I was gone when they implemented MASC. I see a button for it on my keyboard options, but I don't really know what it is or anything about it.
In short Enables your mech to go faster (around 10% faster) and have a better acceleration and deceleration for a short period of time, at the cost of damaging your mech's legs if you go over the 75% threshold. I found this old piece on the forum because I'm lazy to write down everything, but except for the missing speed part, it seems ok http://mwomercs.com/forums/topic/211372-masc/ EDIT: I've used it only on the shadow cat because you can't strip it off, so as you may have guessed I'm not a huge fan of it.
MASC stands for Massive-Ass-Super-Charger, and its stronger than the big ass super charger see it as a turbo charger where you mech suddenly gain great gains on the ass and decided to run faster with meks having the MASC, a slow mech can suddenly run fast, or quick turns or stop and go motions. if you meks have MASC option for it to put on, id say put it on, let the big girl of yours has that stronk butt-clapping muscle. see video as references
It is like sticking poison needles into your muscles for extra power, you get to make it faster but there is a chance of it exploding on a bad dice roll, so to speak. It can get you do ludicrus speed, but turn it on too long and you start taking leg damage when it comes to MWO.
