I just used the about:cache function and saved this entire post, no thanks to blogger auto-save. I'll have to re-insert about 9o photos again and re-format the entry, but wow, what a life saver. This is the second JGY because it's my second fuel rail from them, not because it's my second post about them. If one were to dig deep and go into the 28o z posts, they would see one about a fuel rail upgrade involving JGY by proxy.
This overlaps a bit with the previous post about plenum cleaning and has MANY pictures. I may come back and add a table again like I did for the xmas special entry, but that took a lot of manual effort last time and isn't going to happen again until I find a better way. Deal with the long post until then.
Removing the fuel rail and injectors was pretty easy. As well as taking it off in order to clean the manifold (see above pic of as yet unidentified substance all over the plenum I keep referring to), I wanted to mount the injectors correctly once and for all. I bought this fuel rail used from someone online. It was a JGY vintage fuel rail that came with one set of simple L-type brackets for mounting. I was never convinced it was the right way to mount the rail for my application, and a little research revealed that the rails originally come with a few more brackets of various sizes to accommodate an rb2o as well.
Maybe I was using the rb2o mounts, maybe I was using the rb25 mounts in the rb2o holes, maybe I was using a combination of the two that was even worse. When first installing the rail I made it work, and did so without it leaking, but it was obviously not the way the rail and injectors were meant to be installed. I was never sure if it was just because I had different fuel injectors than people usually use, or maybe the casting of my knock-off plenum was more off than originally thought. I'll get into that more later, but essentially the injectors would bottom out before the mounting bolts did when tightening down the rail brackets to install it onto the plenum.
Another reason for removing the rail and either getting it modified or replaced was since I was switching to a fully hard/braided -AN fuel line setup, I needed to install a stand alone fuel pressure regulator instead of using the standard, although upgraded, Nismo fuel rail mounted FPR that had a nipple connection. I could either spend 5o$ and a week getting the FPR port welded over, or I could simply order a new rail with mounts and hopefully fix all my issues at once. A new rail from JGY ran about 175$ out the door. At a difference of about 125$, and the fact that I could resell the vintage one for at least 5o$, maybe more, I decided not to mess with modifying the one I had.
The reason I say vintage is that JGY redesigned their fuel rail since I bought the first one, the second version having "improved fuel passageways", a lower profile reducing the installed height, and a smooth exterior instead of the ridges you can see on the outside of the previous version. For the difference in cost and effort, it seemed worth it for a new cleaner rail which didn't need modification and came with all the parts from the guys who made it, so I went for it.
My cats seemed to like the package, maybe they had some shop pets at JGY, but Roper and Jake couldn't get enough of smelling the overly taped, segmented together, cardboard panel box that arrived.
I have to give it to them, there was no mistaking who the box came from.
The new rail was wrapped very nicely and initial inspections were very positive. I liked the new design over the old grooved exterior one. Maybe the original intent of the vintage design was for the exterior to act as a heat sink for the fuel passing through.
The rail came with (2) sets of mounts, (3) long and (3) short L-type brackets, as well as (2) NPT to barb fittings for the ends of the rail, (6) ?!? new injector clips, a sticker, a business card, and a nice emblem. I was impressed.
What rail goes hand in hand with what injectors, and my injectors are more different than most. I did a lot of research before ordering a set of injectors. I ended up going with a set of 65# (~720cc/min) low impedance (low-Z) top flow Delphi Multec injectors from Racetronix. Most people go with the packaged sets that you can easily find on ebay from Japanese vendors. I could not find the flow size I wanted though, and because they were larger I also wanted the benefits of an impedance change. Most of the ebay sets don't offer dimensioned drawings and very specific manufacture specs and I appreciated Racetronix's website greatly.
