Graph of oil temp, ATF temp, and MAP

Status
Not open for further replies.
Joined
Dec 16, 2017
Messages
429
Location
California
Not entirely sure if this post fits here or in the ATF, Differential, Trans, Brakes, P/S forum, or somewhere else.

I got my data logging program working and made a graph of all three sensors for a drive on surface streets and a drive on the highway. The temp sensors may need adjustments and better insulation, but the data seems to make sense. Soon I hope to have sensors for coolant temp and oil pressure hooked up as well.

Any other ideas for things I should slap a sensor on to record?

Surface streets up into the city (car was already partially warmed up):



Highway drive, light traffic at about 70 mph:
 
Last edited:
Originally Posted By: Snagglefoot
That’s excellent. Where were you getting the oil temp? It would also be cool to plot air temp or at least get one reading to see what the oil temp gets to on a hot day.

Oil temp taken on the outside of the passage from pump to oil thermostat. See this post for more info: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4770523

I was thinking an ambient temp sensor as well. Perhaps I can tap into the car's existing thermometer for that. Underhood temps could be interesting to look at too.
 
Originally Posted By: Linctex
The bottom (time) is in seconds?

Yes.

Seconds since the program started is the easiest source for X axis data. I have a real time clock so I also have a real time stamp, but that doesn't seem to play nice when graphing.
 
That's very cool.

Could you please do a test to validate my testing on the Caprice ?

(I only shut off the engine, dropped it into Neutraal and pulled off the road, dropping a type K thermocouple down the dipstick tube....nothing as flash as yours).

Test A
Drive on the highway in "D", then repeat for same speed (same road load) in "2" 1,800 RPM versus nearly 4,000RPM, same road load. 95C in the first, 125-135C in the second.

Test B
Warm-up letting the trans shift itself versus holding it at 2,500 to 3,000. Noticeably quicker warmup.
 
Originally Posted By: Shannow
That's very cool.

Could you please do a test to validate my testing on the Caprice ?

(I only shut off the engine, dropped it into Neutraal and pulled off the road, dropping a type K thermocouple down the dipstick tube....nothing as flash as yours).

Test A
Drive on the highway in "D", then repeat for same speed (same road load) in "2" 1,800 RPM versus nearly 4,000RPM, same road load. 95C in the first, 125-135C in the second.

Test B
Warm-up letting the trans shift itself versus holding it at 2,500 to 3,000. Noticeably quicker warmup.

I'll see what I can do. 2nd gear for me would be howling near redline at highway speeds, plus the torque converter does not lock in 2nd. I can try 3rd which will allow lockup and have the motor turning a more sane 3500 rpm. 4th is about 2450 at 75 mph as a reference.

I can try the warmup in lower gears as well.

Mine has an oil to coolant heat exchanger with thermostatic control, so oil warms up relatively quick but has a lot of heat dissipation once it gets hotter than that. 135C is a lot considering that my coolant runs around 91C on highway cruising and might rise to 105C at sustained high RPM and high load.
 
Originally Posted By: CT8
The torque converter generates lots of heat when unlocked.

Indeed. This data shows the spikes clearly since it takes readings on the hot line going to the transmission cooler.

In the first graph, lots of stop and go and generally slow traffic without much airflow has it heat right up until my data logger computer kicks on the cooling fan.

In the second graph, you can clearly see the peaks where I entered the highway and then accelerated after a slow section of traffic, then how it rises again once I'm back on surface streets.
 
Originally Posted By: VeryNoisyPoet
... Soon I hope to have sensors for coolant temp and oil pressure hooked up as well.

Any other ideas for things I should slap a sensor on to record?


Originally Posted By: Snagglefoot
That’s excellent. Where were you getting the oil temp? It would also be cool to plot air temp or at least get one reading to see what the oil temp gets to on a hot day.


Don't know your exact setup ... short of having your own sensors, can you integrate coolant temp and IAT from OBD II? With some cars you can also read outside air temp. I can with one of our cars.

If not, IAT typically tracks ambient temp if the car is moving. Based on my experience with 3 different cars, IAT is about 6°F to 12°F higher than outside temp. and with one car, I consistently read about 10°F above ambient temp. In both cases and for obvious reason, the car has to be moving at a relatively good speed and for a relatively extended period of time after a long idle. For example if you are in stop and go, IAF could get as high as 40-50F or more above the outside temp!

Effects of higher ambient temp on oil and coolant temp. is not linear. e.g. If outside temp is 50F higher from one test to another, don't expect the coolant and/or oil temp. to follow.
@shannow recently had a link in one of his post to another one of his old threads (i call it the facy curve thread) talking about this ...

