Then you just have to honk, especially when people are shouting for you too! Just couldn’t resist, wish i’d have drained the tank but always next time lol!
Event was to celebrate 10 years of the MG “Zed” series of cars by MG-Rover, and took part in the loudest exhaust competition. IIRC i came second with 120db or something like that. Only i just found these videos from a member on the club, d’oh! Better late then never 
http://www.youtube.com/watch?v=aPs4rjOl3yg
http://www.youtube.com/watch?feature=player_detailpage&v=mqh85urCwoY#t=0s