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Fuel Rail



This is a rail I picked up at the junk yard. These rails are kinda hard to find as most people who go to the junk yard will destroy a rail for one injector. I have seen so many rails hanging bent up in the air with one or two injectors removed from the engine. Oh well, hackers are everywhere.



Above is a picture of the stock Nissan fuel rail and a fuel rail I designed and built. The Nissan rail works on a stock system and some modified systems. The line size is sufficient to provide fuel to a 450-500Hp engine, however, the fuel rail does have its problems. The biggest problem being vapor lock in the rail. I had problem after problem with it so I decided not only would I decrease the length of fuel rail exposed to the hot engine, I would make my rail much easier to install and remove. I think I did a good job on the unit. I decided to go all the way and use AN connectors and steel braided line incase I had to increase the fuel pressure to achieve the desired flow rates for my application. There are cheaper ways to go using brass fittings, but I wanted the function and the glittery appearance in my engine compartment, (makes the car go much faster)and to insure no leaks. The new fuel rail is very streamline, fuel is constantly flowing through the rail, so there is less heating of the fuel, less distance traveled equates to less exposure to engine heat. The only limitation to this rail is that it can run the barbed type injector only. I did not see this as a problem at the time I built it, but now that I am increasing the injector size to 72Lb injectors, I am not able to get an injector that large that are designed in the barb type injector. One option I am going to look into is having these 420cc injectors modified at RC Engineering to be a 720cc injector. Maybe I will get lucky on this one, but if this goes like everything else has I wont.
I bought the rail from Arizona speed-marine for 55.00 and they were even nice enough to tap the ends with a 3/8 NPT thread, such nice guys LOL. I built the mounting brackets at work, its nice to work at a place that has a semi machine shop, it has saved me some money. I choose to mount the rail with the stock mounting spots and designed the bracket around them. The hardware I used was stainless steel allen bolts. When I first started modifying my car I was using standard allen bolts that were black oxide, but they did not take long before they started to rust and I did not like that to much. I would suggest using stainless steel hardware if you can afford it, all of the coorosion problems that are associated with steel are removed, and that works out excellent on the water, and parts exposed to the enviroment, just my O2 here.



Injectors




All I wanted was a set of bosses that I could use to build a new fuel rail with. I called many companies, and even ordered what I thought would work from overseas. Turns out the bosses I bought were for the manifold side of the injector, totally useless for my application. DavidU took his time, spent his money, and sent me the parts. That was very cool of him as I was not able to get into contact with the manufacturer Via email, and I didnot want to pay 20.00 for a call to Australlia. I was back at square one again, so I made the drawings for the part and started turning them at my friends machine shop. The parts turned out well, I could have made them smoother with a better lathe, but these parts are perfectly acceptable.These parts are to be used with the oring type injector. I looked all over for a injector that would run in the 72Lb type, but found no barb type injectors that big, but only the oring type. So I guess it is good bye to that expensive rail I have a picture of on this page, to bad it looks totally killer and it functions flawlessly. The new rail will look much the same, but without the earls fittings, there goes all my pretty colors LOL. I have the drawings for this part as well.


Here is the drawing of the injector boss. I did not want to publish this drawing until I had the chance to fully test them for leaks. The boss was tested to 80psi with no problems and I was happy about that.
The mating surface of the oring for the injector was finished up with a reemer I bought from metrics unlimited. I had some concerns that they would leak, but that concern was unfounded. These bosses are ideal for using NPT type couplers. I bought a set of 45 degree earls fittings so the rail would be strait when mounted to the engine.
I have completed the rail and it is waiting to be anadized blue. I will post a good picture of the completed rail when it is finished. I think this is an excellent solution for the oring type injectors. There as always a cheaper way to do the rail, but I was not happy with the looks of the completed unit, so I redesigned a rail I liked.


