the lines in the stock location... u can, and u can use the orginal hardware (if you keep stock sizes) and your running STEEL or STAINLESS line! do not support "aluminum" line with only the stock locations. steel line is much more durable and doesnt need to be achored much... every 24" or so is fine. aluminum is supposed to be mounted every 6-12"min. ever used aluminum line before? not as easy as you would think to bend etc. tight bends to me as easier with steel line, aluminum will crush/wrinkle unless the bends are really wide. i used 5/8" aluminum line to make new oil cooler lines (stock 350tpi oil cooler) bc my steel lines rotted out 30,000miles ago. i had problems making the bends to route it in the stock location. some of the bends have wrinkles in them etc but i dnt really care bc its just the oil cooler. fuel lines i would be much more concerned about.

honestly cough up alil dough and get some braided stainless lines. get two 20' 1/2" DIA braided line and some AN fittings and be done with it. much easier to work with and bends are easy. as ive stated before, daily driven cars (salt, water etc) excessive vibrations and constant cooling and heating of the lines are not good for aluminum, it will become brittle and break. its up to u but i would go stainless or braided.

 

What should I use to mount the new 1/2" s.s. lines to the chassis? I'm sure the stock mounts are not going to work seeing as they are for 5/16 and 3/8 line. Not sure what to do there. I'm just waiting for the weather to clear up a little bit here and I'm going to get started. Also, what fuel filter should I be using since I will be using 1/2" line / fittings? Do I have to mount the filter at 90* like the stock one or can I just run it inline to make things alot easier?

 

get some rubber clamp hose mounts.
http://www.summitracing.com/parts/SUM-G1882/
these will mount them securely and the rubber insulation will help against vibrations/wear. i used self tapping sheet metal screws but u could mark the hole where u want the clamp/line and then drill a hole and use bolts with nuts, stainless would make them never rust but self tapping screws make quick easy secure work of the clamps.

you can run the lines in the stock routing or u can run them where u want them. i ran mine differently. filters u need to choose from, u can use a hard line to AN adapter ( http://www.summitracing.com/parts/SUM-2200076B/ this is the one im running but mines a 3/8" to -6AN) to connect to the hard 1/2" line to a fuel filter of your choice. a 1/2" line will require a -8AN i believe filter http://www.summitracing.com/parts/RUS-650103/ . you want to mount the filter inline but u want it as close to the tank as possible, this way if the line does clog then the whole line isnt blocked.

 

Thanks for the reply! Do you know if there are any 1/2" style fuel filters w/ a compression fitting available? I'm trying to stay away from the AN lines due to price. Plus that filter is quite pricey but if that's the only route I can go than i guess i will.

Thanks,

 

what do u want compression fittings for? i just posted everything you would need to make the connections. the AN fittings are designed to attach to a HARDLINE, AKA tubing, any steel, stainless or aluminum 1/2" tubing. it uses a compression fitting on the hard line but is an adapter that allows u to connect to the fuel filter i posted.

what i posted eariler are the parts u would need to hook it all up minus the tubing. your looking at a 22$ filter, 16$ for the 2 adapter/fittings, and then 8$ for tube clamps/mounts. how is that expensive? now all u need to due is purchase the tubing and hook it all up and your done.
http://www.summitracing.com/parts/SUM-2200076B/ these fittings have a compression furrel on the hard line side but dnt need a compression fitting on the AN side, since AN fittings have a bevel/flare edge for sealing without gaskets/orings.

purchase wat i posted and buy 20ft of 1/2' tubing and be done with it.

 

Thanks. I'm going to order the parts next paycheck. I appreciate all the help. I just hope that this stainless tubing bends ok with a tubing bender...

 

You may want to reexamine this.

Aluminum lines- really only intended for race car use. If you buy aluminum _fuel line_ you don't really have to worry about corrosion/chemical exposure, it should be anodized to protect it (in most cases clear anodized, I think moroso's or someone's is blue) for exposure to alcohol, but aluminum work hardens and fatigues when it moves/flexes, and unless you support almost every inch of it it will eventually get brittle and start leaking (from experience, at the fittings, since the fittings are fairly rigid and the line flexes at the point where it comes in contact with them causing a stress point...)

