HI there,
Thanks for your replies.
I appreciate what induction noise is, I have years of experience preparing and modifying vehicles on two and four wheels, this noise in not normal induction "roar" which i would find desirable.
This noise is the same as the noise you get when blowing across a bottle top, (except much louder) and I guess it is being caused by resonance in the plastic air box/pipes, or something within the MAF sensor housing vibrating.
As I found a noticeable gain in performance with increased low down torque, and a little more top end power, I propose the replace the air box/ducting system from the throttle bodies back and fabricate my own out of 3 inch silicone hoses.
Thanks for your help, and if anyone has any pointers for construction then I would appreciate them.
Jonny