Injector pulse width
Sep 11, 2006, 05:19 PM
#1
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Injector pulse width
Is there a calculation to convert IPW into IDC (duty cycle)? Im seeing around 17-18.5ms from 4500 on up and want to know the duty cycle of the injectors. Any info is appreciated.
Sep 11, 2006, 05:45 PM
#2
Below is somebody elses math but maybe you can use it:
PW in ms max is based on where you redline is.
For example 6500rpm redline
Max PW = (60,000 / (6500 + 500)) * .85 where .85 is max IDC
Max PW in ms = 7.2 ms
So at redline the max available time for your injectors to be open is 7.2ms
18-19ms would be >100% IDC
PW in ms max is based on where you redline is.
For example 6500rpm redline
Max PW = (60,000 / (6500 + 500)) * .85 where .85 is max IDC
Max PW in ms = 7.2 ms
So at redline the max available time for your injectors to be open is 7.2ms
18-19ms would be >100% IDC
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uneekvisions (Jan 19, 2023)
Sep 11, 2006, 07:41 PM
#6
Originally Posted by C6C6CH3vo
Below is somebody elses math but maybe you can use it:
PW in ms max is based on where you redline is.
For example 6500rpm redline
Max PW = (60,000 / (6500 + 500)) * .85 where .85 is max IDC
Max PW in ms = 7.2 ms
So at redline the max available time for your injectors to be open is 7.2ms
18-19ms would be >100% IDC
PW in ms max is based on where you redline is.
For example 6500rpm redline
Max PW = (60,000 / (6500 + 500)) * .85 where .85 is max IDC
Max PW in ms = 7.2 ms
So at redline the max available time for your injectors to be open is 7.2ms
18-19ms would be >100% IDC
invert
18.46 ms/cycle
So, 18.46ms would be 100% IDC @ 6500RPM
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Sep 12, 2006, 05:54 AM
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Originally Posted by AlwaysinBoost
damn! I'm at 95% duty cycle from 5300-6500.
. I'm ordering bigger injectors this morning.-Paul
Sep 12, 2006, 06:14 AM
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I've got a set of 1000cc injectors sitting on the shelf. I just wonder if that will be overkill for my stockish setup. Also a little worried about controlling them with the ECUFlash as I've never scaled injectors or adjusted the latency before.
Sep 12, 2006, 06:50 AM
#12
Originally Posted by PVD04
That's nothing, I saw over 100% from 6500 RPM on up . I'm ordering bigger injectors this morning.
-Paul
. I'm ordering bigger injectors this morning.-Paul
Nevermind. I see that the other formula does not use 85% to get the IDC.
Last edited by mrfred; Sep 12, 2006 at 06:53 AM.
Sep 12, 2006, 07:21 AM
#13
Originally Posted by AlwaysinBoost
I've got a set of 1000cc injectors sitting on the shelf. I just wonder if that will be overkill for my stockish setup. Also a little worried about controlling them with the ECUFlash as I've never scaled injectors or adjusted the latency before.
Then, you adjust the scale until your fuel trims at idle are very close to zero..
Then drive the car around for awhile, and see how off the long term fuel trims get after a long drive.. At that point you can adjust the 11v and 14v injector voltage latency settings until overall you get your trims while driving in check.. Then you'll have to adjust idle one more time.
What this will do is it should get your fuel injectors, to read "ROUGHLY" close to what your fuel map looks like by the numbers.. Its not quite right, but it should be similar..
Doing this will give you the best drivability and then you can tune your maps... Just remember to make the maps rich to start before you do too much..
Sep 12, 2006, 09:40 AM
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Originally Posted by PVD04
That's nothing, I saw over 100% from 6500 RPM on up . I'm ordering bigger injectors this morning.
. I'm ordering bigger injectors this morning.