DIY- B6 A4 1.8T Return style fuel system for E85

[Kodymfk]

UPDATE: Part #'s have been added to some things and I've also made some changes here and there so make sure to read everything if you're interested in doing this.

Disclaimer- Attempt at your own risk!

So I finally got around to converting my fuel system to return style for when I run E85 in the future. It was an fun time! When I was preparing for this, I found more than enough threads to help ensure I do it correctly (Thank you guys for those threads and help with questions). But I didn't find any threads that had documented it start to finish 100% (I could be wrong, I searched high and low though lol). So I decided to document mine :). When I was preparing for this, I wasn't exactly sure which route I wanted to do so I kind of over prepared (I thought I over prepared lol). Well I was wrong lol, I actually under prepared. I bought just enough fittings to get the job done. This was my first time doing something like this. I think it turned out alright. :)

Parts used
1-Walbro E85 fuel pump and E85 filter setup #F90000267 Pump filter kit #400-0085 (motovicity)
2x-5/16 EFI adpters with male end # 799-640930 (Jegs)
1-180 degree -6an hose end with female fitting # 555-110041 (Jegs)
1-Aeromotive 40 micron fuel filter with 2 -6an male adapters #12335 Port Fittings x 2 # 15609 (Aeromotive)
1-034 fuel rail with OEM fpr hook up # 034-106-7008 OEM FPR Adapter # 034-106-5001 (034 Motorsports)
1-20ft of Jeg's Pro Flow line compatible with alcohol/ethanol # 555-111914 (Jegs)
1-90 degree -6an hose end fitting with female adapter # 555-110021 (Jegs)
2x-45 degree -6an hose end fitting with female adapter # 555-110011 (Jegs)
4x-straight hose end adapters with female ends. # 555-11001 (Jegs)
1-Fuel pressure gauge # 083-71511 (Jegs)
1-Small T fitting for tapping in your FPR if you have AMB Intake manifold. AEB Intake manifold has a port for FPR built into it.

I also recommend drawing your fuel system out on paper and note what part goes where so you can get an idea of what parts you will need. Some areas will need up to 3 different fittings/parts just to complete a connection. Chances are you will need more parts than you think. I opted for having to return things instead of having to wait a couple days to get a part that I needed.

I used the A4 mods DIY for fuel pump removal and install. It was very helpful!






I put 2 sleeves on the pump. Fits great with no movement!




Walbro pump was installed with bottom being the same length, stock was from basket (1.75' from lowest part of basket) Also notice I wired it backwards the first time. OEM power + is ACTUALLY BLACK! lolz (I learned that the hard way)


I installed 5/16 EFI -6an adapters to my stock supply and return line.


Blocked off my breather line (some don't even have this line in their car) Made my stock supply, my return line. Attached -6an line with a fuel hose clamp. (make sure it's snug!)


Ran my 40 micron filter down stream a little. It was to big for stock filter placement and that was pretty packed as well. It extends approx 1/2" past sub frame. (plenty of other things lower than it) It looks like it's out a bunch, it's actually not.





with cover on :)



Had to remove some of the rubber on the inside of these metal brackets to fit the -6an in for a clean look.


Here is the engine bay with the fuel rail installed. (NOTE: had to switch out the little bit of stock supply line for the braided line. I first attempted to attach a fitting to it. It ripped to shreds internally and started leaking and building up mad pressure. I switched it out and everything worked flawless after that. Tapped my T fitting at the small boost/vac line that runs to my DV.


I have a 4bar fpr installed. This is my pressure at idle. Not sure if this is normal or not with this setup. Working on finding that out. Any input is appreciated.
Thanks for reading!

[Kodymfk]

NOTE: Will go back through and add helpful tips and information that would make doing this conversion easier as I think on them. Will post the update helpful pics etc in here.




When removing some of the rubber to fit the -6 line. I would trim it with scissors. I would cut 1/4 of the rubber off in the rectangle rubber mount leaving the back side rubber for the hose to rest on while the stock line rubber mounting untouched.

[alien_brain]

WOOP!

[FU5E]

nice write up

[Kodymfk]

Thanks bud!

[AudiA4_20T]

well done, really clean

[Kodymfk]

Thanks man! Hope people can use this.

[Kodymfk]

Have a revision update. Spent a good amount of time and a few extra bucks testing different ways to do the fuel setup out of curiosity lol.

