The Rochesters are ball type injectors, which are the most efficient type of injector you can put in the engine, especially at higher duty cycles. FIC sells Delphi injectors, which are also ball type, so you're ok either way.


Here's a graphic summary if you want to see each of the three different types:

http://www.sdsefi.com/injectors.htm

 

well i thinking around 600 to 650 to make it fun whatever the 35r kit i get will push out pretty much

 

hmmm... I will get this soon enough... Thanks for clearing that up. I thought the pump DOES change the fuel pressure. But you are saying the basepressure doesn't change even with the A-1000. Correct?

Now I have to get into my head how flow could increase through the same diameter tube yet keeping the same pressure...

 

Thanks

 

The pump just pumps. The regulator governs the pressure. As the boost builds, the regulator allows for more rail pressure, which in turn allows for fuel flow to keep pace with the rising manifold pressure.

The situation with the pump is the more fuel the pump is asked to flow, the less pressure it can maintain. Think of pressure as headroom, or excess flow capacity. The closer to 100% capacity the pump must move, the less headroom it has available to maintain pressure in the line.

 

You're headed for a headache.

The only way flow can increase in a line of fixed size, while maintaining the same pressure, is if you hold the injectors open longer, or get larger injectors.

 

I have noticed that too, the AEM EMS needs larger injectors but since it is a standalone it can run most any sized injector perfectly.

 

Im no good at physics You can manipulate your base pressure is what I meant. I have no idea on the change from one pump to another without change anything else. The fuel pressure regulator is what is making the pressure change, not the pump. Think of this........ You use a pump to pump fluid against a scale and use another pipe to bleed off some of the fluid. Now make the pump bigger... to keep the same pressure you need to make the other pipe bleeding off the liquid bigger... THAT my friend is what the pressure regulator does. You tell it the pressure you want and it makes the hole bigger or smaller in order to keep the pressure the same.

The base pressure doesnt do anything for you except idle and low boost stuff. As long as you are within the 30-70 psi range you would be fine. The problem with the pumps is they can not flow the same at higher pressure.

As far as the injector types, it honestly should not matter much. Anytime you are running the car at WOT the injectors will sooner or later technically spray fuel on the back of the intake valves anyways (How is that for perfect spray pattern) . The injector type matters for idle control, and light throttle. And you should be able to control all the light throttle stuff with anything. If you can control an 880cc to idle, you could control any 880cc injector too.

 

Shouldn't be talking about 100% anything. You should not go over I believe 80% they say. 80 or 90%.


Almost every brand their isn't a difference in price between 800,900,1000's. And if so it is like 10-20 bucks.

WAY better to have spare fuel then not enough. Especially when you can tune out the extra where as tuning out the not enough fuel would mean turn down the boost etc.

That and if you ever change your power levels after why spend another 350-400 on injectors?

 

But it doesn't run the wrong impedance injectors 'perfectly', which is why the wrong size is required to come up with something that works.

 

The only reason the EMS would require larger injectors is if they are the wrong type. An injector is a very simple unit... it opens and closes. It has a hole in it that can flow a certain amount of fuel. Thats it... as long as you can open it the right amount it doesnt matter what you use to drive it (Stock ECU, AEM EMS, Motec, etc). Its a damned hole... nothing more

 

Injectors are typically rated at 80-90% static flow capacity. This means that for calculations purposes, approaching 100% duty is fine, because it's only 80-90% actual duty. Obviously, 100% duty observed via an actual log isn't desirable.

 

I think I got it.
I have to think of the PUMP and the INJECTORS as two DIFFERENT systems, separate by the regulator, even though they are in the same fuel "system". I didn't think of the PUMP it as having over-head and the RETURN fuel line.! :}
This remind of a visit to a chicken farm once. They had the feed on a conveyor belt (pump) and the chicken(injectors) would feed off it. What matter is having *enough* on the belt. You can push MORE feed through the belt but the chicken wouldn't care, any unconsumed feed drops back at the end of the belt... unless there is not enough feed. Then watch out for some crazy chickens!

 

Thats a first... comparing a fuel system to a chicken line L(

That is some funny stuff!

Im glad you got it figured out.

Hey Ted, I was wondering can you confirm that injectors are normally rated at 80-90%? As you can see I have made a pretty extensive excel program to calculate a ton of stuff... I would love to know where i could get the info about specific injectors, I always assumed they were rated at the 43.5 psi static... stuck open.

 

I think it is then the EMS has more PRECISE control over the injector. Being that the EMS needs larger injectors to do the same job. I remember some tuners stating that the ECU has less control over the injectors meaning that they run more fuel as they injectors are open longer then specified. The EMS is perfect therefore larger injectors are needed.