The first question I have is regarding the fpr. Car is 90, near future engine is 97, head being delivered is 00. I have the later model mtuned dual feed fuel rail. I am getting very large injectors. Because the fuel pump is probably original, or at very least old, I want a new pump, figured I would go for high flow, some Walbro or another. The question is, do I need, or should I get, some sort of adjustable fuel pressure regulator if using a high flow pump? Should it be straight 1:1 like this: M-Tuned Adjustable Fuel Pressure Regulator -6 M-Tuned
or one of the Begi style fmu deals? If I get a 1:1, does the factory fpr stay? Do I have to modify it in any way if I run another afpr? Aside, why do we call an afpr 1:1 if it still has a vac port, and how does this differ functionally from the rising rate fmu like what begi sells?
More to the point, how does the factory unit work? Is it just preserving a certain pressure delta over the mani pressure reference (hence the vac line to the mani)? Is this delta set/preset in the fpr unit bolted to the factory rail, or is there another regulator? If I run any type of afpr, do I still ref mani pressure?
I did read the faq section on fueling, and did a comprehensive (not exhaustive) search here and on m.net, but still don't really understand how this works. A link somewhere would help, as well, if this has been answered elsewhere. I want to understand this.