[SD1 3500]

Whilst showing my teenage son how a turbo works on my newly acquired Ti I noticed the small boost pipe broken off at the turbo. On tracing this back I found it was connected directly to the underside of the throttle body. The previous owner had refitted the original airbox and filter for me and I suspect the aged and brittle hose had been broken off in the process. I had noticed the car seemed a bit flat compared to my test drive when it had a cone filter fitted and after a quick fix now seems better.
My question is, should that hose be connected to the throttle body and does anyone have a diagram for the original factory spec boost pipe system, or could they describe the correct layout?

 

[E_T_V]

I've posted this up a few times I'm sure but here goes again

Inlet manifold
left - short pipe to fuel pressure regulator
Centre - Long pipe to brake servo
Right - 3 nipples. 1 to ECU (long thin pipe). 1 to carbon canister. 1 blanked off (often used for a boost gauge).

Throttle body
Rear lower - Goes to dump valve on the turbo
Front lower - Goes to actuator on the turbo (via the boost control valve if still fitted).

 

[SD1 3500]

Thanks for that, from a quick look the original bmv is still fitted with all pipes and electrical connection in place.
The only other puzzle is when the cone air filter had been fitted something else was altered as there is a 1/2" dia hose with an aftermarket breather filter on the end, I haven't had chance to trace it back yet so not sure where it comes from. The breather from the cam cover is correctly connected to the intake but I wondered if there is another lower down that connects to the air box itself? I'll try and have a look tomorrow, possibly take the airbox out and see if that gives a better insight.

 

[E_T_V]

There are 3 pipes on the original boost valve. One from the throttle body, one to the actuator, and the third runs back to the airbox. It is possible that someone has put a filter on this but it is small diameter.
It is also possible that the aftermarket filter has an extra port on it for the engine breather but it isn't needed/used as the original can sometimes be spliced into the turbo inlet pipe on some induction kits.

 

[SD1 3500]

After removing the battery and air box I've discovered the pipe with the aftermarket breather on the end is connected to the opposite end of the BMV to the hose from the throttle body. I assume from the diagram I've found and advice given on here, that this is the one that should be attached to the airbox. the trouble being I can't see where it attaches to on the airbox, is there anywhere else it could connect to? Also whilst having the BMV off I wanted to test it. I assume the vacuum normally draws through the throttle body port from the airbox connection and when the boost hits its limit the ECU sends voltage to the terminals on the BMV which it will close the airbox connection allowing vacuum to be drawn from the wastegate actuator? just want to make sure everything is in order and working correctly so if anyone can enlighten me as to where the hose actually attaches to and what voltage the BMV operates on(I suspect 12v)I'd be most gratefull.

 

[E_T_V]

Not sure what voltage the boost valve works on. It effectively stops pressure from the inlet reaching the actuator raising the boost pressure beyond what the actuator spring is set at (about 6-7psi).
It does this by rapidly opening and closing to bleed excess air off to the airbox connection, modulating the air pressure that the actuator "sees". Essentially it is an electronic bleed valve.