>Can some explain to me how this works on a WBX engine?
>Where does it plug in?
>
>http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7919042067&category=46100

Well, it says it plugs in to the IAT  sensor harness, I'm guessing it goes
in INSTEAD of the IAT (Intake Air Temp) sensor. I've heard of "tweak" mods
for Chevy and Dodge engines where you wire in a resistor instead of the IAT
and it gives you a tiny bit of extra "go", so I'm guessing this is just a
potentiometer of the appropriate range to allow you to turn it on or off.
Really, it seems like a dumb thing to do. The IAT is there for a reason,
right? Probably fuel economy, I'd say. I guess if you trick the ECU into
thinking it's getting colder air it runs richer? Advances the timing?
Frangles the spidnik valves harder? Whatever it is, I figure the VAG
Digifant engineers put it there for something, so it's probably better off
left in the loop. Can't imagine that it'd be useful, as you apparently only
get about 7hp when running if the wasserboxer's preferred operating range
of 2000-4000rpm, and that the promised  22hp doesn't show up until 5000rpm
or more (hard to tell-- the graph he has is hard to read). I don't think
I've even had mine over 4500rpm. They say on the Dodge and Chevy message
boards that you're better off getting a good K&N filter and making sure
you're feeding it plenty of cold, outside air.

John Bange
'90 Vanagon "Geldsauger"