You wont get a blow off sound from that you will just get turbo chatter/stall Sounds like you got pidgeons under the bonnet but sexual pidgeons There re mixed views on doing this as people say it reduces turbo life but some people have mentioned they have run without BOV's for severla yrs etc with no problems it just depends on the condition of the turbo etc hope this helps bud Oh yea go on youtube and search for turbo stall, compressor stall, turbo chatter etc ;)