[urq] Re: Throttle Body Port

[sdewitt at stx.rr.com]

There is no such port. Sounds as if you'll have to install a venturi before the turbo to get what your seeking.

----- Original Message -----
From: Ben Swann <benswann at comcast.net>
Date: Thursday, April 14, 2005 9:42 am
Subject: Re: Throttle Body Port

> I tee'd a line off this and ran to a guage inside the car.  
> Results were not
> quite as anticipated.
> 
> The port is under vacuum in most cases.  The most vacuum occurs as the
> throttle body is opening up - as in under acceleration while 
> pushing the
> pedal down.  Vacuum only goes to around 0.8 bar  (-5 PSI) and positive
> pressure to only around .3 bar/4 PSI - these are rough numbers, 
> but show
> what is happening.  The positive pressure occurs only under 
> maximum boost
> when the throttle is held steady or perhaps closing.  I beleive it is
> venturi effect mostly, but sometimes manifold pressure comes into 
> play.
> This port is noramlly used to control the Carbon Canister Valve, 
> and I was
> going to try to use it for another purpose.
> 
> Where might one get a vacuum source that is directly proportional 
> to the
> airflow in the engine and not related to boost?  That is highest 
> vacuum at
> max flow which is perhaps even at high boost.
> 
> Ben
> ----- Original Message -----
> From: "Ben Swann" <benswann at comcast.net>
> To: <urq at audifans.com>; <quattro at audifans.com>
> Cc: "Ben Swann" <benswann at comcast.net>
> Sent: Friday, April 08, 2005 10:55 PM
> Subject: Throttle Body Port
> 
> 
> > I'm still trying to confirm what this port does exactly.  Not 
> what it is
> > being used for, but weather it is alsways vacuum  and directly
> proportional
> > to the airflow through the throttle body and weather the engine 
> is under
> > boost or vacuum doesn't matter.
> >
> >
> > [What exactly does the throttle body port on the UrQ(and others) 
> do?  By
> > that, how does it behave?  Is it using venturi effect to induce 
> increasing> vacuum as flow through TB increases.  Is it always 
> vacuum - even under
> > boost.  Is its highest reading at max flow?
> >
> > Anyone know for sure?
> >
> > Ben]
> >
> 
> _______________________________________________
> quattro mailing list
> quattro at audifans.com
> http://www.audifans.com/mailman/listinfo/quattro
>