Steel and stainless fuel lines are available (you can get them from summit, and someone, I can't remember who right now makes formed ones that match the factory routing but in larger sizes in both, I don't know if they do 3rd gens, never checked). Stainless is difficult to work, I wouldn't recommend it for most applications unless it's a show car, exposed to a corrosive environment or running alcohol (though you're probably running braided or aluminum lines in something running alcohol).

FWIW the tube adaptors that you guys have linked to _are only_ designed for use on _aluminum_ lines, not steel (they will initially seal, they will eventually fail also, both because steel is harder than aluminum and because of galvanic action).

Brass compression fittings adapted over to NPT/FPT is probably the best way of connecting steel line (and once you have pipe thread you can go over to an fittings). Alternatively, you can get a 37* flair and a tube nut and sleeve and use that to connect either steel or aluminum straight to AN fittings.

Be aware, that AN stuff uses a 37* flair, brass and other normal flair fittings use a 45* flair, they are not compatible. Again, the threads will match and you could horse them down together to get them to seal, but the combination will fail. If using flairs make sure they match (and again, you can get flair to pipe thread adapters in both flairs and use the pipe thread to connect from one to the other if you need to).

Braided lines are a whole different problem. I don't recommend them for street use because they are not actually 100% impermeable to gas. The rubber liner in them will actually absorb gas and if it wasn't for the braided coating would probably swell like using vacuum hose for fuel line. If you park a car with braided lines in an enclosed space like a small garage you will smell gas, even if you don't have a leak.

Pick your poison, none of them are perfect solutions. Unless they're irreparably damaged, missing or just won't work I usually strongly recommend keeping the stock lines, since they fix a lot of these problems and on newer cars they use plastics that are actually more durable with modern fuels but are not track legal as a retrofit (but track legal as OEM).

In your case, I don't understand why at least the stock feed won't work. to figure out if the problem is your regulator or your return run a large rubber line from the return fitting to a bucket (get rid of the return line restriction), turn the pump on and see if you can regulate the pressure down at the regulator to what you need. If you can then it's the return line, if you can't it's probably the regulator. If it's the return line, I would first check for any dents, kinks or other restrictions before going to all the effort of replacing it. Also try removing the filler cap on the tank (that would tell you if the vent line is the problem).

The closest thing that I can recommend to a perfect fuel line is Teflon lined braided, but it's $$$ and there are not as many selections for end fittings for the stuff, especially in larger sizes (vintage air is a good source if you have the $$$, they use them for air conditioning lines). If you're going to look at that I'd suggest laying out your runs with some rope and then have a hydraulics shop make your lines for you (crimped ends), that is usually _much_ cheaper than buying the parts and putting them together yourself.

 

My stock fuel lines are feeding my walbro intank high pressure/volume pump with hotwire kit ok. I am dynoing 500 rwhp which is 600hp at the flywheel at 45 psi. If you are running a carb, I don't see why you can't run the stock lines.

Even though it is not recommended, I used this fitting from summit to attach my aluminum fuel line to the an fittings and it hasn't leaked in 7 years:

http://www.summitracing.com/parts/EAR-165056ERL/

I am only using a small bit of aluminum fuel line from the tank to the fuel filter though. Maybe you have a kink in your factory fuel line somewhere?

 

Thanks a lot for your reply. My feed line is perfectly fine. I was just figuring while I'm down there I would replace both lines. I would like to see if i could get a link (if they exist) to the stock routed lines in larger dia? I really don't want to go through this hassle of replacing my lines. I'm on an ultra tight budget and want to do this right. I'm thinking it's the return line, but not 100% sure. Some guys are using this pump with the factory return???

 

You are running fuel injection correct? I'm carbed and MUCH more fuel needs to be fed back to the tank through the return line. Again, both lines / regulator worked great with my factory TBI pump.

 

so basically all fuel lines are not good lol... awsome. not sure i agree with everything u posted 83crossfireTA but im not against it enough to post my indifferences. aluminum line as i stated should be anchored alot... ive never used it as a fuel line but as a coolant line this stuff bends pretty easily. i never knew that braided lines werent perectly sealed from gas... DOH! all those ppl running braided line... haha. also i have been running the summit hard line adapters for over 3000miles and they havent leaked yet... this is with the walbro 255lph high pressure pump..

honeslty i think your prob just gona have to run a new hard line for the return. step it up to a 3/8" line and ull be good. i understand that the carb is bypassing alot more fuel/pressure from the pump than in EFI so more fuel/pressure will be entering the return line. u prob just have to increase the DIA of the return line. but first figure out what the prob is. the regulator or the line.

