Running my car open loop sd ,this is pretty common to do while tuning the car but really why do I need to run closed loop at all? Cant I just dial in 14.7 at idle and cruise, 12.8 at wot and of course car adjusts for my boost in speed density. Why do we need the 02s bounching around trying to maintain 14.7 why can't just set the car to 14.7 with no 02 interference. And 02 s are getting expensive and prone to going bad ,then your mileage goes to heck ,etc.

So whats the pros and cons to running closed loop versus full time open especially in speed density cars like mine.

 

The main issue I'm seeing is, the fueling gets kicked
around big time by IAT (weather and recent driving
history). I see AFR swings of 2 full points (14.5:1
normal, 16-17:1 off a hot park).

Either a lot more finesse with the temperature modeling,
an IAT relocate (still wanting some work for the "real
weather" variation(liable to be huge where you live),
or close the loop.

 

i just live with the iat heatsoak and run my idle afr at 14.0 for normal IATs. In stop/go traffic it may bounce around from 14-16afr but since Im just putting along in traffic when this happens its no biggie.