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Track Time Limited due to High CHT

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67Fast_V

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@67Fast_V I've seen you mention it twice now....DO NOT remove the hood sealers on the rear of the hood next to the windshield. That's a localized high pressure area and if removed, you'll just force more air back into the engine bay rather than evacuating it.

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Great images, Ewheels. Thanks for sharing. Was thinking just to remove the side/ends of the rear seal but maybe that's not a good idea.

I'm going to run a test this weekend with some pressure gages underneath the hood. I have 2 digital manometers and will install them and drive down the road to look at pressure vs. vehicle speed. Then I will stop and remove the side seals. Test. Then remove the rear seal. Test. See the differences. The manometer are good for very low pressures and I can run tubing and have the gages in front of me. Record with my phone.

Maybe a complete waste of time but we'll see how it goes. Will have to keep speeds down, but might be interesting. If I can measure the differences with seals removed and get consistent/repeatable results, then I will block-off the sides of the radiator and run the same kind of tests.

Will share the data when I get it. Thanks again for your input.
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Hi FH - many thanks for the input. Much appreciatedšŸ‘. There is a lot to chew on here. It seems I'm not alone with these high temp problems. Good in a sense to know that vs. unique issues with my car. Let me answer a few of your questions to put my experience in context.

Oil temp is hard to look at while on the track but I have seen it in the yellow and slightly red zone w/ high CHT (250F). So very sporty oil temps as well.

See attached photo of the 180F OEM t-stat (new, 1000 miles on it). I found this condition after my 1st track event. Bypass wide open + main circuit stuck open a tad. I had about 4-5 mins on the track before reaching high CHT. Replaced with 170F. Now I get 7-9 mins of track timeā˜¹.

Current coolant/water mix is 33% assuming OEM was 50/50. I can certainly drop that living in FL.

I bought the A10 because I love the gearing. It has a big advantage over the MT84D manual as you well know. I calculate a 9% increase in ave torque over a 40-146 mph speed range. That's using 2nd through 7th. Running 3rd through 7th, its about 4.5% advantage.

Okay, let's forget calculations. My last event, I had a '20 PP2 GT in front of me on the back straight of Sebring. He exited T16 with a good gap in front (maybe 5-6 cars length). I closed the gap and had to lift off the throttle to avoid getting to close to him. And then I found out that he had a modified exhaust system and high flow air filter. Pure stock for me (with 240-250 CHT). Just a data pt for the A10. No surprise to you I'm sure. I use 3rd through 7th and shift at 7000 rpm.

My goal is to continue that but it sure would be nice to get more than 7 mins of run time. I did try 4th - 7th and shifting at 5500 rpm. Still gets ugly, just takes longer. Maybe 12-15 mins. It would totally stink if I have to do this to keep CHT behaved.

Was running 5W-30 Mobil 1. I wanted to go 5w-50 but scared. Oil pressure really jumps up with rpm w/ the 5w-30. Just worried that oil wedge will not be right with Gen 3. Do you know track guys running 5w-50 in fresh Gen 3 motors?

Seems hood vents are the way to go. Thanks. Hard for me in FL, though. Rains every 10 mins. But I will likely need to go in that direction. Still drive car on the street and to and front the track. AC in south FL is important. Too hot otherwise.

I'm going to work on ducting the radiator before my next event (early Nov) and remove all the hood seals. Can't do your kind of good job but I will try to block the flow the best I can.

My trans temps were surprising good. Only hit 221F max. So this is encouraging but I was hindered by CHT so I should expect higher levels soon. Will keep your limit of 225F as the gage. Thanks šŸ‘.

Oil cooler is an option. That might have to be the next major step. Hole in the hood or air-to-air oil cooler. Tough decision.

My diff temp on 1st event hit 294F. The usual ugliness. Exhaust wrap + 75W-140 reduced 42F. Max is 252F now. Different track but very similar ave speed and track time. Happy enough with that for now, but I like the blower and water idea. Thanks.

