Oil Temp While Tracking
Racer
Joined: Oct 2004
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From: Southern Maryland
Drifting
Joined: Oct 2006
Posts: 1,372
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From: Bristol, VT
I'm not sure if your track car is a base or a Z06, but if it is a using the factory dry-sump provided in the (GS, Z06, ZR1) there are 2 temperature sensors. The oil temp displayed in the DIC corresponds to the oil in dry sump reservoir, but the my ODBii reader uses PID 221154 (Hex Vale: 35FE2) which shows oil temp at/in the engine which is usually a few degrees different. In my experiments I have found that the delta between the two sensors is dependent on the type of driving.
Drifting
Joined: Dec 2010
Posts: 1,779
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From: Las Vegas NV
There is a follow-up to the original article quoted by the OP in the Dec 2015 Grassroots Motorsports, page 133. I'll paraphrase: "..we were seeing oil temperature readings of nearly 320 degrees (or more) on the factory gauge......Turns out that was a false alarm.....Chevy uses a computer algorithm that takes into account various parameters-ambient temps, rpm, load, throttle position and a zillion others-to simulate what it thinks the oil temperature must be....uses that data to model the temperature......Chevy says the system works great-except under occasional weird circumstances, when it doesn't.......so Chevy sent us a mechanical gauge and thermocouple that we installed before our Ultimate Track Car Challenge event at VIR (last July)....The result: nearly ideal oil temps......Readings ranged from about 275 to 285 degrees in the pan...."
Pappy
Pappy
Safety Car
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From: Charleston SC
Drifting
Joined: Dec 2010
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From: Las Vegas NV
A couple of observations for what they are worth, reference the issue originally identified by the OP: I have a 2015 Camaro 1LE SS. It has the same "stacked brick" type of oil cooler as the C7 Z06 (and my C6 Z06 - Z07 option which has the ZR1 cooling package). The cooler appears to be farther from the cat than the Z06, but the entering oil lines are 2 inches from the cat inlet. The Camaro has an LS3 with an 8 quart oil system, but the oil temperature goes right to 225 degrees for even easy street driving - higher than I expected. My C6Z runs about 205 degrees oil temperature most of the time around town. I haven't had the Camaro on track yet to see what the oil temperature does.
Pappy
Pappy
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Melting Slicks
Joined: Nov 2005
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A couple of observations for what they are worth, reference the issue originally identified by the OP: I have a 2015 Camaro 1LE SS. It has the same "stacked brick" type of oil cooler as the C7 Z06 (and my C6 Z06 - Z07 option which has the ZR1 cooling package). The cooler appears to be farther from the cat than the Z06, but the entering oil lines are 2 inches from the cat inlet. The Camaro has an LS3 with an 8 quart oil system, but the oil temperature goes right to 225 degrees for even easy street driving - higher than I expected. My C6Z runs about 205 degrees oil temperature most of the time around town. I haven't had the Camaro on track yet to see what the oil temperature does.
Pappy
Attachment 47938375
Pappy
Attachment 47938375
I finally started hearing noise under the hood and discovered that the right side exhaust flange was leaking and exhaust was blowing directly onto the oil pan.
Temps returned to normal after fixing the leak.
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Melting Slicks
Joined: Feb 2015
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From: Syracuse-Central Square New York Winer of the all Corvette race WGI 8/23!
Steve, A company called DEI Engineering (Dan) has cat covers specific for the C7 Z06. I have run them for over 5k miles tack and street and NEVER a hot oil issue, 261 max oil.
Your comment about the exhaust leak blowing on the oil pan is basically what is going on with the cat mounted next to the oil cooler. You repaired and all was fine as you said and is exactly what I would of expected.
Were blowing fresh air on our oil cooler to for that cheap extra insurance measure.
Your comment about the exhaust leak blowing on the oil pan is basically what is going on with the cat mounted next to the oil cooler. You repaired and all was fine as you said and is exactly what I would of expected.
Were blowing fresh air on our oil cooler to for that cheap extra insurance measure.
Drifting
Joined: Dec 2010
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From: Las Vegas NV
guess the real question, brought out by the OP, is whether or not the LT4 presented oil temperature is being measured by the sending unit in the bottom of the tank, or whether the tank sensor is one of the inputs to a computer algorithm that uses multiple inputs to compute an engine temperature - like the 1LE Camaro. The LS3 in the Gen V 1LE (as tested by Grassroots Motorsports) shows an oil temperature sending unit input as well, but GM has stated that the computations are not necessarily accurate under certain conditions. Grassroots Motorsports concluded that the "certain conditions" meant prolonged high RPMs on track. (The computer generated oil temp shown on the dash was as high as 320 degrees, while the thermocouple in the pan and gauge read 275-285 degrees) If the LT4 has the same set-up, then maybe the oil temps reported by some are not really that high inside the engine, and it could explain why some drivers get higher oil temp readings under similar track conditions - but with different driver technique. IMHO, it is certainly worth asking GM the question.
Pappy
Pappy
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From: Sierra Nevada Foothills CA
One experience that appears to back the claim that the DIC display is calculated.
When I installed the aFe CAI, I failed to disconnect the battery. Of course the MAF was disconnected in the process.
