Is SD worth it without the Custom OS?

[Chris81]

The VE Table cell units are g.K/kPa where the K accounts for intake air temp and kPa accounts for manifold absolute pressure; PCM measures BARO on startup and uses this in VAC calculations, so everything is accounted for...

i.e. if done right, the VE tune will not be affected by [most] weather changes.

Why would the car i'm tuning currently go so lean on a hotter day after I dailed in the VE pretty close a couple days before? The car was setup for AutoVE tuning (SD and OL)

Is it because of open loop?

[ringram]

the pcm tables arnt 100% accurate, so your afr will go off a little, you can try to get to the bottom of the charge blending, or other tables. But often IMO its easier to adjust table A00014 in OS3 to get it in line. There is some info on this, but I run 1% adjustment per 10*C.

[Highlander]

you know... i have seen drifts of 7-10% easily from night to day when humidity gets to dew point and such at night.... there are some nights where there is NO Humidity that it doesn't drift.... i am working on that still...

[Highlander]

Why would the car i'm tuning currently go so lean on a hotter day after I dailed in the VE pretty close a couple days before? The car was setup for AutoVE tuning (SD and OL)

Is it because of open loop?

No.. this could be because of IAT Heatsoaking. check that out...