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Top Feed Rail In R33 With Stock Plenum..yes It Can Be Done


ARTZ
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Okie dokie, I decided to just write a tutorial :D..

Because so many people keep asking In FI and everybody wants to run ID injectors these days

and who can blame them when the results speak for themselves..

Im gunna show you the basics for fitting them under the standard plenum on the 33...

Im not going to bother telling you that you need to remove you intake pipe and everything hanging off it because that is obvious, but if you are not sure how to do that see here>>>

http://www.skylinesaustralia.com/forums/topic/140970-injectors-how-to-removereplaceupgrade/page__p__2985226__hl__rb25%20injector%20__fromsearch__1#entry2985226

Now you will need some injectors

The injectors I used were 750cc XSPURTS

02022012395.jpg Cute litte buggers hey....These are a 40mm length injector almost identical to ID injectors..they're also available in 2000cc but if you need injectors this big your probably not running the stock plenum anymore

ID injectors (1000cc and 2000cc) are 48mm when you take the extension of them and would probably fit as well, I am waiting for someone to confirm this though as Im yet to see it done..It is a very tight fit mainly due to the hose plumbed in underneath the back of the plenum..But I'm fairly confident an extra 8mm would squeeze in there..if not it is possible to machine down the manifold spacers for a little extra room..

Your looking at about 600 to 700$ for injectors

Things you will need

you will need the correct plug adapters to suit..these are relatively inexpensive and you injector supplier might even throw them in if you ask nicely..you will need to wire these into your loom..pretty easy only 2 wires and it doesnt matter which way they go..Aternatively you can get plugin adapters, they look something like this and simply plugin..

full4_27_226.jpg

you will need a fuel rail, no need to spend heaps as these are available for 100$..Do not get a twin entry rail if possible as the extra fitting in the middle can be troublesome..Also beware that if you get a rail to fit a NEO RB25 you will need to machine down or replace the 2 bolt spacers to about 6 or 7mm high .. you can then use the original fuel rail bolts.. if you have 48mm injectors you may need longer bolts and 15mm spacers, the ones that come with your rail kit are too long..

you will need an adjustable -6 fuel regulator, available from 50$ to 500$..take your pick..

you will need a fuel pressure gauge so you can set your required pressure..I got one for 20$ at a speed shop but some fuel regs come with them

You will need about 1 mtre of 5/8 fuel hose, grab 2mtrs to be safe, about 50$ max..get a good quality hose like Gates if you plan to run e85 ...check with your supplier for alcohol compatible hoses

You will need at least 1 90 degree -6 or larger fitting for the back of the fuel rail, looks like this

8-an-90-degree-push-fit-fuel-fitting-hose-end-8an.jpg

your fuel rail kit will probably come with a straight through fitting which wont work..

you may also need other -6 fittings for the fuel return bottom of the reg..I was advised not to put a 90 degree bend here as fuel needs to be able to exit the reg as quickly as possibly to maintain proper pressure. However a 45 degree should be fine..I used a straight fitting and it nearly fouls on me manifold which is not ideal..

you will need hose clamps, at least 4...ask for proper fuel injection hose clamps they are much better than regular ones..Only 1 or 2$ each depending where you get them..

clamp.jpg

^^^^The one on the left is the one you want ^^^^

Once you have it all you will need your new rail ready to go, It should look something like this

29012012568-Copy.jpg

Some things to note,

NB..always use some lube when inserting injectors into rail, WD40 is fine, to make sure the o-rings dont grab and twist out of shape..Also there is no need to use any sealant on the fittings An fittings will seal when tightened, helps to spray a little lube on them as well..

NB.. I attached my reg at the end of the rail in the original location..you do not have to do it this way..the reg can just as easily be placed anywhere in the engine bay you choose and joined to the rail via a hose..this may require some additional fittings..

Hot Tip..attach a lenght of fuel hose to the back end of the rail now as it will be near impossible to do once the rail is in

Now the tricky bit, insert the rail..you will need to slide in from the front and twist and wriggle to find its sweet spot..

