Goodmorning. This is semi tech article #2 in regards to our
Nissan Fuel Delivery system. Here is my first article;
TZR; Fuel Injector Analysis, Physical Properties of.Dislaimer;
First, I want to start of by touching on fuel itself. All
the analysis I will show today, will be based on a fuel rail
at 45pounds of fuel pressure. In real life applications
fuel pressure is dynamic and varies based on fuel delivery
rate. In general, the more fuel you deliver, the less
pressure in the rail. As fuel pressure drops, fuel velocity
rises. In future tech articles, I will show how each fuel
rail functions in worst case conditions of low pressure /
high velocity. This is where the design of a fuel rail
becomes critical. But for now, lets look at the fuel
injectors which is key to any analysis. The intent of this article is to show what the stock fuel
rail looks like from the inside out. This thread will be
fairly brief, and questions and comments are always
welcomed. This is my model, accurate to with in .001 of an inch.
Nothing special here. I did remove the electrical
connections on the injectors to facilitate rotation of the
injectors in the injector pods to see how clocking of the
injector affected fuel delivery. This was covered
extensively in my 1st tech post.
 I was really interested to see how much space and volume is
taken up by the injector pods that protrude into the fuel
rails long bore plenum. You can see how this is very much a
restriction.
 This view is kind of interesting, as it shows how the
injector sits in the rail, and in relation to the port-holes
in the injector pod.
 So what does this mean for fuel delivery? Ideally, we would
want this port-hole to align with the inlet screen of the
fuel injector. It's not terribly off, as you will see in
future articles, but it is off some.
 And next, we have; (drum roll)
The Analysis These are all pretty self explanatory...
I was impressed with how disturbed the fuel flow is on the
inlet. Are you impressed? It sure makes sense, what a
mess!; :)
 Check out the outlet!... talk about a restriction.
This is pretty bad considering on the stock fuel
system, we still need to feed 3 more injectors!
 A similar picture I posted in my first article, But still
relevant here;
 And finally;
In summary, and after much analysis, I found that the stock
fuel rail is fairly competent. However, there are certain
areas that we concentrated on when developing the 300Degree
fuel rail that took care of some of the anomolies we did
find. These will be covered later.
I did like how the stock fuel rail is thermally isolated
from the plenum. If your injectors are clocked correcty,
fuel delivery should not be too much of a problem for some
of the smaller injectors. Unfortunantly, those port-holes
are pretty small. I hope you enjoyed this article.
Next week, We'll take a look at the Border performance fuel rail.
Petz #3
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TZR; Stock 1990 Fuel Rail Analysis, Passanger Side. - 
