op-amps

[xxalexx at ix.netcom.com]

> I have been told that the following tip can be used at the track
> to realize some real performance gains (2/10 -3/10 quicker and .3 to .4
> mph faster in the 1/4 mile.  Disconnect the IAT (intake air temperature)
> sensor and plug in a xxk ohm resistor to fool the computer staying in
> "warm up" mode.  Can an op-amp be used to achieve the same result?
> 
> Another tip was to put a 2nd water temperature sensor in the windshield
> fluid container and wire this to a switch in conjunction with the normal
> water temperature wiring.  Could an op-amp be used instead of this set up?
> 
> Thanks for any opinions.
Temperature sensors or thermistors, which are resistors
that vary with temperature.  
The circuit is a voltage divider.
5V ---resistor---computer  voltmeter-------------thermistor---grd.
 Many cars room temp. is between 3-4 volts.
hot less than 1 volt.  All shop manuals will list temperature
voltage or at least resistance.
Place a 10K pot in series in the thermistor line to lower temp.
or to ground to raise temp.
Water temp. will have bigger  affect.
Alex