I would love to show you a video but i didnt make one, but if you got the old rail out you will figure it out..

once in will look something like this

29012012564.jpg

line it all up, I highly advise test fitting this first and dont expect a perfect fit straight away..

When it looks right spray the o-rings with some lube and start to tighten the 2 botls that hold it in..

Take extra care when doin so to make sure it is not pressing on anything as you tighten them.

The o-rings should press very firmly into the manifolds spacers

Then make sure all wires are tied up and not left to rest on anything that will get hot and melt them

I broke this plug the first time when doin mine as the reg hit against it

as you can see its very close but by twisting the reg a little I got it to fit..

27012012553.jpg

So yeah, Take care ...:)

now to attach some hoses...heres an image of my layout..

04022012569.jpg

Now as you can see the hose from the fuel filter runs up around the back to the rail, I put the gauge in this line.

You can also attach the gauge to your the auxillary port in your fuel reg, the choice is yours but you CANNOT place it in the return line..make sure all hoses are tied up and clear of anything that may get hot..the last thing you want is a melted fuel line = FIRE!!! :devil:

Then run a fuel hose from the bottom of your regulator to the dampner...

Attach the small vacumn line to the regulator and cable tie..

Double check everything you have done and switch ignition to on and prime the pump..

>>>TRIPLE CHECK FOR LEAKS..:yes:

Once you are satisifed nothings leaking you need to set your fuel pressure..this is done by adjusting the small bolt on your reg..you want to aim for about 3bar or 43psi in most applications

heres a how to..

http://www.youtube.com/watch?v=c12jPdR2rJg

And thats it your all done.... Good luck :D

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:cheers: No worries mate hope it helps...

Try to make sure you get your injectors as a matched set with flow charts if possible..IDs come with these as standard

I think XSPURT would supply you with these if you ask as well, I forgot to ask :unsure: ..

Its also good to get deadtime or latency charts for your specific Injectors..

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  • 1 month later...

No Zeb, the collars come with the most rail kits..100$ on ebay

Its an SX reg..seems to be a good quality unit..i'll Pm you a link

Just to update as well, I believe silvers2 has been successful getting 1000cc injectors in too..

There is one pipe under the plenum that causes issues, nor sure if he has fixed it yet..

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im about to try and start it, the rail sits about 1-2mm from the rail and its taken me a long time to put it together :wacko: , had to romove that pipe under the plenum and the bolts on the engine side are an absolute bitch to get to. :yes:

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For anyone interested, the 1000's are in and working, couple of extra things to mention are things like the spacers for the rail, relocating of the air vacumn pipe, some shaving of the manifold and if doing 1000's you have to fit the rail first then put the top part of manifold on last, this part took me ages, working under the manifold. :ermm:

While the manifold part is off may as well get a new gasket, i did cause mine was leaking, :spank: and when you do this tighten it back up the correct way, just like you do with the cylinder head , cams etc... its in the manual..

good luck.. :whistling:

first image just shows the relocated vacumn pipe at front and theres a coolant thingy on the corner that wont fit anymore cause the rails in the way

DSC00927

this is how close the rail is to the manifold, this is where the bolt goes in the twin rail, i had it welded up and still needed to shave the manifold above it. clears it by maybe 2mm

DSC00928

Edited by SliverS2
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didnt think of that one, but its not that expensive to have a fabrication shop do some cutting and rewelding, that bit could have been removed too but i just decided to shave it ,

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  • 1 year later...

For anyone doing this probably should note that the bolts and spacers that come with most fuel rail kits will not work as they are designed for longer injectors... so be prepared to modify them...

From memory i used the standard rail bolts and re-used the little black spacers that are on all RBs and it was about the right height...this is easily adjusted with a few washers to get the height perfect..

you will have to use a bit of common sense deciding how far the injectors should be pushed into the collars...

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Long short I have Arts rail and collars and a set of short ID850 injectors which are the same length as the Xspurt 740s he used .

After exploring most options I don't think the R34 GTt fuel rail is worth the trouble it'd take to get it to fit the R33s lower manifold .

So the last piece of the puzzle is the pressure reg and I don't like the look of the aftermarket ones .

