reisskahn

My stage 3 4x4 saph has been running shite for the last few months boost has for reason dropped to 16psi and its decideds to miss and splutter (rev counter goes berserk) every now then

Ive noticed when the car is started from cold or in the mornings theres a hissing noise coming from around the Turbo area. Upon inspection couldn't figure where it was coming from exactly but took the air hose to turbo pipe off and noticed the compressor wheel is slightly spinning/rotating when the car is idling.

It looks like its struggling to rotate on idle but rotates just fine if i decide to rev the engine.

Question is, is the compressor wheel supposed to be rotating/spinning when the car is idling as i seen another saph today and it wasn't doing that on idle?

Theres no play or movement in the shaft/wheel or any oil in there aswell

tabetha

Sounds quite normal, you need to find your hissing noise, as this is most likely your lost boost.
Check also that the exhaust is tight as they come loose at the turbo, if plates aren't used to hold them, this will lose boost also.
tabetha