Tracking oil temp
10-23-2016 | 02:32 PM
#33
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From: Louisiana
Its supposed to run about the same, but it does;t on the track. Why? Because the factory great exchanger is thermally overloaded with high RPM. I see 60-80F differentials between coolant and oil temps, and ambient temps make a huge difference too. People that believe you have to keep the engine at redline to have fun are the other issue, as all that added RPM= oil temperature. This engine has 24 valve springs, engines post 2002 have dual springs on the intake that are of interference design. This alone adds huge oil temperature increases.
The factory heat exchanger is exactly that, it isn;t designed to keep oil cool, as much as it is to heat the oil up faster, due to emissions constraints. I throw it away whenever possible, and partition the coolant cooling from the oil cooling.
The factory heat exchanger is exactly that, it isn;t designed to keep oil cool, as much as it is to heat the oil up faster, due to emissions constraints. I throw it away whenever possible, and partition the coolant cooling from the oil cooling.
Has anyone upgraded the factory location exchanger to something that keeps oil/water within 20-30F? External air oil coolers are great, but unless I had an accusump with oil up front already, I would prefer to minimize oil lines running around the car. My car will see track time at high temps next year so I think this is something that I should be ready for.
10-23-2016 | 02:36 PM
#34
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From: Cleveland Georgia
This all makes sense to me.
Has anyone upgraded the factory location exchanger to something that keeps oil/water within 20-30F? External air oil coolers are great, but unless I had an accusump with oil up front already, I would prefer to minimize oil lines running around the car. My car will see track time at high temps next year so I think this is something that I should be ready for.
Has anyone upgraded the factory location exchanger to something that keeps oil/water within 20-30F? External air oil coolers are great, but unless I had an accusump with oil up front already, I would prefer to minimize oil lines running around the car. My car will see track time at high temps next year so I think this is something that I should be ready for.
Partitioning coolant and oil cooling is the only way I've been able to control oil temperatures. With that I've had my R40 engine (4.0, 430HP) to 200F in a Cayman at Road Atlanta with track temps of 135F and ambient air temps of 97F.
IAT that day was reading 117F.
10-23-2016 | 02:37 PM
#35
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From: Louisiana
10-23-2016 | 02:45 PM
#37
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I'm certainly not arguing that the DME reported value is correct, but the VDO supplied NTC thermistor will do what it was designed to do. If I know the resistance of the loop, then I am certain that I also know the temp at the sensor, assuming it is functioning correctly / not broken.
10-23-2016 | 02:49 PM
#38
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I agree because it's just an extremely simple electrical circuit. By tapping into the sensor voltage, the DME is bypassed.
I'm certainly not arguing that the DME reported value is correct, but the VDO supplied NTC thermistor will do what it was designed to do. If I know the resistance of the loop, then I am certain that I also know the temp at the sensor, assuming it is functioning correctly / not broken.
10-23-2016 | 02:55 PM
#39
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From: Cleveland Georgia
Ok, you fellas can go down your own paths...
Install 8 stand alone sensors in the sump (all over) with an 8 position switch feeding he same stand alone instrument...Flip between those and compare to the factory sensor.
Install 8 stand alone sensors in the sump (all over) with an 8 position switch feeding he same stand alone instrument...Flip between those and compare to the factory sensor.
10-23-2016 | 03:04 PM
#40
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From: Edmond, OK
Originally Posted by Flat6 Innovations
Ok, you fellas can go down your own paths...
Install 8 stand alone sensors in the sump (all over) with an 8 position switch feeding he same stand alone instrument...Flip between those and compare to the factory sensor.
Install 8 stand alone sensors in the sump (all over) with an 8 position switch feeding he same stand alone instrument...Flip between those and compare to the factory sensor.
10-23-2016 | 03:07 PM
#41
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From: Cleveland Georgia
10-23-2016 | 03:24 PM
#42
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I think we are mixing 3 things here:
1) the inherent error of the sensor (or any sensor)
2) the location of the sensor whether it's the best location to measure and reflect the oil temp
3) DME substituting the reported value
Each will need to be discussed, understood, and addressed individually.
1) the inherent error of the sensor (or any sensor)
2) the location of the sensor whether it's the best location to measure and reflect the oil temp
3) DME substituting the reported value
Each will need to be discussed, understood, and addressed individually.
10-24-2016 | 01:47 AM
#43
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Re 1) from the Porsche oil temp sensor tolerance curve, at the range of interest (100C to 150C), the error is about +/- 5 degrees C (or +/- 10 degrees F).
Re 2), one potential issue with the stock oil sensor is it sits ~1" above the oil sump bottom, on the right side (bank 2) of the engine and OUTSIDE the plastic oil baffle of the sump. So it's perceivable with extreme g-force (e.g., hard and long right turns), it could be starved of engine oil. If that happens, I think we should see pretty sharp oil temp drop (crankcase air temp) though. This may also explain what Jake saw.
Re 2), one potential issue with the stock oil sensor is it sits ~1" above the oil sump bottom, on the right side (bank 2) of the engine and OUTSIDE the plastic oil baffle of the sump. So it's perceivable with extreme g-force (e.g., hard and long right turns), it could be starved of engine oil. If that happens, I think we should see pretty sharp oil temp drop (crankcase air temp) though. This may also explain what Jake saw.
Last edited by Ahsai; 10-24-2016 at 02:10 AM.
07-31-2017 | 10:07 PM
#44
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From: Austin, TX
I realize this is an old thread - but from everything I was able to find, the oil temp can be accessed if the PID code can be determined - as long as the ODB software allows for custom PIDs. ODBLINK Mx wifi does allow for this - now the question is how to determine what the PID code is for temp.
Any thoughts?
Any thoughts?
08-04-2017 | 03:02 AM
#45
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Racer
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From: Austin, Texas
I realize this is an old thread - but from everything I was able to find, the oil temp can be accessed if the PID code can be determined - as long as the ODB software allows for custom PIDs. ODBLINK Mx wifi does allow for this - now the question is how to determine what the PID code is for temp.
Any thoughts?
Any thoughts?
As far as adding in PIDs, seems like that would be necessary, but I have no clue how you would figure out the PIDs you need.