Upon starting the engine and driving it for about 10 miles the oil temperature on the DIC showed zero (0), and remained on zero, while the coolant rose to normal values. After shutting the engine off and restarting, suddenly the DIC oil temp indicated normal, 200F+ values. It if was a mechanical sensor I could not see how that would happen.
When I installed the aFe CAI, I failed to disconnect the battery. Of course the MAF was disconnected in the process.
Upon starting the engine and driving it for about 10 miles the oil temperature on the DIC showed zero (0), and remained on zero, while the coolant rose to normal values. After shutting the engine off and restarting, suddenly the DIC oil temp indicated normal, 200F+ values. It if was a mechanical sensor I could not see how that would happen.
Last edited by axr6; Dec 14, 2015 at 10:46 PM.
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 2,074
Likes: 309
One experience that appears to back the claim that the DIC display is calculated.
When I installed the aFe CAI, I failed to disconnect the battery. Of course the MAF was disconnected in the process.
Upon starting the engine and driving it for about 10 miles the oil temperature on the DIC showed zero (0), and remained on zero, while the coolant rose to normal values. After shutting the engine off and restarting, suddenly the DIC oil temp indicated normal, 200F+ values. It if was a mechanical sensor I could not see how that would happen.
When I installed the aFe CAI, I failed to disconnect the battery. Of course the MAF was disconnected in the process.
Upon starting the engine and driving it for about 10 miles the oil temperature on the DIC showed zero (0), and remained on zero, while the coolant rose to normal values. After shutting the engine off and restarting, suddenly the DIC oil temp indicated normal, 200F+ values. It if was a mechanical sensor I could not see how that would happen.
Melting Slicks
Joined: Feb 2015
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From: Syracuse-Central Square New York Winer of the all Corvette race WGI 8/23!
Burning Brakes
Joined: Aug 2000
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From: Ontario New York
This is all very interesting because I am at this time dealing with an oil temperature display error between my OEM DIC digital display and my AiM MXL2 Dash Logger. The AiM hardware is installed in my 05 Corvette track car.The AiM MXL2 communicates with the ECU OBDII connection to display, alarm and log the 22 Channels of the ECU data stream. ECU_18 is the channel for Engine oil temperature.
My problem is that the MXL2 display is reading 30 Deg F higher than the OEM DIC display. AiM seems to think the problem is in as you described:"engine oil temperatures are not measured, they are calculated based on a complicated algorithm with many variables."
We are still looking into this as being the cause.
I am somewhat confused as to why this is done and also why the Channel 18 data collected by the MXL2 is not the same as displayed on the OEM DIC display. I am going to do more testing with AiM to come up with a solution to the problem.
My problem is that the MXL2 display is reading 30 Deg F higher than the OEM DIC display. AiM seems to think the problem is in as you described:"engine oil temperatures are not measured, they are calculated based on a complicated algorithm with many variables."
We are still looking into this as being the cause.
I am somewhat confused as to why this is done and also why the Channel 18 data collected by the MXL2 is not the same as displayed on the OEM DIC display. I am going to do more testing with AiM to come up with a solution to the problem.
Melting Slicks
Joined: Feb 2015
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From: Syracuse-Central Square New York Winer of the all Corvette race WGI 8/23!
I have not purchased a camera for the AIM Solo yet any thoughts on that I see the Smarty cam is 999.00 but hope there's something else.
Thread Starter
Melting Slicks
Joined: Nov 2005
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The question I still have is, is the computer pulling power for a problem that doesn't really exist? In other words, the engine isn't as hot as computed by the PTCM, but it doesn't know any better, so it's reducing power to protect itself. Is the heat problem really just a measurement problem?
Drifting
Joined: Mar 2012
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From: Raleigh North Carolina
Interesting. When you get it installed do you mind posting pictures? I would like see what the AiM guys advise. So far I feel the OEM temp readings reported by my OBDii sensor are correct but I do want to make sure, so I might end up doing a similar setup.
Burning Brakes
Joined: Aug 2000
Posts: 887
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From: Ontario New York
Interesting, I have the AIM Solo DL data recorder, although just purchased used and hope to use it in the spring. So your saying that even my Solo most likely will have a different oil temp reading than the oem? What have you found for water temps, same-close or different? The sensor change, is this the stock one or adding another somewhere? Looks like we cant trust the oem numbers!
I have not purchased a camera for the AIM Solo yet any thoughts on that I see the Smarty cam is 999.00 but hope there's something else.
I have not purchased a camera for the AIM Solo yet any thoughts on that I see the Smarty cam is 999.00 but hope there's something else.
All the other OBDII channels seem to agree with the OEM display, It looks the oil temp is the only one with the screwed up computer modeled number. I think some of the GM engineers have too much time on their hands. I also have the Smartycam HD GT. By the way the AiM engineers were a big help and I enjoyed working with them.
Burning Brakes
Joined: Aug 2000
Posts: 887
Likes: 10
From: Ontario New York
What I did was purchase a -12 AN fitting that had a 1/8" NPT port to screw the AiM oil temperature sensor into. It now reads the temperature of the oil out of my crank case .
The testing I did with AiM showed that most of the time the temperature displayed on the OEM display is not correct. The test also showed that the error between the real oil temp and the displayed temp on the OEM display did not repeat its self.