The std vac lines are wrapped close to hot areas simply because they are normal rubber, and will melt.
Heat wrapping a downpipe/manifold has 2 advantages. 1. keeps the bay temps down 2. increases the gas temp, hot gasses flow quicker.
This can put stress on pipework though (causing fatigue), and if the item isnt wrapper correctly, can become a fire hazard. Even a little gap in the wrap can cause extreme heat to 'leak' out.
Heat wrapping a downpipe/manifold has 2 advantages. 1. keeps the bay temps down 2. increases the gas temp, hot gasses flow quicker.
This can put stress on pipework though (causing fatigue), and if the item isnt wrapper correctly, can become a fire hazard. Even a little gap in the wrap can cause extreme heat to 'leak' out.