X15 chuffing through air cleaners at low rpm on jake brake

[Colter]

Everyone is correct that this happens with bad tunes when the VGT vanes start to deform and get hung up on the guide plate.

I would point to the turbo as the issue, aftermarket turbo's here are very common. With a good program and weak or odd jakes it is the issue 95% of the time. The chuffing your getting is most likely the turbo hanging up and getting stuck, the build up of back pressure chuffs back through the engine and out the air cleaners. Overtime it will get worse and usually your boost under load begins to drop as the issues continue.

It's a quality or assembly issue in the turbo, you do save money with aftermarket however you will have issues much earlier then you should or right away. Swapping the turbo (as you stated) is the first thing to try, I wouldn't necessarily recommend replacing right off the hop but if they'll exchange it or some shops carry test turbos it'd be nice to confirm before dropping money on a new one.