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Advice about deadhead fuel rails setup

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Hi there,

I look for change my fuel rails setup from parallel to deadhead in my impreza.

Any advice regarding the fluctuation of the fuel, and pressure changing in the rails when the injectors open or FPR adjust the pressure?

The last injector how is affected regarding the pressure change?

Where is the best place to place the pressure sensor for monitoring the pressure?

Put the FPR near fuel tank instead near manifold\rails can be a disadvantage?

Thanks for help


Is there a reason you want to convert to return-less? It's a little unusual to convert a turbo fuel system to return-less since the differential pressure across the injector is effectively reduced as boost increases which reduces the available fuel flow. However if you're going to go this way then I'd plumb the rails with a Y-piece feeding both rails. I'd then place the fuel pressure sensor on the end of one rail. Pressure in a closed system like this is considered to be constant however you can see some minor fluctuation as the injectors open and close and fuel in the rail is consumed and replenished. If you run the fuel into one rail and then across to the other you 'may' see some minor issues with the fuel flow available to the last injector and hence this cylinder could run leaner.

Hi Andre, the reason is I would have lee fuel hos and joint under my hood!

Ok for the Y, in my idea I think to do the same but I was wondering if can be right or non influence the system. I think using fuel damper, one per rail, can help about the fluctuation...but I dont have experience in this way because I ever used the parallel system.

If I run return-less, the pressure can be te same of a return system?

I'd recommend retaining the fuel dampers and you shouldn't have an issue. Changing to return-less to reduce fuel lines isn't something I'd personally consider but it's workable. You can set the base fuel pressure in the return-less system to whatever you want - It's common to be 4 bar but you could go higher. The factory system on the other hand will maintain 3 bar across the injector at all times. This means that if you go to a return-less system at 4 bar, by the time you exceed 1 bar boost you're differential fuel pressure will be less than what you'd have with the stock system.

I run a dead head system in my version 7 wrx. Only issue so far is too much fuel entering the cylinders during cranking probably because of the higher base pressure . Idle and full throttle seem to work as desired. Personally I don't like the idea of returning fuel to the tank.. imo all the fuel should be going into the engine rather than back to the fuel tank.

^ I guess? Returnless is certainly cleaner and can be awesome though if I'm having issues with fuel temperatures such as I've seen on some endurance cars (specifically rotary based) I'd much rather have a constant circulation of fuel to have access to 25-35 gallons of heat sink.

Uhm...I don't know how to do.

Maintain parallel fuel setup with in tank return

Change to returnless

As I write, I look for returnless for have less hose and joint around engine, but I want be sure that configuration is good like the typical configuration...