Kombi valves

[DOS_GRID]

I've got an 01 Allroad and plan on deleting my SAIP. However I would like to keep the Kombi Valves. I have been around enough to have seen the block off plates people install, but that would make the Kombis serve no purpose whatsoever. Has anyone ever tried a small cone filter on the Kombis? Would it create a draw through the filter (venturi effect) when open? Or would it fill the engine bay with exhaust from a push/blow from the Kombis?

[Racin2redline]

Kombi valves and sai are usually deleted because after a few years they are ineffective and clogged with carbon .
the whole idea of the airpump is when a car first starts it is usually rich and emits more emissions than a warmed up engine.
the air pump forces air into the exhaust system via the kombis to create a more lean condition (hotter) and heats the cats up faster to prevent more emissions

if you just delete the sai in a tune and remove the airpump, you can just leave the kombis in place and render them useless

removing the airpump without a tune to kill the vacuum actuated valve will just open the kombis and dump exhaust into the engine bay and cause a huge leak

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[DOS_GRID]

Yes, when the car first starts it needs to run richer so the system allows atmospheric air into the system prior to the O2 sensors and tricks the ECU into a lean condition causing it to run richer. As far as I know, a tune does nothing to kill the vacuum actuated valve (because it is vacuum actuated not electrical) but I do not know what actuates the vac (it may be an electrical actuated spool...) There are no sensors on the pump except electrical load, which is why some deletes of the pump involve a resistor. What makes me wonder though is the internals of the head, would it pull 'some' air into the exhaust w/o the pump? Codes or not, doesn't matter to me. There are a lot of us who have had cracked SAIP tubing without exhaust smells but the Kombis may have been seized shut to begin with. Why leave the Kombis and put in a delete plate instead of just pulling the Kombis all together? I should have posted this in a more broad classification like 2.7T other than allroad specific. And yes, I understand this system has been argued to death, but I have yet to find someone who has run a GOOD system without the pump to see what happens.

[DOS_GRID]

Yup, I see it now... The vac lines go up to an electrical block in back of the intake manifold. Perhaps it is electrically actuated. Hard to see it. Thanks, good call. If I am to do a true 'total' delete, this vac supply (to the block) may come in handy for other purposes.

[frankwizzle]

Highly recommend the full sai delete, there's so much room with all crap out of the way. Cam cap plugs and valve cover gaskets are waaay easier to do.