Road tuning - MAF calibration in cold weather

i'm tuning a 2018 WRX using Cobb and I live in Saskatchewan. I made some calibration changes to the MAF sensor. When I went out on the road to test it the next day, the temperature had changed by about 10 degrees. During testing, the DAM dropped to 0.625 and there were negative values in feedback knock and fine knock learn. What sort of considerations should i take into account when tuning with weather changes like this?

Hi Eric,

There is no one answer for how you should make ignition compensations based on temps. If the car has been fully tuned on the dyno in most circumstances it will need some checks and tweaks on the road. 9/10 The stock compensation tables are pretty damn close.

The Subaru DAM systems can be a great setup and sometimes frustrating. I find it can be very sensitive and can swing ignition in massive steps. Adding quite a bit of advance, hitting knock then pulling out timing. This will show when your DAM drops and you have knock corrections

Did you get logs of the points where knock was detected? Had it been adding the maximum timing and went to far and picked up knock? When it was tuned was it at DAM 1? I have seen a few times people add timing to the main ignition map when the DAM is at .5 or lower, they tune to the knock threshold then send the car out. As the DAM increases it starts knocking.

The tune is based on Cobb's off the shelf map for stage 1 + Big SF on 91 octane. The DAM resets to 1 on reflash. I didn't add any timing aside from the OTS map. Also, this WRX has never been dyno tuned, only road tuned. I've removed some timing in the problem areas and it is helping. It looks like the area the knock starts to show is partial throttle, full power pulls are knock free