fuel pump ratings

[Guest Anonymous]

anyone know what the factory 280ZXT fuel pump is rated at in gallons per hour at 36psi? how about at higher psi?

and will it hurt injectors if they are ran static(100% open) the whole time while this powerplant is running? will the injectors be able to close when i want them to?

[BLKMGK]

Umm, I'm confused on the injector question - how will they run 100% static full time?! And yes, this will damage them if done that way. Injectors are electromagnets and heat up when turned on - if run 100% static for a decent length of time damage WILL occur. In fact, it's been said that you shouldn't run them more than about 85% as a general rule of thumb but I've done it (ahem).

[Guest Anonymous]

well, the won't be used on any combustion engine! i guess i could make or buy an electronic unit that could alternate between 2 injectors instead of just one. so then they could cool down between pulses.

[Kevin Shasteen]

I dont know what the stock Datsun/Nissan fuel pumps ratings are but in a book I was reading about fuel injectors they made mention that not all injectors are eqaul-I'm not just talking about their flow rates either.

 

In addition to selecting the correct injector size one must also make sure a new injector is electronically compatible to the computer that drives it.

 

Futher, the book claims there are only two types of injectors:

1)Saturated = High Impedence or Voltage Mode Types

2)Peak-and-Hold = Low Impedence/or current mode types

 

The book stated if you wished to confirm which type your injectors are you would merely measure its resistance w/an ohmmeter; Saturated injectors resistance falls into the 22-16ohms while the Peak-and Hold injectors only put out about 2-5ohms.

 

Most US passenber cars usa a 12volt saturated injector that uses 12volts to open/close it. These are high resistance injectors that maintain low current flow in the injectors and drivers to keep them cool for longer life. Saturated circuits usually have slower response time which limits their operating range.

 

Book also said not to go beyond the .80/85% duty cycle for too long.

 

Oh well; hoped you enjoyed the book report.

 

Kevin,

(Yea,Still an Inliner)

[BLKMGK]

Correct. PeakHold injectors are "faster" and can supposedly be used with both types of drivers but the saturated cannot be used on a driver setup made for peakhold. The peakhold injectors "snap" open and can be idled down further as I recall. there's a point with injectors where you try to open and close them so fast that hysterysis (sp?!) sets in. The mass of the pintle etc. prevents the injector from opening when the signal is sent for a short period of time, if you try to close the injector before this time period has passed the injector never opens or opens only partially. The result is no fuel or a dribble instead of an atomized spray. Idle quality obviously goes right out the window! I believe that this would be worst on batch fire systems like the older DFI.

 

Also, don't forget that 100% duty cycle isn't a static number. As RPM increases this number gets smaller as there's less time between firings. I ran one of my old maps through an Excel spreadsheet once and was a bit surprised to find that I was static at some points. It's a good idea when programming an ECU to run the math through an Excel spreadsheet so you know where that point is for each RPM.

 

Oh, and I don't think Iever damaged my injectors with this abuse but I do know that one of them was dribbling - the EGTs on one side were ALWAYS colder and the O2 reading was of as well. I think I even managed to figure out which injector it was by pulling plug wires till I found the one that made the least difference in the readings