tune in open or closed?

[zooguy]

do tuners tune in open loop or closed loop?

cause i was thinking, driving around in normal the car warms up and goes in to closed loop. and gets better MPG, idles lower, and a few other things.

well at the track a car makes a pass or two and warms up ... going in to closed loop. then you wait for it to cool off and watch some races adjust tire pressure ... doesnt the car go back in to open loop then? unless you wait for it to warm up for like 5min before you make a pass again. wouldnt that make the car run a little bit richer throwing off your A/F ratio and not making max HP/TQ and maybe fouling plugs?

if a tuner can tune my open loop to be leaner, why run O2 sensors just for them to go bad and cause my car to run bad.

[OutCast]

Not sure if it will answer your question or not but the link below has a wealth of info.

http://www.lt1pcmtuning.com/tips/

[05hd]

I always tune in open loop then add closed loop if it is wanted. Our cars go back into open loop for WOT anyway so max power shouldn't be affected either way if it is tuned right.

[SexyTransAm]

by the time you do a burn out and stage the car is goin to be back in closed loop. but at WOT the pcm reads off open loop tables

[zooguy]

so tuners tune open loop for max power and closed loop for drive ability and mpg's?

[SeanMac]

I've only tuned code 59 so it may not be the same on our cars but... You tune the table or map that you're working on. When the car is running in open loop it does exactly what you've input on those tables or maps. When the car goes to closed loop it takes those tables and input from the O2 sensors to adjust those settings as it needs to get a perfect afr.
On code 59 we could also specify what afr we wanted in closed loop because it required wideband O2s, not sure if that's possible with nb or not.

Any tuners chime in on that? I'm curious to get tuning on this car sometime. Sucks being a 97 tho, not many choices unless I go lsx pcm I think.

HTH