Another fuel return conversion thread

[cmiguel32]

So I've been doing some research on converting to a return style fuel system, however, most of the information I've found doesn't address converting to a return system while using a surge tank. I'm looking to relocate my battery to the trunk and install an IE dual 044 pump surge tank in that spot (with IE fuel rail and FPR in the system).

Overkill, I know.. but I plan to run UM's 1200cc injectors and E85 on my soon-to-come big turbo and it seems like this will solve my fueling needs.

My plan is:

Run new -6AN line from stock in-tank pump to surge tank as low pressure feed (use aftermarket in-line filter)
Repurpose stock fuel feed line and use it as a return line from the surge tank to the 2nd gas tank
Eliminate EVAP line (that ran to the factory fuel filter)

My concern has to do with the suction system that works between the primary and secondary gas tanks. Since the surge tank's return line will be going to the secondary fuel tank, will I run into the same suction system issues as folks that just do a standard return system? Am I going to run into the issue of running out gas when the tank reads 1/4?

Primarily I've looked at the following two threads:
Thread 1
Thread 2

Any advice here would be greatly appreciated!

[cmiguel32]

*crickets*

[blitz2190]

just hook the the new return line to the one that went from the tank to the filter(old return line), that way it will still balance the tanks with the suction jet pump in the tank. That what I did with my 2.7 swap and it worked just fine.

[cmiguel32]

Thanks!

[Br337]

Works great




Sent from my iPhone using Audizine

[cmiguel32]

Works great




Sent from my iPhone using Audizine

Lookin good!

[ADCS]

Also, you should grab the passenger side tank cap, where the pump sits, from an early return style 3.0 in order to cleanly eliminate the extra vent port the 1.8t has. You will only have 2 ports that way (feed + return) instead of 3 and having to plug the 3rd one.

[cmiguel32]

Also, you should grab the passenger side tank cap, where the pump sits, from an early return style 3.0 in order to cleanly eliminate the extra vent port the 1.8t has. You will only have 2 ports that way (feed + return) instead of 3 and having to plug the 3rd one.

Yeah-- reading my mind! Just found a pump assembly/cap from a 3.0 on wolf auto parts.

[cmiguel32]

So to mimic Clint's diagram from the above quoted thread, this is how it would look:



I think I could get away with using these fittings on the stock feed/return lines from the gas tank and then use braided line for the rest of the set up.

And then run one of these Fuel filters

[ADCS]

Yes, those are the fittings I used. Quick and you don't have to hack the OE lines.

You can also get those EFI quick conects from Summit Racing (where I bought them) or even Amazon. Russell EFI fittings. 5/16 is the size you want for the OE fittings.

[cmiguel32]

Yes, those are the fittings I used. Quick and you don't have to hack the OE lines.

You can also get those EFI quick conects from Summit Racing (where I bought them) or even Amazon. Russell EFI fittings. 5/16 is the size you want for the OE fittings.

Thanks! Definitely more economical going that route. Ordered all the fittings and line I need.

I'm trying to devise/implement some kind of mechanism that would allow me to easily drain the surge tank for switching between 93 octane and E85. I imagine it would also include some kind of switch that would allow me to run the factory in-tank **now lift pump** (without turning on the surge tank pumps) to fill the surge tank (after emptying old fuel) with new fuel.

[Seerlah]

Do a by pass line before the surge tank, and comes back in right after. May be the simplest way to go about it. Open bypass line to just use pump in tank. Close for e85 and surge tank use. Now creativity comes into play on location of parts for easy access, mechanical bypass valves, triggered valve via switched relay, switched relay for surge tank pumps, etc. This is modding to me, and where the real creativity comes out

This is how I drain my fuel tank, in case you want to maybe incorporate this trick into your design. This will allow you to drain your whole tank, while your concern before was just the surge tank. If relay is in the closed position with power to the pump, the fuel will just keep flowing.

[cmiguel32]

Do a by pass line before the surge tank, and comes back in right after. May be the simplest way to go about it. Open bypass line to just use pump in tank. Close for e85 and surge tank use. Now creativity comes into play on location of parts for easy access, mechanical bypass valves, triggered valve via switched relay, switched relay for surge tank pumps, etc. This is modding to me, and where the real creativity comes out

Didn't think of that. My 93 tune will require a high flow pump and I was avoiding upgrading the in-tank pump in favor of two high flow pumps in the surge tank (plenty of headroom).

Another thought is having both fuel pump relays on switches. Ignition obviously primes the in tank pump (now lift pump) which would begin to fill the surge tank. To empty the surge tank I would think you could "switch" off the lift pump and run the car at idle for X number of minutes to deplete the fuel in the surge tank. Obviously some accurate calculations would be required, unless there's a way to install some kind of floater and gauge system for the surge tank.

