Not at all.
It will have the same vacuum at 7 feet that it would at 4 feet with all other details being equal.
You can't just T it into the pipe though (didn't know if you knew or not)
There are three way of putting the tube into the pipe, and I always prefered number 2 over the others.
1 works fine
2 is my personal favorite
3 seems hacked in to me, but works fine too.
Notice the angle on 1 and 3 ends inside the pipe.
All three will generate plenty of vacuum for case evac.