I'm not sure if both of these questions belong here, sorry if they don't. Also I am still kinda new to TBI/cars so I apologize if these questions have a really obvious answer.
First question: What are the advantages to swapping a TPI fuel pump into a CFI/TBI? Doesn't the regulator only allow a certain amount of fuel pressure anyway?

Second question: What is the advantage of parallel plumbing the crossfire?


I've been reading post but I cant seem to find clear advantages to either of these

 

the problem with the original two stage turbine CFI pumps is even when new they were often not quite up to the task of providing the nessesary fuel pressure for proper operation of the CFI-also CFI often performs better if fuel pressure raised to 14-15 PSI instead of the factory 13 PSI setting.Use of a TPI or other upgrade pump gives extra capacity to boost fuel pressure and often improves a stone-stock CFI as well.If your CFI has "tip-in"hesitation,a low erratic idle,or seems to run a litte "uneven" a weak fuel pump is the usual cause. With a stock crossfire fuel feed,the TBIs are in "series"and the front and rear injectors have slightly different flow rates-with parallel plumb,injectors with same flow rates can be used.I have done quite a few modifications to my "hot rodded"CFI,but have not done the parallel plumb yet-runs smooth as it is, but more highly modified cfi might benefit from parallel plumb.

 

Tbi pumps don't give you the reserve fuel that a tpi pump can, like if you mod your cfi & it requires more fuel(upping the psi w/ an adjustable regulator), the stock pump may not flow enough for the regulator to build the pressure. A tpi pump will flow more fuel, but the pressure will only go up if its resticted (like a regulator does). What gets past the regulator goes back to the tank, a tpi pump will send more fuel back to the tank.
I think they parallel plumb those cfi units to have equally regulated injectors. Stock cfi has a compansated(front) & regulated(rear) injectors.
Myself, I like the single 2 barrel tbi units, the ones from an 87-89 chevy truck are a good swap, uses the same tps, inj, & iac connectors. They accept 5 1/8 air cleaners too.

 

Thanks for the info guys. My car is still stock so I guess I wont have to worry about these upgrades for a bit. Unfortunately I just changed my fuel pump (not tpi) so I'm running a little over 13 psi, it'll work for now. thanks for quick responses too