charlie2020
10-05-2002, 02:21 PM
Maybe someone with an *MDM or Apex AVCR can help out with stock injector duty cycle at idle with *259cc. What im trying to figure out is lets say I heard that the duty cycle (this is just an example) at idle is 2% with 259cc injector and stock ECU.
How much fuel is 2% of 259cc/min or 24.6lb/hr = 5.18cc/min or .492lb/hr
VS
How much fuel will be inexcess with everything the same except now 370cc/min or 35.2lb/hr with a 2% duty cycle at idle = 7.4cc/min or .704lb/hr
(259cc/min) 5.18cc/min vs (370cc/min) 7.4cc/min = 38.332% bigger
I really can't get this accurate until someone tells me the stock ECU duty cycle at idle with 259cc/min injectors.
The reason behind this is because I want to prove to my self that this is true and why my SAFC has to be leaned out at idle some 27% to be able to maintain 14.7 A/F ratio.
So no matter what, your car weather turbo'd or NA with bigger injectors, you will always need the the same amount of fuel required as when it was NA at idle with stock ECU and injectors, and for that matter probably holds true for the first
2,500 - 2,750 rpms because you really are not making that big a difference over stock. No wonder drivability just keeps getting better the more I lean out the first few thousand rpms of Low throttle driving and gas milage improve.
So I come to the conclusion that the one of the MAJOR difference (but not all) between a 259cc ECU and 370cc ECU is the modification of the duty cyle/injector pulse width at idle and the first few thousand rpms until the actual full 370cc is needed this why a stock ECU works pretty good in stock fourm except idle and the first few thousand rpms but once you get going the right amount is fuel (370cc) is now there but a little to much fuel in stock fourm.
Please correct me if I am wrong.:confused: ;)
What I explained above totally jives with settings on the SAFC with stock ECU which are generally Lean to Less lean
1 2 3 4 5 6 7 7500rpm
Lean-----------------------Less Lean------------------Even Less Leaner
How much fuel is 2% of 259cc/min or 24.6lb/hr = 5.18cc/min or .492lb/hr
VS
How much fuel will be inexcess with everything the same except now 370cc/min or 35.2lb/hr with a 2% duty cycle at idle = 7.4cc/min or .704lb/hr
(259cc/min) 5.18cc/min vs (370cc/min) 7.4cc/min = 38.332% bigger
I really can't get this accurate until someone tells me the stock ECU duty cycle at idle with 259cc/min injectors.
The reason behind this is because I want to prove to my self that this is true and why my SAFC has to be leaned out at idle some 27% to be able to maintain 14.7 A/F ratio.
So no matter what, your car weather turbo'd or NA with bigger injectors, you will always need the the same amount of fuel required as when it was NA at idle with stock ECU and injectors, and for that matter probably holds true for the first
2,500 - 2,750 rpms because you really are not making that big a difference over stock. No wonder drivability just keeps getting better the more I lean out the first few thousand rpms of Low throttle driving and gas milage improve.
So I come to the conclusion that the one of the MAJOR difference (but not all) between a 259cc ECU and 370cc ECU is the modification of the duty cyle/injector pulse width at idle and the first few thousand rpms until the actual full 370cc is needed this why a stock ECU works pretty good in stock fourm except idle and the first few thousand rpms but once you get going the right amount is fuel (370cc) is now there but a little to much fuel in stock fourm.
Please correct me if I am wrong.:confused: ;)
What I explained above totally jives with settings on the SAFC with stock ECU which are generally Lean to Less lean
1 2 3 4 5 6 7 7500rpm
Lean-----------------------Less Lean------------------Even Less Leaner