Is vacuum unit needed?

[Smudgemanuk]

The pipes going into my vacuum unit are looking very scabby, so I was about to fit some new pipe, when i wondered...

What does this unit actually do?
Is it needed or can it be removed?

Part diagram depicted below

Thanks Chris

 

[Nodzed]

Hi, no its not, its for US emission's, not all Euro Zeds had them fitted and can easily be blanked off, you can get the blanking plates on her, try @t-tony

 

[Nodzed]

Hi, no its not, its for US emission's, not all Euro Zeds had them fitted and can easily be blanked off, you can get the blanking plates on her, try @t-tony

I could be talking Botox I am referring to the smog pump, are you?

 

[Rudyrov]

The system in the picture above opens and closes a valve in the muffler or silencer.
I don't think it does anything important, if mine had it I would block it off and be done with it.

 

[Jam03]

Seems like you want to do the equivalent of the “golf tee” mod. I don’t know the full details, but I doubt it’s a system required to be working to get through an MOT.

 

[colb]

Nodzed is referring to the secondary air pump/fan in the engine bay that runs for a few seconds when the car is cold started, it pushes air into the exhaust to lower emissions for the USA market. Its not required here in the UK and has no effect on the MOT. As Nodzed says @t-tony makes blanking plates to delete this and get rid of the pump/fan unit. The blanking plate replaces the silver round one way valve attached to the front right of the cylinder head. The exhaust system in the diagram is for a valve or flap in the exhaust, that can be deleted but lines need to be plugged either end.
Item 15 in the diagram here shows secondary air system valve that can be deleted and replaced by the blanking plate. Plug the other hose that is fitted to it as well.
https://www.realoem.com/bmw/en/showparts?id=CM12-EUR-12-1999-Z3-BMW-Z3_19&diagId=11_6199

 

[Stevo7682]

If your car has a valved exhaust must be a Tu so will also have secondary air pump
But back to exhaust valve most run open all the time as they don't work right anymore
The valve in the exhaust if open best left alone intrical part of that bit if exit pipe .
The vacuum line goes to the solenoid unit which is located in the left boot recess behind carpet.

You will find the little black unit with 2 vacuum pipes one from front one from valve on exhaust with engine running pipe from front has permanent vacuum if younwere to hace engine running bypass the solenoid join the 2 vacuum pipes together should shut exhaust valve and keep it shut letting you know valve is working and vacuum hoses ok.
Problem then lies with solenoid of power supply from wherever that comes from not actuating it in normal use.
Stephen.

 

[Smudgemanuk]

If your car has a valved exhaust must be a Tu so will also have secondary air pump
But back to exhaust valve most run open all the time as they don't work right anymore
The valve in the exhaust if open best left alone intrical part of that bit if exit pipe .
The vacuum line goes to the solenoid unit which is located in the left boot recess behind carpet.

You will find the little black unit with 2 vacuum pipes one from front one from valve on exhaust with engine running pipe from front has permanent vacuum if younwere to hace engine running bypass the solenoid join the 2 vacuum pipes together should shut exhaust valve and keep it shut letting you know valve is working and vacuum hoses ok.
Problem then lies with solenoid of power supply from wherever that comes from not actuating it in normal use.
Stephen.

Perfect, thank you

That is pleasant news to learn my car has a valved exhaust!

Much appreciated

 

[Smudgemanuk]

Thanks for all your help everyone

I have learnt lots from this thread! Even more from the whole forum

 

[Rhek]

Quick question
If you have an aftermarket exhaust without valve, if vacuum hose not blanked off will that affect emissions? Or running/ mpg
Thank you