Help with fuel system design for LS1 install
 

[ Also posted this on LS1tech but looking for opinions from any possible source. ]

Trying to piece together the fuel system for the LS1 ('99 Z28 donor) that's going into my '72 Chevy shortbed. (This is my first fuel-injected project, so please be gentle with your advice and criticism.) Here's what I have so far:

• Custom gas tank with 3/8" NPT inlet and outlet
• Walbro 255 GSL392 external fuel pump
• WIX 33737 (Corvette) filter/FPR

I'm planning to do braided fuel line with AN fittings all the way from the fuel rail to the tank. I already know what fittings I need for the 'Vette filter/FPR and fuel pump. I need to know the following:

1. What size line should I be running throughout? I'm assuming AN-6 will be appropriate but I also know what happens when one makes assumptions.
2. What fitting(s) will I need at the fuel rail?
3. What is the proper layout from gas tank to fuel rail for the lines, filter, and fuel pump? My assumption (see disclaimer above) is that I will have the 'Vette filter with the inlet and return lines plumbed directly to the fuel tank, then line from the 'Vette filter outlet to the fuel pump, followed by another line up to the fuel rail. Is this correct?
4. The vendor for the custom gas tank says I need a 90° anti-siphon valve for the overflow fitting on top of the tank. The tank came with a 90° barbed fitting to go to a 3/8" hose, but that can be removed. What exactly should I have here? Searching for an anti-siphon valve via Google hasn't given me anything close to what I think I would need.
5. Am I missing anything?

Thanks in advance for the help. I have virtually no local resources and so I'm ordering everything online. Really want to make sure I get it right the first time and don't end up missing a fitting or buying stuff I don't need.

Thanks again,
Brent

Re: Help with fuel system design for LS1 install
 

Anyone have any thoughts on this? Truly don't mean to be impatient or demanding — just would like to get the parts I need ordered soon.

Re: Help with fuel system design for LS1 install
 

I realize this is an older post, but it looks like you don't have an answer yet, so......

Yes, -6 (3/8") with the exception of the return line from the filter/regulator to the tank, which is -4 (5/16")

IF you have a fuel rail that is a return-less system; that is, only one fuel line on the rail, then it should be a Russell #640850. It will look like this:
http://static.summitracing.com/globa...s-640850_w.jpg

Or you can use a Dorman #800121, like this (I would recommend threaded fittings however):
http://ecx.images-amazon.com/images/...500_AA200_.jpg

1] Return line from the tank to the Vette filter/regulator,

2] Feed line from the tank to the pump, then to the Vette filter/regulator,

3] Feed line from the Vette filter/regulator to the fuel rail.

In this setup, flow from tank to engine is right to left:

http://i191.photobucket.com/albums/z...-regulator.jpg

I am gonna take a guess here, is this suppose to be a vent tube that will allow air in, but not let fuel out? If so, many people on here have used these when doing Blazer tank swaps:

http://cgi.ebay.com/ebaymotors/Gas-F...=p4506.c0.m245
http://i14.ebayimg.com/02/i/001/33/13/1575_1.JPG

Re: Help with fuel system design for LS1 install
 

A little late, but good info nonetheless! (Already ordered everything and most of it's here; the rest will arrive Friday.) And thanks for the link to the eBay item. :)

My only question is whether I can use the -6 line for the return as well. The 5/16" return line connector goes to -6AN so I assume there won't be a problem. For a return line, I can't see why a bigger line would be a problem. (Too small, sure, but....)

Thanks again!

Re: Help with fuel system design for LS1 install
 

Yeah, my bad. In my application the OEM return is 5/16", so that's what rolled off my fingertips! -6 should do fine as well.

Re: Help with fuel system design for LS1 install
 

Hi, just starting my fuel lines tonight...how did you connect you lines to the gas tank "spouts"?

I bought the parts from Glock's fuel system list....just wondering though how you got the line started at the fuel tank / sender? (I've never used braided lines before)

So, do I:

1. cut the ends off the 3 fuel sender's tubes,
2. then put a nut on each fuel sender line,
3. then flared the fuel sender line with your 37' flaring tool,
4. then threaded your a/n end onto the nut?

I am running two fuel tanks if that helps too..

Thanks!!!

Thanks for your help!

Re: Help with fuel system design for LS1 install
 

So your question is: How do I attach AN hose to my trucks factory pickup/sending unit?

Or am I missing something?

What type of hose are you using? If you are using teflon SS hose you will not be able to clamp your hose to the sender. One option there would be to use a compression fitting to AN adapter. If you are using regular SS hose you can simply slip it on the pick up and clamp it. Hope this helps.

Re: Help with fuel system design for LS1 install
 

I need this dumbed down as much as possible; will the dorman 800121 and 800120 work for the fuel rails in a return style system using fuel injection clamps?
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Re: Help with fuel system design for LS1 install
 

No that's exactly it. I bought regular braided hose and all the A/N connectors that glock had listed in his build thread.

