The Big Fat Track Car Cooling Thread

[Plimmer]

At what point were you going to pit? That's probably 60 degrees over peak power and a good 30 past a number any racecar would see. If you continue running at these temps, you'll launch the engine for sure.

Agree, 240’s is when I back off and run a cool down lap, keep rpm under 6,000 and cruise the straights. Normally just need 1 lap to get temps back into 220’s then send it again.

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[SVO MkII]

You need to watch CHT. My needle is dead center even with CHTs up in the 230F range. When I plugged in my obdii scanner I saw ECTS are close to cht.

I think this may be a translation problem between the Mustang OBD II data output and most OBD app inputs. Here is why I say this.

For the past year, at all of my HPDE events, the engine coolant temp gauge never moves past the middle of the gauge. The cylinder head temp will climb consistently into the 220s and 230s. (The inferred oil temp always zips right up there, but that is a topic for a different thread.) I have never received any warning related to excessive engine temp. At Road America a couple weeks ago, I ran for the first time with the Track Addict app installed, getting a OBD II feed. Looking at the detail data afterwards, it was showing my "engine coolant temp" as consistently running in the 220s and 230s. I was surprised that I could run with my coolant temp consistently in the 230s with; a) factory temp gauge in the middle of normal, b) no warning message regarding high engine temp, and c) no power limiting reaction from the ECU (I could watch boost in real time for each lap with coolant temp, and I never lost max boost, all while coolant temps shown at 230-235). That got me thinking that just maybe what Track Addict was displaying as coolant temp, was really cylinder head temp.

So, I installed the Torque app this AM and synced it with my OBD II sender. I sat in my garage with the car idling and watched the factory coolant temp gauge, the factory cylinder temp gauge, and the Torque coolant temp display. All three moved in unison until about 170 deg, at which point the factory coolant temp gauge stopped moving. The cylinder head temp gauge and the Torque coolant temp display remained in lock step all the way to 216 deg. At this point, something opened up, or came on, causing the temps to fall back to about 185. Then the pattern repeated. (It's worth noting that I have a 160 deg t-stat installed, so I'm a bit puzzled that this pattern started at around 215 deg) All the while, the factory coolant temp gauge did not budge.

What does this mean? Either I am correct that what is being sent/received by these OBD II apps is actually cylinder head temp, or "normal" coolant temp for the Ecoboost engine is at least as high as 240 deg, and the factory coolant temp gauge is calibrated not to budge between 170-240. I would be inclined to suspect the former.

 

[TeeLew]

The OBD II is just a serial stream of data. It looks like either Torque or your OBD scanner has cylinder head temp mapped to the coolant temp channel. This would be a good question to send to both the Torque people and whoever made your OBD scanner.

Your experiments seem pretty conclusive, though. Regardless of the label, that channel is head temp.

It makes sense. Anyone running 240* coolant temp is going to be blowing stuff up left & right. Those kind of temps are when you blow radiators, not just the rad cap.

 

[jgilkey]

I’m in the process of developing a system that can read the different sensors on vehicles, and looking at this makes me think the sensor data isn’t always available on the OBD port. It is probably still available on the LIN bus or other CAN bus. The OBD connection is primarily for inspection and emissions purposes. To cut down on bus traffic, after startup, not all sensor values are transmitted. Does your OBD scanner register for updates of specific sensors, or does it just sniff the data already on the line?

 

[fatbillybob]

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What does this mean? Either I am correct that what is being sent/received by these OBD II apps is actually cylinder head temp, or "normal" coolant temp for the Ecoboost engine is at least as high as 240 deg, and the factory coolant temp gauge is calibrated not to budge between 170-240. I would be inclined to suspect the former.

Well if all we can really see is CHT that's pretty lame...but what I would expect from Ford...pretend to deliver but under delivery

 

[HeelToeHero]

I think this may be a translation problem between the Mustang OBD II data output and most OBD app inputs. Here is why I say this.

