Saturday, July 19, 2008

Bad Wedding, Fuel Rail and Air slide valve hole cover

I have been busy cutting the fuel rails, and tapping them at the ends for 3/8NPT. So far all 4 are done, and the next step is to actually drill the holes for the injectors. I ordered a 14mm drill bit, and a 3/4 so that I could make all 3 cuts. The plan is to drill the first bit with the 3/8th drill bit all the way to the center, and then use the 14mm (correct size for Fuel Injectors) to make about a 1/2" deep cut where the injector actually sits in, and the 3/4" is to chanfer the angle at the start of the hole, so that the fuel injector seal is not torn open. I also need to hone and polish with my dremel the inside so that it is nice and smooth. Final touch will be to paint it in a nice satin black finish to contrast against the silver intake. Will look neat.
This weekend though was taken up going to a wedding, but I will start with the new cabling on Sunday. It should not take too long, as I have all the parts of where the cables go scoped out, and just need to run the cable, install the relay board in a place that will not get too wet under the hood, and then start the long process of figuring out what goes where. I am also going to run new power cables to the front lights so that I can relay them, and avoid overloading the 30 year old cabling, and switches.
My main concern right now is getting the exact length in between injectors so that they seal perfectly, and do not have fuel leaks, as that generally is a bad thing. I have also backordered 2 m14X1.5 female to AN6 male adaptors that will replace the lines coming in from the fuel pump right behind the booster, so no need to cut the original hoses and clamp them. It think that it is a far neater, and safer solution overall, and safety needs to be first.
The fuel system itself is designed with 300PSI hoses, connectors, and gaskets, even though the fuel pump will only get to 125 max, and is used to running at 75 for the CIS system.
As what creates the pressure on the system is the fuel pressure regulator, and the mustang 19LB injectors run at 37PSI, the fuel pressure regulator will be set at 37 PSI. When designing an FI system, always remember to put the fuel pressure regulator after all the injectors, in the return line, as this way, you will get the correct pressure before it. The way you get pressure in a hydraulic system is through blockage, and that is what a FPR does... It blocks the flow of gasoline UP to the pressure you set it. You really do not care about the pressure after the FPR, and putting multiple FPR's is just a recipe for a very hard to tune car as you have built up the pressure before the injectors. Some racing applications, and nitrous might use 2 or even 3 pressure regulators depending on the different needs, but that is way past what I intend to do with this car... I just want a nice car for a pleasant sunday drive, and if I get passed by a vespa, so be it.

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