Parallel Fuel Rails
 

Before I get a remap it has been suggested that I should get a parallel fuel rail kit to prevent cylinder 3 running lean. I'm looking at a VF34 with supporting mods, so around 350bhp.

Question is, what do I need:

Rails, fuel line and FPR. What's the difference between something like these http://www.ebay.co.uk/itm/HIGH-FLOW-...item51a511d793 and a £250 set from Carl Davey or RCM? How much fuel line do I need? What other bits are requires - FPR adaptor, t-pieces etc.

Cheers

Jon

Hi Jon

Cheaper rails people used before and they're been OK with them(have look or search over 22b)

You should be OK with running yours without the Parallel rails,we run VF34 without the parallel rails and we are been fine without them

Main thing to what I would invest more is good FPR(Fuelab) and good AN fittings,not sure how much fuel lines you will need,but I would have look on the Teflon fuel lines

Have look on this older thread

https://www.scoobynet.com/general-te...-fuel-mod.html

Jura

I haven't gone parallel fuel rails at 400 I wouldn't worry about doing it at 350. I been fine for 2 odd years at that.

I've got a SARD FPR on it's way (and no not a £30 ebay genuine "honest guvnor" jobbie) with the adaptor and gauge. It's also been suggested that there's a DIY option using the existing rails which I'm looking in to.

If it's simple, cheap and makes sense to do while the car is coming apart then I don't see any harm in doing it:norty:

If you've upgraded your pump then I would recommend a proper Fuel pressure regulator. I had the OE reg fail and lost an engine as a result.

Every engine I've built since has had parallel rails and an aftermarket FPR. Stay away from the FSE regulators they are shoite!

I used to rate FSE and have heard that they are fine for non-turbo cars but not for anything with a blower. I've bought a SARD one and have the walbro fitted already. I'm running 95% duty on the WRX injectors so th pinks are a must for the next stage:thumb:

Anyone know where there's a how-to on modifying your own fuel rail to take parallel feeds?

Is that it? :wonder:

All or nothing, 100% duty on my 380's. :D

Not samiliar with Newage rails, you got a pic, Jon?

On some it's not really DIY, as you need to weld/braze the fittings onto the end of the rails. Early rails, which won't fit your manifold are easy, just buy these. http://www.ebay.co.uk/itm/170797661152

Does Carl not do a conversion to fit early rails to Ph2 manifolds?

This is the best image I can find which isn't very good:(

http://i.ebayimg.com/t/SUBARU-IMPREZ...rZQ~~60_35.JPG

I've sussed it though I think - I need to cut the three metal pipes going to te rails and flare the ends. Then remove the FPR and replace it with an adaptor that provides the fourth hose join. Then add a SARD FPR and some fuel hose, a couple of t-pieces and plumb it all back together.

The classic fuel rails are much easier to do as they have the removable ends that you can then change for flanged pipes or AN fittings. I could change everything, fit billet rails and add AN fittings - whilst it would look top dollar there's no real improvement for the stage of tune I'll be entering. The parallel fuel rail mod is only a safety precaution and probably not completely necessary but as the inlet is coming off I may as well do it.

My brain hurts :freak3:

So did mine until I sat down and worked through it...

Lol, thanks, I need to go down this route as well.

Just putting together my shopping list now:thumb:

Keep us updated Jon. What fuel filters are people using?

I'm currently planning to retain the OE filter as it's new but I might change for an in-line facet or similar when it's time to change, need to get my Merlin Motorsport catalogue out:wonder:

Hi Jon

When you are thinking go with aftermarket fuel filter,have look on OE Filters with the AN fittings(they cost around £30)

About the fuel rails,depends on you,I would go with those above posted rails,they should be OK(people used them without the problem,although people used JAWarehouse something like those http://stores.ebay.co.uk/JAWarehouse..._sid=155562105 )

Jura

Hey Jura - I'm converting the OE fuel rails and not going for set of billet ones. That means I'll keep the push fittings rather than convert to AN fittings which will keep it simple - the change of fuel filter will purely be to make the fuel line runs a bit more ergonomic if the change leaves them tight under them FMIC pipework.

just done my fuel setup. went with cdf racing fuel rails (excellent service by chris) roger clark fuel pipes and fittings and a fuel lab fpr.

Been looking through some stuff whilst deleting more lugs from my inlet. I was going to do an evap circuit delete anyway but looking at the circuit in the picture attached there's a feed to an evap pipe that will be removed when I do that parallel fuel lines. Looking at the diagram I working on the principle that as long as I delete and block all of the lugs and get the fault code switched off as part of the mapping this is not required. Am I missing something and apart from emissions control does this circuit affect how the car will run.

Also, once this has gone I understand I can remove the charcoal cannister that's under the boot - what else can I remove?

Is this a good start?

http://www.ebay.co.uk/itm/Impreza-hi...vip=true&rt=nc

Hi Jon, Im considering the same. I'm going to an 18G from a standard vf35 but am considering whether I should either go with a fpr or uprated injectors, have 550 as standard.

I'm sure mines would be fine but would like to prevent maxing them out hence I go with one of the options above. I could get lateral to match and re-flow my 550's but to get the biggest bang for my buck from the turbo I will need to make sure sufficient fuel is supplied. My dilemma is whether I get get an fpr or get mines re-flowed. desicions decision

good to know the FSE fpr are to be avoided, what about the Sytec, Sard, Automotive, turbosmart or fuel lab (being the best) although surely they effectively do the same.

550s should be fine with an 18G, as for a FPR - I found a seller on ebay doing genuine sards complete with a gauge and the impreza fuel rail adaptor for £120. I did the checks when it arrived to make sure it wasn't a fake and it all looks good:thumb:

Is it fair to say you can fit a fpr without fitting parallel fuel rails. Sounds as if it is possible and something Jon is planning to do as long as you modify the existing fuel lines.

Am I correct in this statement.

Yes you can fit a FPR without parallel fuel rails - you already have a FPR in the system so all you are doing is uprating it to increase the extant pressure.

I'm going to modify my fuel rails to make the subaru serial set-up a parallel set-up rather than buy some of the blinged up stuff in the first link. You don't need to do this, but when I do I'll write up a how to so anyone can copy - it might be a few weeks though.

This is the jobbie I bought:thumb:

http://www.ebay.co.uk/itm/320914949467

But be quick, it's the last one:norty:

i bought the last one. it was the seller i found early on mate. I hope its the correct device and exactly whats needed for my application. It wont be going on the car for awhile as turbo is on order which will take a week to arrive still.

Thanks for the info - look forward to you convertering your fuel rails to parrallel. whats the reason for going parrallel over direct fpr swap out only

It's a safety precaution and not necessarily needed at VF34/18G power levels. On the current system cylinder 3 is at the end of the fuel loop and also runs hottest being nearest the turbo. That makes it most likely to suffer det is which not good, but it the chances are slim.

As I'm stripping the inlet manifold off anyway it was logical to make the change, but it's a lot of work if you're not planning to remove the inlet.

I'm watching this thread with interest. These arrived this week....

Attachment 58171

sorry to jump in guys, as you lot know about this subject would a td06 20g turbo be to much for my99 uk 2000 injectors,the car it took the turbo off had the same setup as mine (but mines a td04 16g at mo)

just see this also , says double your money back :
http://www.ebay.co.uk/itm/100-Genuin...20914949467%26