At the time, I argued for a while what the physical and operational differences between side fed and top fed were, as it mattered if they would fit my vintage fuel rail and this wasn't distinguished on many websites, including Racetronix's. As I said, most were sold for the application and did not give many details about the actual injector design. No, it's not the physical orientation of the injector with respect to the injector ports, it is simply how the injector connects to the rail. OEM style side fed injectors sit inside the rail in the fuel flow path with the wiring plug on top. The fuel flows around and through the injector, directing the needed fuel into ports in it's side. This cools the injector better during high duty cycle applications, if you are maxing out your injectors for instance. Top fed injectors plug into a rail and are fed inline between it and it's spray end. The wiring plug is located on the side of the injector. I had no plans to max out my injectors for very long durations (that was the whole point of bigger injectors in the first place), most of the upgrades for the rb25 were to top fed injectors, and all the rails were built as such, so I moved in that direction.
I lucked out when I ordered my previous vintage JGY rail because the injectors fit snugly into the injector ports. I made two major assumptions before ordering it online that looking back on were probably a bit of a leap. I assumed the rail was for use with top fed injectors, and that there was one size of injector ports used for these types of applications.
As it turns out the rail was for top fed fuel injectors and it also had the correct size injectors ports. Most aftermarket rails for rb25s are top fed, so this wasn't that far of a stretch, but I was still happy it worked out for the best as there was the possibility that I could have spent significant amounts of money on the wrong rail, or the wrong injectors, or both. I did not learn until recently when ordering the second JGY rail however, that they actually make it for two sizes of injectors. It was now very impressive that the vintage rail even fit my over-sized injectors.
As I did not know what size my injectors were off the top of my head when ordering the new rail, I quickly looked up the dimensional chart online as I was on the phone with JGY. They were going to order the smaller one as this is standard, which has an injector port in the 11 mm range. As seen by the diagram above, the OD of the fuel rail side of the injector is 13 mm, not to mention the unlabeled OD of the o-ring in it's compressed state is even larger, and that would have to clear the ID of the fuel rail injector port for the injector to be able to be installed. The JGY rep was surprised at this information, but informed me they have a larger ported fuel rail that would work, at a 14 mm range. I say range because this was converted and rounded from standard inch sizing.
This larger ported rail would also come with a full set of new injector clips. An added design bonus of the new rail were the injector clip cut-outs on the side of the fuel rail. The vintage design had small scallops taken out of the bottom of the rail near the injector ports where the clips gripped which never seemed as secure as they could have been, although the one (yes, one) I had which still had sides by which to grip the rail with, clipped onto it and never slipped out. The new one has a groove cut into it's entire length that the clips easily grip around without being able to rotate and potentially slip out of the scallop.
After evaluation of my clips, which had been installed at a shop several years ago because I didn't receive any with my first fuel rail order, I was glad I got the new set of clips with the new JGY rail. Per above, only (1) of them still had it's sides to hold the injector in place to the rail. The rest of them only clipped into the injector itself preventing it from being forced too far into the rail itself. This did not, of course, keep the injector from being pushed out of the rail which was a much greater concern of functionality of the clips, or lack there of. It seems that the previous shop simply grabbed clips that were removed from old cars and pieced a set together, regardless of their apparent condition. It didn't really matter as the injectors couldn't be forced into the rail further than the electrical plug anyways, and could not be pushed out of the rail by potentially high fuel pressure due to how the rail mounted to the plenum, sandwiching the injectors between itself and the intake.
Up until this point I was very impressed with the JGY product and customer service. The rail had come quickly, it was tig welded per my request to close the FPR port (which is a normal mod request), it came with several sets of mounts and clips, all of which fit my injectors, as well as the injectors fitting the 14 mm range ports very snugly. It's almost like they planned it.
The first pair of holes lined up perfectly, the third pair lined up perfectly. The second "set" was really just one, on both the plenum and rail sides, but it was offset by it's imaginary "pair". It's like they put it in the jig backwards when drilling the mounting holes. This was under the assumption that it was designed to bolt to the engine like the stock rail, with the FPR in front.
Drop.
If you flip around the rail so that the FPR is towards the rear the mounts all line up, including the center bolt hole. Again, I gave the benefit of the doubt to the makers of the rail and assumed my casting was made incorrectly back in the day. After looking at pictures online and checking out the Isis knock-off intake plenum that McKinney accidentally sent me, I quickly ruled this possibility out.
