CHT Sensor Availability

[pos911neg]

Hello -

I hope this is not a distasteful question on a part vendor site - But has anyone purchased a CHT sensor lately (84' Carrera)? Pelican is out of stock on the Bosch and Porsche part... I am trying to find a replacement brand - but every site I have checked that carries this part is out of stock (********, Rock, FCP, Advance Auto, Ebay, etc......)

Any suggestions or am I in for the $260 Porsche part?

Thanks!!!

Jim.

[Flat6pac]

Read down, there was conversation last week and it crossed BMW part number because Bosch seems not to be available.
Bruce

[darrin]

here's a link to the other thread -- Where to buy cylinder head temp sensors

note that it doesn't look like the CHT addressed in that post was a BMW part after all -- looks like (at least for now), we're stuck with the $260 Porsche part as the only real option, with the Bosch-numbered part generally unavailable

[spuggy]

Or the 993 CHT sensor, which looks remarkably similar, and is available. Or the 914 sensor, which would require converting the spade to a JT plug.

[darrin]

Originally Posted by spuggy

Or the 993 CHT sensor, which looks remarkably similar, and is available. Or the 914 sensor, which would require converting the spade to a JT plug.

spuggy -- do those both register the same resistance values as the one used by our Carreras?

[spuggy]

Originally Posted by darrin

spuggy -- do those both register the same resistance values as the one used by our Carreras?

Response curve of a temperature sensor is dictated by the semi-conductor technology used. Bosch NTC temp sensors all have the same response curve (there's only the one datasheet).

So all you're left with are wiring/connector issues. A 2-wire sensor is better, as the older 1-wire design sometimes had connectivity/grounding issues via the head.

Magneti Marelli, by way of illustration, use a slightly different technology for their sensors. Similar, but different, temperature curve. In practice, I doubt it would cause any issue anyway (because I'm guessing the Motronic just regards <65C as "cold" and > 65C as "hot") - but to give you an idea, the different curve on an MM sensor (if there were one physically suitable for a 3.2) would result in ~10 degrees of error at the very extremes of the scale - like at -40C. The two different curves coincide somewhere around 110C, IIRC. Like, meh, no biggie.

I only know about the MM sensor because Italian vehicles tend to use them; the one for my Monster is stupidly, not-even-funny expensive in a Ducati box, as opposed to buying the same sensor for a Fiat Panda or a Land Rover, or whatever the equivalent was... My issue with the Ducati turned out to be something else entirely - but I pretty much concluded that any Bosch sensor that physically fitted would be "close enough" for practical purposes.