a post mostly about temperature dots

radix023 · 11-17-2018, 09:00 AM

so I've recently changed the device I'm using for Torque and setting things back up got me thinking about what I've been seeing with regards to temperature.

The temperatures displaying in F on torque for oil, coolant and intake are displayed with one decimal place, so : 132.8F or 138.2 F. And also the steps displayed on torque from the ECU were always in the same step of 1.8 degrees. So since everything else on the car is metric, I figured the sensor and ECU were working in Celsius and indeed it does seem to be.

I idled my car so I could match dots on the coolant display with the temperature provided by the ECU via torque. Here's what I found:

I'll refer to the coolant dots by numbers from the left to the right.
I was only able to determine ranges for six of the sixteen dots.

dot 1 : < 56C
dot 2 : 56C
dot 3 : 59C
dot 4 : 62C
dot 5 : 65C
dot 6 : 67C
dot 7 : 70C to at least 101C

I observed that at the thermostat open at 84C the coolant temperature stayed planted for a few minutes before starting to rise again. I think the difference between the oil temperature (lags the coolant on warmup) may have had something to do with it. Oil temp had to get around 78C before coolant temperature moved up with any speed.

Idling I never got to the eighth dot. The fans will engage and blow the radiator before it turns. Since I was idling/parked for safety I am not sure when that one hits. I'll have to be attentive when driving empty roads to see if I can figure that out.

So this confirms that the dots are nonlinear. The 260 limp mode is likely 127C and that *might* be the 16th dot ( > 127C).

The seventh dot is two left of the stem of the thermometer on the display for quick reference.

One of the other things I changed was I turned on the voice stuff on torque and that gave me new info. It now announces when it has reached operating temperature. That's dot seven. When it got there, the idle had dropped to 650 RPM the fuel flow to 0.5 gal/hr. That is, below dot seven the ECU keeps the revs higher than 650 but at temps within seven it idles at 650.

That's all. I hope you found my mild OCD jag interesting...

SouthArk370Z · 11-17-2018, 09:09 AM

Interesting. Thanks for sharing.

dts3 · 11-17-2018, 11:46 AM

I've never trusted those dots from day one. I'm in the process of installing Defi gauges, one of which will be a water temp, so maybe I can contribute something soon, as I will not be relying on the ecu at all.

I thought the 260deg. limp mode was based on oil temp. and not water.

radix023 · 11-17-2018, 11:53 AM

It's my understanding as well that the oil temp is the trigger for the limp mode at 260 but that would be the only thing depending on oil temp. When the oil temp is riding higher (I've certainly seen 210-220F) the coolant temperature would be lower (which is the inverse of what you see when the car is warming up). If the "panic" temperature regarding oil is 260, I can't see the coolant getting or being marked higher was my point. 9 dots is a lot of space, but I don't see what use indicating temperature between 260F and 350F would be. I might be overthinking that part.

dts3 · 11-17-2018, 06:53 PM

Quote:

Originally Posted by radix023

It's my understanding as well that the oil temp is the trigger for the limp mode at 260 but that would be the only thing depending on oil temp. When the oil temp is riding higher (I've certainly seen 210-220F) the coolant temperature would be lower (which is the inverse of what you see when the car is warming up). If the "panic" temperature regarding oil is 260, I can't see the coolant getting or being marked higher was my point. 9 dots is a lot of space, but I don't see what use indicating temperature between 260F and 350F would be. I might be overthinking that part.

I see what you mean. All the more reason not to trust the dots / temp reported on the CAN bus.

Rusty · 11-17-2018, 08:47 PM

I have a SpeedHut water temp gauge plumbed into my upper radiator hose. The 6th Dot is when my thermostat opens. The 7th Dot is between 180F to 195F. My Z has never been to the 8th Dot. I've seen 190F water temp and 220F oil temp.

Limp mode is triggered by oil temp. But the ECU will start to pull timing at around 220F oil temp.

Felix 808 · 11-20-2018, 11:12 AM

Nice info OP, but best to get a guage so you know what's going on by a glance.

This gives me oil pressure & water temp.

Uxi · 11-27-2018, 11:13 AM

Really want to replace that whole left gauge with something more modern. A little LCD display like they use in every other car, if not something generally fancier. I'd be surprised there's no aftermarket solution, though niche of a niche. They really should have updated that with the 2015 facelift.

radix023 · 12-10-2018, 07:01 AM

so one last addendum...

Apparently I left the HVAC in the "auto" position the other day with thermostat set to about 67F. I'm doing my usual, letting the car warm up and don't notice the switch in the auto position. The ECU waited until I had the second dot on the coolant display (56C/132.8F) before the HVAC fan came on.

