Thread: Nismotronic SA map tuning.

There seems to be some conflicting info here. If the resistor is not required, why does the instructions say a resistor is needed if using the breakout box?

im no electrician so yes, please explain guys, why the conflicts of info?

Well, with the 5k resistor in series with the IAT, it drops the current in the circuit to .001A, or 1mA. When the IAT starts increasing in resistance, the current will decrease, while the voltage across the IAT increases. This is where the breakout box gets is signal. With the 5k resistor removed from the circuit, the breakout box is seeing higher than normal voltage readings since the 5k resistor will have a low voltage reading across it.

So in other word, the 5k resistor has voltage across it at or around 5v, as the resistance in the IAT increases, the voltage across the 5k resistor decreases and the voltage across the IAT increases, while the current decreases.

If the 5k resistor is in place for circuit protection, I can understand that. But if it is to offset the voltage across the IAT, then it is kinda pointless and a multipliers can be applied in the tuning.

I don't think I want to go this route anymore this Nismotronic is waaayy too confusing man smh.

you dont have to run on a map system, maf's actually work great imo.. you can even sorta have a mixture of the 2, only using the map an iat to log or map to control boost an shit..

tuning nismotronic with a maf is very similar to nistune or calum tuning, sure some stuffs named different an might even work different but its basically very similar..

What do you find confusing?

You should be running the resistor on the IAT circuit, it is there for circuit protection!

The documentation for how to wire it is in the HELP section and on the website, if you follow those instructions it is pretty simple to get it setup and working.

I promise to provide more how to and documentation this fall/winter when things start to slow down at the shop!

And, as Lycnh pointed out .. the MAF based fueling is still available in the SA software. We give you the option to run whatever you feel comfortable with or want to explore and learn how to tune.

For most Nissan tuners, they will pick right up on how the MAF based system works BUT that won't be the case for other tuners that haven't dealt with a Nissan load strategy before. This is why we give you the option to run either (or even both) load sources if you really wanted to.

The resistor limits the current through the IAT thermistor, and also limits the current draw on the 5V power supply in the breakout box. It should definitely be there.

The IAT Installation Instructions includes a wiring diagram.

Dave

Ok, makes sense. Is it safe to assume that the Ecu compensates for the 5k resistor since the iat will never truly reach 5v? I assume there is a natural room for error, +- 5%?

The IAT CONVERSION TABLE (See SETUP tab, SENSORS, IAT SENSOR) sets the voltage to temperature conversion, so you control the resistor compensation. See GM IAT sensor accuracy in this table, which varies with temperature, but is only ±1.0 to 1.4 ºC in a reasonable range of IAT.

Dave

My mistake, I'm used to people using resisters to make the ECU see a certain value, thus I thought he was using it to set a default value, in this case it's different, follow what John and Dave said.