Maybe they did accidentally flip the jig around and drilled the mounting holes starting from the wrong end. Maybe they forgot to drill one of the mounting holes and my application just happened to need that one. Guess again. Apparently when they said it was "guaranteed to fit ... the factory manifolds" they meant on a rb25 in a 24o sx even though they sell their rail under the RB MOTOR parts tab and there is no mention of what car the engine needs to be swapped into or with what variation of mounts in order for the rail to be "guaranteed to fit".
I called JGY and was informed that all rb25 engines come with the FPR positioned reward and that they had never seen one any differently. Interesting. I told them they were wrong and they walked into the shop to tell me that their rail was on an engine in a 24o sx with the FPR facing reward and it fit perfectly. I politely told them that mine was in a 24o z, but that they sold it for the engine, not the swap, and that it would have been good to know application details of the parts I ordered ahead of time. They said my swap was not usual.
What is usual about any swap?!? The WHOLE point is that it is NOT usual.
Either way, I asked if they could please drill another hole in another rail (or the one I had) so that I could install it with the FPR forwards. My engine sits VERY far back in the bay, and by flipping the rail it moved the end of the rail much further back. I was just worried about it clearing the firewall, let alone clearing the 9o* -8an fitting that still had to be attached to it in order to connect the fuel line. I do not have a drill press and did not want to attempt drilling a mounting hole with a hand drill that close to fuel passageways. Simply put, they said no, that they would have to make a new jig just for me and that would not be financially worth it. They suggested using only two mounts to mount it.
If I wanted to do that I would have re-used my vintage rail and not spend 18o$ on a new one!
According to JGY, the plenum was designed to use the upper (2) mounts with an rb2o rail, and the lower (3) mounts with the rb25 rail. Maybe I would luck out and be able to use the upper (2) mounts instead of only (2) of the lower (3) mounts as suggested. I was using the upper (2) on my vintage rail already, but as described, that was obviously incorrect (either with one or all of the wrong brackets, mount locations, orientations, or directions).
Let the testing begin.
There are several different combinations of brackets, orientations, and mounting holes that can be used to put the rail in obviously incorrect locations, close enough to work locations, or perfect locations. Some of this depends on what injectors are used, based on their installed length or distance between the plenum and rail. Previously, my injectors would bottom out before the mounting bolts were threaded all the way down between the bracket and plenum. This created significant force on the injectors, and also the threads as I was able to thread the bolt beyond it's limit with respect to the injectors. Over-exaggerating the issue, this would either bend the rail between the injectors, or crush the injector into the plenum distorting the tip or breaking the o-ring seal.
I tried every orientation, direction, and combination of small or big mounts the upper and lower plenum mounts.
As a side note, the original o-ring seal on the spray side of the injector did not fit into the smallest injector port in the plenum. I attempted to drill this out with a machine drill bit when I first bought the plenum, but it wasn't big enough and I didn't want to ruin the fit to the point that it would leak by using a hand drill. I know the runout of the chuck was enough to do this, as was the inherent lack of precision and angle of the hand drill, all of which defeated the use of a nice bit, but I had to start somewhere and just because you can't control everything doesn't mean you shouldn't control what you can.
Making up for the poor clip selection, the shop that did the original tune pulled the rail, cut off the Delphi spray side o-rings, and installed standard Nissan ones. The id of the new o-rings may or may not have had to be trimmed in order to fit the Delphi od of the spray cylinder area, but now they fit perfectly as shown in many of these injectors shots.
Back on topic, place the injector into the plenum as it will sit when installed. Measure the distance between the plenum and the injector clip face that will sit against the fuel rail when installed. This is the minimum distance that the rail needs to be installed away from the plenum. I say minimum, but really needs to be as close to this number as possible without going under.
It just so happened that I was able to find a configuration resulting in an installed measurement of just over my injector length where the fuel rail and plenum injector ports also aligned, making for a great install. As shown above, previously I was about o.1oo's too short, causing the slightly longer injectors to bottom out before the mounts could be bolted all the way down. Put simply, this is why I ordered the newer JGY rail with a complete set of mounts.
