outside air 15 vs 80 degrees @ wot
12-02-2006, 02:07 PM
#1
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outside air 15 vs 80 degrees @ wot what happens does this lean the system or does it run fatter when its
cold and clear sky, af wise , or does the sytem just stay at the same
timing and fuel mix.
cold and clear sky, af wise , or does the sytem just stay at the same
timing and fuel mix.
12-02-2006, 02:33 PM
#2
lower air temperature causes higher air density, and thus, higher airmass. air fuel ratio is used to convert the airflow to fuelflow. then fuel flow is divided through number of injectors and their individual flow capacity into individual pulse widths, providing you with amount of fuel that's proportional to the amount of air in a cylinder.
note that timing tables are referenced against airmass, not airflow or VE. the reason for it is that the airmass is the closest thing we got to compression/torque measurement. more airmass/compression/torque you got, the less timing it needs.
simple version: more airmass needs more fuel, and less timing.
whether you get colder air (nitrous, intercooling, CAI), more pressure(forced induction) or just more effective volume (port, polish, more displacement) is irrelevant.
note that timing tables are referenced against airmass, not airflow or VE. the reason for it is that the airmass is the closest thing we got to compression/torque measurement. more airmass/compression/torque you got, the less timing it needs.
simple version: more airmass needs more fuel, and less timing.
whether you get colder air (nitrous, intercooling, CAI), more pressure(forced induction) or just more effective volume (port, polish, more displacement) is irrelevant.