Originally Posted by mikemike616
Yeah I actually thought that might be the problem initially but it just didn't make sense to me that colder temperatures would result in lower boost. The weather has gotten continually colder since the tune was done. I'll email the tuner. How do I know if my tune is locked?
As the air gets colder and denser it becomes easier for the turbo to make more boost. To combat this and keep the boost constant the ECU will reduce WGDC's based on intake temperature. If you install an aftermarket EBCS the WG does not have to work as hard to reach boost since it is now in interrupt mode so generally your WGDC table is lower than stock.
Now the TD table for intake temp lowers WGDC's by total percent based on how low the intake temps get. If these tables are left stock the ECU will pull out too much WGDC because the stock values are now too aggressive. If you need less WGDC to reach boost target, you also need less NEGATIVE WGDC Compensation as the air gets colder. Basically, the IAT vs WGDC compensation table is possibly too aggressive.