Exhausts

[munkay]

How big should the exaust outlet be for an RX7?

a friend of mine just had a powerflow system fitted to his RX7
 from the cat back its the same diameter pipe as the standard exhaust all the way through, including the outlet pipe.
the exhaust sound ok until 4000rpm
after 4000 rpm the exhaust whistles getting loudr and louder!
not sounding like an exhaust at all
he had a DTM exhaust on before and that didnt whistle! any ideas? thanks in advance

MuNkAy

[babz_audio]

i wouldnt really fit the powerflow system to an rx7, everyone i know thats had them fitted something has gone wrong, they rattle or aint right...better off buying a jap make or even a second hand one off here