[Seerlah]

Check out my edit

Too tired in the morning to give your post thought. Because it would actually require thinking. Hahaha. I'll. Check it tomorrow. But obviously the main ignition switch would still trigger the tank pump. And for 93 octane, you would only need that. I would personally try and use one relay double pole for the surge tank pumps and bypass valves via in cabin switch. But have a mechanical overide back up ready for the surge tank incorporated in case of electrical failure via relay. Hope that makes sense!

[cmiguel32]

Check out my edit

Brilliant! I'd just have to modify so that I can run just the surge tank pumps independent of the in-tank. That seems like the easiest solution. E85 is fairly accessible around me so really I'll be draining the fuel tank twice a year-- when low temps drop below 50 degrees and when they get above 50 degrees.

[Seerlah]

And another edit

I'm confident you have the creativity to design a system. Just gave some ideas, and you can figure the rest. Be sure to post up the end result!

[Seerlah]

Actually comprehended what you had in mind. My advice is to combine all posts in this thread so far to design, sharpen, and manifest a suitable fuel system that you already have in mind. You have a well grounded starting point in just a few posts by just a few contributers. Now just improve on our ideas and ask questions along the way...because anyone can improve on an idea (ie lurker...like I just did).

[BumblebVR6]

Any reason you're using a dual pump surge tank vs. a single? Looks like the 044 pump can support 600hp and the AEM 380 will support 800hp. I see you're using the F21 kit. Planning on pushing the car higher than those numbers? Thanks for the info Chris. I'm sure all this information will be of great use to many in the future.

[cmiguel32]

Any reason you're using a dual pump surge tank vs. a single? Looks like the 044 pump can support 600hp and the AEM 380 will support 800hp. I see you're using the F21 kit. Planning on pushing the car higher than those numbers? Thanks for the info Chris. I'm sure all this information will be of great use to many in the future.

Yeah the F21 is going to be very temporary. I've been learning a lot about this platform as the build progresses and I do hope others can benefit from the knowledge/posts!

I plan to run an EFR7064 on E85 at 30+ psi. I'm pretty sure fueling needs will exceed the limits of 1 pump.

[BumblebVR6]

Yeah the F21 is going to be very temporary. I've been learning a lot about this platform as the build progresses and I do hope others can benefit from the knowledge/posts!

I plan to run an EFR7064 on E85 at 30+ psi. I'm pretty sure fueling needs will exceed the limits of 1 pump.

That is a 350-560 hp capable turbo. If you run the single tank with the AEM pump (good for 800 hp) you shouldn't have any issues from what I'm reading. Even the Bosch 044 will support 600. And these would be extreme cases "if" the car was on a track with extreme G forces applied. The in-tank pump should be able to compensate and keep the surge tank full even in these extreme conditions. Again, just going off of what I've read. Looking forward to seeing the progress on your build!

[Seerlah]

This is what I am thinking. One of these valves off a 3 way -6an tee for the 93 oct bypass line. Then a -6an check valve on the other end of the -6an on another 3 way tee as it comes back in to the other side of the bypass (Fragola fan).

http://www.google.com/search?client=...56.Rpco3pCUrPk

Simplicity, then an electronic cutoff switch for the surge tank pumps. This will allow you to run just the tank pump when running 93. For electrical wiring, safest to run 3 separate relays for each pump. Have the coil circuit for the sump pumps go through a switch (double pole) and that easily turns off the surge tank pumps.

Remember to pick up e85 compatible pumps. Once again, throwing out ideas. But I like this stuff and this is route I would have taken if it were me.

[Seerlah]

That is a 350-560 hp capable turbo. If you run the single tank with the AEM pump (good for 800 hp) you shouldn't have any issues from what I'm reading. Even the Bosch 044 will support 600. And these would be extreme cases "if" the car was on a track with extreme G forces applied. The in-tank pump should be able to compensate and keep the surge tank full even in these extreme conditions. Again, just going off of what I've read. Looking forward to seeing the progress on your build!

You are right. Ample lines and something like the Walbro 450 should suffice. But I have been wrong many times before, so I don't know for certain!

[blitz2190]

the aem says it will support 700hp at the pressure your looking at on e85, like Seerlah said all you need is the right size line.

[AudiA4_20T]

Props for the MS paint skillz

[Seerlah]

I plan to swap to e85 too and run the Walbro 450. That is why I suggest it so many times. lol

What I picked up so far. Need regulator, a couple more fittings, lines to tank, and actual pump. And wiring kit for 10 gauge to pump. Currently running the atp setup with afpr on atp adapter. 034 gave me their rail and rail adapter for the stock fpr for $80. Not going to disclose why, but kind deeds go a long way. E85 pump like 3 minutes from my house.

[cmiguel32]

Thanks for all of the responses, guys.

This has given me a lot to chew on. The idea of using pumps that aren't rated for E85 is definitely a concern. The Walbro 450 seems like a good option for a 93 tune, just not sure about E85. I always like to err on the side of caution and would rather have way more headroom than necessary. At any rate, it seems like running straight braided lines for send and return from the tanks (in tank and surge) to the rail and back is a prudent idea.