I'm trying to find a piece-by-piece order of what to do but searching the board and even google just gives a hodge-podge of information that is only half there, if that.

Any information, especially how to join the braided line to the fuel sender as shown in my pic attached would help! Thanks!!

Re: Help with fuel system design for LS1 install
 

YES they will, I was using this until I found out that certain drag strips may have an issue with the rubber line. It was brought up that NHRA does not allow more than a total of 12" of rubber in a fuel system setup. I switched all mine to braided hose.

http://i112.photobucket.com/albums/n...y/DSCN0002.jpg
http://i112.photobucket.com/albums/n...y/DSCN0001.jpg

Re: Help with fuel system design for LS1 install
 

Awesome! I will order them up. I have no intention of going down the track and really, I barely drive it. Thanks!
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Re: Help with fuel system design for LS1 install
 

X2 I used a 800120 on my return line.

Ignore the rust please:lol:

http://i104.photobucket.com/albums/m...y/P1060310.jpg

Re: Help with fuel system design for LS1 install
 

these pics need to be in the FAQ fueling section....

Re: Help with fuel system design for LS1 install
 

You can see and read about what I ended up doing about halfway down page 12 in my build thread, starting at post 292 (link). Here are a few pics from that thread:


http://67-72chevytrucks.com/vboard/a...1&d=1249258630

http://67-72chevytrucks.com/vboard/a...1&d=1249258630

http://67-72chevytrucks.com/vboard/a...1&d=1249258630

http://67-72chevytrucks.com/vboard/a...1&d=1249747822

http://67-72chevytrucks.com/vboard/a...1&d=1249747822

Re: Help with fuel system design for LS1 install
 

This info helped a lot. Thanks guys

Re: Help with fuel system design for LS1 install
 

In the picture of the sending unit, what does the pipe in the middle of the sending unit do?

Re: Help with fuel system design for LS1 install
 

I agree this needs to be a FAQ section. With part numbers of what everyone is using for their builds.

Re: Help with fuel system design for LS1 install
 

i have all of my part numbers on the reciepts around here somewhere from my build. i can dig them up if needed.

Re: Help with fuel system design for LS1 install
 

I'll add this thread to the LS FAQ.

http://i104.photobucket.com/albums/m...y/P1060304.jpg

Re: Help with fuel system design for LS1 install
 

How do you connect to the regulator with hard line?

Re: Help with fuel system design for LS1 install
 

Possible dumb question here, but....

If there is a fuel line and return line coming from the rails to the regulator, but there is only one "input" on the regulator, then two out (one to pump and one to return in tank), where does the return line from the fuel rail go???

Does the two lines coming from the rails need to "join" before the regulator??

First LS Swap obviously... :uhmk:

Re: Help with fuel system design for LS1 install
 

What year is your engine? Sounds like you have the return style fuel rail. This style has the fuel regulator built into the fuel rail. The corvette regulator is not needed for this style. The two lines from the rail just go straight back. One to the pump (either internal or external) and the other line is the return that goes to the tank.

Re: Help with fuel system design for LS1 install
 

It's a 5.3 out of an 03 Tahoe. Has two lines right off of the intake.

So no need for a regulator? I don't remember seeing any kind of regulator in the system?? What should the rails looks like?

That would be good news, could be why I'm confused about this fuel system layout lol

Re: Help with fuel system design for LS1 install
 

Two lines off the intake or two lines off the fuel rail? , Is the second line going to the purge solenoid by chance? Can you post a pic of what you have? Be able to give you better advice that way.
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Re: Help with fuel system design for LS1 install
 

Hey folks,

I'll jump in with a question also. I am finishing my budget for my LS1 swap and I'd like some advice.

I am running an LS1 our of an 02' F body, which I believe is the "returnless" style rail. I am buying a tank with an intake Aeromotive stealth efi pump from Boyd's. My plan is to run the feed and return lines from the tank to Vette regulator, and then a single feed line to the LS1 rail. I plan on using all braided hose for simplicity of install.

Approx how many feet of line did you need? I dont have the motor yet so I cant measure. Im just doing this to finalize the spreadsheet

Would this kit be a good idea, along with an extra few feet (4-5?) of -4 AN line for the return + extra straight/90* fittings? I know I will need extra -6AN fittings and clamps.
http://www.summitracing.com/parts/SUM-PUMPKIT1/

I've never messed with fuel plumbing other than carbed stuff. Braided line/fittings are new to me.

Re: Help with fuel system design for LS1 install
 

My apologies.... off of the fuel rail. I can post pics once I get home. But I am pretty sure these are fuel rail lines. When I pulled the caps off, fuel spilled out of them... They are steel lines one on top of another, pointed towards the back of the motor...

Exactly like Br3W City's first pic, post #10

Re: Help with fuel system design for LS1 install
 

........

Re: Help with fuel system design for LS1 install
 

Top line is supply lower line is return. Regulator is in fuel rail, you don't need the vette regulator.