Zach... im sure hes running EFI... he stated 45psi at the engine... if it was carb he would be alot less and the regulator would by bypassing the fuel/psi to get the 7-12psi that a carb needs. what i think might be happening is that your maxing out the regulator... too much fuel/psi needs to be bypassed to get it low enough to what you set the regulator at so basiaclly u need a larger carb regulator perhaps?

 

Thanks for the reply. I'm actually hoping it's the regulator so I don't have to drop the tank again and go through the hassles of running new line... I will test the regulator tonight after work to see if it is indeed the line, or the regulator. If it is the regulator, is there a regulator you guys would recommend?

 

Im running the Walbro 255 with return regulator on the stock lines to feed my Holley 750 and I don't have any pressure problems at all.

 

why not ditch the factory tank and go with a fuel sell. fitting are already there then you can run your braided lines.

 

bc u have to mount the fuel cell. mounting a fuel correctly and "track" legal is a PITA. not to mention you have to figure a way to get a sender in one for the stock or aftermarket gauge. they also dont have provisions to mount stock type intank fuel pumps.

if it would help i saw a article in a MAG that allows you to sump your stock tank... they sell the piece that has to be welded on and already has fittings welded on. also with a fuel cell u cant mount it in the stock location so now u have this huge empty space under the car lol. i thought about a long narrow fuel cell in the cargo area but not sure if i would do it. and i dnt kno the NHRA rules for fuel cell mounting

 

What kind of regulator are you using?

 

I'm curious as well.

Well, last night I finally had a little bit of spare time. I took off the 5/16" barb fitting off the bottom of the regulator and tossed on a spare 3/8" barb. I ran 3/8" rubber hose to a has can and I was able to adjust the fuel pressure all the way down to 0! I know how I had my stock return line ran to the regulator before hand was pretty restrictive.

My question to you guys now is this. Instead of going through all this work on replacing the return line to the stock tank, Can I cut the rubber section of the stock return line and run that right to the regulator??? I think this might take care of the restriction. Is that small section of rubber line on the frame rail actually all rubber hose? I would like to cut this in half and route it to the bottom port of the regulator and see if it works.

Any thoughts on this?

 

did you try it with the stock return line connected and the gas cap open (to make sure the restriction is in the line and not the tank pressure)?

Since others seem to be getting away with doing what you're trying, if it's not a problem with the tank vent then I would be looking for a crushed spot or other restriction in the return line, especially since it looks like you're getting quite a bit of pressure at the regulator, and for this to work for someone else the pressure in their return line has to be less than 50% of the set pressure of the regulator, which with the typical carb working well at 3-7psi, that could be as low as 1.5psig.

I don't know what setup you started with, but the TPI fuel lines have a threaded attachment from the hard line to the rubber line, it just unscrews. I don't remember what the later TBI setups had (the similar vintage TBI trucks had a threaded attachment and no rubber line but a factory braided line, the early crossfire TBI setups had hardline the whole way with the exception of a very short length of rubber from the frame rail to the fuel filter mount)

 

Thanks for the reply. My existing TBI lines have the steel line that threads into a rubber type of line then another threaded connection back to steel line. I what I have now is somewhat (rigged to work) I want to cut the rubber section of line in half and run that right up to the bottom of a barb fitting on the regulator's retun to get rid of any restriction I had looping around. How would I know if the tank pressure is too much? How would that happen?

 

If I'm understanding your answer, you want to go regualtor return to barb fitting to rubber hose to hard line.... I don't see any reason not to, but I don't know what you're running now.

As far as pressure in the tank, running fuel up to the front and back as well as daily temperature changes... all are prone to increase fuel temperature/vapor pressure in the tank, there is a vent and a check valve to prevent that, but they can get plugged (In theory, if there is pressure in the tank both the line out and the line in should be seeing the same pressure and it shouldn't matter, but in practice I've seen weird things happen, like in your case, you won't be able to regulate down to below that pressure unless you relieve it somehow)