[Kodymfk]

As you see at the top when I finished this setup, I was at 80psi pressure. This was due to the return hat having a much smaller hole in the elbow of the return. This created back pressure (bottle neck). It's suppose to be at 4 bar at idle (58ish psi) and the very small hole with a rubber diaphragm internally cause a good amount of back pressure. I decided to have fun and stock up fuel hats etc and try a hand full of different routes. I went as far as creating an out of fuel tank system to test different routes I was curious about.

[Kodymfk]

I ended up adding a secondary return line (used a Y adapter) however, lets not forget. our current stock return line works as a siphon pump as well so we must make the least path of resistance (most of the flow) go to the the stock return hat side. I eliminated the plastic internal return hat setup by replacing it with a 90 degree flared end bulk head. Ran -6 straight to the siphon pump. I used the IE -6 fuel adapter to connect to the siphon pump. I ran a secondary return line to above the fuel pump. Ran an adapter that reduced the secondary return line to -3. I did this so most of the fuel would go to the drivers side return hat to keep the siphon pump running but still be able to relieve added fuel pressure. The siphon pumps needs a decent amount of pressure to run.

NOTE: Will be updating this more through out the week. Wanted to get some of it online in case people were running into back pressure issues. Thanks for reading!

[Kodymfk]

The update: I still haven't had time to note new part numbers.

What I did was, I removed the return flow EFI adapter that connect to my stock quick connect. Ran -6 from return hard line (Most of my return line is my old supply hard line) to the Y adapter. Ran -6 to the driver's side return fuel hat where the siphon pump is, into my -6 conversion (pic above) that I made to adapt to the stock siphon pump. What I did to allow this happen was, connect an Integrated engineering fuel connector adapter to the siphon pump itself. I believe it's 5/16. You slide it on under the lip and screw it on and it makes it a -6 fitting. Then I drilled out the old return line in the drivers side fuel hat and installed an 90 degree dual flare end bulk head with metal o-ring washers on each end to insure it seals. This allowed me to run -6 line flow all the way to the siphon pump with now restrictions. I also added a bulk head adapter to the passenger side secondary return line except I ran a straight bulk head fitting to clear the fuel pump plug then installed a 90 degree fitting. For the other port on the Y (secondary return) I simply bought screw on fitting adapters -6 to -4, -4 to -3, then -3 to -4, -4 to -6 then connect my -6 fitting. This created more resistance to the secondary side which in turn would make more fuel go to the driver's side fuel hat. The driver's side fuel hat runs the siphon pump system and surprisingly takes more pressure than you would think to run. If it doesn't run properly, you will experience empty tank at 1/4 and or have overflow fuel on drivers side. I'm sure there are other ways to do this, I found this way to work well for me. If I need more flow to go to secondary side. I simply remove the 2 -3 fittings and keep the -4 ones. I am planning to try and garden hose style valve, setup on the secondary side in the future. This will make it more adjustable I would think. I'm sure there are other ways to this. I found this way to work best for me and keep all stock fuel features in play. Thanks for reading.

[Audi body]

Awesome kody! Great write up and thanks for the come back changes!

[alien_brain]

woop will be doing this with yer help soon i reckon...

[Kodymfk]

Awesome kody! Great write up and thanks for the come back changes!

No problem bud, happy to see people using it.

[Kodymfk]

woop will be doing this with yer help soon i reckon...

Sounds like a plan

[Kodymfk]

UPDATE:
Decided to swap out the OEM style FPR. I felt it was kind of a bottle neck in the system. It worked alright but I felt it was border line maxed out in flow all the time lol. Looking in the picture below you will see the bottle neck i speak of. So I decided to install an aeromotive FPR. The aeromotive FPR inlets and outlets were of equal or greater size of the -6 line. I tested plugging the secondary line with this setup in play, the pressure didn't rise which means I could remove the secondary return line if I wish. Other than that, I didn't notice any difference other than I can adjust pressure on the spot to desired amount.

[Kodymfk]

Planning to mess around with it a bunch and see what results I get. Will mess with 2 return lines I have and go back to only the siphon pump return line and see what happens also.

