Air intake temps, turbos, testing?

Charlie Smith charlie at
Fri Sep 28 02:31:34 EDT 2001

Earlier, Michael Gough wrote:
> Hey list,
> I am thinking of doing a bit of comparative testing. I have a standard Audi
> 5000 air intake temp sensor, I assume it gives a resistance based on
> temperature, is there a table somewhere that shows what resistance is given
> at what temp? Or...could a simple water temp guage and sender be used with a
> sender put into an intake pipe before and after the intercooler? I am trying
> to collect data to determine how much my intercooler is cooling down the
> charged air, and also if a newer (more efficient) turbo would be a huge
> benefit or not. I am going to compare the intake temps at 8psi to the intake
> temps on my Volvo 940 (small Mitsu. turbo) at 8psi, and also to temps of a
> K26 and the K24 if anyone here has any data.

A problem using the temperature sensor for something like a water 
temperature gauge is that it may not read high enough, and that it 
may be very slow reacting

If you want to compare air temperatures before and after the intercooler,
get a Davtron model 307 comparative temperature gauge.  This is a digital
unit about 1.25" x 2.5" and about 3" deep.  It includes two temperature 
sensors to install in the air plumbing before and after the intercooler.
It has a 3 position switch for "in", "diff", and "out" readings.  They can make it for degrees F or C, your choice.

Davtron is an aircraft equipment maker.  This is a very high quality unit
and I think it was somewhere around $150, I really don't remember.

Look at:    or here's info from that web page:

                      Davtron Inc. 
                     427 Hillcrest Way 
                   Redwood City, Ca. 94062 
                    Phone (650) 369-1188 
                     Fax (650) 369-9988 

For additional information call us at the number above or email us at
                     mailto:Davtron at 

You can see comparable gauge pictures, although the 307 isn't shown.

    - Charlie

  Charlie Smith   charlie at  614-471-1418      Columbus Ohio   USA     photos & technical info

  95 S6 Quattro  -  24 PSI, RS2 6 speed, and other features  
  96 Dodge Ram   -  30 PSI, w/Cummins turbo diesel

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