11-17-2018, 09:00 AM	#1 (permalink)
radix023 Base Member Join Date: Mar 2017 Location: ATL Posts: 114 Drives: 2016-370z-silver-m6 Rep Power: 8	a post mostly about temperature dots so I've recently changed the device I'm using for Torque and setting things back up got me thinking about what I've been seeing with regards to temperature. The temperatures displaying in F on torque for oil, coolant and intake are displayed with one decimal place, so : 132.8F or 138.2 F. And also the steps displayed on torque from the ECU were always in the same step of 1.8 degrees. So since everything else on the car is metric, I figured the sensor and ECU were working in Celsius and indeed it does seem to be. I idled my car so I could match dots on the coolant display with the temperature provided by the ECU via torque. Here's what I found: I'll refer to the coolant dots by numbers from the left to the right. I was only able to determine ranges for six of the sixteen dots. dot 1 : < 56C dot 2 : 56C dot 3 : 59C dot 4 : 62C dot 5 : 65C dot 6 : 67C dot 7 : 70C to at least 101C I observed that at the thermostat open at 84C the coolant temperature stayed planted for a few minutes before starting to rise again. I think the difference between the oil temperature (lags the coolant on warmup) may have had something to do with it. Oil temp had to get around 78C before coolant temperature moved up with any speed. Idling I never got to the eighth dot. The fans will engage and blow the radiator before it turns. Since I was idling/parked for safety I am not sure when that one hits. I'll have to be attentive when driving empty roads to see if I can figure that out. So this confirms that the dots are nonlinear. The 260 limp mode is likely 127C and that might be the 16th dot ( > 127C). The seventh dot is two left of the stem of the thermometer on the display for quick reference. One of the other things I changed was I turned on the voice stuff on torque and that gave me new info. It now announces when it has reached operating temperature. That's dot seven. When it got there, the idle had dropped to 650 RPM the fuel flow to 0.5 gal/hr. That is, below dot seven the ECU keeps the revs higher than 650 but at temps within seven it idles at 650. That's all. I hope you found my mild OCD jag interesting... SouthArk370Z, Tick64 and cv129 like this.

11-17-2018, 09:09 AM	#2 (permalink)
SouthArk370Z Premium Member Join Date: Nov 2010 Location: South Arkansas Posts: 8,435 Drives: 2014 Challenger Rep Power: 324197	Interesting. Thanks for sharing. __________________ Steering Lock Links - Search The370Z Bookmarklet - FSM @ NICOclub Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma

11-17-2018, 08:47 PM	#6 (permalink)
Rusty Ronin Samurai - Assassin Join Date: Dec 2011 Location: Fayettenam,Pennsyltucky Age: 68 Posts: 34,864 Drives: 2011 Nismo GM 6M Rep Power: 2684436	I have a SpeedHut water temp gauge plumbed into my upper radiator hose. The 6th Dot is when my thermostat opens. The 7th Dot is between 180F to 195F. My Z has never been to the 8th Dot. I've seen 190F water temp and 220F oil temp. Limp mode is triggered by oil temp. But the ECU will start to pull timing at around 220F oil temp. Felix 808 likes this. __________________ 浪人 - 殺し屋 "The Difficult Anytime, The Impossible By Appointment Only" http://www.the370z.com/members-370z-...o-journal.html

11-20-2018, 11:12 AM	#7 (permalink)
Felix 808 A True Z Fanatic Join Date: Oct 2011 Location: Camarillo, CA Posts: 1,063 Drives: 2011 PW/Grey T/S 7AT Rep Power: 2806	Nice info OP, but best to get a guage so you know what's going on by a glance. This gives me oil pressure & water temp. __________________ Semper Fi Μολὼν λαβέ

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11-17-2018, 11:46 AM	#3 (permalink)
dts3 Track Member Join Date: May 2018 Location: Farmington Hills, MI Posts: 599 Drives: 08 Expedition Rep Power: 6764	I've never trusted those dots from day one. I'm in the process of installing Defi gauges, one of which will be a water temp, so maybe I can contribute something soon, as I will not be relying on the ecu at all. I thought the 260deg. limp mode was based on oil temp. and not water.

11-17-2018, 11:53 AM	#4 (permalink)
radix023 Base Member Join Date: Mar 2017 Location: ATL Posts: 114 Drives: 2016-370z-silver-m6 Rep Power: 8	It's my understanding as well that the oil temp is the trigger for the limp mode at 260 but that would be the only thing depending on oil temp. When the oil temp is riding higher (I've certainly seen 210-220F) the coolant temperature would be lower (which is the inverse of what you see when the car is warming up). If the "panic" temperature regarding oil is 260, I can't see the coolant getting or being marked higher was my point. 9 dots is a lot of space, but I don't see what use indicating temperature between 260F and 350F would be. I might be overthinking that part.

11-27-2018, 11:13 AM	#8 (permalink)
Uxi Enthusiast Member Join Date: Apr 2015 Location: Southern California Posts: 298 Drives: 16 NISMO Tech PW 6MT Rep Power: 3598	Really want to replace that whole left gauge with something more modern. A little LCD display like they use in every other car, if not something generally fancier. I'd be surprised there's no aftermarket solution, though niche of a niche. They really should have updated that with the 2015 facelift.

12-10-2018, 07:01 AM	#9 (permalink)
radix023 Base Member Join Date: Mar 2017 Location: ATL Posts: 114 Drives: 2016-370z-silver-m6 Rep Power: 8	so one last addendum... Apparently I left the HVAC in the "auto" position the other day with thermostat set to about 67F. I'm doing my usual, letting the car warm up and don't notice the switch in the auto position. The ECU waited until I had the second dot on the coolant display (56C/132.8F) before the HVAC fan came on.