New Idea for Fuel Lines

p5150

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So hear me out on this one:

Being that the stock lines have been proven to support 500 hp, I am planning on going with some slight modifications to the stock lines to run a dual-feed fuel rail on my NA-T 2jz. If one line can support 500+, then it only makes sense that 2 could support 1000.

All of the three fuel hardlines (charcoal canister return, fuel feed, and fuel return) are the exact same diameter. Here is how im planning on doing it:

STOCK FUEL FEED LINE: powered by one Walboro with an inline aeromotive fuel filter in place of the stock filter. This will be attached to an SS braided via compression fitting. The braided line will run to one side of the fuel rail.

STOCK FUEL RETURN LINE: will be modified to be powered with a secondary, identical walboro which will run from tank-> SS flex line -> filter -> hardline -> SS line to other side of fuel rail

STOCK CHARCOAL CANISTER LINE: will serve as the return line to the tank. There are a couple of difficulties to overcome. For one, the line doesnt go down to the bottom of the tank. I think this could cause a lot of foaming. A hardline will have to be added so that the fuel is ejected near the bottom of the tank.

Also, it gets very restrictive near the tank after the flexline that connects to the hardline that runs the length of the car. I will probably stick in a thicker hardline at the tank for the return.


So this is what it will boil down to:

With the engine not running, the return line should be able to send all of the fuel back to the tank without causing a spike in the pressure. This will be evident in how low I will be able to drop the pressure on the AFPR.



I havent been able to find anybody who had done the same thing, so I was looking for some inputs to see if anybody was running a stock fuel return line with dual walboros.
 

boostadikt

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or you could just spend 25$ for 10ft of steel pipe line....take some time and do it right.... your choice
 

p5150

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boostadikt said:
or you could just spend 25$ for 10ft of steel pipe line....take some time and do it right.... your choice
I guess you are referring to the return line?


So do you know of anybody running a stock return line with dual pumps?
 

Kevin S. OG

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I would not run 2 feed lines using the old return line your going to vapor lock and have two pumps fighting each other.

I am running into the same problem. Upgrade the fuel feed line to -8 or -10 remove the old feed line and use a bulkhead AN coupler at the tank hole where the old fuel feed line use to be.

Use the aeromotive fuel pump not the walbro the walbro is only good for up to 500hp i dont know if thats its forced air rating or na rating for the 255lph

buy the aeromotive fuel pump from the get go! use the aeromotive fileter with it and the mounting bracket remove the old fuel line bore the whole out so you coupler could go through the tank and seal it then run 1/2" fuel line for -8an setup use 5/8ths line for -10 an fuel set up.

keep the return the same size or use the old feed line the feed line is one size up from the return and the vapor. so using the 700hp rated aeromotive for turbo efi should be the way to go!. try to stay with a single pump because with two pumps they will push against each other just upgrade the single and the lines and you should be good to go.

2x the pumps means 2x the weight 2x the stuff to go wrong 2x the filters just upgrading the original is the way to go.
 

p5150

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Well the pumps arent going to "fight" each other. Pressure is pressure. As long as the excess fuel is able to feed back into the tank it doesnt matter if I have 2 3 or 4 pumps.

I have seen the other threads with other people's setups - not that they dont work or are ineffective but it isnt the route im looking to go.

And if ONE stock fuel line has been proven to run 500 hp with no problem then why cant I just use two lines with two pumps?

The issue isnt the fuel supply lines. Im confident that running two lines will provide enough fuel. The issue is if the return line will be big enough and at what point will it be unable to relieve the pressure?

Are you sure about the stock feed line being bigger?
 

suprra_girl

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we've done it here on a 1jz... drilled out other end of rail... to feeds in stock return.. has one bosche big hp pump feeding a surge tank with two elec external pumps feeding the rail... seems to work quite well with 650rwhp on 20 odd psi :)
 

p5150

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so suprra girl - you are saying that you are still using the stock return line?
 

joliroger4

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I run 2 walbros with a stock return. Single -8 feed split into two -6s before the rail and a return of -6 clamped to the stock return line. I can't get less than 32psi with vacuum at idle. That's right at the edge of where I want to be. It'll do for now, but its not my preference to be on the edge like that.
 

p5150

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joliroger - you are the man.

Thats exactly what I was looking for. Based on what you said I will get a bigger return line. Thanks again.
 

figgie

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1 thing to keep in mind.

the stock fuel line might be able to support 800 rwhp. BUt how efficently is it doing it? What I mean by that is what type of pressure losses are you seeing at that level of fuel flow?