It even uses the (2) upper mounts!
This overlaps a bit with the previous post about plenum cleaning and has MANY pictures. I may come back and add a table again like I did for the xmas special entry, but that took a lot of manual effort last time and isn't going to happen again until I find a better way. Deal with the long post until then.
Removing the fuel rail and injectors was pretty easy. As well as taking it off in order to clean the manifold (see above pic of as yet unidentified substance all over the plenum I keep referring to), I wanted to mount the injectors correctly once and for all. I bought this fuel rail used from someone online. It was a JGY vintage fuel rail that came with one set of simple L-type brackets for mounting. I was never convinced it was the right way to mount the rail for my application, and a little research revealed that the rails originally come with a few more brackets of various sizes to accommodate an rb2o as well.
Maybe I was using the rb2o mounts, maybe I was using the rb25 mounts in the rb2o holes, maybe I was using a combination of the two that was even worse. When first installing the rail I made it work, and did so without it leaking, but it was obviously not the way the rail and injectors were meant to be installed. I was never sure if it was just because I had different fuel injectors than people usually use, or maybe the casting of my knock-off plenum was more off than originally thought. I'll get into that more later, but essentially the injectors would bottom out before the mounting bolts did when tightening down the rail brackets to install it onto the plenum.
Another reason for removing the rail and either getting it modified or replaced was since I was switching to a fully hard/braided -AN fuel line setup, I needed to install a stand alone fuel pressure regulator instead of using the standard, although upgraded, Nismo fuel rail mounted FPR that had a nipple connection. I could either spend 5o$ and a week getting the FPR port welded over, or I could simply order a new rail with mounts and hopefully fix all my issues at once. A new rail from JGY ran about 175$ out the door. At a difference of about 125$, and the fact that I could resell the vintage one for at least 5o$, maybe more, I decided not to mess with modifying the one I had.
The reason I say vintage is that JGY redesigned their fuel rail since I bought the first one, the second version having "improved fuel passageways", a lower profile reducing the installed height, and a smooth exterior instead of the ridges you can see on the outside of the previous version. For the difference in cost and effort, it seemed worth it for a new cleaner rail which didn't need modification and came with all the parts from the guys who made it, so I went for it.
My cats seemed to like the package, maybe they had some shop pets at JGY, but Roper and Jake couldn't get enough of smelling the overly taped, segmented together, cardboard panel box that arrived.
I have to give it to them, there was no mistaking who the box came from.
The new rail was wrapped very nicely and initial inspections were very positive. I liked the new design over the old grooved exterior one. Maybe the original intent of the vintage design was for the exterior to act as a heat sink for the fuel passing through.
The rail came with (2) sets of mounts, (3) long and (3) short L-type brackets, as well as (2) NPT to barb fittings for the ends of the rail, (6) ?!? new injector clips, a sticker, a business card, and a nice emblem. I was impressed.
What rail goes hand in hand with what injectors, and my injectors are more different than most. I did a lot of research before ordering a set of injectors. I ended up going with a set of 65# (~720cc/min) low impedance (low-Z) top flow Delphi Multec injectors from Racetronix. Most people go with the packaged sets that you can easily find on ebay from Japanese vendors. I could not find the flow size I wanted though, and because they were larger I also wanted the benefits of an impedance change. Most of the ebay sets don't offer dimensioned drawings and very specific manufacture specs and I appreciated Racetronix's website greatly.
At the time, I argued for a while what the physical and operational differences between side fed and top fed were, as it mattered if they would fit my vintage fuel rail and this wasn't distinguished on many websites, including Racetronix's. As I said, most were sold for the application and did not give many details about the actual injector design. No, it's not the physical orientation of the injector with respect to the injector ports, it is simply how the injector connects to the rail. OEM style side fed injectors sit inside the rail in the fuel flow path with the wiring plug on top. The fuel flows around and through the injector, directing the needed fuel into ports in it's side. This cools the injector better during high duty cycle applications, if you are maxing out your injectors for instance. Top fed injectors plug into a rail and are fed inline between it and it's spray end. The wiring plug is located on the side of the injector. I had no plans to max out my injectors for very long durations (that was the whole point of bigger injectors in the first place), most of the upgrades for the rb25 were to top fed injectors, and all the rails were built as such, so I moved in that direction.
