I did something very similar for awhile. I put a short ram intake from a '95 Civic DX in my '96 Accord LX.

The only thing I really got out of it compared to a proper intake was better (i.e. louder and deeper) sound. The gas mileage seemed to go up by 1-2 MPG too, but that was probably just wishful thinking.

Honestly, I think it's a bad idea. Too much dirty air right there.