silvertibbs

Okay according to other posts a larger fuel pump (like a Walrbo) creates more pressure and a FPR regulates it so that there is suffiecient fuel flowing into the engine. This seems less costly than a full on standalone and FMU.

Does it provide the same function as a standalone or FMU? Obviously for tuning purposes the standalone would be far better.

I might just be talking out of my @$$ here. I'm kinda confused. :roll:

Dweet

when you put in a higher flow fuel pump you are just in sense raising the stock pressure. this may be too much for a stock FPR to take. so thats why you should use an aftermarket FPR. If you use an aftermarket RRFPR (rising rate fuel pressure regulator) you will not need an FMU. however the way the ECU/standalone regulates fuel delivery is through the pulse width to the injectors which is totally different than what you are thinking it does. Also the standalone can be programmed to adjust the timing differently as well. i could type up a whole paper on how this system works but i dont feel like it smile.gif

did i clear anything up at all?

silvertibbs

Yeah, makes perfect sense Dweet. I couldn't understand the difference between spending all that money on a standalone, when just getting a larger fuel pump and RRFPR worked just the same. Other posts had suggested this in my eyes.

So if I understand correctly, a standalone FMU covers ALL the bases regarding fuel delivery and can change them accordingly.

Dweet

you also need bigger injectors and a pump with a high rate of flow. you have to choose your sizes according to the amount of power you are going to put down

silvertibbs

Oh yeah! I knew that smile.gif You gotta be able to feed what you're pumping right!! LOL

1997tibby

OMG!!!!! FUEL PUMPS DO NOT MAKE PRESSURE!!!!!!!! doesnt matter what pump you have in your car the pressure will stay the same!!! pump creates flow, resistance to flow creates pressure, like a pressure regulator!!

Dweet

thus due to the change in flow the pressure increases.. hence why you need an aftermarket FPR to properly control the extra flow to the pressure its supposed to be at. thats why i said in sense you are raising the stock pressure. dont tell me if you put a higher flow pump in a car the fuel pressure wont go up!

its like answering what came first? the chicken or the egg?

so yes fuel pumps WILL increase pressure on a stock FPR. on an aftermarket, they can be adjusted

OdessitPashka

and FMU is exactly the same thing as RRFPR...

Dweet

an FMU doesnt regulate fuel though, it just adds fuel pressure as the boost increases

silvertibbs

Nice, so I'm sorta on the right track. This is good to hear. This is how I follow everything from the tank to the engine.

1. The Fuel Pump forces gas through the lines
2. The Fuel Pressure Regulator creates pressure to obtain a good Air/Fuel mixture. And if you get an RRFPR it's adjustable, making it possilbe to keep up with a larger fuel pump.
3. Now the FMU should come after but I'm not sure. It senses boost and adjust's the pressure accordingly.
4. Injectors allow the fuel to mix with the air. The higher the cc the higher flow they have. Just make sure to pick the right ones.
5. Finally an SAFC controls the A/F ratio to suit your set-up as stated above.

So there is my understanding of Fuel Management now. But what is the big deal about a standalone. Is the SAFC a standalone, or a cheaper option? That is really what I need to know.