hissing noise on acceleration

[shanilglanza]

hi everyone,
i have noticed a hissing noise when accelerating. i have recently changed the stock turbo to a tongs ct9 hybrid. i had a crack on my exhaust manifold and got it welded but the welder could not weld it completely as the crack was in an awkward place.
can it be the manifold making that hissing noise. when the car is on idle the noise is not there.

 

[Chris_GlanzaV98]

Check the manifold have someone rev the car and have a listen could also be you bov make sure its no opening too early !

 

[JordEP91]

I had the exactly the same thing to find out the manifold was cracked