Based on my experience/data, i have noticed minimal (but not 0) impact. don't have my excel sheets in front of me but if I recall correctly, i have bunch of data @ 40°F and lower in winter vs. 80F and higher in summer and the max coolant temp. observed in summer was only 5-8°F higher going up the same steep hill. If the car was moving on flats, maybe 5F difference max.

I can read my trans temp (TC and Pan) but don't have ways to track the engine oil temp. it is under to do list for one of the cars mainly out of curiosity but it should track the coolant temp closely (+15°F to +40°F ?? Depending on the car)...

basically I observed minimal (5F-8°F) difference in coolant temp with respect to ~45°F difference in ambient temp. However have a feeling that ambient temp may have more impact (>5-8°F) on the oil temp. than it has on the coolant temperature. Maybe more instantaneous difference ... hence one of my to do list of reading the oil temp
grin.gif

But it all depends on where the data is collected and so many other variables ...
 
I have two oil temp sensors on my Gen Coupe. The factory one is up in the head near the oil control solenoid for the cams and the other is just after the filter and is connected to a gauge.

The filter sensor will run hotter than the head sensor until about 140F. Then the head sensor starts to read higher and generally will run around 10F hotter once warmed up. If after it's warmed up I let the car idle, then the two will begin to read closer together and eventually will read the same as the oil filter senor increases in temp.

Coolant temps are consistent at around 185F-187F. Peak oil temp is seen when cruising down the highway with the higher the engine load(car speed)the higher the oil temp. With +90F ambient temps, AC on and 70 mph cruising I see around 210F oil temps at the head.
 
Originally Posted By: OilUzer
Don't know your exact setup ... short of having your own sensors, can you integrate coolant temp and IAT from OBD II? With some cars you can also read outside air temp. I can with one of our cars.

Pulling data from OBD II will be tough since I already have a Scanguage hooked up for fuel economy display and reading trouble codes. I do have ideas about reading sensors in parallel, since the car uses 5 volts and shared ground just like my Arduino.
Quote:
If not, IAT typically tracks ambient temp if the car is moving. Based on my experience with 3 different cars, IAT is about 6°F to 12°F higher than outside temp. and with one car, I consistently read about 10°F above ambient temp. In both cases and for obvious reason, the car has to be moving at a relatively good speed and for a relatively extended period of time after a long idle. For example if you are in stop and go, IAF could get as high as 40-50F or more above the outside temp!

IAT is strange on my car, as it seems to read a few degrees lower on OBD II compared to the ambient temp. It did the same thing before and after a MAF replacement so not sure what's happening there.
Quote:
Effects of higher ambient temp on oil and coolant temp. is not linear. e.g. If outside temp is 50F higher from one test to another, don't expect the coolant and/or oil temp. to follow.
@shannow recently had a link in one of his post to another one of his old threads (i call it the facy curve thread) talking about this ...

Very cool! One of the reasons why I love this forum.
Quote:
Based on my experience/data, i have noticed minimal (but not 0) impact. don't have my excel sheets in front of me but if I recall correctly, i have bunch of data @ 40°F and lower in winter vs. 80F and higher in summer and the max coolant temp. observed in summer was only 5-8°F higher going up the same steep hill. If the car was moving on flats, maybe 5F difference max.

Sounds about right if the cooling system is in good shape and the vehicle isn't overloaded. Mine didn't get much hotter even when climbing a grade in 110 degree southwest heat last summer.
Quote:
I can read my trans temp (TC and Pan) but don't have ways to track the engine oil temp. it is under to do list for one of the cars mainly out of curiosity but it should track the coolant temp closely (+15°F to +40°F ?? Depending on the car)...

It should run lower than coolant temp. Transmissions aren't happy running too hot, so +15 to +40 compared to coolant would fry the transmission in short order. Before I added an external cooler, mine ran 10+ degrees below coolant temp unless I was pushing it. Now with cooler, transmission thermostat, and extra fan control, I've never seen it more than 94C / 201F even when working hard.
Quote:
basically I observed minimal (5F-8°F) difference in coolant temp with respect to ~45°F difference in ambient temp. However have a feeling that ambient temp may have more impact (>5-8°F) on the oil temp. than it has on the coolant temperature. Maybe more instantaneous difference ... hence one of my to do list of reading the oil temp
grin.gif

But it all depends on where the data is collected and so many other variables ...

