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injector duty cycle

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Old 05-27-09, 11:10 PM
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NY injector duty cycle

I am wondering if i am running out of injector. I just went out for a street tune, 12 psi, low 11. afr's on 650/1000 injectors. rewired Supra pump, stock regulator, 35R, and i don't remember exactly but i think the injector times was at 6.xx MS on the logger.
I haven't ben on the dyno with this set up yet, so i don't know how much it's making. i just want to know if i can run a little more boost or am i maxing out those injectors. i know i should just get bigger secondaries, but i want to see where i'm at power wise.
Old 05-27-09, 11:15 PM
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such high duty cycles at that boost level can also be caused by low fuel pressure. just my 2 cents though as i'm no guru on this forum.
Old 05-28-09, 12:09 AM
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Originally Posted by killahrx7
such high duty cycles at that boost level can also be caused by low fuel pressure. just my 2 cents though as i'm no guru on this forum.

I 2nd that...
I ran 550-1600's to 22psi and this was running mid 10's afr.. Was seeing in the mid 80's duty..
Old 05-28-09, 05:08 PM
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well i have tried using duty cycle calculators and could not come up with a solid percentage. does anyone know of a good known way to find out. i tried searching but it leads to dead links.

how did you guys come to the conclusion of my high duty cycles? i am running a microtech and i can still richen it up more. i just want to know if they are near their capacity.
Old 05-29-09, 10:14 AM
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like i said i'm no guru but there's a thread somewhere explaining duty cycles. what i normally go by is when the milliseconds are reaching close to 8 millisecs. i know that my duty cycles are close to a 100 % duty cycle. also your ecu should show you what duty cycle your running at. now my point that i was trying to explain is that one of the reasons why you have such high millisecs at 12 psi is that your fuel volume or pressure not sufficent so you have to make the injectors pulse at that rate. try replacing the regulator with an aeromotive with a guage so you can see your fuel pressure.
Old 05-29-09, 11:02 AM
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https://www.rx7club.com/single-turbo-rx-7s-23/my-ems-lists-injector-duty-milliseconds-how-do-i-know-%25-duty-831881/
Old 05-31-09, 05:58 PM
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it looks like as it sits, my duty cycles are in the 80%+ range. unless someone can give me confirmation.
Old 06-03-09, 09:11 PM
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Originally Posted by pistones
it looks like as it sits, my duty cycles are in the 80%+ range. unless someone can give me confirmation.
Depends.

You can run 80 percent on your primaries and only 50 percent on you secondaries.

Do the math for each.

I wouldn't recommend using "what the EMS told me" for IDC.

Is that primaries, secondaries, average? Just look at your maps.

A poorly tuned 850cc/1600cc can run out of injector on a stock car.

To get the most out of your injectors find the sweet spot between the two.

Try to run both primaries and secondaries at 80 percent or lower at your choosen RPM.
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