Re: Help with fuel system design for LS1 install
 

Thanks for the help fellas.... Here's a pic just to clarify what I have. I will list some part numbers for the fittings I use, in case any one else needs some help.Attachment 949129

Re: Help with fuel system design for LS1 install
 

Here are some part numbers for the "return style" fuel rails. Thanks for all the help guys!!!


Russell Performance 640850 - Russell Fuel Rail Fitting Adapters- Feed Line 3/8

Russell Performance 640860 - Russell Fuel Rail Fitting Adapters- Return Line 5/16

Russell Performance 670470 - Russell AN to Metric Adapter Fittings- each end of Walbro 255 fuel pump

Summit Racing SUM-220690 - Summit Racing® Hose Ends- -6AN hose connector with female 6AN female threads

Summit Racing SUM-230615 - Summit Racing® Stainless Steel Hose- 15ft hose using for feed

Summit Racing SUM-230620 - Summit Racing® Stainless Steel Hose- 20ft using for return.

Re: Help with fuel system design for LS1 install
 

This might be off topic, but I originally put my LS2 into a 2000 S10 pickup and according to the S10 forums the stock fuel pump would supply enough pressure to feed the engine with the vette fuel filter inline with it.

But I am in the process of restoring my 87 K5 and putting the LS2 in it. Can anyone tell me if I can take out the stock S10 pump and drop it into my K5?

I don't have anyone around to help me get the bed off the pickup or else I wouldn't ask.

This restoration is costing me enough and I want to save money where I can.

Thanks guys!

Re: Help with fuel system design for LS1 install
 

For us dudes with return style fuel rails, what filter is being used?

Is there is WIX filter being used? I'd prefer that, and can I use -6AN fittings with it, push connect possibly?

If so, anyone know if they're 3/8 or 5/16??

Also, does the filter go between the tank and pump, or between the pump and fuel rail?

Re: Help with fuel system design for LS1 install
 

I'm using a fuel injection compatible in line filter, iirc its an Earl's. It uses regular -6 AN, no need for PTC except for at the rail. Feed is 3/8, return is 5/16.

pump->filter->engine. You can run a pre-filter, but it needs to have high enough flow to not cause issues with suction. I personally don't/.

Re: Help with fuel system design for LS1 install
 

Thanks Br3W! I've got the PTC fittings for the fuel rail and was running my braided line and it occurred to me that I forgot about the filter lol. I will check Earl's!

Something like this?? http://www.summitracing.com/parts/TFS-23000/

Re: Help with fuel system design for LS1 install
 

Just put in an order for (hopefully) all of my stuff. Man these fittings get pricey. Im sure that I am missing a few items, but I wanted to get the bulk of it and buy more fittings locally as I need them. Im running a 98 LS1 with returnless rail

Heres my list so far:

WIX-33737 regulator/filter
Summit SUM-PUMPKIT1 -6AN kit (20ft, includes 3 adapters, 2 straight, 1 90 and clamps)
Summit SUM-230406 -4AN 6 ft kit (for return)
SUM-220490 straight end (-4an for return)
RUS-660060 3/8 NPT to -4AN (for return)
(2) SUM-220690 straight ends
(2) SUM-220687 90 ends
RUS-644123 for vette filter
RUS-644113 for vette filter
RUS-640940 for vette filter
RUS-640850 for fuel rail

Anyone see any problems?

Re: Help with fuel system design for LS1 install
 

What pump are you using? If not an in line/external pump, what would be a suggestion?
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Re: Help with fuel system design for LS1 install
 

I bought some 3/8 compression to -6 AN fittings off eBay.... I just had an OEM plastic clip fail on my 04 Impala at the fuel filter. Granted mine are 8 years old, but my suggestion is to pick up a few extras...

http://i.ebayimg.com/t/Fuel-Line-Ada...8Og~~60_35.JPG

For my fuel pump I chose a factory pump for a 2005 Silverado/Sierra that is internally regulated. I am building an oversized tank, 13" deep and will be perfect for the fuel pump assembly. www.vaporworx.com makes a ring (or a kit) out of stainless or aluminum to mount the pump using the factory o-ring and cam lock. If you need a tank thats not as deep (lowered trucks,) they designed the system to use the Gen5 Camaro or CTS-V pumps...

http://desmond.imageshack.us/Himg855...pg&res=landing

Re: Help with fuel system design for LS1 install
 

So I have an ls1 with no return and im going to use the stock tank along with a walbro exxternal pump, do I need to also use a wix filter or not? Also can I use braided black hose and just slide it over the sending tube and clamp it?
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Re: Help with fuel system design for LS1 install
 

The Wix filter for the Corvette is also a fuel pressure regulator, which you will need. Clamping high-pressure fuel injection hose like you'd do with low-pressure fuel lines is A Bad Idea™.

Refer to this post to see what I did with my LS1.

Re: Help with fuel system design for LS1 install
 

How do I do a return port if im using the stock tank from a 67 how do I return the fuel back
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