Motor Question?
 

<center><img src="http://pictureposter.audiworld.com/61186/2006_0215image0005.jpg"></center><p>
First I would like to thank whomever the top picture belongs to.. sorry I forgot your user ID.

OK heres my ?
on manual cars the vac line pictured above runs right to the brake booster..

but on auto's it splits. one side goes to the brake booster and the other connects to the driver side valve cover which then goes to the plenum..

<img src="http://pictureposter.audiworld.com/61186/dsc01294.jpg">


can anyone tell me if the two setups are interchangeable, or exactly what the auto version does.
I'm considering replacing the pipes and if the simple manual version would work I would prefer to go with that one..

Could it be related to cruise control unit?

Here is a diagram of both systems
 

<img src="http://www.itallics.com/images/auto.jpg">


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<img src="http://www.itallics.com/images/manual.jpg">

anybody?

I suspect the auto-version has a more complex system for a reason
 

... which unfortunately eludes me.

Are you sure we don't have a one-way valve between the IM and brake booster on the 12v with the MT?

It eludes me as well, I 99% positive there is no valves on the manual
 

look at the first pic in the post.. it is just as I remembered it from when evol and I changed his valley pan gasket.. Just one pipe no stops along the way...

OK I was 99% wrong
 

in the first pic the part of the line that is held by the clip is the check valve, its built into the line

I thought I saw one!

are you trying to be an Audi engineer. If they put it there it does something, that any help?

no I'm not
 

I just want to know why its different from the manual..
Its the same engine and that seems like a significant difference but it doesn't seem to be a significant system or they would have done it to both..
I just find it strange.