Air temp senor Q's..
Turbo Mini Forums

Just bought one on e these cheapies less the sensor..

http://cgi.ebay.co.uk/CYBERDYNE-DIGITAL-AM...A1%7C240%3A1318

Will any sensor do, like one from a scrappy rather than buying the factory item from the states?

If a scrappy sensor will do which car and where on them should I be searching?

Thanks in advance.

JF.

different sensors have different temperature/resistance curves. without knowing the correct sensor for that gauge, it would be impossible to say what would be suitable.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

OK, thanks, that is a start...

Maybe I will have to buy the factory item usless i find that all important restistance.

JF.

its not jsut a resistance, its a curve, for megasquirt (for example) its calculated as the resistance at 0 degrees 25 ish degrees and 100 degrees and a best fit curve through these points. its not always linear :(

im sure a temp gauge with a proper thermocouple (k-type) wont run to much, and it would be more accurate than anythign relying on an automotive temp sender.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Looks like you will have to get one of these:



Not a standard sensor by any means.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Cheers paul...

I have found the sites for these items, i believe there is an older type "3 wire" guage, i suspect i have this type.

I do not have it in my possession yet.

My aim is to have 3 sensors, one measure air just in front of the filter, ie the before turbo compression.

Another in the plenum and another in the inlet manifold so i can regulate and check upen inlet temps and see if exhaust wraps and heatshield air etc..

i plan to have the gauge switchable to these sensors..

Could prove a few things

JF.

Most, but not all, temperature sensors on modern cars are NTC2500 type.

Typically Rover use the green sensor for air temp.

Two wires, one to earth the other to the gauge.

You could always try one and see if it gives a reasonable value.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Yes, anywhere close will do.

Just to guage the drops and peaks.

A bit like out famous TM banannas.

JF.

This is what you are looking for:

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

If you only want comparison between the three (rather than absolute readings), you obviously need three identical ones.

Before you buy three sensors, I would suggest one of these

http://www.maplin.co.uk/Module.aspx?ModuleNo=2205

probably the 4k7 ohm one (I think the NCT2500 is 0 to 5k ohms but Paul can put me right)..... and try it first to see if you get a sensible sweep of readings

Schrödinger's cat - so which one am I ???

Looks like a good plan Rod, to kind of dial it in to a "near enough" figure?

I had planned to use 3 sensors that are identical.

Thanks for all the input.

Could be a geat little set up for pre cooler/after cooler readings...

JF.

Basically to make sure the gauge operates over the resistance range of the (3) sensors you intend to buy - and to prove the gauge works before you buy three sensors !!!

To actually see if the temperature was "correct" (ie, calibrate it) you would need to get a bit more sophisticated and have access to the temperature/resistance curves of the chosen sensor(s) and a DVM with a high impedance ohm range to measure the actual resistance of the potentiometer as you swing it about and see if it matches the curve...... All starts to get a bit complicated.....

But seriously, just a simple potentiometer like the Maplins one, provided it has got the same range as the sensors you would be buying, will show you if you are in the right ballpark.

Schrödinger's cat - so which one am I ???

once youve got a sensor you could always rig up a test rig on the stove with a thermometer and a bowl of pan of water.

no longer a series, but still 1.3 turbo.

i mean a metal bowl called a pan lol

no longer a series, but still 1.3 turbo.