what is this big peice of plastic in my engine compartment????????

ok i have an 87 mr2 the air intake starts at the passanger side of my car goes round the back of the trunk then on the drivers side it goes into an filter thats on the inside of my trunk, then it goes into the enginge compartment and right inside the enginge compatrment there is a t connector one way goes to the engine and the other way goes up to this big empty plastic container like thing. does any one know what the hell this thing does??????????? it doesnt look like it does anything to me. please help..

If it is similar to the MKIIs, I believe it is called a resonator box.
It is designed to reduce the noise of the intake.

hyde is correct, you can remove all that and get an aftermarket intake. your car will sound better and have a little more push

I found out the intake is in the trunk to help with emissions (heat from engine bay)... despite how stupid it may look. I mean... what kind of airflow can you get inside a bloody trunk?!

The scoop on the passenger side of the car leads around the trunk and directly into the air filter.
That is where the air flow comes from.