The most OE looking thing I can think of is the Nismo type B universal one that uses tubes both sides rather than the flange system OE rail mounted ones use .

The universal reg looks it's based on the Z32 300ZX one and has its own two bolt bracket as part of the unit .

Maybe it can be mounted on the bracket above and to the right of the std FPR or to the bolt on the front of the No 1 inlet runner .

A .

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  • 1 month later...
  • 3 months later...

My turn :)

http://www.trak-life.com/diy-converting-top-feed-injectors-r33-gts-t-skyline-rb25det/

Just about every car enthusiast with their offensively powerful turbocharged vehicle will eventually hit a brick wall with the fuel demands by their motor. Question is, do you stop there? Certainly not! Time to get that fuel system up to scratch and invest more money into your prized depreciating asset that upsets the other half. (In our defense though your pride and joy will probably cost you less than your partner’s wardrobe and will have better resale value so you can use that excuse next time.)

As you may know, Nissan decided their humble R33 GTS-t should use side feed injectors for whatever reason and yes finding ways to upgrade to better modern better flowing injectors is a nightmare. Often people would make the choice of going high flowed side feeds (milling out the stock injector). However this has many issues which predominantly revolve around spray pattern, consistent fuel delivery and failure. All of which the Fridge unfortunately suffered from recently – hence the conversion to top feeds instead.

RB25DET-Top-Feed-02-1024x678.jpg

So chances are if you’re reading this article you’ve either maxed out your current R33 GTS-T Skyline injectors and are looking to upgrade your injectors the right way OR gone high flowed side feeds and absolutely hate it. Then again you could be an avid trak-life.com supporter and just like reading our articles.

RB25DET-Top-Feed-03-1024x678.jpg

RB25DET-Top-Feed-05-1024x678.jpg

Rest assured, this guide should give you plenty of information on how to convert your annoying side feed injectors to top feed injectors and you’re under safe hands.

RB25DET-Top-Feed-01-1024x678.jpg

Parts Required:

  • 6x Top Feed 1/2 Height 14mm Injectors
  • 6x 14mm to 11mm converters/spacers
  • 6x EV1 to JECs Connectors
  • 1x 11mm Slim RB25DET Fuel Rail & Fittings
  • 2x -6AN to 3/8” Barb 90 Degree Fittings
  • 1x 1/4npt grub
  • 2m of EFI Fuel Hose (preferably E85 compatible)
  • 4x EFI Fuel Hose Clamps
  • 1x Fuel Pressure Regulator
  • 1x Fuel Pressure Gauge
  • Some form of lubricant

Tools:

  • Socket Set
  • Allen Key Set
  • Spanner Set
  • Phillips & Flat Head Screw Drivers

Duration: 3 Hours (excluding time to remove old injectors & rail)
Difficulty: Medium
Profanity Level: Medium
Prerequisite: Stock Fuel Injection system removed

So now that your engine bay is looking empty with the fuel injection system missing and your throttle body removed, it’s time to get cracking. But before anything, take a deep breath and brace yourself for a few hours of swearing. Upside, look at all that room for your top feed injectors!

RB25DET-Top-Feed-06-1024x678.jpg

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Step 1:
Clean and fit the male to male fittings to the end of the rail, make sure there’s enough force to crush the crush washers if not you may be prone to having fuel leaks. At the same time, fit the grub screw to the top of the rail (if you’re not using this port as a fuel return)

RB25DET-Top-Feed-08-1024x678.jpg

RB25DET-Top-Feed-09-1024x678.jpg

Step 2:
Lubricate the injector bosses and slide the o-rings on, taking as much care as possible to avoid dust/grit between the boss & o-rings

RB25DET-Top-Feed-10-1024x678.jpg

Step 3:
Clean the plenum injector seats and carefully install the injector boss & o-ring for each cylinder on the plenum. This is best done by applying a thin layer of oil on the seats and using a cloth to gently push in the injector boss. Do not rush this, as it’s air tight it will go down very slowly.

RB25DET-Top-Feed-11-1024x678.jpg

Step 4:
Start by lubricating the top injector collars and inserting them into the rail. The use of motor oil is more than sufficient. These collars should just slide into place with not much issue once lubricated.

