Loud pop and hiss noise while driving low power

[unspankable]

I thought I blew a boost hose off for the first time but I looked at all the hoses and they all seem good and tight.
What else would make this rapid escape of air noise and cause these symptoms?
When I give it throttle in neutral with no load I hear a whooshing noise and if I give it a lot of throttle it sounds like my blow off valve which is a plumb back is venting to atmosphere.
Can a failed blow off valve cause you symptoms as well?

 

[Erick_V]

Does the car still feel like it has full power? You could have loosened one just enough to hear the hiss but make most of your boost. I’d get back under and jiggle them as if you’re trying to pull them off to verify. Also, OEM piping/BPV? While you’re under there you could verify that the BPV is plugged in and still seated to the turbo. The plug can be accessed from under the car or from the top if you have skinny arms. When I blew a coupler (cold pipe where it connects to the intake manifold) it made the pop then hiss sound under load and obviously no power

 

[unspankable]

S280 with stock piping and Turbosmart Kompact.
I tightened all the hoses.
Loss of power. I think it's something near the turbo charger.
This blows 😔 😂

 

[ronniec687]

S280 with stock piping and Turbosmart Kompact.
I tightened all the hoses.
Loss of power. I think it's something near the turbo charger.
This blows 😔 😂

If your using the shitty worm gear hose clamps that the S280 kit came with id highly suggest replacing them with spring loaded constant tension hose clamps. You can get them much tighter and they wont loosen on their own.

 

[Erick_V]

I’m willing to bet one is just loose enough to cause the hissing, it’s going to be hard to see visually. Have to do a boost leak test to find the leak or you can upgrade the clamps and not worry anymore. I’d use constant tension clamps like @ronniec687 mentioned.

https://www.turbosmart.com/product/...Kl9sX_g9yd79jU_lBJoxhAHkT6-GWyfEVY78e1GTSlsFr

I’m sure there are cheaper options but these tend to work well.

 

[unspankable]

Alright I'll go over everything again. Thank you!

 

[unspankable]

Turned out to be the symposer hose. Thanks for everyone's input!

 

[Erick_V]

Glad you got it figured out!