Coolant Temp sender

[Steve_D]

Does anyone have a source where I can search for a sender with a certain resistance at 100 degree C?

The TVR temp gauge is well known for giving a low reading. I can put a variable resistor on the gauge and measure the resistance needed for, say, 100* so with that figure I'm hoping to find a sensor which gives a better match. I'm not even concerned about thread size as that can be resolved.

Many thanks
Steve

[stevieturbo]

Or a different gauge ?

Not all sensors are linear too, which could cause problems

Or something like this

https://www.spiyda.com/magento/index.php/fuel-gaug...

I'd say for normal OEM type sensors you'd struggle to get any resistance curves for them. For some more modern 2 wire you might do, a lot may be the same or close to the Bosch NTC, eg

http://www.bosch-motorsport.de/media/catalog_resou...

These can be bought very cheap

[Steve_D]

Thanks Steve.
I had forgotten about those wizards. Seems the most obvious choice when time=money.

There are probably more versions out there so was that one you know and trust or just the first you found as an example?

I've had a quick look around and people seem happy with it and how well you can match the setup.

Steve

[stevieturbo]

Steve_D said:

Thanks Steve.
I had forgotten about those wizards. Seems the most obvious choice when time=money.

There are probably more versions out there so was that one you know and trust or just the first you found as an example?

I've had a quick look around and people seem happy with it and how well you can match the setup.

Steve

I've never used it myself, but as far as I've seen it's about the only one out there, and it's a guy in England who makes them.

I have seen some US sellers offer one...but it looks like they've copied Spidya's and increased the price.

[Steve_D]

Thanks will get one on order in the morning.

Steve

[Evoluzione]

Something like this?

http://www.eltekgroup.it/var/public/10082300_WTS%2...

The WTS05 has loads of charts for it too:

http://www.compsystems.com.au/joobi/user/media/ima...

http://livedoor.blogimg.jp/tedesco/imgs/4/e/4e24c0...

[Steve_D]

Evoluzione said:

Something like this?

http://www.eltekgroup.it/var/public/10082300_WTS%2...

The WTS05 has loads of charts for it too:

http://www.compsystems.com.au/joobi/user/media/ima...

http://livedoor.blogimg.jp/tedesco/imgs/4/e/4e24c0...

Its much the same as I have been finding. None match the 133ohm @ 100 degrees that my gauge needs. Even if it did at 100* I doubt it would be right across a range.
Whilst the wizard is expensive I'm keen to see if it works then perhaps offer it as an option for our customers.

Steve

[E-bmw]

I take it your temperature gauge is within the instrument binnacle, if not why not just get something like this that is the closest match to the others.

http://www.ebay.co.uk/itm/2-52mm-Universal-Car-Poi...

[Steve_D]

The gauge is normally in a veneered dash with all the instruments matching in style so aftermarket is not really an option.
I'm liking the wizard as it will arrive at a match even if the gauge itself is out of calibration which is always a possibility at 20+ years old.

Steve

[anonymous-user]

Really annoys me when you see the prcie of those little circuits, with £3 worth of processor and no automotive rated parts on it (stupid screw connections, no environmental protection, no load dump protection etc) pretty much total crap they charge you lots of money for!!

[Steve_D]

Max_Torque said:

Really annoys me when you see the prcie of those little circuits, with £3 worth of processor and no automotive rated parts on it (stupid screw connections, no environmental protection, no load dump protection etc) pretty much total crap they charge you lots of money for!!

Yes, but if you don't have the expertise to make it yourself then you have little option.

Steve

[stevieturbo]

Steve_D said:

Yes, but if you don't have the expertise to make it yourself then you have little option.

Steve

Exactly !!

Maybe Max will make a cheaper batch

[AER]

If you only want it correct at a single point (i.e. 100°C) you could put a variable resistor across it (i.e. in parallel with the sensor) and tweak it to measure the correct value, then replace this with a fixed resistor of the same value.

[Steve_D]

AER said:

If you only want it correct at a single point (i.e. 100°C) you could put a variable resistor across it (i.e. in parallel with the sensor) and tweak it to measure the correct value, then replace this with a fixed resistor of the same value.

True but you are left wondering what is happening elsewhere in the range.
I want to be in a position to offer a true fix for our TVR customers.

Steve

[AER]

The measuring circuit of a thermistor input is usually tuned anyway to the give the appropriate resolution over the temperature window you want to measure by changing the fixed resistor values, so you might find your best solution isn't actually another thermistor, but a tweak of these fixed resistor values in the measurement circuit. If you can "get in there" and figure out what they are, it's not too difficult to estimate the thermistor coefficient and work out what the resistor network needs to look like to correct your measurement.