Chip PT Pressure Transducer Question ECU

Brandon Rogers brogers at
Wed Nov 10 12:44:17 EST 2004

FWIW - I've got an Autometer vacuum/boost gauge plumbed in - it shows about
11 psi vacuum at idle and about 16-17 psi vaccum under decel, where anything
less than Atmosphere is considered vacuum.  Hopefully that makes sense.


----- Original Message ----- 
From: "Ben Swann" <benswann at>
To: <suffolkD at>
Cc: <quattro at>; <200q20v at>
Sent: Wednesday, November 10, 2004 7:08 AM
Subject: Re: Chip PT Pressure Transducer Question ECU

The recalibrated PT will show less than actual boost.   You need to plumb a
guage in - tee in just prior to the ECU port.


[Date: Tue, 9 Nov 2004 23:20:18 EST
From: SuffolkD at
Subject: Re: Chip PT Pressure Transducer Question ECU
To: 200q20v at, quattro at
Message-ID: <111.3cc0a7d5.2ec2f102 at>
Content-Type: text/plain; charset="US-ASCII"

Minhea chip question.

The ECU now has a modified PT.
So when the car had the stock PT setting the dash showed 1.8 bar at "full"

Mine had leaks and issues which a few of us focused on and fixed/repaired.
Now the Chipped ECU only reads 1.6 max no matter what (it was 1.3-1.5 in the
Yes 93 octane fuel used........

Q:  WHEN the PT is "recalibrated" does the dash display read lower because
the mod/recalibration?
So 1.6 = 1.8/9 stock?

Also, where would the best place to T into the vacuum lines for a VDO boost
By the ECU not optimum?

I've been told chipped cars read 0.9 at start up, but my old 10V avant
0.9 non"chipped"..........even 0.1 under vacuum deceleration.
TIA - Scott by BOSTON]
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