whirring noise from kenne bell

[phantom_87]

Hi guys i got a kennebell kit installed in my falcon about 2 weeks ago and it has now started to give a whirring sound after the first week.

When i first picked the car up it never made the sound it has now. It happens when the rpm is just lifted above idle and when driving it happens when the car is on a steady rpm and on down revs.
when i lift the throttle i am ever so slightly touching the accerator.

We took the belt of the car to eliminate that the noise was coming from the engine. Then i also put the standard belt on to bypass the blower and the noise was also not there.
We then put the normal belt back on and the whirring noise was back.

Is this meant to be normal or do you think i should take it back to the shop to have it looked at.
Only reason i am asking is because it wasnt happening for the first week and a half of having the kit fitted.
I know these blowers are meant to give a whinding noise when under abit of acceleration.

Thanks
Daniel