Not ready for a bigger radiator just yet. Seems my main issue is airflow through the radiator, hence the hood vents, ducting etc. Will attack that first.

I wonder if anyone has done or tried any fan shroud rework??? I'm thinking about going in this direction as well before my next event.

Thanks again for the input. I will let you know how things go. Cheers.
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Oil cooler is a must. Also remove heat from the little boiler of your OEM system.
Use water watter too dont forget.
Oil. I did nonissue 5w50 in summer (in california woth 110f) i do feel 0w40 is a better combo also to reduce drag. I also use MOTORKOTE as friction reducer \protection. Go 0w40. Pressure should be around 80psi or moe on WOT. it is normal.
Remember to cha ge fluid often. Including trans. Start to gst a friend in some dealership. (Bring donuts lol )
Last TRACKMUSTANGSONLINE.COM is a more track oriented forum. :)

Feel free to contact me on IG @italian_stang cauae is easier to chat. Or you can DM here.
I've been doing since 2 years now.
Ps. That pick was daytona so rain too but. If you dont really daily is ok.
 

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Iā€™m pretty sure that you have a problem with your cooling system for your oil and cht to be so high, especially so fast
Before installing my oil cooler, my oil never went into the yellow, was at the end of the green but not in the yellow
I also use 0w40
At speed you donā€™t need/use the fan so only a few possible issues:
1/ front radiator blockage due to dirty condenser, leaves, etc
2/defective water pump
3 defective t-stat
4/defective/blocked radiator/hoses
For 3, you could remove it completely for a track day. That will eliminate that possibility. That will be what I would do first
As for my oil temperature sensor, since I have an external oil cooler, my sensor is in line in the line out of the block and going to the cooler
 

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To add to what @luc said.... seems unlikely on a brand new car but you might have air pockets in your coolant as well. You could try burping your system and see if it takes in any more coolant.
 

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Id you remove the shroud you have for sure a better flow at speed. But..if you use the car around you need a fan especially when hot ambient. U can change it with a 16" fan only. But not sure is a good solution especially without vents.
Remove the flaps in your shroud help a bit.
 

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To add to what @luc said.... seems unlikely on a brand new car but you might have air pockets in your coolant as well. You could try burping your system and see if it takes in any more coolant.
That is and was my first doubt.
Could be air pocket. But cruising is ok for him. I wohld flush the system to add water wetter anyway. Following the procedure to remove bubles that you find on youtube (like for mishimoto new installation)
 
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67Fast_V

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That is and was my first doubt.
Could be air pocket. But cruising is ok for him. I wohld flush the system to add water wetter anyway. Following the procedure to remove bubles that you find on youtube (like for mishimoto new installation)
A lot to digest. Appreciate the input guys.

@luc - AC condenser is clean. T-stat seems okay but will check. Hoses are good. Water pump is moving fluid. Car is low mileage '20. Good thoughts, though. Thanks,
@Fly - I will check out the 0-40 oil and additive. Oil cooler is on the list. Will DM if something comes up. Thanks.
@Ewheels - hard to believe its air pockets as hard as I have run this but will look-up the burping procedure. Thanks.

This weekend I'm going to remove the t-stat to confirm it's good. Before installing originally, I put it on the stove and mapped out lift vs. temp. Looked good. Fully opened for sure. Tested 8 times :). Driving around town is great, so I know it's definitely opening. I will put some water wetter and drop the antifreeze ratio while at it. Also I will look up the burping procedure. I just normally leave the radiator cap off and let the t-stat open and run the engine for awhile.

You might find this data interesting. See below. I'm just shocked at the temp gain. Ave rpm is very sporty (and I short shifted into 4th at 6800 and 7th at 6700). A lot of heat load going into the cooling system that needs to get rejected. This might be the big driver as to why it's worse for me (with the A10) vs. M6.