[Kodymfk]

UPDATE:

I wanted to briefly explain currently what I'm running for it's slightly changed since initial install. I will start from pump, back to return fuel hat. I am running the Walbro E85 pump with their fuel line kit to the stock fuel hat. From the stock fuel hat I'm running the stock supply line that connects to the stock filter, I have one of the EFI 5/16 to -6 male adapters installed into the stock supply line so my system now has a -6 connection. From there I have -6 line to -6, 40 micron fuel filter (can source these almost any where) back to -6 line then to the fuel rail (034 Motorsports fuel rail). From the rail I have -6 line going to the Aeromotive X1 FPR #13303 (Do your homework and confirm part #) and from there, I'm running -6 line out of the FPR straight into the old stock supply line (Hard line), I have it hose clamped on with fuel hose clamps. From the other end of the hard line I have -6 line hose clamped on going to a -6 Y splitter. On the Y splitter, one of the ends is reduced down to -3 then back to -6 to create resistance/pressure, then it's ran into a bulk head in the pass side fuel hat (supply side). I did this to create a path of resistance so it would force more of the fuel to go to other y split that works the siphon pump. I have the other Y split running into my return side fuel hat right into the siphon pump with my fancy bulk head setup. I wont go into detail on that, you can view everything about it by simply reading above posts I've made. All of this is pretty much noted above but I've been getting a lot of questions about it so I figured i'd explain once more.

ALSO (read below)

Due to more people being interested in a DIY E85 swap with the stock block in mind, I have decided to make one. I will make a DIY for the stock block guys out there wanting to go e85, but not wanting spend a fortune doing it. After spending a great deal of time figuring out my current system, I have found areas where I can save a good amount of money for a stock block guy looking to go e85. This is a very good bang for your buck in my opinion. I am currently working on this; however, I do not have an end in mind yet. It may take a few weeks before it is posted online.

[vtraudt]

Can you post a schematic or drawing to better illustrate what you did on your system, and how the simplified version would look like?

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[Mr. Wolfsberg]

Just a thought don't know if it would work but instead of you -6 to -3 and back fitting in your return line I wonder if you could just use a turbo oil feed line restrictor for a Garrett turbo to get you restriction, I would imagine the hole in it would need to be drilled out and opened up since those are like 1/8" holes but that might cut down on some fittings. But like I said I don't know if that would work since I think those might be a -4 now that I think of it.

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[Audi body]

Kody did you upgrade the wires to your fuel pump to handle the higher ampridge? I know I had to upgrade mine to 10awg since the stock is so much smaller.

[Kodymfk]

Kody did you upgrade the wires to your fuel pump to handle the higher ampridge? I know I had to upgrade mine to 10awg since the stock is so much smaller.

I did not. I wired it as if it were stock. I didn't use a relay either.

- - - Updated - - -

Just a thought don't know if it would work but instead of you -6 to -3 and back fitting in your return line I wonder if you could just use a turbo oil feed line restrictor for a Garrett turbo to get you restriction, I would imagine the hole in it would need to be drilled out and opened up since those are like 1/8" holes but that might cut down on some fittings. But like I said I don't know if that would work since I think those might be a -4 now that I think of it.

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I did it that way to be adjustable. I essentially created my own venturi device that is in our return side tanks. I've since then realized there an adjustable venturi device that is adjustable, on the market and plan to try it on the next fuel system I do. The reason I went from -6 to -4 to -3 then back etc was to make it adjustable. I have a high flowing fuel system that created back pressure at idle due to the return hat check valve being a restriction along with wanting to have my fuel tank properly flow as if it were stock. The -4,-3 setup allowed me to adjust it just right. I started with -6 to -4 and it was not enough so I added -3 and that did the trick. This can be avoided by using the venturi device that can be bought.

[Kodymfk]

very bad with photo shop and other diagram making programs and such will give it a shot. Any good programs to try doing it with? Paint?

[vwdann0]

I don't understand, what's the point of this conversation?

[old guy]

I don't understand, what's the point of this conversation?

It gives you more tuning options if you are running a larger turbo. The OEM configuration is called a return-less system. What that means is that the fuel pressure is presented at a constant pressure. The pressure is regulated by a non-adjustable valve located in the fuel filter. Fuel is supplied at a constant 4-bar (58 psi) of pressure.

Return-less system.
With a normally aspirated engine this is pretty standard stuff. But it all changes when you add forced induction (turbo). At zero boost the injectors are supplying 58 psi to the intake manifold. Now add 20 psi of boost. The delta between the 58 psi from the injectors and the 20 psi of boost reduces the effective fuel pressure at the injectors to 38 psi. In order to account for this pressure differential the tuning maps have to increase the duty cycle (pulse frequency/duration) of the injectors to supply more fuel. This becomes increasingly more difficult as you increase the boost and fueling demands.

