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High CHT at the Track. Normal??

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9
Exp. Type
HPDE
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3-5 Years
FL
Hi Folks - new here and wanted to ask a question. I posted this on the Mustang6G Forum but maybe would be helpful to ask the question here. Got some good feedback from ewheels already. Looking to see if this makes sense to others. I just can't believe a PP1 GT stock could be this bad. See below.

I'm having an engine cooling issue and wanted to know if this is common for Gen 3 S550 GTs. I have done some digging but it's not clear to me and hence my direct question.

I have mostly a track car ... '20 GT PP1 A10 but stock at the moment and I can't run more than 3-4 laps (maybe 6-9 mins) before I hit 250F CHT and go into cool down mode. I'm really surprise that this is occurring. I replaced the t-stat w/ a 170F because the OEM was defective. Around town, CHT is 182-198F range. So perfect/no issue. But when I open this up at the track, the engine gets hot very quickly. The trans temp is good for now ~ 221F max and the rear diff is okay for now as well ~252F max (note this is after wrapping the exhaust and changing to 75W-140 ... which made a huge difference).

Have others had this same problem at the track ... or is it likely unique to my car? Would appreciate your thoughts/experience. Thanks.
 
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Flyhalf is writing the book on this, use the search button and you'll find more info than you can imagine concerning cooling/shifting issues
 
13
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Exp. Type
HPDE
Exp. Level
3-5 Years
FL
Flyhalf is writing the book on this, use the search button and you'll find more info than you can imagine concerning cooling/shifting issues
I have found some of his posts in the past (good stuff) but I will start digging more. Thanks for the input.
 

JDee

Ancient Racer
1,301
1,181
Exp. Type
W2W Racing
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20+ Years
halfway between Mosport and Shannonville
Two words to start you off.
Hood Vent. A good one, like Race Louvers makes. Many of them out there are just decorations, Race Louvers units are wind tunnel proven. I put one in and cooling issues became a thing of the past, amazing what it did to temps. Added bonus, more downforce.

 
13
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HPDE
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3-5 Years
FL
Time to start cutting that hood! @67Fast_V

View attachment 69357

Thanks Jdee/Ewheels. Good advise 👍. I just don't know if I can do that emotionally 🙁 ... and the darn rain in south FL. I would need to put some kind of catch pan under it and duct the water out. And remove for the track. A lot to think about. Have only had the car for 4 months. Get out the grinder ... yikes. Nice cutting job, Ewheels. Good work there. Love the blue tape. I use it for everything, to.
 
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Time Attack
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Under 3 Years
SoCal
Thanks Jdee/Ewheels. Good advise 👍. I just don't know if I can do that emotionally 🙁 ... and the darn rain in south FL. I would need to put some kind of catch pan under it and duct the water out. And remove for the track. A lot to think about. Have only had the car for 4 months. Get out the grinder ... yikes. Nice cutting job, Ewheels. Good work there. Love the blue tape. I use it for everything, to.
You could always buy another hood to cut up. That's what most people do.
I was going to fabricate a rain tray as well but I bought a daily instead 😆
 

JDee

Ancient Racer
1,301
1,181
Exp. Type
W2W Racing
Exp. Level
20+ Years
halfway between Mosport and Shannonville
Thanks Jdee/Ewheels. Good advise 👍. I just don't know if I can do that emotionally 🙁 ... and the darn rain in south FL. I would need to put some kind of catch pan under it and duct the water out. And remove for the track. A lot to think about. Have only had the car for 4 months. Get out the grinder ... yikes. Nice cutting job, Ewheels. Good work there. Love the blue tape. I use it for everything, to.

Rain is a non-event, I've been through a couple of gulley washers and it just ran like it always does. Idled the motor through one torrential downpour sitting still and have been through several wet days on track with no adverse effects.
 
Sounds like to me you have some type of cooling issue. It could be related to venting, but I don’t think so. I’ve seen a few stock GT350s and GTs here in TX at COTA in 100* degree heat with power CHTs.

I fought similar issues in 2019. I never did find the specific issue, but I think it was related to my radiator - I’m thinking it might have been partially clogged.

is this a new problem? Or have you always had this issue?
 
