Good morning all , wonder if anyone may shed some light on this. I have a fab vrs and a Ibiza fr 130 . ( fabia feels better in every way ) 

my question is . If I release the vacuum pipes from n75 on the fabia I get a hiss ( like I’m releasing a build up of pressure ) if I do same on the Ibiza I get nothing .. both seem to drive ok . Although the Ibiza doesn’t feel as lively .. both stg1 too .. I’ve not investigated at all and I have no eml lights on .. 

I have no idea what that box actually does 

It controls the turbo vanes, it does this by bleeding air into the vacuum line which is the hiss you can hear.

1 hour ago, sepulchrave said:

It controls the turbo vanes, it does this by bleeding air into the vacuum line which is the hiss you can hear.

Thanks for the reply . So it should hiss when unplugging the vac lines .. so my next question is I’m guessing the Ibiza has a leak somewhere.. ! As no hiss 

Did you unplug the vac line that goes to the vac supply or to the actuator? Did you definetly take off the same pipe on each car?

 

Was the car running when you did this?

Thanks for reply . I unplugged the vac lines as a whole from the box . Car was turned off .. the fabia makes a hiss sound , like it had a build up of pressure and the Ibiza is silent .. only difference I notice with the Ibiza is turbo seems to come in later then the fabia . I wonder if this is connected 

Why are you unplugging vac lines?. The Fabia vrs has a vacuum storage canister at the front of the engine bay.

32 minutes ago, Gt4thomas said:

Why are you unplugging vac lines?. The Fabia vrs has a vacuum storage canister at the front of the engine bay.

This is where I unplugged from . As a whole .. there’s a wire clip . You pull that all all the lines come off as one . 

3 hours ago, serafumi said:

Thanks for reply . I unplugged the vac lines as a whole from the box . Car was turned off .. the fabia makes a hiss sound , like it had a build up of pressure and the Ibiza is silent .. only difference I notice with the Ibiza is turbo seems to come in later then the fabia . I wonder if this is connected 

 

I would say there is probably an NRV passing or a small leak causing all the stored vacuum to dissapate quicker on one rather than the other, assuming you had them both running at the same time and then turned them off and unplugged the vac lines at the same time on both cars?

 

I would say its probably not affecting performance or you would be getting underboost codes but to prove anything you could do with plotting actual boost vs requested on a steady 3rd or 4th gear pull with VCDS and see what the curves look like. Maybe each one is mapped differently

 

If it ain't broke...

.......fix it until it is?