[cmiguel32]

Props for the MS paint skillz

Google drawings actually, though I honed my paint skillz on Windows 3.0

[Seerlah]

The Walbro 450 was designed for e85.

http://walbrofuelpumps.com/walbro-f9...-fuel-pump-e85

[cmiguel32]

The Walbro 450 was designed for e85.

http://walbrofuelpumps.com/walbro-f9...-fuel-pump-e85

I misspoke. I meant for volume to support 30% more fueling for an e85 tune.

[Seerlah]

One way to find out (amongst others). I plan on cracking 400whp, so I'm thinking 1000cc can get me there. One pump from tank with -6an line. Actually should fpr shop.

What fuel pressure regulator were you planning to run?

[cmiguel32]

One way to find out (amongst others). I plan on cracking 400whp, so I'm thinking 1000cc can get me there. One pump from tank with -6an line. Actually should fpr shop.

What fuel pressure regulator were you planning to run?

I've been looking at Aeromotive

Clicky

[Seerlah]

I've been looking at the 13129, myself. Any particular reason you are wanting the one in your link versus this cheaper one.

https://www.aeromotiveinc.com/produc...ass-regulator/

Aeromotive 13129 Fuel Pressure Regulator, Black and Silver Anodized. This is a new smaller body version of the 13109, it has the same basic specs and handles up to 1000hp. Two AN-6 o-ring inlets on the sides, one AN-6 o-ring outlet on the bottom, and an 1/8" NPT fitting on the front. Can be used in a single or dual feed setup. Universal for fuel injected engines. Compatible with gasoline, alcohol, E85 and race gas. Comes with a universal bracket. No gauge or fittings are included. Adjustable for 30-70psi base fuel pressure, 1:1 rising rate.

[cmiguel32]

I've been looking at the 13129, myself. Any particular reason you are wanting the one in your link versus this cheaper one.

https://www.aeromotiveinc.com/produc...ass-regulator/

"alcohol compatible" which I would interpret as E85 too.

[Seerlah]

13129 should work fine. Bad business tactic to compete against themselves, so that is why I figured it is not listed in the description (quote above is from a different website and it says it is e85 compatible). I'll research more to be absolutely positive the 13129 is e85 compatible, and update (unless someone knows and wants to save me the trouble). Might as well save. These puppies are like $115 shipped brand new.

[cmiguel32]

13129 should work fine. Bad business tactic to compete against themselves, so that is why I figured it is not listed in the description. I'll research more to be absolutely positive the 13129 is e85 compatible, and update (unless someone knows and wants to save me the trouble). Might as well save. These puppies are like $115 shipped brand new.

Sounds good to me!
Found this company as an alternative to the IE surge tank. Allows use of the Walbro 450lph in a surge tank. Or dual AEM 320lph E85 pumps.

Clicky

[Seerlah]

I remember those. One of the best on the market. Before e85 blew up people used those for race fuel apps. IE can be a hit or miss. Gave up looking for it on my cell phone (waiting for new laptop in the mail), but thread in my section has guys rewelding the IE surge tank because of the thin walls and welds. He did not complain to IE, but fixed it himslf and kept it moving (recently).

I am fairly confident the 13129 will work with e85. I'll just email or call them to confirm. Any questions you want me to inquire about?

[cmiguel32]

I remember those. One of the best on the market. Before e85 blew up people used those for race fuel apps. IE can be a hit or miss. Gave up looking for it on my cell phone (waiting for new laptop in the mail), but thread in my section has guys rewelding the IE surge tank because of the thin walls and welds. He did not complain to IE, but fixed it himslf and kept it moving (recently).

I am fairly confident the 13129 will work with e85. I'll just email or call them to confirm. Any questions you want me to inquire about?

Just let me know if it's e85 compatible and I'll get one too!

The more I read about this radium surge tank and watch the installation videos, the more I'm inclined to go this route with the dual AEM e85 pumps. Should be plenty of flow and won't cost much more than a dual 044 IE set up. Furthermore, the entire setup would be compatible for e85.

[Seerlah]

044 pumps are not e85 compatible.

[cmiguel32]

044 pumps are not e85 compatible.

Exactly ;)

[Seerlah]

Try -6an from the pump to a high flow rail with return system, and pump of choice. I'm not dead set on the 450lph myself, but is praised highly among the b5 s4 people. Even when it comes to an updated version that had to deal with a pressure rating issue (learned in the b5 s4 section). If the aem is better, I'll run with that...depending on price

But if you don't have enough fueling then, it is at that point you look into a surge tank. But blitzb2190 says you should be able to handle 700 from the pump. But you will need to look at graphs with taking boost pressure, fuel pressure, and voltage drop to estimate true lph of your setup.