I can tell you that it is not low by any chance. At that level and through those lines you are making the fuel pump see nearly 15-20 psi above the AFRP setting. Lots of fuel pumps fail for that reason.
 

QWIKSTRIKE

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I ran a -6 return on pushlock aeroquip hose and push lock fittings. The hose cost 30.00 I think and took 20-30minutes to install.The stock hanger was drilled out and the feed was made from 2 -6 90 degree push lock bulkhead fittings. Braided hose was then added about 6-8" long feeding to 2 aeromotive inline filters; Which continued to feed both ends of the rail. The return was drilled out also and replaced with a 90 degree push lock fitting leading to the Aeromotive pressure regulator. The rail was drilled and machined in the center for a return going to the fuel pressure regulator.
 

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suprra_girl said:
we've done it here on a 1jz... drilled out other end of rail... to feeds in stock return.. has one bosche big hp pump feeding a surge tank with two elec external pumps feeding the rail... seems to work quite well with 650rwhp on 20 odd psi :)
Sounds like my plans. I'm going to feed the surgetank with a single walbro, and do dual -6 an lines to the tapped fuel rail fed by a Bosch 044. Feed for the surge tank, and returns will be the stock lines.
 

p5150

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well I plan on using two lines - not just one. Since the stocker line (singular) has been proven to support 500 hp then I dont see why two lines (plural) couldnt easily support an 800hp (peak) setup. I havent seen people getting a new fuel line for their 400 hp setup or even 500 hp setup. On a daily basis I should only have about 600 or so on pump gas so with dual feeds I think it will be fine.

Figgie: I see what you are saying about the fuel pressure being higher near the pump, but I dont know if it is as significant as you say. Have you actually measured the pressure at the output of the pump vs the fuel rail?
 

hottscennessey

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I thought about doing it that way P5150, I was actually going to take an additional factory feed line from a parts MKIII and drill out the pump hanger to accomodate a second feed line. That way you could leave the factory return alone. Just an idea.
 

figgie

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p5150 said:
well I plan on using two lines - not just one. Since the stocker line (singular) has been proven to support 500 hp then I dont see why two lines (plural) couldnt easily support an 800hp (peak) setup. I havent seen people getting a new fuel line for their 400 hp setup or even 500 hp setup. On a daily basis I should only have about 600 or so on pump gas so with dual feeds I think it will be fine.

Figgie: I see what you are saying about the fuel pressure being higher near the pump, but I dont know if it is as significant as you say. Have you actually measured the pressure at the output of the pump vs the fuel rail?
Beautiful thing about the motec ;)

initially two transducers. One in the rear of the car about 6 inches off the fuel pump (walbro at that time) and the other right on the afpr. at full flow at idle there was about 10 psi differential and it didn't change with pulse width. stock lines are restrictive and that led me to dump them after running the car once.

though my system is a bit difference now. I made it sort of returnless. By that I mean that I have the AFPR within 1 inch of the fuel pump and then it returns the fuel towards the tank again. This lets me use the AFPR in the back to monitor fuel pressure at the head and then I added pressure transducer on the fuel rail to monitor pressure there. Keep in mind though I am fueling my car with a weldon 2345 through -10 lines that splits into two -08 lines up front. This fuel pump flows enough gasoline to power 2000 hp.
 

suprra_girl

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i'm pretty sure we're using the stock return line and just added from another parts mk3 a feed line... and clipped it into the stock locations and had the fitting on the end made up to fit the rail :) something like that... next time i see him i could take pics if you like, but it looks like ya sorted :)
 

Kevin S. OG

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I dunno i plan to use the K.I.S.S. method

Reallocate the slightly larger fuel feed line as the return line up to the fuel tank.

Keep the vapor line going to my CO2 canistor as a vapor line (unchanged) so i dont vapor lock my fuel tank and extra effort to my pump & burn it out.

keep my walbro 255lph for my opel gt since it will only have 275whp with it all NA 2.0 ltr altezza motor. at least i didnt loose anything by buying it by mistake.

I will buy this fuel pump.
A1000 Fuel Pump, P/N 11101

Rated fuel for injected engines:
up to 1100 HP - naturally aspirated
up to 800 HP - forced air induction



use a AN -8 bulk head adapter like quickstrike backed up then run 1/2" line from the tank to the front of the car to replace the oem fuel line limited to 500hp

run a single line and single pump like factory did. This set up should be ok for drifting but if engine dies i will just get a fuel cell not a bunch of crap between the tank and the engine with a handfull of pumps and holding tanks.

