Boost all over the place in freezing temperatures

[mfish]

I'm FBO with inlets on a 93 pump custom MHD self tune. Boost is dialed in under normal conditions.

With the same exact tune the boost is all over the place in really cold weather (around 15 degrees Fahrenheit)

Is there anything I can change in the tune so boost will be well controlled in low temps?

Regular Temps (around 50 degrees) - Normal Boost 1: http://datazap.me/u/mfish123/normal-boost-regular-temps

Regular Temps - Normal Boost 2 (around 50 degrees): http://datazap.me/u/mfish123/normal-...emps-example-2

Freezing Temps - Oscillating Boost 1: http://datazap.me/u/mfish123/freezin...illating-boost

Freezing Temps - Oscillating Boost 2: http://datazap.me/u/mfish123/freezin...oost-example-2

[V8Bait]

WGDC and PID tables likely not matched well. Would help to have WGDC base and after PID logged to see which one is the culprit, but probably the base table or airflow adders are too high. Throttle is basically what's controlling your boost for you

[andy_divers]

Yep. You have you dc and pid setup to give you the boost you want in normal conditions. At 15*f those values are too "strong" for that air resulting in actual load exceeding target load. Oscillations are from the dme riding the target boost line while the needed DC to hold boost is much lower than normal

[mfish]

Thanks for the feedback. Correct me if I'm wrong, but it sounds like I'd need a "regular temps" map and a "freezing temps" map, right? If I was to tune for freezing temps by lowering the base and adders wouldn't I then under boost in regular temps.

[andy_divers]

No. You need to use you pid tables to be more active in hitting target load instead of raising you base dutys.