1989 328. Hyperflow cat with a X-Ost muffler, everything else stock. Recently got an infrared temp guage with laser and decided after a sprited drive to check temps. Cat temp was about 430 F right after shut down, muffler just under 400 and exhaust manifolds about the same as the cat. Are these typical tempuratures? Jeff
Cat temps are measured internally in the heart of the matrix. 400 degrees in there is not uncommon at idle. External temps read with infared are much lower than internal temps and there are so many variables it is really not very meaningful.
