Fuel Damper Valve Needed?

[ascianna]

Went to hook up my fuel lines today and noticed a fuel damper valve on my donor engine's previous inlet fuel line....do I need to keep this?

[Quiny]

I kept mine, figured it couldn't hurt. They use it for some reason and chances are that reason still exists.

[Bob_n_Cincy]

Mine was in the fuel tank on the 04FXT. I kept it there.
Bob
P1050087s4.jpg

[metalmaker12]

With stock pump yeah why not, with upgraded pump I would say not needed.

Ps on upgraded pumps, the stock fuel controller will limit voltage to much to get the more powerful pumps to do there job. This is when you just hard wire the pump to a relay and call it a day.

[Quiny]

I went with the Boyd tank and the pump they provided, I assume it's considered an upgraded pump. I also did keep the fuel pump controller. I am now curious about fuel pressure. I will do some testing after I finish mounting body panels.

[wleehendrick]

Quiny, please keep me posted on what you learn. I just started on wiring and would like to know whats best. The instructions for the Aeromotive 340 pump in the Boyd tank are generic, and say to use a relay with either 12V or the vehicle harness supply. Given that this pump can support 2-3X the flow required for a typical EJ, its propbably not an issue, but it would be nice to verify.

[Buzz Skyline]

It was on the fuel line going to the engine? Or the return line? I didn't put mine on yet, but I've found a few accounts of engine failure that could be due to pressure variations in fuel lines. So I want to make sure I put mine back in at the right place.

[Bob_n_Cincy]

It was on the fuel line going to the engine? Or the return line? I didn't put mine on yet, but I've found a few accounts of engine failure that could be due to pressure variations in fuel lines. So I want to make sure I put mine back in at the right place.

The Fuel pressure damper goes in the pressure line going to the engine. My 04FXT had it in the tank right after the pump. My 06NA and 07NA impreza has it on the left front fender right before the engine.
Bob

[Mechie3]

My 06 came with one on the return and feed lines.

[taco20]

Hey Wleehendrick the stock fuel controller cannot handle the Aeromotive pump. The one from my 05 Sti couldn't handle the pump and pulled back fuel pressure. Was fine at startup but once warm pulled voltage to the pump and pressure would drop to low. I bypassed the fuel controller and used the stock fuel pump relay and all went back to normal. I even removed the fuel controller and got no codes or issues. Good luck with your wiring.

[Quiny]

Quiny, please keep me posted on what you learn. I just started on wiring and would like to know whats best. The instructions for the Aeromotive 340 pump in the Boyd tank are generic, and say to use a relay with either 12V or the vehicle harness supply. Given that this pump can support 2-3X the flow required for a typical EJ, its propbably not an issue, but it would be nice to verify.

I will let you know, I can say that it seemed ok during the gokart. I haven't looked into it yet but would removing the pump controller remove the pump shutdown during key-on engine-off? I like the fact that I can leave the key on without the pump humming away.

[gwarden]

Hey Wleehendrick the stock fuel controller cannot handle the Aeromotive pump. The one from my 05 Sti couldn't handle the pump and pulled back fuel pressure. Was fine at startup but once warm pulled voltage to the pump and pressure would drop to low. I bypassed the fuel controller and used the stock fuel pump relay and all went back to normal. I even removed the fuel controller and got no codes or issues. Good luck with your wiring.

Wish you told me this yesterday before I wired in the fuel controller

[wleehendrick]

Hey Wleehendrick the stock fuel controller cannot handle the Aeromotive pump. The one from my 05 Sti couldn't handle the pump and pulled back fuel pressure. Was fine at startup but once warm pulled voltage to the pump and pressure would drop to low. I bypassed the fuel controller and used the stock fuel pump relay and all went back to normal. I even removed the fuel controller and got no codes or issues. Good luck with your wiring.

Good to know; thanks for the info, taco!

[Scargo]

I cannot speak to a stock setup and I can only speak of my personal experiences. I have done a lot of reading about the damper and find it inconclusive or not applicable in my case.
Track only STi: I have a Walbro 255 in-tank pump feeding ID 1000's. I have opened up the fuel supply where it's all 5/16" ID or better and AN-6 fittings and lines. I run Boomba manifold and rails. Aeromotive adjustable and variable fuel pressure regulator. No dampers. My initial fuel pressure is 37 PSI. With this setup I've made reliable 376 AWD HP on pump gas. I'm in EFI's dyno database.
I would ditch the stock metal fuel lines before I'd be worrying about the dampers if you're doing mods to make decent power.
Glyn

[Buzz Skyline]

After hunting around a bit and looking at the diagrams for Subaru parts dealers (parts.subaru.com), it looks like the 2002-2004 WRX only has a damper on the fuel return line. Others have them on both, or have one in the gas tank in line with the fuel pump.