Re: Boost/vacuum numbers...

[STEADIRIC@aol.com]

>   While riding in my friend's '88 5000tq, I noticed that when he let up on
>   the throttle, the boost guage would go down to 0.1 bar; sometimes he
>   says that he can get to 0.0 bar on a long hill.  In my '91 200tq20v,
>   I only get down to 0.4 bar (maybe 0.3 sometimes), but never that low.
>
>0.0Bar is damn hard to produce in a laboratory. His gauge lies big time.
>
>I typically see about 20InHg vacuum on decel, occasionally peaking in
>the 25InHg region, on a fresh engine, all new hoses/etc, expensive and
>accurate gauge.
>
>   Do I have a vacuum leak somewhere?  No obvious driveability problems I
>   can see or feel.  Any ideas of what to check for?  Or is there no
>   problem?
>
>I would think you should see well less than .4Bar, but if you average
>out lying gauges/sensors, you get .2 bar, which is in the right range.
>In a '91, your hoses shouldn't have rotted out yet (unless Audi has
>switched to new high-tech accelerated-rotting hosing), so you're pro-
>bably OK. If your idle is stable, and starting is not a problem, then
>I wouldn't try to fix it, you'll only break something.

Hmmmmm, I typically see 20in/hg crusing, Down to 6.5in/hg closed throttle 
decel. and up to 68in/hg on full boost.  This is all with a Aircraft 
STC'd Sensitive Manifold pressure gauge.  Meaning that it's spot on.


Later!

Eric Fletcher
'87 5KCSTQIA2RSR2B

STEADI RIC@aol.com