Most likely that register is for return air. Not a good idea to close it. The burner gets intake air from the PVC/outside. The actual air that gets heated and cooled is separate and has nothing to do with the PVC intake or exhaust. The more return air the better.
__________________
99 Z28 Trick Flow 215s milled to 61cc 228/232 Cam Fast 102 built 4l65e trans 4000 converter 12 bolt 410s Electric WP deleted PS/AC Dyno & Track tuned
2015 ATS Coupe. AWD 2.0 Turbo
2012 2500hd Silverado with LTZ 20s on 35x12.5x20
86 Buick GN Lesabre 1 of 117 (4-Sale)
|