If I remember correctly it works out to be around 2-3 Enth difference between TIE/Normal/Crunch. It's probably as a percentage but I don't know if it's 20%, 25% or 30%.
Just to be clear it would work like this (let's assume it's 20% and you have 10.0 baseline Enthusiasm)
TIE= 8 'effective' Enth +33% Enth after the game
Normal=10 'effective' Enth +0% Enth after the game
Crunch=12 'effective Enth -50% Enth after the game
Playoff Normal=10 'effective' Enth +33% Enth after the game
Playoff Crunch=12 'effective Enth +0% Enth after the game
As I said it's likely to be a percentage and it might be higher than 20% (but almost definitely not lower), I'm not sure about the exact number.