Upgraded fuel rails / lines. When do i need them?

[Ronny_Nordstrom]

SO i am building my engine from bottom to the top, JE pistons, FCP rods, U&L Girdle, 2.5 tdi v6 oilpump, modded rs6 turbos, injectors and E85 tune later in the summer.

When do i need to change out our stock s4 fuel rails for like IE or 034 rails and upgraded fuel regulator? Would love to hear more about this fuel upgrade and what all need to be done beside swaping rails.
Will be running single HELLCAT LPFP.

Aiming for 700-750hp

[S4James]

you dont need em.

[vavJETTAw36]

I went lean and burned up an engine at 600whp with a 525 on e85. The factory lines are not up to the task from my experience. It was pretty obvious In my logs the pump couldnt maintain pressure but I killed the motor before I got to upgrading lines.

If I were you I would 100% upgrade the lines.


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[VR6Bomber]

Why would you not?

[RMode]

Your regulator will need to be changed, as the stock one cannot bypass enough fuel from that pump. As a result, base pressure jumps up, which then can make tuning things a little more of a headache than needed. A stock ecu appreciates a fairly narrow range of base fuel pressure.

As far as the lines, they are 8mm stock. Whether or not that is enough depends on a lot of factors.

The way to know if the line is sufficient size, is measuring fuel pressure post rail, with a pump that you know is sufficient. So on yours, we know your pump is sufficient. Remember to wire it correctly, so you're actually getting what it can put out. From there, you would want to monitor fuel pressure at the end of the rail (where the stock regulator is) via an external sensor, and log it. If pressure drops as boost and rpm increase, you know the line is insufficient. This also will vary depending on the fuel you're using (E85, Methanol, Petrol), and altitude.

Many upgrade rails at lower power than yours because it's relatively easy, not tremendously expensive, and for aesthetics.

[CELison]

I ran stock lines to the firewall. Then -6an in parallel to 034 rails with an A1000 fpr. Pretty easy and simple set up.

[vavJETTAw36]

I ran stock lines to the firewall. Then -6an in parallel to 034 rails with an A1000 fpr. Pretty easy and simple set up.

What do you mean you ran stock lines to the firewall? You mean from the firewall to the rails?


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[RMode]

What do you mean you ran stock lines to the firewall? You mean from the firewall to the rails?


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Stock from the tank to the firewall, then converted to -6 to to feed the rails

[CELison]

What do you mean you ran stock lines to the firewall? You mean from the firewall to the rails?


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From the tank to the firewall. More clearly stated: I didn't touch anything from the pump to the firewall.

[slow ride]

I'm just going to mod the stock rail to be dual pass with a single return out to a aftermarket regulator and stock lines. Helps keep the rail balanced at higher flow and the aftermarket regulator can deal with the larger pumps at idle etc.

[Ronny_Nordstrom]

I ran stock lines to the firewall. Then -6an in parallel to 034 rails with an A1000 fpr. Pretty easy and simple set up.

So i can remove the stock one and install a A1000 FPR before the rails and be fine?

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I went lean and burned up an engine at 600whp with a 525 on e85. The factory lines are not up to the task from my experience. It was pretty obvious In my logs the pump couldnt maintain pressure but I killed the motor before I got to upgrading lines.

If I were you I would 100% upgrade the lines.


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So i guess this is a MOST then for me.

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From the tank to the firewall. More clearly stated: I didn't touch anything from the pump to the firewall.

you have any pictures of your setup?

[CELison]

So i can remove the stock one and install a A1000 FPR before the rails and be fine?

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So i guess this is a MOST then for me.

- - - Updated - - -



you have any pictures of your setup?

No, FPR goes after the rails, not before. And you can't use that FPR with stock lines. I ran my own fuel lines from the firewall, to the motor, then back to the firewall.

[Ronny_Nordstrom]

No, FPR goes after the rails, not before. And you can't use that FPR with stock lines. I ran my own fuel lines from the firewall, to the motor, then back to the firewall.

yeah sry meant after. Can't i make a adapter so i can connect the stock lines on the firewall and after that to AN line and fitting that goes to FPR and rails ( 034, IE, etc ) stock lines should be fine from tank to firewall.

[CELison]

yeah sry meant after. Can't i make a adapter so i can connect the stock lines on the firewall and after that to AN line and fitting that goes to FPR and rails ( 034, IE, etc ) stock lines should be fine from tank to firewall.

Yes, Sorry I thought you wanted to just swap an A1000 in. I run aeroquip -6an lines. So a line from the firewall that goes under the manifold (heat wrapped). There is a Y under the manifold and both lines poke out be the TB where they meet 034 rails. Once the lines exit the rails they go straight through the firewall (cut 2 holes w/ grommets) and then Y back into 1 where the AC lines used to go through. Then that one line goes to the FPR. After the FPR I have an E% sensor then back to the factory lines at the firewall.

[Ronny_Nordstrom]

Yes, Sorry I thought you wanted to just swap an A1000 in. I run aeroquip -6an lines. So a line from the firewall that goes under the manifold (heat wrapped). There is a Y under the manifold and both lines poke out be the TB where they meet 034 rails. Once the lines exit the rails they go straight through the firewall (cut 2 holes w/ grommets) and then Y back into 1 where the AC lines used to go through. Then that one line goes to the FPR. After the FPR I have an E% sensor then back to the factory lines at the firewall.

will have to keep this in mind when i get to do my lines.