Return system.
When you go with a return type system you have control over the effective fuel pressure. The return system utilizes a rising rate fuel pressure regulator. The rising rate regulator maintains the effective fuel pressure by adjusting for the delta between the fuel pump pressure and manifold boost pressure. For example, if you are running 20 psi of boost the rising rate regulator adds 20 psi to the fuel pressure thus maintaining a constant effective pressure.

This gives you the ability to easily change the amount of fuel delivery over a much wider range without having to change the injector size or duty cycle. You simply increase or decrease the pressure offset from the rising rate fuel pressure regulator. Essentially it gives you more control over your fuel delivery without having to change the injectors or injector duty cycle.

I suspect one of the main reasons Audi/VW went to the return-less system is because of the ever increasing emissions regulations. The one advantage of a return-less system is that the overall fuel temperature remains lower and thus less emissions for the Evap system to deal with. A return-less system is a one way path to the injectors. A return system is constantly circulating fuel from the gas tank to the rising rate regulator (located under the hood) and back to the fuel tank. This increases the overall fuel temperature and thus the associated hydrocarbon emissions that need to be dealt with.


Hope that makes sense!

[vwdann0]

It gives you more tuning options if you are running a larger turbo. The OEM configuration is called a return-less system. What that means is that the fuel pressure is presented at a constant pressure. The pressure is regulated by a non-adjustable valve located in the fuel filter. Fuel is supplied at a constant 4-bar (58 psi) of pressure.

Return-less system.
With a normally aspirated engine this is pretty standard stuff. But it all changes when you add forced induction (turbo). At zero boost the injectors are supplying 58 psi to the intake manifold. Now add 20 psi of boost. The delta between the 58 psi from the injectors and the 20 psi of boost reduces the effective fuel pressure at the injectors to 38 psi. In order to account for this pressure differential the tuning maps have to increase the duty cycle (pulse frequency/duration) of the injectors to supply more fuel. This becomes increasingly more difficult as you increase the boost and fueling demands.

Return system.
When you go with a return type system you have control over the effective fuel pressure. The return system utilizes a rising rate fuel pressure regulator. The rising rate regulator maintains the effective fuel pressure by adjusting for the delta between the fuel pump pressure and manifold boost pressure. For example, if you are running 20 psi of boost the rising rate regulator adds 20 psi to the fuel pressure thus maintaining a constant effective pressure.

This gives you the ability to easily change the amount of fuel delivery over a much wider range without having to change the injector size or duty cycle. You simply increase or decrease the pressure offset from the rising rate fuel pressure regulator. Essentially it gives you more control over your fuel delivery without having to change the injectors or injector duty cycle.

I suspect one of the main reasons Audi/VW went to the return-less system is because of the ever increasing emissions regulations. The one advantage of a return-less system is that the overall fuel temperature remains lower and thus less emissions for the Evap system to deal with. A return-less system is a one way path to the injectors. A return system is constantly circulating fuel from the gas tank to the rising rate regulator (located under the hood) and back to the fuel tank. This increases the overall fuel temperature and thus the associated hydrocarbon emissions that need to be dealt with.


Hope that makes sense!

Thanks for the insight

[Kodymfk]

Haven't had a chance to make a diagram really. Still waiting on buddy to come up with extra funds so we can convert his stock block stage 3 setup (Kraftwerk turbo TM5+ kit) to e85 in hopes to find the maximum stock block power on e85. We are planning to come up with a cost efficient setup for return style conversion/e85 on stock block along with adding a 3 bar map sensor. This is a huge plus for stage 3 guys on stock block looking for a few more pounds of boost and hp's without building a block or breaking the bank. Vtraudt and I are working on this, the goal is to see how many more hp's can we squeeze out while not breaking the bank and keeping all stock safety features in play. This means you'll be able to run e85 hassle free, winter or summer with no tune adjustments needed after initial tuning. You will be capable of running ethanol mixes as low as e70 (winter formula) and e85+ (summer mix). I've been driving my A4 problem free with no issues on the same tune that I was tuned for in the summer. Here is a pic of my upgraded turbo setup since last summer. I still occasionally drive her in the winter but nothing beats driving a nice and comfy allroad in the winter cold months (gotta love heated steering wheel lol) to and from work.

[B6A4Dave]

4x-straight hose end adapters with female ends. # 555-11001 (Jegs)

part number brings up "JEGS Performance Products 11001 - JEGS Ignition and Switch Panels"

Can you double check that for us? as well as updated parts list / diagram?

