Weather changes and SD

[zapp168]

As it is getting colder out what changes in my car should I expect with SD tuning? I have noticed my idle is not as stable as it used to be as the temperature is dropping, I am not sure if something else maybe wrong or just one of the weather changes I have heard with SD.
Thanks

[2002_z28_six_speed]

Listening in...

I am trying to figure this out right now by plotting average AFR by IAT by ECT.

But, I am having problems figuring out an exact formula through aquiring data. The data just goes up and down, up and down. Never the same results each time. I am sure it is out there on the net somewhere.

[Bruce Melton]

The MAF is your friend. How do you think GM builds all weather cars that pass emmissions for 100k miles.
I have tried MAFless here in WI and it was a joke. > Can run without MAF but some days it takes a few tunes if a weather front comes through.

[2002_z28_six_speed]

The MAF is your friend. How do you think GM builds all weather cars that pass emmissions for 100k miles.
I have tried MAFless here in WI and it was a joke.


From my experiences with SDOL I completely argee. It is like what happened to analogue circuits. Analogue and Digital devices can do the same task but digital takes much less design time and there is less to worry about. :rockon:

It is just a better model. Period.

[Gelf VXR]

As it is getting colder out what changes in my car should I expect with SD tuning? I have noticed my idle is not as stable as it used to be as the temperature is dropping, I am not sure if something else maybe wrong or just one of the weather changes I have heard with SD.
Thanks

Do a search on posts by RedHardSupra, he has written a speed density paper and has provided spreadsheats to calculate VE and another that allows you to compensate for atmosperic pressure and temperature and then reflash

[redhardsupra]

sounds like your temperatures dont get accounted for properly, which means your temp blend bias table is off. if your car is going lean at idle, it should get more bias toward IAT, and if it goes rich, it should go toward ECT, in the appopriate airflow range.