RB25DET-Top-Feed-12-1024x678.jpg

At the same time lubricate the injector top & bottom o-rings and test fit them. You may admire your artwork if you choose.

RB25DET-Top-Feed-13-1024x678.jpg

Step 5:
Fit all the injectors into the injector boss for each cylinder, this step might be a little tricky as there is very limited room available – however with the aid of a few beers this may reduce stress levels

RB25DET-Top-Feed-14-1024x678.jpg

Step 6:
Time to get the rail on, but before that make sure you have slipped on the correct bolts into the bottom row as it will be nearly impossible to slide the bolts on once the rail is on the plenum & injectors. Carefully lower the rail in place and start with applying light pressure on cylinder 6 and gradually working your way to the front. Once complete it should look flat and not touch anything.

RB25DET-Top-Feed-15-1024x678.jpg

RB25DET-Top-Feed-16-1024x678.jpg

Step 7:
Align all the injectors so the connectors face upwards and predominantly vertical (not essential). Wriggle the bolts out nearly all the way and slide in the shorter spacers down. Once ready bolt up from the middle up and then the outer bolts lasts using a 90 degree Allen Key (possible to use a Hex Head socket, however there is quite limited room).

RB25DET-Top-Feed-17-1024x678.jpg

RB25DET-Top-Feed-18-1024x678.jpg

RB25DET-Top-Feed-19-1024x678.jpg

Step 8:
Time to get the fuel feed sorted, attach and secure fuel hose to the fitting and attach it to the back of the rail then feed the hose back to the top of the fuel filter. Cut to length and attach.

RB25DET-Top-Feed-21-1024x678.jpg

Step 9:
Now to get the return line sorted, attach and secure fuel hose to the 90 degree barb fitting and attach it to the front of the rail. Cut the fuel hose to length then feed this hose to the Inlet Side of the fuel pressure regulator.

RB25DET-Top-Feed-22-1024x678.jpg

Step 10:
Using the convertor connectors, attached to the factory harness. Using some silicone spray will greatly help with this process.

RB25DET-Top-Feed-23-1024x678.jpg

RB25DET-Top-Feed-24-1024x678.jpg

Step 11:
Connect all the injectors back to the harness, make sure it is in the correct order or else you’ll have issues with your car running correctly. Connect the injector harness back to the main harness

RB25DET-Top-Feed-25-1024x678.jpg

Step 12:
Attach/extend vacuum hose back to fuel pressure regulator, attach the return line and mount fuel regulator in a sensible location as adjustments will be required

RB25DET-Top-Feed-26-1024x678.jpg

Step 13:
Re-attach throttle body and all required hoses/lines

Step 14:
Before starting, make sure the fuel system has been primed to remove all the air pockets. This can be done by flicking on the ignition without starting the car multiple times. You should be able to hear air pockets flow back into the fuel tank. At the same time it is wise to roughly adjust your fuel pressure to 3bar OR 43.5psi without the engine running.

Step 15:
Time to rescale the ECU to accept the new injectors, this can be easily done if you have access to your ECU’s programming interface if not time to tow your car to the tuner!

RB25DET-Top-Feed-29-1024x678.jpg

Step 16:
Start your car, it should fire up instantaneously and purr if the injector scaling is correct!

RB25DET-Top-Feed-28-1024x678.jpg

Step 17:
Time to recheck the fuel pressure once again, it should ideally show 3bar minus total vacuum at idle, i.e. 2.6 bar OR just disconnect the vacuum hose and adjust the regulator so it display 3 bar at idle.

RB25DET-Top-Feed-271-1024x678.jpg
All done! Time to enjoy your new injectors and screw in more boost (and a good tune too).

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  • 2 weeks later...

Guys I'm having a huge struggle trying to fit those injector adapters into the manifold. It seems like it just isn't gunna happen for me....

Has anybody got any tips for me? I've been trying for hours with no success and my thumbs are hurting :(

Ps: I bought the rb25det top feed rail from aeroflow... Not the best choice as the bolts that come with it are huge!

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