Well here is my final fuel rail. I cant say much about the intake manifold except it needs a good home to someone. I used this manifold to proto the new rail.
This rail unlike my other custom rail is setup for oring injectors. As I mentioned, I could not find large enough injectors that were the barbed type to get my engine to 600 horse power. The oring injectors were my only choice. Having looked around at different manufactures, I did not fint a part I liked, so I designed and built my own custom part like I have done many times for my car. I am happy with the results of this part. I made the injector bosses, and the drawing is listed on this page as well. I decided to anodize the brackets and the rail, because it is more durable, and I am not one of those guys that spend allot of time out in the garage polishing my aluminum, chrome and all that stuff, maybe if I drank a few mooseheads, but doubtful at that LOL. I choose the black and red because my fuel pressure regulator is done in those colors, and the black rail will look good next to the texture black valve cover.
The fuel pressure gauge is a 100psi unit so that will put the gauge reading right about in the center of the gauge where it is most accurate.
On a final note: I had some concerns with the injector moving in the injector boss as the fuel pressure got to about 80psi. I did not want to chance that the injectors would force themselves out of the boss and bend the mounting brackets. I also did not care for additional brackets to secure the rail as it would make the rail harder to remove.
I was walking through the junk yard and came across a set of oring injector clips on a car, I dont remember the make, that looked like they would work with my injector boss, and I would be able to safety wire the clip to the boss and fix my problem. I was correct the clips fit the injectors and bosses perfectly. I safety wired the clips to the boss and I have no more worries about the injectors pushing on the rail and brackets at all now. The only force applied to the rail brackets in any form is the oring compression of the injectors into the manifold and the turbo boost pressure. Not a problem in the least, and I got to use my new safety wire and safety wire pliers ( I bought them to do work on my mom and dads boat)on my own stuff LOL.
Well that is about it on the fuel supply system for my car. I expect to get many good years of use of these parts, and they look good as well.



This is the new fuel damper I got for the car. I have always had fuel pressure jitter to some degree, but this new part has removed all the jitter in the system all together. I was really surprised when I found this part on the internet. I have looked for a good fuel pressure damper for a very long time. So when I did a search on performance fuel damper there it was. The part was about $110.00 and seeing the results it has made, well worth the money.



FINALLY! I have bought a part and the connector, installed the part without a big hassle, and it worked! I thought I was going to have to modify the fuel rail again, but this install turned out quite nicely. I think I will need to lengthen the valve cover breather line about 1/2 inch. That is alot when you are using steel braided line, you have to get that stuff to fit just right, or it has a tendancy to saw right through just about anything. I thought the part just may hit the hood and that would have been a bummer, but it fit and I don't have a divit in my hood LOL. That is about it for this problem, excellent part guys check it out.

In Tank Fuel Pump Install





Here is a picture of the stock 280zx fuel pump pickup and sender. I had to modify this part to do the intank fuel pump.



Here is a picture of the modified sender and a picture of the inside of the tank where the return line and new pickup sock goes. This is a stock tray for the ZX and I donít think I will have to modify it to get the sock to mount and fit. The return will stay as it was stock.
I am going to use steel braided line as it is extremely high pressure and it is impervious to just about any chemical you can think of, well within reason anyway. I have rethought the 90 degree AN fitting and am going to use a strait fitting so it will be easier to remove and install the sender if the hose is directed down towards the bottom of the tank. I will leave just enough room to get a wrench on the fitting to tighten it and make sure the braided line doesn't touch any metal. A note on steel braided line: You really have to be careful when utilizing this type of hose. If for some reason the hose it touching another part and there is movement of the hose in any way, it will saw through the other part. Also I dont want any possibility of a spark(BOOOOOOOOOOOM) I have never been comfortable working with fuel tanks for that very reason, so I usually go to the extreme when designing and fabricating anything for fuel and fuel cells. One screw up here and your done, not my preferred method of reaching the afterlife.


Well after getting into the install, I came to a decesion regarding the wiring of the pump. I had intended to run the wires on the tank to make the sender easier to remove, but after much pondering of the situation, I decided to run the wires the same way I did before. I also have installed a terminal block to the pump and sender wires so I can remove the sender without taking the wiring off of the sender. I pondered that issue of the connection for some time as well. I did find a very high quality connector I could have used, but decided the terminal block was the safest way to go. As I said, there really is no room for a screw up here floks, one spark and its all over. I did not feel the actual tank material was thick enough to install the wiring through. I wanted to make sure there would be zero issues with the wiring. I wanted to make the seder totally seperate from asnything dealing with the pump, but for sefety reasons I ran the wiring the way I felt was the safest, not as convenient, but safe.