For the past year, at all of my HPDE events, the engine coolant temp gauge never moves past the middle of the gauge. The cylinder head temp will climb consistently into the 220s and 230s. (The inferred oil temp always zips right up there, but that is a topic for a different thread.) I have never received any warning related to excessive engine temp. At Road America a couple weeks ago, I ran for the first time with the Track Addict app installed, getting a OBD II feed. Looking at the detail data afterwards, it was showing my "engine coolant temp" as consistently running in the 220s and 230s. I was surprised that I could run with my coolant temp consistently in the 230s with; a) factory temp gauge in the middle of normal, b) no warning message regarding high engine temp, and c) no power limiting reaction from the ECU (I could watch boost in real time for each lap with coolant temp, and I never lost max boost, all while coolant temps shown at 230-235). That got me thinking that just maybe what Track Addict was displaying as coolant temp, was really cylinder head temp.

So, I installed the Torque app this AM and synced it with my OBD II sender. I sat in my garage with the car idling and watched the factory coolant temp gauge, the factory cylinder temp gauge, and the Torque coolant temp display. All three moved in unison until about 170 deg, at which point the factory coolant temp gauge stopped moving. The cylinder head temp gauge and the Torque coolant temp display remained in lock step all the way to 216 deg. At this point, something opened up, or came on, causing the temps to fall back to about 185. Then the pattern repeated. (It's worth noting that I have a 160 deg t-stat installed, so I'm a bit puzzled that this pattern started at around 215 deg) All the while, the factory coolant temp gauge did not budge.

What does this mean? Either I am correct that what is being sent/received by these OBD II apps is actually cylinder head temp, or "normal" coolant temp for the Ecoboost engine is at least as high as 240 deg, and the factory coolant temp gauge is calibrated not to budge between 170-240. I would be inclined to suspect the former.

If you look through this thread someone posted the tables that show that they don't start limiting engine rpm until 244F. So if you're under that I imagine you wouldn't see a message.

 

[SVO MkII]

If you look through this thread someone posted the tables that show that they don't start limiting engine rpm until 244F. So if you're under that I imagine you wouldn't see a message.

Is the 244 ECT or CHT? I assume CHT. Also, I assume the limiting RPM is applicable to the V8. For the Eco, they just cut boost when they want to invoke "safety mode".

 

[TeeLew]

It has to be. By the time coolant gets to 245*, something has already destroyed itself.

 

[SVO MkII]

Is the 244 ECT or CHT? I assume CHT. Also, I assume the limiting RPM is applicable to the V8. For the Eco, they just cut boost when they want to invoke "safety mode".

I think it is also worth noting that the average CHT for an Ecoboost engine, especially under hard use at the track, is probably going to be slightly higher than the V8. Turbo engines run hotter. Think about how much heat would be generated in one half of a 620 hp 4.6 V8.

 

[fatbillybob]

Is there a relationship of cht to oil temp? So if cht is 240 oil temp is???

 

[SVO MkII]

Is there a relationship of cht to oil temp? So if cht is 240 oil temp is???

Yes, especially since the oil temp is an "inferred" temp, where CHT is one of the inputs.

 

[SVO MkII]

Is there a relationship of cht to oil temp? So if cht is 240 oil temp is???

And to answer your second question, yes, oil temp will probably follow CHT closely under normal driving. For example, I just installed a real oil temp gauge in my car. When my coolant temp is normal (presumably 180), my CHT is around 195, and my actual oil temp is around 190. On the track is where they will start to diverge. You could see ECT at 200, CHT at 230+ and actual oil temp at 250-260.

 

[HeelToeHero]

Is the 244 ECT or CHT? I assume CHT. Also, I assume the limiting RPM is applicable to the V8. For the Eco, they just cut boost when they want to invoke "safety mode".

You should check the thread, but I saved a screen shot of the table.

 

[SVO MkII]

You should check the thread, but I saved a screen shot of the table.

Unfortunately, big thread. Thanks for posting this. Are we sure that "ECT" isn't referring to "Engine Cylinder Temp"? If the factory is allowing the engine (the V8 in the above example) to operate normally with an overall coolant temp of 245, the CHT has to be approaching 260, or even 270? That's an accomplishment, for sure!

 

[TeeLew]

... to operate normally with an overall coolant temp of 245, the CHT has to be approaching 260, or even 270? That's an accomplishment, for sure!

Ya, it just can't be. Which begs the question, what's your *real* coolant temp?

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