13
9
Exp. Type
HPDE
Exp. Level
3-5 Years
FL
Rain is a non-event, I've been through a couple of gulley washers and it just ran like it always does. Idled the motor through one torrential downpour sitting still and have been through several wet days on track with no adverse effects.
Rain is a non-event, I've been through a couple of gulley washers and it just ran like it always does. Idled the motor through one torrential downpour sitting still and have been through several wet days on track with no adverse effects.
Good info JDee, Thanks. I'm surprised the rain water doesn't get on the coils and such and cause an issue. But I guess it's hot enough to where it evaporates and/or sealed well. Getting water on a running engine is certainly not ideal but there are worse things. My big issue is cutting the hole.

On the cutting, I'm in that boat @Ewheels/Tmsboss... buy a used or new hood and cut that one. It's $1300 for new hood and center vent and some low cost paint. Would be great to find a used one. And I do have some time to wait but not a lot.

I have an event coming up on Nov 9th and I'm going to try a few simple mods to duct the air into the radiator and get it out of the engine bay. And @Ewheels, ... I will try to keep the CHT under 250F ;)but as fast as this climbs, I don't know if I can. Ordered some materials today. Will do some testing this weekend.

I want to start working on the wheels, suspension bits, etc but when I can't run more than 2 or 3 laps, doesn;t make sense to focus on that now. I do have some 19 x 11 and square 305's. I bought 8 new RE71Rs to put on. Got them super cheap when they were dumping them on the market. Need to install ARP studs in the front as the next step but 250F CHT has me pre-occupied.
 
13
9
Exp. Type
HPDE
Exp. Level
3-5 Years
FL
Sounds like to me you have some type of cooling issue. It could be related to venting, but I don’t think so. I’ve seen a few stock GT350s and GTs here in TX at COTA in 100* degree heat with power CHTs.

I fought similar issues in 2019. I never did find the specific issue, but I think it was related to my radiator - I’m thinking it might have been partially clogged.

is this a new problem? Or have you always had this issue?
Only have had the car for 4 months. It's a low mileage '20. CHT was fine on the street for 2 months and then on my first track event, I ran 2 laps and was done. 250F+. Limped along for 2 more sessions and took it home. Pulled the OEM thermostat and found it to be defective (bypass was wide open). Figured that was it. Replaced with 170F and thought I was good. Ice cold running on the street. Happy as I could be. CHT 182-198F, Perfect. No more cooling problems. Great.

Next event 4 wks later, 3 laps and I was done. Start CHT ~190F and goes to 215F on the 1st lap and then 230F and then 250. Done. Mid boggling to me, but this is an A10 and I'm not goofing off w/ it. 7000 rpm shifts and lowest gear possible. When I loaf around at 5500-6000 and stay in higher gears, I have more time before 250F occurs.

I'm not a good driver but my lack of skill doesn't seem to stop me from going hard. I have done this tracking thing all wrong. There is no question in my mind I have taken the wrong approach. I started out with one of the fastest cars possible (C7 Z06 Z07 package) and then started back peddling and now I have this '20 GT. And a bit frustrated with these issues. I would like to learn how to drive it. Sorry, I digressed a bit.

Seems most on the Forum think it's lack of airflow through the radiator and the A10, and not something unique ie a problem with the engine or cooling. And from what they have said and experienced on the track, I believe they are right. I will check the new 170 T-stat to be sure that's not defective. But my pride is way off to the side and I'm all ears if you have some thoughts. Cheers.
 
Only have had the car for 4 months. It's a low mileage '20. CHT was fine on the street for 2 months and then on my first track event, I ran 2 laps and was done. 250F+. Limped along for 2 more sessions and took it home. Pulled the OEM thermostat and found it to be defective (bypass was wide open). Figured that was it. Replaced with 170F and thought I was good. Ice cold running on the street. Happy as I could be. CHT 182-198F, Perfect. No more cooling problems. Great.

Next event 4 wks later, 3 laps and I was done. Start CHT ~190F and goes to 215F on the 1st lap and then 230F and then 250. Done. Mid boggling to me, but this is an A10 and I'm not goofing off w/ it. 7000 rpm shifts and lowest gear possible. When I loaf around at 5500-6000 and stay in higher gears, I have more time before 250F occurs.