Sebring T16 to max speed, 3th - 7th gear
dSpeed = 85 mph
dCHT =9.0 F
dECT=9.2 F
dTrans = 1.1 F
dDiff = 2.0
dTime = 16.6 secs
Ave rpm = 6110 ... can you imagine sitting at full throttle for 17 secs at 6100 rpm
Don't have oil temp. It's not available to be recorded.

Lets say you have a max allowable dT of 40F (200F-240F CHT). I used up 20+% of that in 1 straight-away. And this track has 3 sections where I use 3rd - 7th (4 gear changes). So 1 lap is 9+6+6 = 21F. Done in 2 or 3 laps. That's the math.

Will keep you posted on what I find. Thanks again for the input, fellas.
 
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67Fast_V

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Update. Have good news and bad news. Bad news first.

1. Bad news: Was hoping the new 170F thermostat was bad but not the case. Pulled it and put it on the stove and it opened at 172F and fully at 203F. Check that off the list.

2. Bad news: Found out that my cooling fans are not coming on unless the AC is running. I checked fans after first track event (1st overheating) and they were running, Did the same after the 2nd track event, no issues ...running. However everytime I checked them was w/ the AC on, not thinking about it. Let me ask this, when is the only time the AC is off in south FL :)? Ans: While on the track.

After I filled the system w/ 170F reinstalled, I turned the AC off to determine when the fans would kick on. 180F CHT came and went. 190, 200, 210 ... still no fans. AC on, fans on, and it cooled down immediately. So I have some trouble shooting in front of me. The 3 fuses are all good. Maybe the relays. If anyone has some thoughts, would appreciate the help.

3. Decided I would seal the perimeter of the radiator while the undertray was off. This thing is wide open all the way around except for the top (so 3 of the 4 regions have monster holes/openings). Dumping massive amount of flow past the radiator. The right side factory seal was hanging off and no longer attached. So I made some seals and went at it. Much better now. Maybe 80-90% sealed up. Happy w/ the results. Huge improvement in physical area closure.

4. Went for a run down the road to see if not having the fans on during track time would impact the cooling. 65 mph steady and AC on and off (fans on and off) made no functional difference. Same exact CHT either way. Not a surprise, but I had to check.

5. Good News: I did notice that CHT is 4-5 deg F cooler now w/ the radiator sealed (+ other things). Would run about 184-185F SS cruising before and now 179-181F. Ambient temp is identical, about 89F. So the 4 deg F is real. Unfortunately I changed 3 things that could cause the reduction. Radiator sealing, water wetter, and dropped the % antifreeze from 33% to 22%. I suspect the sealing was the driver, but I can't be for sure. Regardless, I will take the extra cooling.

A few more cooling mods are coming. Will update when I get them implemented. I will leave the 170 t-stat for now, but I'm not keen on < 180F cruising temps. Cheers :beer: .
 

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Update. Have good news and bad news. Bad news first.

1. Bad news: Was hoping the new 170F thermostat was bad but not the case. Pulled it and put it on the stove and it opened at 172F and fully at 203F. Check that off the list.

2. Bad news: Found out that my cooling fans are not coming on unless the AC is running. I checked fans after first track event (1st overheating) and they were running, Did the same after the 2nd track event, no issues ...running. However everytime I checked them was w/ the AC on, not thinking about it. Let me ask this, when is the only time the AC is off in south FL :)? Ans: While on the track.

After I filled the system w/ 170F reinstalled, I turned the AC off to determine when the fans would kick on. 180F CHT came and went. 190, 200, 210 ... still no fans. AC on, fans on, and it cooled down immediately. So I have some trouble shooting in front of me. The 3 fuses are all good. Maybe the relays. If anyone has some thoughts, would appreciate the help.

3. Decided I would seal the perimeter of the radiator while the undertray was off. This thing is wide open all the way around except for the top (so 3 of the 4 regions have monster holes/openings). Dumping massive amount of flow past the radiator. The right side factory seal was hanging off and no longer attached. So I made some seals and went at it. Much better now. Maybe 80-90% sealed up. Happy w/ the results. Huge improvement in physical area closure.