Yeah. I'm interested to see what happens there. My oil is thermostatically controlled, so that may behave closer to the coolant instead since the hotter it gets the more cooling capacity opens up.
 
Originally Posted By: SHOZ
I have two oil temp sensors on my Gen Coupe. The factory one is up in the head near the oil control solenoid for the cams and the other is just after the filter and is connected to a gauge.

The filter sensor will run hotter than the head sensor until about 140F. Then the head sensor starts to read higher and generally will run around 10F hotter once warmed up. If after it's warmed up I let the car idle, then the two will begin to read closer together and eventually will read the same as the oil filter senor increases in temp.

Coolant temps are consistent at around 185F-187F. Peak oil temp is seen when cruising down the highway with the higher the engine load(car speed)the higher the oil temp. With +90F ambient temps, AC on and 70 mph cruising I see around 210F oil temps at the head.

That's cool you have two data points to work with there. Makes sense that filter temp would be lower when moving, since that usually is after any oil cooling system, whereas the head is exposed to more heat. How hot do the temps go when idling around in slow traffic?
 
Quote:

That's cool you have two data points to work with there. Makes sense that filter temp would be lower when moving, since that usually is after any oil cooling system, whereas the head is exposed to more heat. How hot do the temps go when idling around in slow traffic?
It will drop to just a bit over coolant temp with prolonged idling. But a quick slow down and then accelerating to highway speeds will bring it up higher than it was when cruising. This drops back in a few miles.

There is no active cooling with the oil. I use to have an oil filter heat exchanger but took it off due to complexity and difficulty working with all the coolant hoses. It also forced me to use a non spec oil filter due to size restriction.
 
Originally Posted By: SHOZ

There is no active cooling with the oil. I use to have an oil filter heat exchanger but took it off due to complexity and difficulty working with all the coolant hoses. It also forced me to use a non spec oil filter due to size restriction.

Interesting that a turbo car didn't come factory with an oil cooler, but looks like you have sufficient cooling without it. Perhaps if you were towing or taking it to the track it might need extra cooling.
 
Last edited:
VeryNoisyPoet,
Yes, it will nice to collect all data ... I may adapt your way of sensor attachment as oppose to drilling ...
Btw, i was talking about oil temp. being approx. +15°F-40°F over coolant temp. You are correct, trans temps that high are not desirable!
 
Last edited:
Originally Posted By: VeryNoisyPoet
Originally Posted By: SHOZ

There is no active cooling with the oil. I use to have an oil filter heat exchanger but took it off due to complexity and difficulty working with all the coolant hoses. It also forced me to use a non spec oil filter due to size restriction.

Interesting that a turbo car didn't come factory with an oil cooler, but looks like you have sufficient cooling without it. Perhaps if you were towing or taking it to the track it might need extra cooling.
It is the first year for the model. Two years later they upped the HP and added an oil filter Hx with oil temp gauge. I have upgraded the radiator as it was not up to the job when racing. Stock hardware with a tune saw 240F coolant and +300F oil temps at the track on hot days.

I changed the t-stat last summer as it was getting lazy. It generally ran 180F to 183F. With the new OE t-stat it raised the coolant temp about 5F and so did the oil temp. T-stat is rated at 180F to open, 208F fully open. Coolant fan comes on at 208F but I never see that unless I purposely let it idle to raise the temp.
 
240F coolant temp
cry.gif


all my cars run under 200F. Once in a great while i see 208F max ever in my v6.

2 cars always under 190F for most parts.
 
Last edited:
Originally Posted By: SHOZ

Interesting that a turbo car didn't come factory with an oil cooler, but looks like you have sufficient cooling without it. Perhaps if you were towing or taking it to the track it might need extra cooling. It is the first year for the model. Two years later they upped the HP and added an oil filter Hx with oil temp gauge. I have upgraded the radiator as it was not up to the job when racing. Stock hardware with a tune saw 240F coolant and +300F oil temps at the track on hot days.

I changed the t-stat last summer as it was getting lazy. It generally ran 180F to 183F. With the new OE t-stat it raised the coolant temp about 5F and so did the oil temp. T-stat is rated at 180F to open, 208F fully open. Coolant fan comes on at 208F but I never see that unless I purposely let it idle to raise the temp.


Aha. Did the oil filter Hx you installed get the temp back under control on track days?

I also just had to replace a lazy thermostat opening way too early. Rated 194F but opening before 180F so coolant would run around 182F on highway. Now it behaves better and runs 196F on highway.
 
Status
Not open for further replies.
Back
Top