[V8] 5spd throttle body questions

[urq]

AFAIK the dashpot is in effect an emissions control device ... the MT cars
have it because they are often operated at high manifold vacuum (throttle
lift during shifts) which causes high NOx.  It gives the engine RPMs a
chance to drop before the throttle plates completely shut.  

Since #2 has an engine intended for an AT car the TB has no dashpot.  I have
noticed no functional difference on #2 as a result of having no dashpot.
It's a good thing that quattros don't get smogged on the dyno though ... the
lack of dashpot might cause high NOx at shifting.  

My tuppence on the high idle problem is not to worry about the dashpot or
trying to adjust it ... I agree that the problem is likely to be related to
the vapor recovery system.  There's supposed to be a solenoid which closes
the path to the intake from the carbon canister. ISTR reading that you were
able to draw air from the canister ... is perhaps the solenoid remaining
open and allowing air into the engine bypassing the throttle body?  One of
the output checks the ECU has opens and closes the canister valve, you may
want to run this to see if you can hear the valve clicking open and shut ...


Steve B
San Jose, CA (USA)

-----Original Message-----

I had one of those inuitive mornings where you fix things in your mind as
you are slowly waking to concsiousness.  I remembered that the 5spd cars
have the dashpot to aid in engine rpm control during shifts.

Is there any difference other difference between the 3.6 and 4.2 cars?
Venturi diameter, etc?

Also, I seem to recall that someone has used a non 5spd TB on a 5spd car
and reported no real difference or trouble shifting.  Was that you Steve
Buchholz?

I've been paging through etka and realizing/remember just how simple these
are when compared to a turbo 5.  There's like five vacuum lines and 3
breather hoses.  That's it.  Any other vacuum leak would have to come from
something more troublesome like a bad seal on one of the parts of the
intake manifold or throttle body.

Still trying to find some info about adjusting the dashpot.

Ed