I'm guessing here. What you probably have is a "k" type thermocouple with
some kind of amplifier.  If you lengthen the wires you risk changing the
resistance, thereby changing the accuracy.  The extension cables might have
a known resistance and made out of some oxygen free metal.

Regards,

Mike

----- Original Message -----
From: "David Marshall" <vanagon@VOLKSWAGEN.ORG>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, December 28, 2003 12:37 PM
Subject: What makes a pyrometer's cable so special?

> I just bought a VDO Pyrometer for a customers 1.9TD installation.  VDO
> stressed to me that the cable can not be lengthened and if you need a
longer
> cable than what comes with the kit I must order one that length.
>
> So, I ordered the gauge and a 14' cable that goes between the sensor on
the
> exhaust manifold and the gauge.
>
> The cable that came with the gauge and the additional 14' long cable is
two
> conductor, looks like aluminium 16 ga wire for each conductor.  There is
> nothing [to me] that appears to be 'special' about this cable other than
the
> freaking price that I paid for it.  There is no shielding and the plastic
> covering that covers the two wires seems to be a little extra tough.
>
> Can someone enlighten me about what I am missing here!
>
> Also, on a semi-related note, how hot is too hot for a Turbo Diesel motor?
>
> Thanks in advance!
>
> David Marshall
>
> Fast Forward Automotive Inc.
> 4356 Quesnel-Hixon Road
> Quesnel BC Canada  V2J 6Z3
>
> http://www.fastforward.ca    mailto:sales@fastforward.ca
> Phone: (250) 992 7775        FAX: (250) 992 1160
>
> - Vanagon Accessories and Engine Conversions
> - Vanagon, Transporter and Iltis Sales and Importation
> - European Lighting for most Volkswagen models
>
>
> Due to the large volume of email  we  receive,  PLEASE  include  previous
> emails when responding.  This will allow us to read the complete dialogue
> in one message and will result in quicker and more  accurate  responses.
>
> David Marshall
>
> Fast Forward Automotive Inc.
> 4356 Quesnel-Hixon Road
> Quesnel BC Canada  V2J 6Z3
>
> http://www.fastforward.ca    mailto:sales@fastforward.ca
> Phone: (250) 992 7775        FAX: (250) 992 1160
>
> - Vanagon Accessories and Engine Conversions
> - Vanagon, Transporter and Iltis Sales and Importation
> - European Lighting for most Volkswagen models
>
>
> Due to the large volume of email  we  receive,  PLEASE  include  previous
> emails when responding.  This will allow us to read the complete dialogue
> in one message and will result in quicker and more  accurate  responses.