jasonius

iTrader: (1)

May sound like a silly question, but can the flow direction be reversed throught the fuel rails..? (05 WRX) Obviously oem reg. would need replacing (SX awaiting fitment..!)

I'm planning on doing the parellel feed mod and it strikes me that if the flow can be reversed through the o/s fuel rail most of the oem fuel pipe under manifold can be used. Just a case of a couple of 'T' pieces, short amount of additional fuel hose and a little re-plumbing..!

Am I talking utter b@llocks, if not it has to be the easiest method of doing this mod..!

FB Tuning

iTrader: (30)

If you're converting to a parallel feed, then it doesn't make any difference which way the fuel flows through each bank, as long as you position the fpr at the end of the run.

If you are fitting an aftermarket reg (and 90 degree elbow in place of the standard regulator) then you can keep the standard series setup, and still run the fuel through in the reverse direction.

360ste

iTrader: (1)

Saw an article similar, it was saying rather than fit a parrallel setup to improve the fuel dist to pot 3. Just reverse the feed and return lines when fitting a after market regulator thus putting pot 3 at the start of the supply. So hopefully reducing the risk of piston melt due to excess heat and reduced fuel supply. Not tried yet anyone done it and got comments? See this thread and yes I was pi$$£d when I started it
http://bbs.scoobynet.co.uk/showthrea...highlight=fuel

p1mark

360ste you are referring to a classic set up, and Jasonius has an 05. Subaru have reversed it themselves for later cars. I have reversed it on my classic, just swapped the pipes over.

fujack103

If theres anyone in the know then help me out with this plz

https://www.scoobynet.com/general-technical-10/507921-just-a-bit-of-advise-plz.html

DaveW

But if you reverse the flow then surely the last one in the line can still run lean?

p1mark

Yes of course, i think that the general theory is feed no,3 first as thats the troublesome cylinder (close to turbo/crank oil feed last etc, as well as last in fuel run)

jasonius

iTrader: (1)

So the oem reg. would be ok left in place (albeit with flow going through it reversed)..?

P1mark; IIRC the fuel flow on my 05 WRX is 4-1-3-2 (nsr-nsf-osr-osf) oem reg at the front of o/s bank (ie after #2).

I know the newage STi has the reg. on the rear of the n/s bank, does this mean the supply is different to the wrx or just that the reg. in a different location..?

Finally, how important is it to keep hoses/pipes equal length..? If it is an important issue then my idea of utilising the original pipework (reversed) is a no a brainer..!

DaveW

The route for fuel is:

From tank - fuel pump - filter - rails (either single or parallel) - regulator - return to tank.

Keep to that and you'll be ok, so if you are running the oem reg then you'll need to move it so its the last thing before the return to the tank.

And it probably is worth making the fuel lines the same length in a parallel conversion, although it can't be that important as just look at what you have at the moment.

I'm getting another set of rails and cutting them up and using hose to link them up in parallel, it will mean removing the manifold but I need to do that anyway.

fujack103

Im feeding the rails from both ends. So i need to have another fitting drilled in that manifold i got made and fit the pressure regulator/return hose to it? I was just thinking if i T'ed into the supply hose it should maintain the desired pressure to the rails. On some new cars the regs in the fuel filter by the tank.

jasonius

iTrader: (1)

Have you removed a manifold before..? I've got injectors to swap so I really could do with removing mine. Just wondered how much of a job it is..?

BTW is you car a newage (sti or wrx)..?

fujack103

You dont have to remove the manifold just remove the small bolts that hold the injectors in?

Bob Rawle

You can't run through the reg in reverse, you need to remove the factory reg and use an open adaptor then use the sx on the flow pipe entry and connect the tank feed to the old return point. better than std. On a GC8 it makes a huge difference, not so much on a GDA/GDB.

bob

DaveW

Cheers Bob, nice to know.

Never removed a manifold before, only doing mine to fit a freshly painted one and do the fuel rails.