I just want to upgrade the oem parts and not add a bunch more stuff to the car.

here is the filter i will use also

P/N 12304
Billet, in-line housing with -10 AN O-ring boss ports and hi-flow 100-micron (coarse) cleanable, stainless steel element. Red, Type II Bright Dip Anodized. Recommended before fuel pump. 5" long X 2" diameter. Flows 2,000 lb/hr with a pressure drop of less than 0.5 PSI.

here is the mounting brackets i will use.

Billet Filter Mounting Bracket, P/N 12305

NEW! CNC Billet Fuel Filter Mounting Bracket for use with Aeromotive filter P/N's 12301 and 12304.
 

p5150

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That stainless steel filter is what I plan on using as well. Im still going to stick with the dual walboros for now though.
 

p5150

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So after all of that discussion, this is what I decided to do. Figuring out how to plumb the dual feeds was too complicated and costly. A lot of adaptor fittings have to be purchased to incorporate things like the aeromotive filter.

Also I had heard from others that the fuel lines dont take a standard compression fitting because they are an off-size, and figuring out the thread pitch and size of the other components like the tank output and line from the fuel filter was just a pain in the ass.

Here is the verdict. It better work because it is all on the way. www.anplumbing.com is the best place to get this stuff:

Dual walboros feed together to billet Y block and out a -10 45 degree AN bulkhead fitting that goes through the top of the tank. The stock line will be removed and this will go in its place.

-10 Braided 2 foot section from tank to filter. 5/8 aluminum hardline up chassis to 1/2npt(-10an) feed x -6 AN output Y block to -6 lines going dual feed on the rail.

1/4 NPT x -6 AN center fuel return to AFPR. From the AFPR its a -6 flex to 3/8 hardline back to the tank with a flex section between the tank and chassis.

The charcoal cansiter line will be plugged and a vented gascap will be installed.
 

joliroger4

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Just to follow-up on this. I recently installed a full-6 return and I can set my fuel pressure as low as 24psi now. I posted a bit back that with the stock return I was only able to get as low as 32psi.

Edit: Oh, one thing I should add, is not to use the straight bulkhead fittings on the top of the tank hanger. If you try and use a straight bulkhead fitting with a 90 degree hose end, the fitting will hit the trunk floor and the tank wont go back in. You need a 90 degree bulkhead fitting with a straight hose end. Hopefully this will prevent a few of you from having delay and order more fittings like I did.
 
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p5150

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I have a straight bulkhead with a 90 hose end. Im not looking forward to it not fitting.... Did you try to massage the trunk?
 

joliroger4

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There is no chance in hell, the gas tank wont even come close. I tapped the bottom of the trunk floor with a hammer a few times and I could tell it wasn't going to budge plus I didn't want to damage the sheet metal, so I just bought the right fittings before I did any damage. Do yourself and car a favor and get the right fitting and hose end.
 
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bigaaron

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What do you guys do for the fuel pickup in the tank when using an external pump?
 

suprahooked

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bigaaron said:
What do you guys do for the fuel pickup in the tank when using an external pump?
I am using a sump. I plan on blocking off the lines going in the tank.
 

figgie

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bigaaron said:
What do you guys do for the fuel pickup in the tank when using an external pump?
Sumping a la Duane.

Only way to keep the pump happy. Also we are lucky in that regards since the tank is mild steel.
 

upgradedsupra

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figgie said:
Sumping a la Duane.

Only way to keep the pump happy. Also we are lucky in that regards since the tank is mild steel.

LOL..Yes mine has worked fine :)

Duane
 

p5150

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joliroger4 said:
There is no chance in hell, the gas tank wont even come close. I tapped the bottom of the trunk floor with a hammer a few times and I could tell it wasn't going to budge plus I didn't want to damage the sheet metal, so I just bought the right fittings before I did any damage. Do yourself and car a favor and get the right fitting and hose end.
Thanks for the input - I thought I had this thing licked with my 90 hose end. Fuck. I guess I will have to wait a week for this shit to come in.
 

bigaaron

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The only problem I have with that is I would never have critical parts like fuel fittings and a filter hanging that low off the back of the car.
 

bigaaron

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It looks like I would get pulled over and ticketed before I get a block away from my house! :biglaugh:
 

upgradedsupra

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bigaaron said:
The only problem I have with that is I would never have critical parts like fuel fittings and a filter hanging that low off the back of the car.
It is not low enough to hit anything
 

p5150

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Update to this - one of my high-quality Walboros siezed and blew my fuse. I had to pull it out.

I shitcanned the Walboros and put in dual MKIV pumps.