At what point should injectors be switched out?
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At what point should injectors be switched out? On 80+% throttle, I'm hitting about 80-90% duty cycle on my stock injectors. Heard a rumor anything above 80%, time to switch them for larger ones. . .thoughts? Thanks
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You should be fine. With a cam is where I had to change. Call it 380 HP. I always ask. What is your A/F ratio at WOT? It should be 12.8 or so. If you are below 85 - 90% you should be good. My freind ran at 115% for a while.
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Basic flow dynamics and electrical theory here. Injectors, like any other electronic solenoid's are built to operate at 80% of there capacity, once you see over 80% duty cycle, they may still work but you are going to shorten the life of them considerably. My general motto is, 80% or under = good, 80% or over time to upgrade
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So, yes, time to upgrade. Now, I'm sure I'm mistaken, but I should have 26#'ers. I think I've read this is based on 45# pressure, yet stock pressure is about 56-58# right? So, IF I plan on getting to say 5-600 rwhp, should I go for say 45's? Thanks!
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From what I've read, it's not so much about hurting the injector, but rather you're not injecting the amount of fuel in the window of opportunity before the intake valve begins to close. Granted, bigger cam yeilds a longer duration of the intake valve being open, but still, we're talking about miliseconds of available injection window. So know the computer calls for a certain duration of injector to be open and that could be longer than the intake valve is open. Now you get puddling on top of the intake valve which further complicates matters in terms of air fuel ratio.
The scanner logs Duty Cycle as injector %. Look for Inj.%. When you go wide open throttle watch the % > 80% you want to start shopping for injectors or have your piggy bank ready for when the stockers fail.
This also depends on how you've gone about tuning your PCM. If you have tweaked your IFR tables instead of tuning the airflow tables and commanded fueling, the PCM's calculation of IDC will be skewed.