Hey I was told by my tuner that I needed larger injectors because at high rpm the injectors has less time to shoot the fuel in. He didnt say I needed larger injectors to make more power. He says I could make more power by turning up the boost but that I couldnt rev it as high. But then I spoke to another knowledgable person and he said your injectors are at its highest load at its peak torque not high revs. So i was wondering what I should do...Cuz I was running lean at high boost and high revs. I need to know if it is my fuel setup, I have is setup the endyn way if anyone knows that style (http://www.theoldone.com/articles/fuelpump/). I have it setup the external way. I didnt look under the hood of my car while it was on the dyno either to see if the fuel pressure dropped. But the tuner did a mathematical way to say that I do in fact need larger injectors if i want to rev higher at a higher boost level. Can anyone help me out??

 

well, what do you have?

injectors- size, type (p/h or saturated)
redline
power from car currently?

 

well without answering those questions would you be able to help? I mean the injectors are large enough to make more power but not at such hi revs at such his psi. does that make sense to anyone?

 

Well how can someone figure out if your injectors are maxed out if you dont tell them your setup?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ek00fbp &raquo;</TD></TR><TR><TD CLASS="quote">well without answering those questions would you be able to help? I mean the injectors are large enough to make more power but not at such hi revs at such his psi. does that make sense to anyone?</TD></TR></TABLE>

because the design of the injectors themselves are "flawed".

saturated are slow. if you're running 550 saturated, theres a good chance that they just can't keep up up top
thats why, big injectors are all peak/hold. they are faster, and can be better controlled.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by T-RO &raquo;</TD></TR><TR><TD CLASS="quote">Well how can someone figure out if your injectors are maxed out if you dont tell them your setup?</TD></TR></TABLE>

Im not asking if their maxed out, I'm asking if injectors can start to max out due to high revs??

I know my injectors can be used on setups with more power Im just wondering if high rpm gives the injectors less time to squirt in the fuel thus needing larger injectors not because of the power but because of the lack of time it has to actually inject the fuel. anyone??

 

Yes, the higher the rpm the less time the injector has to spray. For example, you could make 250 ft lbs at 5k rpm and be at only 50% duty cycle and then up around 7500 rpm making only 200 ft lbs and and be at 95% duty cycle even though you're not flowing as much fuel as you were at 5k rpm.

The higher the rpm, the harder/faster the injector has to work (duty cycle).

 

have you looked into a standalone system?

mike

 

Saturated or high impedance injectors work great on stock type engines because they are quieter & don't build up as much heat, but they are also slower reacting.
Peak & hold or low impedance offer a lot more flow and react much quicker. Usually, you can't run a low impedance injector on a stock ECU since the drivers are different. The style of nozzle end also determines how quickly the injectot reacts as well as the spray pattern. Fuel pressure also plays a role. Ideally, you want your injectors to stay within a 70 to 90% duty cycle.

Here is what our injectors will support per injector. Take this figure and multiply it by the number of cylinder you have as a quick way to see if you have enough injector for the power you make.

SCI0310 310cc High Impedance 52-hp per cylinder
SCI0400 400cc High 68-hp
SCI0440 440cc High 77-hp
SCI0525 525cc High 90-hp
SCI0580 580cc Low 100-hp
SCI0680 680cc Low 117-hp
SCI0780 780cc Low 135-hp
SCI0880 880cc Low 117-hp
SCI01000 1000cc Low 151-hp
SCI)1600 1600cc Low 275-hp

Rod Short
Sales Manager
Precision Turbo