Discussion and questions related to the course Motorsport Wiring Fundamentals
Im looking into Oil Temp/Pressure options and came across a newer dual sensor Bosch unit.
The piece I'm looking into specifically is the PST-F1 unit to measure oil temp/pressure however the document mentions the use of a 4.6kOhm pull up and the Haltech Elite can only do 1k.
Here is where things get confusing for me; Bosch's site states this regarding the temp portion "For temperature measurement please use a pull-up resistor with an optimal value of 4.6 kOhm." After doing some digging, the resistance value seems almost identical to the their more common sensors that dont mention any pull up resistor.
Here is the link to the PST-F1 sensor info - Bosch PST-F1
And this is a PDF of a Bosch NTC Sensor - Bosch Motorsports Temp sensor
Is it a safe assumption the PST-F1 will work just fine by using the calibration provided without the use of a pullup resistor?
it will work with the 1K pullup resistor and the calibration that counts on that.
By using a different resistor, you get a larger voltage range and thus increased resolution. That is why they say that is "optimal"
For most fluid temps you will actually get better resolution with the 1K pull-up anyway. With 4.6K you will only get better resolution at temps below about 30°C which is not generally the operating range you are interested in for oil temp.
Thanks for clarifying guys! I didn't quite understand how the pull up resistors affected sensor resolution before
Tacking on to an existing thread here - has anybody had any success using this sensor mounted in a direct to engine block application in a racing scenario?
It has to be mounted direct to the engine since it has the temp sensor on the tip so it was designed to work like this. And yes, it is the only pressure sensor that I havent yet had one fail (or heard of one failing from any customer) when direct mounted to race engines.
Thank you. I was waffling and located a second port on my engine block so decided to go with standalone pressure and temp sensors for the oil system for redundancy/peace of mind.