I just installed the Stillen z-tube/open air K&N/Stillen airbox combo. Love the sound of it, but when I initially step on the throttle there is almost a chirp sound from the airbox (like a sharp whistle) but only at the initiation of throttle, nothing afterwards. Do I need to re-check the MAS/airbox connection to make sure it's seal well, or is this normal? Thanks!

 

yes

 

Yes to which part - that the sound is normal, or there is likely a leak at the MAS/airbox connection?

The thing that confuses me is that if there is a leak there I would expect that whistling sound to occur under all types of throttle, instead or just when I get on it initially. Though, I guess it can't hurt to check.

 

I get it too, usually around like 3-4k rpms partial throttle, checked for leaks time and time again, even had others check. I guess its just normal. I don't notice it at all when its hot out and the cars been running for a few minutes either

 

sounds is normal with any cone filter.