Does this sound like a boost leak or something worse?

[22john]

Hi, installed a K&N air box and HFAF not too long ago, however at high throttle in second gear I get a weird high pitched whistle.

You can hear it in this video at about 0:04 as I accelerate out from around the bend..
https://www.youtube.com/watch?v=IXk4U7xIUbo

I'm thinking that it's a leak where the air box meets the intake hose as I've had some trouble making it fit perfectly. What is the easiest way to test for a boost leak here?

Also, has anyone else fitted this K&N Kit (57s-9500) and had trouble with it not fitting perfectly?

 

[sjb2190]

You should be able to feel a boost leak. Alternatively send smoke up the pipe from another point?