Injector style differences

[Fraser Cassells]

Brake specific fuel consumption, it is a number used in a formula to figure out what size injector you need. The engines efficiency is represented by the bsfc.

[Michael Cummings]

thanks for those links fraser i myself was always wondering about a few of those points addressed about injectors.  Good read for sure.
I read that the fuel pressure regulator can give you a bit more flow by increasing the injector opening width....are there any good aftermarket fpr's? .and does an safc have any functions that tweak the fpr?

[Mike Schmid]

An adjustable fuel pressure regulator can give you more fuel flow but not by increasing the time the injector is open, just by pushing more fuel through the injector when it is open....

Think of the injector like a garden hose with a spray nozzle on it.  There's pressure in the line, and a valve on the end.  The bigger the opening in the sprayer the more water will get out, this is the difference between a 450cc/min and a 750cc/min injector.  The FPR would chage the pressure in the hose... It's like if you turned the wall tap down or up, the sprayer stays the same but depending on the pressure more or less water gets through.  

Yes, there are good aftermarket fuel pressure regulators, and no the AFC cannot adjust or control fuel pressure.

[Michael Cummings]

does anyone know of a good link to some different aftermarket fpr's?

[Kimyee Lai]

Actually Fraser, I passed your injectors on to I think it was Damian, whoever it was that was trying to pass aircare, at Jovan's barbeque on the 25th of October.  I believe he asked you about it and you said to pass it on to him?

[Andrew Scott]

I thought that the fuel pressure regulator dictated the opening of the return line at the end of the fuel rail - ie. If you narrowed the opening to the return line, you upped the fuel pressure, since the pump is putting out a constant pressure, and there is less pressure releif at the end of the rail.

Thats why with a FPR like the B&M you can only raise fuel pressure by making the hole to the return line smaller.

To expand on Mikes metaphor, think of it this way:

You have an old, ratbaged garden hose with a small hole in the middle of it. If you turn it on and run the water through it with no obstruction, very little or no water will likely come out of this small hole. If you plug the end of the hose with your hand then water will squirt through the hole. A fuel pressure regulator is basically what your hand is doing. If your hand lets some water through the end of the hose then the water will squirt through the hole with less pressure.

(maybe?)

[Mike Schmid]

The fuel pressure regulator changes the fuel pressure with a diaphragm though... It has to because it ups the fuel pressure 1psi for every 1 psi of boost in order to keep the fuel pressure constant relative to manifold pressure.  There's more to it than just a hole in a chunk of metal.

[Andrew Scott]

The fuel pressure regulator changes the fuel pressure with a diaphragm though... It has to because it ups the fuel pressure 1psi for every 1 psi of boost in order to keep the fuel pressure constant relative to manifold pressure.  There's more to it than just a hole in a chunk of metal.

I know, I was simplifying it for the sake of theory.