I think I know why the mpg of my sister MDX SH-AWD is so bad...
Actually MDX SH-AWD only have torque-vectoring at the two rear wheels, just like my F car, not four wheels. (Sorry, I was wrong in the past!!!)As the torque vectoring at rear wheels could be activated anytime when you make a turn during acceleration, MDX has to constantly transfer the engine power to rear wheels through a very long drive shaft which is longer than the drive shaft of my F car (why? Thanks to the engine and transmission layout of the F car which is a RWD), and also longer than the additional front drive shaft of M35 AWD for the front tires.
However, the front drive shaft of M35 is almost useless except you push the limit, like at least 70% throttle or 50% on wet during a turn!!! (Of course, I will NOT do that on public roads!!!)
I think the additional drive shaft for rear wheels of FWD with AWD function should be longer than the additional front drive shaft of M35 AWD. In addition, AWD on FWD cars should be activated is much more frequency than that of M35 AWD, as AWD on FWD could be activated even when you just give 30% throttle during a turn!!! (why??? during acceleration, the front tires lose grip but rear tires get more grip!!!
)So, I guess the MPG loss of FWD cars with AWD could be even worse than that of RWD cars with AWD!!! That's only my guess. I NEVER has any real world experience!!!
