| I just finished, among other things, installing a 300 degree fuel rail and 740cc Nismo injectors into my 93 TT. I figured I'd drop my notes here in the event they help someone in the future. Nothing mind blowing but possibly helpful. There are a lot of words here because I'm bad at being concise, but it's not a lot of information. I have driven the car about 20 miles since finishing and all seems well, though I am not boosting at all right now because I'm running way lean, or at least I was before I did all this work, and I am waiting on my wideband to arrive. YMMV. Absolutely do pressure test the rail off the car (submerged in water) like the instructions say. I was surprised at how badly one of my fittings was leaking when I did the test. It would have sucked to have figured that out on the car. The less you have to deal with fuel, the better. One of my injectors was leaking (air, during off-car testing) slowly from its tip (not from the o-ring seat). Greg (SZ) assured me that the injector was good. I cycled the injector by connecting it to battery a few times, since some say that'll stop such a leak. That didn't work for me, but doing final testing on the car, with the rail hooked up to fuel but not installed in the lower plenum, confirmed the injector was not leaking once it had fuel in it. Torquing down the AN fittings is kind of an art. None of my standard "feelings" (snug, tight, about to strip, etc) applied. I found, using my standard "bolt feelings", that the space between hand tight and feeling like pushing any harder would be dangerous was surprisingly small. In general I didn't sung anything up more than 1/8-1/4 of a turn after getting it hand tight, and this worked just fine, even though it required more force than I would normally expect from say, a screw or a bolt. The only exception was 1 of the 4 fittings that attaches directly to the rail. The only fitting that was seriously leaking during my pressure tests, it required that I tighten it up maybe 1/2 a turn after hand tight. Basically I used my judgement and decided that going further for this one fitting was what needed to be done, and it looks like I was right. Be careful though and use judgement based on your specific situation - you absolutely don't want to strip or damage any of this expensive set up. Like a lot of others, I had to slightly bend the bottom hard pipe on the fuel pressure regulator to get the angles right so that the SS line's connection to the FPR didn't put pressure on or jab into the fuel injector connector that lives right under all that mess. That whole fit (SS line to FPR) was very tight. I think that if I didn't have the 90* fitting on the driver's side rear of the fuel rail positioned just right (basically straight up) and hadn't, via trial and error, figured out the right length of fuel hose to connect that line to the FPR, it just wouldn't have fit properly. The most tricky/tightest part was the last bend towards the driver's side to connect the SS line to the fuel hose then to the FPR. Because I had to tweak the fittings during pressure testing, the alignment of the fuel rails and SS lines changed between original fitting and final installation. Even slight changes in angles were enough to make it very hard to get both rails seated properly into the lower plenum while they were connected to one another via the SS line at the front of the rails. The first time I put the car back together the driver's side rail wasn't seated properly and I had a massive boost leak. Ultimately I had to seat and bolt in the rails without them connected to one another, then connect them once they were seated properly. Having played with the fittings during pressure testing I felt confident in my ability to tighten them by feel while putting them together on the car, and it seems to have worked out (no leaks). I found a post in the 300 degree forum about someone else who experienced this same issue. With standard wrenches it was a tight fit to get the fitting together and tight with everything installed on the car, but I was able to do it. If you had thinner-walled wrenches than me, that would make it easier. This is just kind of a general note, but the first on-car leak test I did, I didn't connect the fuel pressure regulator. That'll get you 0psi of fuel pressure. I wasn't sure exactly how things would behave - if I'd get some pressure, but not enough for a test, or what. Anyway, you get 0psi. This might be obvious to most people but I wasn't sure exactly what would happen, so I tried it. More general information: I tracked how my fuel pressure fell during my on-car leak testing. As a starting point I just turn the key off and on until I maxed out the FPR with the car off. I believe all my fuel stuffs are working properly, and here are my numbers. Maybe they are useful to someone at some point. 0min - ~42psi
10min - ~36psi
20min - ~34psi
30min - ~32psi
60min - ~30psi This is a picture of the little rig I worked up to help me pressure test my fuel rail with air. Don't forget that you've got to make sure your test equipment doesn't leak, either. This is a picture of that rig all done up with the rail in my kitchen sink. Kitchen sinks should of course always be full of car parts. This is the chip puller I used to safely remove my existing EPROM when installing my new SZ chip to support the 740cc injectors and my Selin translator. I still have other stuff to do on the car right now, but this is a big clump of junx that I think is complete and working properly. Andy
|
