As of now, Heat Crash only has three variables for user weight, 21.8 lbs/9.9 kg (Tepig) 122.4 lbs/55.4 kg (Pignite) 330.7lbs/150 kg (Emboar).

The calculation of Heat Crash's damage is based on the user's weight and the target's weight.

gamefreak may have already have programmed the game so Heat Crash's variables for the user's weight is the weight for Tepig, Pignite, and Emboar. If so, the calculation would always be:

r = 21.8 lbs/9.9 kg ÷ TargetWeight

r = 122.4 lbs/55.4 kg ÷ TargetWeight

r = 330.7lbs/150 kg ÷ TargetWeight

Did Gamefreak program the games so that Heat Crash would only do damage for the weights of Tepig, Pignite, and Emboar?

If they did, how would Heat Crashe's damage be calculated if it was hacked onto a Pokemon that does not learn Heat Crash?