I'm not a good driver but my lack of skill doesn't seem to stop me from going hard. I have done this tracking thing all wrong. There is no question in my mind I have taken the wrong approach. I started out with one of the fastest cars possible (C7 Z06 Z07 package) and then started back peddling and now I have this '20 GT. And a bit frustrated with these issues. I would like to learn how to drive it. Sorry, I digressed a bit.

Seems most on the Forum think it's lack of airflow through the radiator and the A10, and not something unique ie a problem with the engine or cooling. And from what they have said and experienced on the track, I believe they are right. I will check the new 170 T-stat to be sure that's not defective. But my pride is way off to the side and I'm all ears if you have some thoughts. Cheers.
Hmm. I disagree. You should get more than two laps before the car goes into limp mode—stock or not. Something is off broken or defective. Given that it’s fine on the street but not on the track, I’ll bet you have a flow issue. Either a restriction or air bubble in the system.

Before I started cutting the hood, I’d make sure that the belts are good, water pump is okay, and that coolant levels aren’t changing due to a head gasket leak or air bubbles. Outside of the thermostat you replaced, is the entire cooling system stock?

If all that is good, I’d replace the radiator with a mishimoto unit and swap out the water pump with the GT500 unit.

Alternatively you could take it to a dealer and have them fix it
 
13
9
Exp. Type
HPDE
Exp. Level
3-5 Years
FL
Hmm. I disagree. You should get more than two laps before the car goes into limp mode—stock or not. Something is off broken or defective. Given that it’s fine on the street but not on the track, I’ll bet you have a flow issue. Either a restriction or air bubble in the system.

Before I started cutting the hood, I’d make sure that the belts are good, water pump is okay, and that coolant levels aren’t changing due to a head gasket leak or air bubbles. Outside of the thermostat you replaced, is the entire cooling system stock?

If all that is good, I’d replace the radiator with a mishimoto unit and swap out the water pump with the GT500 unit.

Alternatively you could take it to a dealer and have them fix it
Thanks HB for the feedback. Car is pure stock except for 5w-30 Mobil 1, SRF brake fluid, exh wrap on the pipes near diff, and 75w-140 diff fluid. Belts are fine, all new. Water pump is moving fluid the best I can see when the t-stat opened after replacement. Coolant level has not changed much the best I can tell when I checked it today (between min and max) which is where I put it after t-stat replacement. Car runs great. No miss firing. Nice and cold driving around town. No odd behaviors. All if fine until I open the throttle hard and keep it there.

I'm not sure how to start the conversation w/ a Dealer about this, so I'm on my own for now.

Don't know anything about the GT500 w/p and whether that would fit on my Gen 3 Coyote 5.0L. But I will start digging. Thanks.

I can replace the radiator but I will try some lower cost mods first to determine if incremental changes in airflow do anything. If they don't, then I think I will take your suggestion and replace the radiator. I'm sure I would end up doing that anyway as I push harder and make other mods. For sure a new trans cooler is coming and an oil cooler. Might as well go after the radiator as well.

If the incremental airflow changes help, then I'm going after the big hole in the hood, pronto. Well anyway, that's what I'm thinking at the moment. Appreciate the input :thumbsup:.
 
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sfo
67,

you are correct In your opinions. I’m less kind. Sorry to the s550 lovers but the s550 is a pos. I bought new a 2019 GT A10 pp1 off dealer lot and gutted it into my T2 racecar. I also come from vetted. I raced a C5z also in T2.
With a 100 miles on my GT I went for first recon laps to see where I had to improve. You are right a few laps in stock trim and limp overheat. In my case the diff then A10 then motor.
the c7z was not good on heat without mods. If you could track your c7z and not overheat that speaks to how you run a car. I would therefore suspect a flaw somewhere in motor cooling on your s550. That is a wag. The s550 overheats in this order and is known…diff, A10, motor.
Flyhalf did the original figuring of the overheat issues. he has solved his issues as an evolutionary process. I came after him and skipped most of his pain with what I think is better packaging only because I have the advantage of his process. Where he and I philosophically depart is his locking open of the trans bottle neck to get that last needed cooling control.
If you search either here or on m6 there are pics and part numbers of what I did and what I think is better packaging. Part of my development is parallel development that another member also used. We both have no problems using the same setup for trans and motor cooling. One caveat to my statements is that flyhalf is running e85 making 485rwhp. That’s a lot of heat. In the T2 class I have to run a 50mm restrictor plate that cuts power to around 350 best guess. That means I can’t make as much heat.

