On the bulkhead there is a black box with lots of vacuum tubes on it. The clipped section on mine was not secured and I was getting lots of strange noises at 1500 rpm and on shutdown. I have since clipped it back in place and the car seems to be running so much better and a whole lot quieter. It may be placebo but I am curious as to what it is and what it controls?

It's the vacuum box.

 

It controls the turbo actuator, anti shudder valve etc.

 

So I'm not surprised your car is running better now!

 

It uses the vacuum from a pump and then controls which pipe to "suck" on to activate the turbo etc.

 

If there's been a leak then it may not have been able to move the turbo veins enough.

Edited 9 June, 201511 yr by Phil-E

I am guessing that strange noise was down the the anti shudder valve not shutting down the engine quick enough. It now seems to stop the engine instantly! Happy man here lol, hope it has not caused any damage anywhere.

Correct. It closes a valves and blocks the air intake into the engine to stop the engine running-on slightly and prevent it from shuddering.

 

Only possible damage could be a tiny bit extra wear on the engine mounts but probably nothing to worry about.

 

Did your car used to kick out black smoke before if you got your foot down?

 

Phil

I have never seen even the slightest puff of smoke from it Phil. It had an MOT fast pass on emissions of 0.01 which surprised me