4. Went for a run down the road to see if not having the fans on during track time would impact the cooling. 65 mph steady and AC on and off (fans on and off) made no functional difference. Same exact CHT either way. Not a surprise, but I had to check.

5. Good News: I did notice that CHT is 4-5 deg F cooler now w/ the radiator sealed (+ other things). Would run about 184-185F SS cruising before and now 179-181F. Ambient temp is identical, about 89F. So the 4 deg F is real. Unfortunately I changed 3 things that could cause the reduction. Radiator sealing, water wetter, and dropped the % antifreeze from 33% to 22%. I suspect the sealing was the driver, but I can't be for sure. Regardless, I will take the extra cooling.

A few more cooling mods are coming. Will update when I get them implemented. I will leave the 170 t-stat for now, but I'm not keen on < 180F cruising temps. Cheers :beer: .
so 4-5 CHT equates to almost 10F in coolant temp? If so, that is a good start?

I too have a PP1 and it seems well sealed in my case (2021).
 
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67Fast_V

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so 4-5 CHT equates to almost 10F in coolant temp? If so, that is a good start?

I too have a PP1 and it seems well sealed in my case (2021).
Unfortunately the delta of 4-5F will be the same for CHT or ECT as related to the test I did yesterday. Also note that CHT and ECT during cruising are within 0.5 - 1.5F of each other in my '20 GT PP1. I logged the data and looked at it yesterday. That's not the case when on the track. I see 8-12 deg F delta under those conditions.

On the sealing, I'm not sure why the "21 would be any different but maybe Ford improved it. Not sure. Easy to check. If you take the front top cover plate off (has ~10 small push pins, 5 mins to remove), this is cover over the top of the radiator, look to the left and right and you should see monster holes/openings if your '21 is like my '20.

Like 5" x 6" openings on the right and 4" x 5" on the left. Can't miss them w/ cover off. Big bypass opening dumping air around the radiator. This elevates the pressure in the engine bay and results in more air that has to escape which drives the need (amongst other air sources) for hood vents that a lot of track guys install and see big benefits from.

Also note that the bottom is ugly sealing wise as well. At least for my '20. Can't see it unless you remove the under tray. Just something to consider if you want to track your car.
 

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I went in and checked when a stock 2015 turns on the fans: 212 the fans will run at 40% and at 223 they are 100%.
Iā€™m guessing your model year might be the same.

Also sealing the radiator is the single most important thing you can do. You want to all 4 sides to be as close to 100% sealed as possible. I use duct tape, HVAC tape and double sided tape to make sure its as good as possible.
 
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67Fast_V

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I went in and checked when a stock 2015 turns on the fans: 212 the fans will run at 40% and at 223 they are 100%.
Iā€™m guessing your model year might be the same.

Also sealing the radiator is the single most important thing you can do. You want to all 4 sides to be as close to 100% sealed as possible. I use duct tape, HVAC tape and double sided tape to make sure its as good as possible.
Thanks for finding the temps for me. The digging I found was 185F for the low speed. I figured 190 (+10 from stock thermostat) would do it. Called test off at 210F. Tomorrow I will let it go to 215 CHT and see if they come on. I don't understand why Ford would let it get that sporty (+32F from T-stat opening). Why let it thermal cycle that much.

I agree on the sealing. Pretty important. I'm about 80%. Some area are hard to chase out. Plus I wanted a little cold air to wash over the horn box on the left lower corner and then I put a dedicated hole in my sealing plate on the right upper corner to direct some flow to the fuse box and other electrical components on that side Now is that cold airflow truly needed, I'm not sure. I'm pleased closing off about 100 in^2 worth of "leaks". That's eqv to roughly 30% of the PP1 radiator open area.
 