I lucked out when I ordered my previous vintage JGY rail because the injectors fit snugly into the injector ports. I made two major assumptions before ordering it online that looking back on were probably a bit of a leap. I assumed the rail was for use with top fed injectors, and that there was one size of injector ports used for these types of applications.
As it turns out the rail was for top fed fuel injectors and it also had the correct size injectors ports. Most aftermarket rails for rb25s are top fed, so this wasn't that far of a stretch, but I was still happy it worked out for the best as there was the possibility that I could have spent significant amounts of money on the wrong rail, or the wrong injectors, or both. I did not learn until recently when ordering the second JGY rail however, that they actually make it for two sizes of injectors. It was now very impressive that the vintage rail even fit my over-sized injectors.
As I did not know what size my injectors were off the top of my head when ordering the new rail, I quickly looked up the dimensional chart online as I was on the phone with JGY. They were going to order the smaller one as this is standard, which has an injector port in the 11 mm range. As seen by the diagram above, the OD of the fuel rail side of the injector is 13 mm, not to mention the unlabeled OD of the o-ring in it's compressed state is even larger, and that would have to clear the ID of the fuel rail injector port for the injector to be able to be installed. The JGY rep was surprised at this information, but informed me they have a larger ported fuel rail that would work, at a 14 mm range. I say range because this was converted and rounded from standard inch sizing.
This larger ported rail would also come with a full set of new injector clips. An added design bonus of the new rail were the injector clip cut-outs on the side of the fuel rail. The vintage design had small scallops taken out of the bottom of the rail near the injector ports where the clips gripped which never seemed as secure as they could have been, although the one (yes, one) I had which still had sides by which to grip the rail with, clipped onto it and never slipped out. The new one has a groove cut into it's entire length that the clips easily grip around without being able to rotate and potentially slip out of the scallop.
After evaluation of my clips, which had been installed at a shop several years ago because I didn't receive any with my first fuel rail order, I was glad I got the new set of clips with the new JGY rail. Per above, only (1) of them still had it's sides to hold the injector in place to the rail. The rest of them only clipped into the injector itself preventing it from being forced too far into the rail itself. This did not, of course, keep the injector from being pushed out of the rail which was a much greater concern of functionality of the clips, or lack there of. It seems that the previous shop simply grabbed clips that were removed from old cars and pieced a set together, regardless of their apparent condition. It didn't really matter as the injectors couldn't be forced into the rail further than the electrical plug anyways, and could not be pushed out of the rail by potentially high fuel pressure due to how the rail mounted to the plenum, sandwiching the injectors between itself and the intake.
Up until this point I was very impressed with the JGY product and customer service. The rail had come quickly, it was tig welded per my request to close the FPR port (which is a normal mod request), it came with several sets of mounts and clips, all of which fit my injectors, as well as the injectors fitting the 14 mm range ports very snugly. It's almost like they planned it.
The first pair of holes lined up perfectly, the third pair lined up perfectly. The second "set" was really just one, on both the plenum and rail sides, but it was offset by it's imaginary "pair". It's like they put it in the jig backwards when drilling the mounting holes. This was under the assumption that it was designed to bolt to the engine like the stock rail, with the FPR in front.
Drop.
If you flip around the rail so that the FPR is towards the rear the mounts all line up, including the center bolt hole. Again, I gave the benefit of the doubt to the makers of the rail and assumed my casting was made incorrectly back in the day. After looking at pictures online and checking out the Isis knock-off intake plenum that McKinney accidentally sent me, I quickly ruled this possibility out.
