Confusing R34Gtt Fuel Rail Pics .

[discopotato03]

Hi all , as some know I'm interested in using top feed EV14 injectors in an R33 spec RB25DET and if at all possible using an OE R34 GTt fuel rail .

I have a couple of pics of Neo GTt rails but one has me a bit confused . The first shows the FPR up the front where the secont one has it mounted to a different separate section I've not seen before . It's a little hard to see but I think the user mounted one of those barb adapters in the usual FPR mount and has it now on the other bit . Can anyone used to playing with GTt rails see whats going on ? Also are all Neo fuel rails the same on Skylines and Stageas ?

Cheers Adrian .

[discopotato03]

Now really confused . I was looking for more pics and came across this thread which just happens to have pics of a Neo 25 in the FPR area .

http://zilvia.net/f/engine-tech/329467-neo-rb25-bogs-then-dies-im-about-shoot-myself.html

Am I looking at two FPRs because the two gadgets that look like them both have what looks like vacuum lines , do Neos have two rail outlets and regs to avoid boiling issues ?

Cheers A .

[scotty nm35]

There is only one FPR, the other one is a dampener I am fairly sure. No idea why they have vac lines going to the dampeners though. The VQ25det runs a very similar setup as the 34 neo's, other than being twin rails.

[GTSBoy]

(Some) dampeners need to be referenced to the signal pressure too.

[iruvyouskyrine]

Here is a screenshot from Nissan FAST of an RB25 NEO fuel rail setup, sorry for the shitty text but i was on a laptop and had to use the trackpad, but hey it works. I suspect i have a problem with my fuel rail as the hose that links the barb on the rear of the rail is not there to link it to the barb in the middle of the rail, will provide pictures tomorrow night.

[DVS JEZ]

Some rb20's have a pressure referenced dampner too

[discopotato03]

Yep thanks for that . Nissan must have thought they needed a damper on the supply and return sides . I've got some time off soon so will be chasing a complete Neo turbo fuel rail to work with .

Cheers Adrian .

[iruvyouskyrine]

On my Neo I don't think I have either of the fuel dampers at all? The fuel regulator is there but I cannot see any dampers. Would I still be fine to leave the dampers out, I don't think that aftermarket fuel rails have dampers so I'm thinking I should be fine to use it? For reference I am running a Walbro 400lph running straight off the battery.

Also in the second picture you can see the fuel line comes straight off the barb at the rear of the rail and runs down through the plenum runners. Shouldn't this run to the front of the rail and connect up slightly confused about it all. Might have to take the top of the plenum off and have a look, don't really want to though.

[WMDC35]

the fuel line has just had the pipe that runs to the front of the manifold removed

[discopotato03]

I managed to buy a Neo Turbo fuel rail yesterday so when I get SKs spare manifold and the injectors and colars I can make some progress .

I'm told R34 era Stagea engines and bits are more common here than R34 GTt parts which is handy .

Slightly OT but someone at JJ was telling me that Neo's are different to earlier RB25s in the cam change hydraulics , if someone was to plonk a Neo head on an earlier RB25 block are mods needed aside from pistons and comp ratios ? Only reason I ask is because if I ever had to rebuild my engine I'd consider using the later rods pistons and the Neo top end and inlet manifold - Neo wearing std engine number basically .

Cheers A .

[GTSBoy]

The actuator and so on are a bit different on the Neo, but I imagine the oil feed from the block is the same. Can't imagine why they'd change it.

[iruvyouskyrine]

On my Neo I don't think I have either of the fuel dampers at all? The fuel regulator is there but I cannot see any dampers. Would I still be fine to leave the dampers out, I don't think that aftermarket fuel rails have dampers so I'm thinking I should be fine to use it? For reference I am running a Walbro 400lph running straight off the battery.

Also in the second picture you can see the fuel line comes straight off the barb at the rear of the rail and runs down through the plenum runners. Shouldn't this run to the front of the rail and connect up slightly confused about it all. Might have to take the top of the plenum off and have a look, don't really want to though.

ImageUploadedByTapatalk 21372396331.451074.jpgImageUploadedByTapatalk 21372396355.833979.jpg

Okay i managed to get my car to a point where i tried to start it. I had the fuel feed attatched to the barb underneath the regulator in the first picture, and the return coming off the barb at the rear of the fuel rail as seen in the second pic. The car would crank fine but refused to start, it ran on start ya bastard but would die as soon as i stopped spraying. Fuel pump was audibly priming and i was getting spark no worries, just didnt even sound like it was trying to start.

So i swapped the fuel lines around (feed to rear of rail, return to the front barb under the regulator) and it now starts and idles fine. Have i got the fuel lines on backwards? I really feel that i have but im not 100% sure, and would it even run if i did have them backwards? Or would the fuel pressure just be as much as the Walbro 400l/ph pump could generate?

Any help/feedback would be appreciated. Will get a pic tomorrow night.