The stock fuel pump flows 90 liters/hr which equals 1500cc/min. Each stock injector flows 290cc/min for a total of 1740cc/min. Is this a deficiency or is the injector "off" enough of the time, even at redline, so that the lower flow capacity of the fuel pump relative to the capacity of the injectors becomes irrelavant. How would the ECU respond with a higher pressure fuel pump to match the capacity of the injectors?

 

Each injector flows 290 cc - but what pressue are you basing that figure off of? Remember, stock fuel pressure at idle is 52 ish psi. When you see injector flow numbers, they are almost always based off of the industry standard of 43 psi of rail pressure. Not to mention what voltage the pump and injectors are tested at.

 

The 2k2 Maxima infectors flow 315cc/min at 3.5 bar and about 270cc/min @ 3.0 bar (according to my flow chart from RC). The 350Z injectors do flow about 280-290cc/min @ 3.0 bar but like the Maxima and all of the other returnless fuel system Nissan is using it should be running 3.5 bar (52psi). Hence, they're flowing more than 290cc.

 

I didn't know that this number was based on a fuel rail pressure of 43psi.

 

you also have to consider at what pressure the fuel pump is rated.

all in all, the injectors are not firing at the same time... if they were all opening at the same time, then perhaps you would see a pressure drop as the pump couldnt keep up between cylces, but its fully sequential and not only that but I have never seen a manufacturer one a fuel injector to the max... i believe the typical industry standard is about 85%.

 

I have metered the Maxima ECU and injectors to 80% which is what I think Nissan writes the maps to. JWT used to write programs to take the older ECUs and injectors to 90%.

 

You might want to check the FI forum. There is a lot of discussion going on concerning fuel delivery, and while it is being done on FI'd cars, it still pertains to NA.

-D