so if you find my thread pics are there how to set up the cooling. In short motor cooling is easy basically a big 67000 btu cooler. Trans is easy. Same cooler wired into the stock system. Diff easy I used old oem trans cooler to cool the diff. All problems solved.
I think my coolers are bigger than flyhalf And I do not need the trans bypass he is using…but I also cannot make as much heat.

that said if I needed the next step in cooling I would instead leave the bypass alone and the dorky dual element filter that I think flyhalf also modified. I say keep stock what you can keep stock. If I needed more cool I would take the ppe aluminum A10 trans pan and tap it’s ports and add the big cooler here then just keep the oem trans cooling system intact as oem. This would cool the trans similar to how we cool motors…no tricks. In fact if I was doing trans cooling all over again I would go with same 67000btu cooler I’m using now plumbed it on the ppe pan and leave the oem trans cooler system alone. The reason I did not do that to start is the ppe pan was not available to tap and drill bung ports At the time. There is already a port on the ppe pan from ppe it just needs to be made bigger like AN 10. Then you can drop the cooled fluid right into the dipstick hole. Use a totally reliable tilton continuous duty pump. My method allows additional cooling control by flow control. Flyhalf method still has the bypass as a possible bottleneck. he has maxed out his cooling but it works. Hope this helps.
 

JDee

Ancient Racer
1,301
1,181
Exp. Type
W2W Racing
Exp. Level
20+ Years
halfway between Mosport and Shannonville
The problem is not getting more airflow through the rad, it is getting the air that's being jammed in there out of the engine room. That's what vents do. Cutting a hole in the hood for a vent is not a big deal, it's a hunk of aluminum, nothing more. Look at virtually any race car around, they're all sporting massive venting in the hood and fenders. That's because it works.

You have to remember, these are street cars, not designed or built as race cars. When you start to do race car stuff with them you are exceeding by far what the factory built the car for and drastic steps have to be taken to solve problems.

Calling a street car a pos when you're expecting far more from it than it was designed to give is really not fair to the car or manufacturer at all. They were meant to drive around mostly at legal speeds, maybe the odd burst now and then. Now we're running them flat out all the time and expecting them to live without needing help? Kind of odd thinking IMHO.
 
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Exp. Type
W2W Racing
Exp. Level
Under 3 Years
Scottsdale
My two cents worth, You have a engine cooling issue. The radiator is what does the cooling. I track in Arizona. My car has never had any issues but not running with a C10. The auto trans makes extra heat that requires cooling up front. I would for sure run hood vents. I saw a big difference in temps right away. Then I would go a kenny brown 3 pass radiator. I think your issues will be resolved.
 
13
9
Exp. Type
HPDE
Exp. Level
3-5 Years
FL
The problem is not getting more airflow through the rad, it is getting the air that's being jammed in there out of the engine room. That's what vents do. Cutting a hole in the hood for a vent is not a big deal, it's a hunk of aluminum, nothing more. Look at virtually any race car around, they're all sporting massive venting in the hood and fenders. That's because it works.

You have to remember, these are street cars, not designed or built as race cars. When you start to do race car stuff with them you are exceeding by far what the factory built the car for and drastic steps have to be taken to solve problems.

Calling a street car a pos when you're expecting far more from it than it was designed to give is really not fair to the car or manufacturer at all. They were meant to drive around mostly at legal speeds, maybe the odd burst now and then. Now we're running them flat out all the time and expecting them to live without needing help? Kind of odd thinking IMHO.
Sorry guys, I didn't mean to start anything here.

@bob - great advice, thanks so much for sharing :thumbsup:. I will dig and find your mods and take a close look. Thank-you. Great Forum to share. Makes life even more special. My experience was GT is motor on the 1st ever session and then the diff on the 3rd session (all within the 1st event with the car). The A10 is close. I did find a 226F temp towards the end of my last event (#2). Was 222F on the 1st event. Good to log the data. Helps understand the true picture.