Maybe they did accidentally flip the jig around and drilled the mounting holes starting from the wrong end. Maybe they forgot to drill one of the mounting holes and my application just happened to need that one. Guess again. Apparently when they said it was "guaranteed to fit ... the factory manifolds" they meant on a rb25 in a 24o sx even though they sell their rail under the RB MOTOR parts tab and there is no mention of what car the engine needs to be swapped into or with what variation of mounts in order for the rail to be "guaranteed to fit".
I called JGY and was informed that all rb25 engines come with the FPR positioned reward and that they had never seen one any differently. Interesting. I told them they were wrong and they walked into the shop to tell me that their rail was on an engine in a 24o sx with the FPR facing reward and it fit perfectly. I politely told them that mine was in a 24o z, but that they sold it for the engine, not the swap, and that it would have been good to know application details of the parts I ordered ahead of time. They said my swap was not usual.
What is usual about any swap?!? The WHOLE point is that it is NOT usual.
Either way, I asked if they could please drill another hole in another rail (or the one I had) so that I could install it with the FPR forwards. My engine sits VERY far back in the bay, and by flipping the rail it moved the end of the rail much further back. I was just worried about it clearing the firewall, let alone clearing the 9o* -8an fitting that still had to be attached to it in order to connect the fuel line. I do not have a drill press and did not want to attempt drilling a mounting hole with a hand drill that close to fuel passageways. Simply put, they said no, that they would have to make a new jig just for me and that would not be financially worth it. They suggested using only two mounts to mount it.
If I wanted to do that I would have re-used my vintage rail and not spend 18o$ on a new one!
According to JGY, the plenum was designed to use the upper (2) mounts with an rb2o rail, and the lower (3) mounts with the rb25 rail. Maybe I would luck out and be able to use the upper (2) mounts instead of only (2) of the lower (3) mounts as suggested. I was using the upper (2) on my vintage rail already, but as described, that was obviously incorrect (either with one or all of the wrong brackets, mount locations, orientations, or directions).
Let the testing begin.
There are several different combinations of brackets, orientations, and mounting holes that can be used to put the rail in obviously incorrect locations, close enough to work locations, or perfect locations. Some of this depends on what injectors are used, based on their installed length or distance between the plenum and rail. Previously, my injectors would bottom out before the mounting bolts were threaded all the way down between the bracket and plenum. This created significant force on the injectors, and also the threads as I was able to thread the bolt beyond it's limit with respect to the injectors. Over-exaggerating the issue, this would either bend the rail between the injectors, or crush the injector into the plenum distorting the tip or breaking the o-ring seal.
I tried every orientation, direction, and combination of small or big mounts the upper and lower plenum mounts.
As a side note, the original o-ring seal on the spray side of the injector did not fit into the smallest injector port in the plenum. I attempted to drill this out with a machine drill bit when I first bought the plenum, but it wasn't big enough and I didn't want to ruin the fit to the point that it would leak by using a hand drill. I know the runout of the chuck was enough to do this, as was the inherent lack of precision and angle of the hand drill, all of which defeated the use of a nice bit, but I had to start somewhere and just because you can't control everything doesn't mean you shouldn't control what you can.
Making up for the poor clip selection, the shop that did the original tune pulled the rail, cut off the Delphi spray side o-rings, and installed standard Nissan ones. The id of the new o-rings may or may not have had to be trimmed in order to fit the Delphi od of the spray cylinder area, but now they fit perfectly as shown in many of these injectors shots.
Back on topic, place the injector into the plenum as it will sit when installed. Measure the distance between the plenum and the injector clip face that will sit against the fuel rail when installed. This is the minimum distance that the rail needs to be installed away from the plenum. I say minimum, but really needs to be as close to this number as possible without going under.
It just so happened that I was able to find a configuration resulting in an installed measurement of just over my injector length where the fuel rail and plenum injector ports also aligned, making for a great install. As shown above, previously I was about o.1oo's too short, causing the slightly longer injectors to bottom out before the mounts could be bolted all the way down. Put simply, this is why I ordered the newer JGY rail with a complete set of mounts.
It even uses the (2) upper mounts!
thanks for the purchase, glad you liked it! nice car
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