Remember, we're talking about modifying the ets to allow the evaporator to get colder than spec....therefore the evaporator will freeze literally on the outside. The txv is still operating; it senses cold so it closes....no refridgerant going through. You now have a high side pressure increasing with very little or null low side vapor getting to the compressor. the ford scorpio spec is -2 c on it's evaporator....I want mine lower too.
Here's another thread....
BTW, I think someone had mentioned that the reason that car companies don't utilize more TXV is because of cost....I don't by that in today's economy. Competition is fierce and a main selling factor of the car is it's air conditioning. That comment about cost would be true if we assume both systems employed in that particular car performed the same. That's the right business choice.
I believe that auto engineers use the best system for their car today and it's based on passenger comfort. The argument can be made that car companies don't use a "hybrid" system 'cause it would add another $125.00 to the vehicle when they can get a max cooling cheaper with a FOT....that would make sense too. the only company I know of to use the hybrid is Bentley.
there is a lot of resistance to make things better here when we talk about AC. Replacing the original is good, easy, been there done that, if your benz performs well in your climate. Well, not everyone is that fortunate.
http://www.autoacforum.com/messageview.cfm?catid=2&threadid=14142&FTVAR_MSGDBTABLE=