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Just to add to the discussion. I have 3 seasons on track and my car start having CHT temp issues I think the higher I seen it was 239f. However my ECT is also high 220-225f and my problem is that car is pulling timing (Stock Tune, OEM PP1 car 2017). My coolant is never changed so I'm guessing this is contributing to the issues that I'm having otherwise the coolant system looks functional. During my research I learned:

1. Changing the Oil Cooler to something like Mishimoto is a must because the factory oil-cooler is super cheap and can brake on track leading to catastrophic engine failure. More here:

https://www.motorsportandperformance.com/blogs/s550-faq/mustang-gt-oil-cooler-failure

2. Hood Vents are also a must because air flow is reduced otherwise there is a reason why GT500 had such a massive Hood Vent.

3. Triple Pass radiator not only is better for cooling but gives you additional cooling capacity which is helpful for keeping coolant temps down.

4. 5w50 oil might help as this is what FP racing school cars are running and they use OEM radiator but run External Oil Cooler.

Hope this helps.
 
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67Fast_V

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Just to add to the discussion. I have 3 seasons on track and my car start having CHT temp issues I think the higher I seen it was 239f. However my ECT is also high 220-225f and my problem is that car is pulling timing (Stock Tune, OEM PP1 car 2017). My coolant is never changed so I'm guessing this is contributing to the issues that I'm having otherwise the coolant system looks functional. During my research I learned:

1. Changing the Oil Cooler to something like Mishimoto is a must because the factory oil-cooler is super cheap and can brake on track leading to catastrophic engine failure. More here:

https://www.motorsportandperformance.com/blogs/s550-faq/mustang-gt-oil-cooler-failure

2. Hood Vents are also a must because air flow is reduced otherwise there is a reason why GT500 had such a massive Hood Vent.

3. Triple Pass radiator not only is better for cooling but gives you additional cooling capacity which is helpful for keeping coolant temps down.

4. 5w50 oil might help as this is what FP racing school cars are running and they use OEM radiator but run External Oil Cooler.

Hope this helps.
Good suggestions, thanks.

If I could run 239F CHT or 225F ECT, that would be success compared to where I am now.

It appears that my #1 issue is airflow. Hence drove me to seal the perimeter of the radiator. Next I'm going to modify my fan shroud. Cost effective and easy to do. How much is this worth ... not sure, but I will find out in a few weeks. After that is the hood vents. Looking for a used hood to cut.

Oil cooler is on the list, just need to find a good way to package w/ the new A10 tranny cooler.

The PP1 radiator is a good size unit. It is actually 72% bigger than my previous car's radiator+ factory Aux cooler (C7 Z06). So will hold off on new radiator to see how the airflow related mods work. Others have recommended the 5w-50 as well and that's good to know that FP school is using it. Thanks.
 

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Good suggestions, thanks.

If I could run 239F CHT or 225F ECT, that would be success compared to where I am now.

It appears that my #1 issue is airflow. Hence drove me to seal the perimeter of the radiator. Next I'm going to modify my fan shroud. Cost effective and easy to do. How much is this worth ... not sure, but I will find out in a few weeks. After that is the hood vents. Looking for a used hood to cut.

Oil cooler is on the list, just need to find a good way to package w/ the new A10 tranny cooler.

The PP1 radiator is a good size unit. It is actually 72% bigger than my previous car's radiator+ factory Aux cooler (C7 Z06). So will hold off on new radiator to see how the airflow related mods work. Others have recommended the 5w-50 as well and that's good to know that FP school is using it. Thanks.
Itā€™s not normal for your car to get that hot so fast. Key words here is so fast
Obviously adding airflow through the radiator will help but youā€™re treating the symptom, not the issue
In a simple term, you are putting more heat load through the cooling system that it can handle
Is your problem with an abnormal heat load and a normal cooling system or a normal heat load but an abnormal cooling system ?
Obviously the end result in the same but the diagnosis and cure is not
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