Chiburbian

iTrader: (1)

I have been chasing down an alleged hot running problem with my NB2 that is likely caused by confusion in thermistor calibration.

Can we create a sticky thread with this info? I'd be happy to post it myself once we all agree on the proper default settings.

Here is what I have so far and please correct me if I am incorrect!

GM AIT
Bias: 2490 ohms
48F (): 7000
87F (): 1930
146F (): 560

Stock AIT (NB2?)
Bias: 2490
-4F (): 16150
104F (): 1150
176F (): 330

CLT (NA)
?
?
?

CLT (NB1)
?
?
?

CLT (NB2)
14F (-10C): 9250
71.6F (22C): 2320
176F: (80C): 330

If running in Standalone mode and not sharing sensors, Bias resistor is installed and entered as 2490 ohms in Tunerstudio.

If running in parallel sharing sensor with stock ECU, Bias resistor is not installed on MS and the value 1544 is entered into Tunerstudio.

Chiburbian

iTrader: (1)

Once we get this all sorted out we can change the title and sticky it perhaps?

The problem that I ran into was that as of this morning going into work I was using the values:

CLT
14F (-10C): 9000
68F (20C): 2200
176F: (80C): 320

This was resulting in me routinely indicating 200-218F in 70F degree ambient days in steady cruise down the highway. I got this info from the DIYautotune website labeled as 99-00. Before I can trust what my car is doing I need to have accurate numbers in regards to sensors.

References thus far:
DIYPNP MegaSquirt installation for the Mazda Miata
https://www.miataturbo.net/megasquir...-values-74383/

By the way, in my particular case I may have a defective water temperature gauge, and this thread is part of my troubleshooting process for determining if that has anything to do with my problem. Also, I have been noticing that before I start my car in the morning my coolant reads about 10-12F higher than my indicated AIT (which also seems high compared to weather report, but then I park my car in an enclosed garage)

Braineack

iTrader: (62)

no one should be running parallel.

use RX7 CLT (S4 and S5).

use GM for AIT, if using the GM AIT.

Dont use the stock AIT.

NBs run ~200°F.

All this is documented, either on the DIYPNP instructions pages, or the miataturbo.wikidot.com site done years ago.

Chiburbian

iTrader: (1)

Ok, so the page you reference (wikidot):
Software - Miata Turbo FAQ

Are all model years the same in regards to the RX7 setting in tunerstudio?

Also, I am unable to locate any DIYPNP pages that list the above instructions. The DIYautotune page still lists calibration values.

Braineack

iTrader: (62)

Almost positive that all clt sensors read at the same scale from 90-05--as well as the AIT sensors. The published NB resistance curve matches the rest if you plot them together IIRC.

If you think your CLT sensor is reading too high by 10°F, I'd adjust the bias until it's where you're happy with it. This does not alter the resistance curve but moves the reference point up or down the scale. That will account for any -/+ % error.

Zaphod

Yepp, they are all equal... (If it comes to resistance and readings)

rikaro

so the values is the same for all NA and NB oem sensor? I have having issues getting accurate readings because my 3rd party prosport gauge (sensor mounted on top radiator hose) is reading different values than it is in tunerstudio.

I'm using ms3 basic by rev. and am using these values below.

bias res 2490
CLT (NB2)
14F (-10C): 9250
71.6F (22C): 2320
176F: (80C): 330

240_to_miata

iTrader: (2)

I have used these for my 96
-4*F 16000 ohms
68*F 2450 ohms
140*F 580 ohm

But I have also tested a Rockauto replacement. It was pretty close

https://www.miataturbo.net/megasquir...r-curve-55633/

freedomgli

In Calibrate Thermistor Tables > Common Sensor Values there is the option for "Mazda" and another one for "RX7 (S4&S5)". Which CLT sensors are the developers referring to when they calibrated the table for "Mazda" if the most popular Megasquirt application is Mazda Miatas and they use a setting called RX7?

Braineack

iTrader: (62)

The developer owns[ed] an RX7.


iirc, the curves are actually the same. I'd have to double check.

freedomgli

IIRC, they're not the same, hence the question. I don't have TS in front of me to check how they are different though. I just remember checking them both and seeing that they were different and not knowing which one to choose! There is no documentation on the thermistor common values drop down list options.

freedomgli

Just to close the loop on this one. They're not the same. But at least now I know to use RX-7_CLT(S4 & S5) setting for the OEM NA/NB Miata CLT sensor.