How does the 13b Fuel delivery work?
 

As Stated above....im new to the rotary and planing on getting a FD Soon...Im just wondering how the Primary and the Secondary work.. like how they have different cc Fuel injector in each Fuel rail? im also wondering if The Stock Twins can Break 400hp like the supras twin since their both sequential... Thanks

Here is a link to the 3rd gen FAQ thread where you can educate yourself about the car and answer your questions:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/faq-3rd-gen-other-useful-links-68640/

I'll feed you the answer to the fi question. The primary and secondary injectors are different ccs. The secondaries start working around 3000 rpm.

So is there a way to tune both system to fire at the same time? or will that just flood the engine

Yes and yes.

This is not a subject that you should worry about. Your local tuner will add the required equipment and tune the engine accordingly. All you need to do is tell him your budget and performance goals.

The point of owning the car is that i wanna learn how it work and not toss it in the some performances shop....i have a tuner whos been using power fc and made 700+ on a 1jz

at the time there was no accurate way to have a single injector that could deliver enough fuel accurately for the engine throughout it's rev cycle. there is also 2 intake ports per rotor so it was optimal to simply split up the injectors into pairs, a low RPM set and a high RPM set.

A more appropriate question is, why would you want to do this?

What are your plans and goals for the car?

My goal is to have a reliable 450hp 13b

the term "reliable" depends on your perspective.

you can build a reliable 13B that can push those figures relatively easily but the issue is the fuel system won't reliably handle it. the higher you go the more you have to do maintenance and tuning more often to be "reliable". the engines usually fail due to inconsistencies with the tune due to injector fouling, fuel filter fouling, pump voltage inconsistencies, pump volume inconsistencies, improper tunes for reliability and ambient heat factors.

the engines themselves can handle up to ~500 wheel horsepower with almost no modification.