Was just curious how they worked and what was the purpose of using one.


Thanks.

 

can't help you with how one works, though i would imagine that it depends on the type of regualtor. my guess would be some sort of internal diaphragm that changes the flow - but again, i'm not sure.

anyway, the purpose is as simple as what the name implies. it allows you maintain fuel pressure by increasing or decreasing it to the set level depending on engine load.

 

The purpose of an FPR is to maintain a specified fuel pressure so the carb/fuel injectors can work properly. Too low of a pressure and you get insufficient fuel delivery. Too high of a pressure and you get overrich problem or fuel injectors locking up.

An FPR is just a mechanical pressure bleed-off device. It's basically a restrictor into a spring-backed diaphram. The spring dictates pre-load and defines the pressure bypass level. As fuel pressure rises, it pushes against the diaphram. Once the fuel pressure overcomes the spring tension, the diaphram opens to relieve the excess fuel pressure. Simple but effective component.

Adjustable FPR's have a stud or bolt that adds more pre-load onto the spring, this changing the fuel pressure level.

Boost-dependent FPR's add a vacuum fitting on the back side of the diaphram to add more pressure to the diaphram so the fuel pressure increases as boost rises.


-Ted