Proposal to introduce provisions for non-original replacement silencing systems (NORESS, independent aftermarket muffler systems) with multiple, manually or electronically adjustable, rider-selectable operating modes or variable geometries (NORESS with “flexibilities”). These "flexibilities enable the replacement systems to meet the requirements of Annex 3 (i.e., during testing) while producing much higher noise (sound pressure) outside the Annex 3 conditions. This amendment would require such NORESS to meet the ASEP requirements of UN R9 and UN R41. The amendment further introduces language taken from UN R51. In effect, NORESS with flexibilities performance under normal driving conditions would not be permitted to deviate from its performance under testing.
29. The expert from Germany presented an overview of issues with noise emissions of non-original replacement exhaust silencer systems (NORESS) for L-category vehicles (GRB-67-03), as well as a possible solution in the form of a Supplement 3 to the 01 series to UN Regulation No. 92 (GRB-67-02). Following a brief exchange of views, GRB generally supported the approach and agreed that the proposed modifications should become a new series of amendments. GRB experts were invited to transmit their comments, if any, directly to the expert of Germany, so that he would be able to submit an official document for consideration at the next session.