This is the whole assembly of the pump and bracket. The bad thing about this setup is that I had to install the pump on the bracket after it was in the tank. I could not fit the pump through the sender hole. I did decided to assemble the output line and pickup on the pump and then secure it to the bracket Via the two clamps. This should be a good strong install. The hardest thing to do is tighten down the hose fitting and the pump wires with the sender partially installed into the tank, but it is not unmanageable. I used stainless steel hardware to secure the pickup bracket and the pump bracket and poly locks to ensure nothing would come lose and no rust. That was just a precaution as all of us know with the high quality of fuel here in the US the chances of water in the fuel is remote LOL yea right. The pump output hose is teflon. I am not a big fan of teflon hose, but I wanted to stay away from rubber for in the tank. I had to come up with a creative way of tightening the hose so it did not kink at the connection and leak. What I used was a spare spring clamp, cut the ears off so that it was basically a spring loaded metal circle and clamp. I then used a stock fuel injector clamp over the whole thing to tighten it down and get an even compression the entire circumference of the hose. The calmp is also stainless steel.
I used #10 oil proof and gasoline proof copper wire on the sender. I utilized wire crimp connectors, crimped the connector and also soldered the connector. I finished up the wires with heat schrink to add to the durability of the wire and to provide additional insulation for the crimp connector. One Note: I have also ran #10 wire from the fuel pump relay all the way back to the fuel pump. I learned early on that there was a voltage drop across the stock wiring when the pump was requiring a good amount of current to pump the fuel at high pressure levels. Unfortunately, the bigger wire did not solve my problem so that is when I did the twin turbo fuel pump in the car. Anyway, that is about it for the in tank fuel pump.


Fuel Pump Selection answers




When I first started doing upgrades to my car the first thing I had to do was to install a high flow fuel pump.
My first pump was the Porsch 944 turbo external fuel pump and that part worked very well with 3 BAR static fuel pressure. I needed to go to 4 BAR fuel pressure to get the flow from smaller injectors that were utilized in the JWT Nissan ECU upgrade. The Bosch pump started falling apart at 70 psi of pressure. That is 58.8 psi of static fuel pressure and 11psi of boost on the pressure regulator. I was getting about 3000cc's of fuel and needed about 3300cc,s of fuel.
I began to look for a better solution in fuel pumps. I looked Walbro, Holley, MSD fuel pumps, and just about anything I could get on external fuel pumps from anyone. I found that all of these pumps, no matter what they were rated at, when you looked at the data sheet on them had a serious dropoff when the pressure got to about 80psi.
I asked JWT what pump they used for their application and the answer was the Nissan Twin Turbo pump. Great it was an in tank fuel pump and I was not keen on installing an in tank pump. I could not find what was a viable solution to my problem so I got a pump and started looking at ways to get it installed. I did get it installed with much hassle and it worked the VERY BEST of all the pumps I looked at. I did extensive testing of this pump and here is what I came up with. The pump will deliver at least 3300 cc's of fuel to the injectors at 90 psi of fuel pressure, measured at the pump outlet. I did find there was a 4psi presssure drop in the zx system up to the regulator. I am not sure if it is the -6 AN fittings causing the pressure drop or the fuel damper (stock unit) or the filter or what. I just know to expect a 4psi drop in fuel pressure at my regulator.

There is one other option that has worked for another person I know regarding the external fuel pumps. AFTER, ALWAYS AFTER, I completed my work,MSD came out with a box that is a voltage stepper for fuel pumps. What tis box does is to increase the voltage to the fuel pump and it is triggered by the boost of a turbo engine. The manifold pressure is fed directly into the box via a vacuum line that is attached to a pressure sensor, and that monitors the engine, so when it comes up on boost, it starts adding voltage to the fuel pump to increase the fuel flow.
This unit has worked for a guy in the same boat as me, high static fuel pressure and high boost applications. So this is an option to doing the intank install like I did.
I only know one thing, the twin turbo fuel pump is an animal of a pump, and will have no difficulty supplying the correct volume of fuel to my new 72Lb injectors at 3 BAR fuel pressure. So when you start adding up the cost of other solutions, like MSD's recommendation of parallel pumps, the cost gets high for the pump setup. So for 250.00 out the door from Nissan, that is the cheapest, and best solution for anyone if they are up to an intank install if they dont already have one.
I consulted MSD on their recommendations on a pump solution, and their first comment was to get a larger injector. Not the answer I wanted to hear. So after explaining to them I could not just change injectors, they suggested a parrallel pump configuration. So the price of a fuel delivery went up considerably, not to mention I had to get two pumps mounted on the car, find a way to get two pump pickups into my tank and go for it. That wasn't the solution I wanted to hear either. So the two pump case was not really viable. Then I considered doing a boost pump in the tank and an external pump in series. This option is utilized by many car manufacturers, but you will get nominal gains of 10%-15% overall flow. So that was not a good solution either.
I gave the twin turbo pump a shot and figured if I did not do all that it was said to do, at least I could always go with the series setup and get to where I wanted. The pump worked, and for the cost of the pump it was the best deal around. One other thing, Nissan also makes a bigger pump for the skylines that puts out about 10% more fuel then the twin turbo pump does so woohoo. This issue is put to bed, and I can finally not have to worry about the fuel gauge readings as both gauges are now accurate.