100% + duty cycle?
Thread Starter
single digit dreamer
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From: omaha ne
100% + duty cycle? i got one for ya, this would take a scope to see i am betting, if your injectors are at 100% or higher dutycycle do they truley stay wide open?
a friend of mine is telling me that you can't get the injector to be open 100% of the time, he says it will always close between cycles even if the cycles are overlaping? what do you all think?
a friend of mine is telling me that you can't get the injector to be open 100% of the time, he says it will always close between cycles even if the cycles are overlaping? what do you all think?
Re: 100% + duty cycle? I've seen others post that their injector duty cycle exceeds 100% based upon ATAP readings.
If you have substantial mods (like FI or a heads + big cam), it may be time to move up.
If you have substantial mods (like FI or a heads + big cam), it may be time to move up.
On The Tree
Joined: Jun 2002
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From: Sacramento
Re: 100% + duty cycle? The injector is just a solenoid. If you apply power to it 100% of the time (a 100% duty cycle), then it will never close.
If you want to see this for yourself you could get an injector plug from a junkyard car (doesn't have to be a ls1) and apply +12 to the injector from the battery. Wont hurt anything. You'll notice that it staysclicks when you connect/disconnect it.
If you were to hook this up to a fuel rail and pressurize it, it'd stay on for as long as you've got it hooked up. Yup, I've done this <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
- Steve
If you want to see this for yourself you could get an injector plug from a junkyard car (doesn't have to be a ls1) and apply +12 to the injector from the battery. Wont hurt anything. You'll notice that it staysclicks when you connect/disconnect it.
If you were to hook this up to a fuel rail and pressurize it, it'd stay on for as long as you've got it hooked up. Yup, I've done this <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
- Steve
Thread Starter
single digit dreamer
iTrader: (6)
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From: omaha ne
Re: 100% + duty cycle? i understand the part about the injector just being a solenoid, what i am not sure about is if the computer asks for the injector to be open for 30ms and it only has 20ms before the computer asks for another 30ms does it just stay on or does it shut off briefly before opening again
Adkoonerstrator
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From: Deep in the seedy underworld of Koonerville
Re: 100% + duty cycle? When the injector is at 100% duty cycle it doesn't have a choice but to stay open all the time. Its just a stupid solenoid and will stay open as long as 12volts are there. There is no loop between the injector and computer to let the puter know that the injector is running all the time. The injector can't close if the computer signals are overlapping(100+% duty cycle).
One thing I will say is that the injector pulsewidth info from Atap may be off a little. I calculated my duty cycle before and it was actually over 100% by like 4000rpm but, the O2's did not start dropping off until around 6000 rpm. This kinda shows that there was still enough fuel being delivered even though Atap was saying the injectors were maxed out long ago.
Get those big injectors in there and you won't have to worry about duty cycle anymore. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
John
One thing I will say is that the injector pulsewidth info from Atap may be off a little. I calculated my duty cycle before and it was actually over 100% by like 4000rpm but, the O2's did not start dropping off until around 6000 rpm. This kinda shows that there was still enough fuel being delivered even though Atap was saying the injectors were maxed out long ago.
Get those big injectors in there and you won't have to worry about duty cycle anymore. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
John
