Does raising the framerate while not changing the bitrate result in quality loss?
If the result of increasing the frame rate is that more pixels are displayed per second, then yes, keeping the bit rate the same will almost certainly mean a loss in overall quality. Not all such losses are objectionable or even necessarily noticeable. For example, if the bit rate is 30 Mb/s and you reduce it to 15 Mb/s, probably not many people would notice.