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Perfect Top Feed Rail In Theory For R33 Rb25Det .


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Ok. I do sort of understand your concerns.

I tried to search for cases of overreaching fpr. Nothing.

Tried other terms . Nothing.

Could you link me to something if possible.

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The most down time on a daily driver .

For the record I found pics at GTR.co.uk of a GTT with an RSP fuel rail on it but who RSP is fk knows . It has what looks like a flat section of aluminium welded to the top of the rail up front and two sets of holes to fit the standard FPR . They've used the front one so that it clears the GReddy plenum section . It also looks like it has a banjo fuel fitting in the back of the rail .

For some reason I can't post links at the moment so search "RB25DET Skyline GTS- GTT owners POST your engine spec-power!!!" .

Go the page 4 of this thread and scroll down to the pics of the GTT engine bay , look closely at the pretty blue fuel rail .

This is a thread started in 2007 and Lithium was there too .

Just on the XR6T rails , they have the feeds on the side not the top .

A .

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At the moment an R33 GTR pump , my tuner reckons EV14s like higher base pressures than other types and the problem is that when the pressure goes up the volume comes down .

A .

To some extent. My understanding is they start becoming unreliable at around 80 psi, taking longer to open due to the extra pressure. This makes the flow vary.

I haven't seen any issues with fuel pressure rising at idle, and that is running a 460L e85 pump at full voltage. So you shouldn't have any problem running the stock or Nismo reg until you max the flow of the Walbro. (around 450kw) Obviously base pressure can change this figure a little, but it is certainly true for ethanol at factory pressures.

Adrian, If you have a crash big enough to break the fittings off an aftermarket fuel rail, then the risk of petrol getting out is THE LEAST OF YOUR WORRIES.

I think you overthink things about 10 zillion times too much.

I agree, not much chance of rail damage. The rail is very well protected on most cars. You have more chance of damaging a hardline under the car.

There are plenty of OEM alloy rails, most are cheap cast crap. These would break much easier than the solid highflow forged fittings and rails I mainly use. Most OEM rails run two bolts, but the injector can't fall out, the injectors are clipped into the rail, which is a better idea in case the bolts ever came loose, so I agree, keeping the OEM rail in most cases is the best option. That's why I agree you should bolt the Neo rail in place with a robust bracket to the 3 bolt positions found on the 33. Why is it so hard seeing you can fabricate something yourself?

You seem happy to run high percentages of ethanol on rubber lines that weren't designed for it, you know full well it will make them fail eventually, but that doesn't seem to cause you any concern. I don't see how a simple rail upgrade could cause the end of the world...

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I run E42 because I don't think higher percentages do much for you in a street car , I think round the burbs E70 E85 gives woeful consumption though injector design comes into it .

Actually I surprised myself and got just over 500 kays from my previous two tankfulls so between 740 side feeds my tuning and that brew it can be done .

It should get better with more modern injectors where mixtures closer to 1 Lambda or at times

slightly above are supposed to be the go at light loads .

Scotty IMO there are two useful features in those GTt rails , they take 14mm injectors and fuel enters and leaves in the right places .

The ok factor is the OE reg and the useless factor is they don't fit .

An aluminium rail that takes 14mm injectors and has fuel entering and leaving where the Neo does is good and if it bolts on it ticks all the boxes .

Most people may like the front and rear plumbing , it may only be Nissan and me that don't .

It shouldn't be too hard to to weld a couple of adapters on the rail to take 90 degree 8mm barb fittings and then you have an alloy rail that fits and plumbs like OE . Minus reg .

To fit that use the EFI Hardware adapter or weld a cross piece on top drilled and tapped to fit it .

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Nissan use front and rear plumbing on the later engines. Personally I don't think it matters if a little air gets into the rail, it would run along the top anyway, not the bottom where the injectors feed from. VQ's have the reg on the end of the rail for the turbo model. I simply cut them off and welded stainless 6an fittings to the end of the stock rails, they haven't rusted away yet...

Just be glad you don't have the V35/350z non return fuel system.

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  • 4 months later...

done and dusted... started after you and finished before you :)

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.

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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.

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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.

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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!

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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)

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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

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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.

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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.

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

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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

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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.

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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).

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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.

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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.

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

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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

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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

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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!

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

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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.

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All done! Time to enjoy your new injectors and screw in more boost (and a good tune too).

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Nice job Johnny, I can make up kits now using the 1400's but still don't have the spacing required to fit the ev14's. Next time a 33 comes down for some I will sort out the rail spacing for those too.

The fact you can install the top feeds without removing the plenum is great.

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Nice job Johnny, I can make up kits now using the 1400's but still don't have the spacing required to fit the ev14's. Next time a 33 comes down for some I will sort out the rail spacing for those too.

The fact you can install the top feeds without removing the plenum is great.

That's fantastic, now a local solution for all the boys :)

The only thing you really need to remove is the IACV, but that's given because it's nearly impossible to reach the last rail bolt.

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After going through the same conversion process I understand how important local support is..

Ordered my kit

After a 3 week wait I realised missing injector seats. Seller didn't believe me, reckons I lost them myself

After showing him photos he finally agreed to send me the seats, but only willing to send via economy unless I pay for postage

Paid postage to get them delivered by express, waited 2 weeks and still not here, so called up aus post and was advised that the post code was incorrect so it took a trip to nth NSW and back

All up took over 1 mth to get my kit with the right parts, didn't work out cheaper either. Plus sellers overseas so there's a 12-24 hr turnaround for emails

Anyway after 2 mths here's mine

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That's fantastic, now a local solution for all the boys :)

The only thing you really need to remove is the IACV, but that's given because it's nearly impossible to reach the last rail bolt.

I had no issues, never removed anything, other than that large hose under the throttle... Easiest injector install I have done.

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  • 1 year later...
  • 2 years later...

Just to round off old thread .

As mentioned my R33 ended up with a Plazmaman rail and injector collars and initially ID850 short EV14 injectors .

The reg is a Turbosmart that mounted neatly off the front of the rail with a 90 deg fitting so that it missed everything and linked to the filter in its std mount . That part went a lot easier than I thought it would .

As mentioned just changed to short EV14 980cc injectors (0 280 158 040) . The poor old injector loom now has 3 set of plugs because its used original Sumitomo and US Car and now EV1 style connectors . I have a new sub loom coming from Kudos which just has the EV1 plug connectors .

The pump is a drop in R33 GTR Nizmo .

Someone asked about the Neo manifold , yes I have this and if I get that far it will go on later . There are slight mods needed to fit the 33 TB because of its top air barb and channel . The IAC valve is just cut and shut two wires .

As for the Neo rail , I have a couple of those and a bare lower manifold so can use as a jig to play with injector lengths . Others have recently found that short EV14 injectors are too short and don't drop in without some sort of adapter to sit them higher in the manifolds injector seat . Currently I like the idea of long nose 3/4 length EV14s , the 3/4 body should be close to standard length . Trouble is EV14s in this style aren't made in larger sizes and I think they top out in the 630-700cc range at 3 bar base pressure . Maybe just enough to scrape in 300-320 ish wheel wasps on Eflex which is as far as I'd go on a 270k 22 yr old std R33 bottom end .  

A .  

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