I have a 4" 45* elbow. I used thin wall "sewer" pipe PVC in white.
the 4" filter slides right on the 4" pipe. I did not try to attach it to the elbow directly. there is a small sleeve or about 2" of pipe coming out of the elbow that it connects to.
from there the 4" end of the rubber coupler goes over the other side of the 4" elbow (again a 2" sleeve) and the 3" end stretches tight over the TB and clamps down.
Visit your local Home Depot Racing/Ace Hardware Racing location for all appropriate parts
