Race Technology

I am trying to use as much of the original sensors. Currently I am trying to get the watertemp sensor and the MAP sensor connected to the DL1.

Does anyone have a mathematical program to generate a formula after I have taken measurements?

Also, I am trying to find out how the pull-up resistor of 1kOhm needs to be wired. Any help is welcome.

ps: Love the DL1

Hi:

Kyle Disque, who sometimes posts here, has very successfully used Excel to extract the equation from the data.

Regards,

Thanks a lot Al ...

Here is a diagram of how to wire in the pull up resistor:


For the math, I used Excel (on Martin's recomendation).

1. You need to have a table of actual values and sensor's resistances at those values.
2. Then, to get the milli volt output you create a column with the formula: "= <input voltage>*<Sensor Ohms>/(<Resistor Ohms>+<Sensor Ohms>)*1000" replaceing all the <>'d values with constants or cell references.
3. Then create an X/Y skatter graph of the actual values and the millivolt output
4. Right click on the graph plot line and select "add trendline".
5. Make the trend line a third order polynomial
6. Right click on the trendline and select "format trendline"
7. Under options select "display equation on chart"
8. Right click on the equation and select "Format data lables"
9. Under Number select Number and set Decimal places to 8
10 Take a bow, you're done

I'm not so sure about using the original sensors, if they're still being used by the ECU. I'm no EE, but if the impedance of the ECU is higher than the DL1, it will mess up the signals to the ECU. Even it's not higher, it mat mess it up. You should consult with someone knowledgeable in EE to make sure. Martin/Andy .... ?

-Kyle

If it's still connected to the EFI, then you shouldn't need the pull-up resistor: that's already being provided. Just connect a single wire from the side of the sensor where the voltage varies (stare at your wiring diagram... one side will be connected to ground, or to a reference voltage... or both for a tps. Look for the wire that doen't go to any other sensor).

For the impedance, as long as the parallel combination of the EFI & DL1 input impedances is much bigger than the sensor resistance, then you're fine. I can't imagine that it wouldn't be ok. I've done it on a GSXR600 (water temp, manifold pressure, throttle position sensor) and it worked fine