Im very interested in doing this for my BT Built..pricing it all out.

Awesome thread man!!! Ive been needing to go Return fuel for a while and given the new build..its a must!

Where did you source the sleeves for the Wally pump? any modifications needed to the pump hanger? hat? etc.

[Mr. Wolfsberg]

Also I'm pretty sure I know what your referring to when you say fuel hat but just to verify could you point out in a picture what your referencing, thanks

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[Mr. Wolfsberg]

Also I just wanted to say I found anfittingsdirect.com is a good place for inexpensive E85 compatible hose, its only $3.50 per foot, and they have AN fittings (go figure), silicone adaptors, intercoolers and other stuff for great prices. I'll let you know the quality of everything when it shows up.

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[Mr. Wolfsberg]

part number brings up "JEGS Performance Products 11001 - JEGS Ignition and Switch Panels"

Can you double check that for us? as well as updated parts list / diagram?

Im very interested in doing this for my BT Built..pricing it all out.

Awesome thread man!!! Ive been needing to go Return fuel for a while and given the new build..its a must!

Where did you source the sleeves for the Wally pump? any modifications needed to the pump hanger? hat? etc.

I looked on JEGS and the part number for those straight female an fittings is 555-110001.

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[B6A4Dave]

Also I just wanted to say I found anfittingsdirect.com is a good place for inexpensive E85 compatible hose, its only $3.50 per foot, and they have AN fittings (go figure), silicone adaptors, intercoolers and other stuff for great prices. I'll let you know the quality of everything when it shows up.

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I looked on JEGS and the part number for those straight female an fittings is 555-110001.

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props to you sir!!!! The line was one of the most expensive parts!

Have you used their products before? Quality?

[Mr. Wolfsberg]

No I haven't but I figure for $70 I can give it a try, they list exactly what their line is made with, has a PTFE inside lining which they state has an identical chemical composition as Teflon but can't call it Teflon as its trademarked by DuPont. Also I also found Jegs has Aeromotive 340 Stealth fuel pump kits for $113 shipped that are E85 compatible!

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[Mr. Wolfsberg]

Sorry for the crappy cell pictures





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[B6A4Dave]

No I haven't but I figure for $70 I can give it a try, they list exactly what their line is made with, has a PTFE inside lining which they state has an identical chemical composition as Teflon but can't call it Teflon as its trademarked by DuPont. Also I also found Jegs has Aeromotive 340 Stealth fuel pump kits for $113 shipped that are E85 compatible!
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I've had bad luck with the Aero 340 pumps... Ran 2 of them on a Full-Blown hanger on a 1000whp Integra..

They get pretty damn hot and dont do that well.... I'd rather get a big wally.


$95 on Amazon - http://www.amazon.com/Walbro-F900002.../dp/B0085ECSIU

[Mr. Wolfsberg]

I've had bad luck with the Aero 340 pumps... Ran 2 of them on a Full-Blown hanger on a 1000whp Integra..

They get pretty damn hot and dont do that well.... I'd rather get a big wally.


$95 on Amazon - http://www.amazon.com/Walbro-F900002.../dp/B0085ECSIU

Wtf?! A walbro is what I was initially looking for but the cheapest one I could find before was about $185 so thankyou goodsir! Glad I didn't click buy yet on the jegs lol.

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[Mr. Wolfsberg]

very bad with photo shop and other diagram making programs and such will give it a shot. Any good programs to try doing it with? Paint?

My apologies if I screwed this diagram up Kody but please correct anywhere I may have screwed up this system.

[B6A4Dave]

Im interested in fitting of the pump into the stock basket...

Did you have to get an adapter like the 034 one? (https://store.034motorsport.com/bill...osch-60mm.html)

Or did the Wally pump just fit right in? I see you used the 2 sleeves, but what are they? where did you source them?

Hoping to get some answers as I need to do this to my car very soon..

[B6A4Dave]

btw:

I'd assume the stuff Silicone Intakes gets is the same as ANFittingsDirect, and here is a good review a Subaru guy did on the difference in quality between legit earls or russells and SI/ ANFD

http://forums.nasioc.com/forums/show....php?t=2236246

[Mr. Wolfsberg]

Got my line and stuff in, actually came quicker than some Amazon stuff I ordered. Line looks line good stuff. Actually feels like it has a silicone coating over the steel braid