Leaderboard

So with the tooth wheel sorted, it's time to check & calibrate all the other inputs, the Speeduino needs to run. Coolant Temperature: I built a coolant sensor, using a precision NTC thermistor probe, I have, with an R25 value of 10K ohms. All of the temp sender units, I've collected over the years, are single wire ones, using the engine block & the chassis earthing system, for the return of the "resistance" circuit. I wanted to make all the sensors feeding into the Speeduino, to be two (2) wire, so that there is only one earthing point for them all, back within the Speeduino PCB itself. I grabbed an old sensor, & drilled out all the sensor element, until it was a clean bare brass shell. Then I inserted the insulated thermistor probe, & glued it in with Aradite. Then to calibrate in for use with the Speeduino. The standard "bias" resistor fitted to the Speeduino PCB has a value of 2490 ohms. That works out well, as the 10K ohm thermistor, has resistance values of 20 deg C (19.9) = 12.566K ohms 60 deg C (59.9) = 2.5K ohm 100 deg C (100.5) = 0.669K ohm So the mid point of the range we are wanting the readings to be most accurate, is 60 deg C, where the resistance of 2.5K ohm, is almost exactly the same as the bias resistor, at 2.49K ohm. That should provide good accuracy. I plugged all the three temp points & their corresponding ohm values, into the settings, in TS, & burnt it to the Speeduino processor. As the coolant measurement, will be in the 80-95 deg C range, most of the time, I decided to check it with the only standard high temperature, I have handy, which is boiling water. Off to the kitchen to "borrow" my wife's electric kettle. I suspended the probe inside, & it read 20 deg C, which was the ambient temp here this morning. Then I turned on the kettle & watched the temperature rise through the range in Tuner Studio, until it stopped at 100 deg C, just as it boiled. So fitted it to the engine, at the highest point of the water coolant system. Next sensor will be the TPS (Throttle Position Sensor), which I've just pulled off my 7K EFO setup. P.S. I had been concerned that I was going to have to reroute the coolant drain cock, located directly below the water pump, whose removal was just blocked by the addition of the Toothed Wheel. However, I discovered if I rotated the engine, so that the "missing tooth", was opposite the end of the drain cock, it was possible to remove the drain cock, with a socket. Cheers Banjo