On my C7Z experience, I had '17 model which had GM's aux cooler (added heat exchanger in parallel w/ the main radiator) which helped a lot. I did overheat the car once using a lot of 2nd gear. So what I did is ditch 2nd and drove 3rd - 5th. I was actually almost as quick using the higher gears cus I struggle with shifting under lateral load. So I got use to 3rd and dialed that in. Worked well w/ my experience and the car was darn quick, even with my lousy driving. The '20 GT is 10 secs/lap and 15-20 mph slower at my two local tracks. The Z was a scary beast at least for me when you push hard. However I'm anxious to bridge that time/speed gap and I think the GT has potential.

However when it comes to cooling, I tried the same approach with the GT of using higher gears 4th - 7th and it's still very problematic as described.

@JDee - I think we are saying the same thing in terms of the physics just describing it a little differently. I have to reduce the back pressuring of the air in the engine bay and that's my focus over the next couple of weeks prior to my next event. I understand about cutting the hole, ... I just have to get past the sociological aspects 🙁.

I have a lot to chew on here and of course a problem to fix. Thanks for your help, guys. Cheers.
 
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sfo
Hood vents are good but add drag. So do that with some thought. 2 big players are tracspec and race louver. I think the trackspec ones are really nice. The race louver is good too and they make a specific T2 legal one so that's what I must use. My big coolers work so well I don't even duct the air to force through coolers. Flyhalf not only has ducting but water cooling sprayers since he is time trialing. That is a slightly different game where you will do a cool down lap then fast lap for time. I'm 20-40min as hard as I can go.

On the A10 it uses ULV. Like how I decide on motor oil viscosity I thought about A10 oil viscosity at the temps I'm running at. So I mixed ULV and LV to up the viscosity at temp. This totally did not work for Flyhalf. I'm not sure why but he does drive to the track...so many it is driveability at street temps/speeds.

I found when I mixed the stone cold gearbox would not immediately shift. I guess oil too thick. No problem racecar. So I just let it idle for a bit then it warms up and shifts fine. Once I do a warmup lap shifting is as expected. Getting heat in is the least of my worries. YMMV on that one. I'm still undecided on mixing ULV with LV or using straight ULV as OEM. For now I'm too lazy to change it so I'm mixed ULV/LV.
 
13
9
Exp. Type
HPDE
Exp. Level
3-5 Years
FL
Hood vents are good but add drag. So do that with some thought. 2 big players are tracspec and race louver. I think the trackspec ones are really nice. The race louver is good too and they make a specific T2 legal one so that's what I must use. My big coolers work so well I don't even duct the air to force through coolers. Flyhalf not only has ducting but water cooling sprayers since he is time trialing. That is a slightly different game where you will do a cool down lap then fast lap for time. I'm 20-40min as hard as I can go.

On the A10 it uses ULV. Like how I decide on motor oil viscosity I thought about A10 oil viscosity at the temps I'm running at. So I mixed ULV and LV to up the viscosity at temp. This totally did not work for Flyhalf. I'm not sure why but he does drive to the track...so many it is driveability at street temps/speeds.

I found when I mixed the stone cold gearbox would not immediately shift. I guess oil too thick. No problem racecar. So I just let it idle for a bit then it warms up and shifts fine. Once I do a warmup lap shifting is as expected. Getting heat in is the least of my worries. YMMV on that one. I'm still undecided on mixing ULV with LV or using straight ULV as OEM. For now I'm too lazy to change it so I'm mixed ULV/LV.
@S550AZ - thanks for the two cents. It does seem that mine is heating up faster than most, if not all. Now why ... I don't know. The stock cooling is not adequate but why only 2-3 laps ... and not 7-8 laps like most. I still have the t-stat to check and I will go back over everything. Hood vents are on the list but not before my Nov event.

@bob - thanks again for the data dump. Great info. I can see you and Flyhalf have different cars but a lot of common elements. That stinks that you have to run a restrictor but I guess rules are rules. I will check out your build, coolers, and such. Cooling mods are coming soon. I will do whatever is necessary to be able to run a 20-25 min session w/o overheating with 550 hp (93 octane) at the crank and 7500 shifts, 3rd through 7th. I want my Z06 power and lap times back 🙂. In the meantime, seems I have my hands full getting pure stock to work.

Flyhalf said keep ULV fluid and based on your experience as well, I will stick with OEM. Hood vents seem like a must have for cooling (and downforce) based on everyone's input. Just have to buy a new hood and cut that. Likely worth the penalty in drag if temps are lower allowing engine to make more power than otherwise.

Thanks guys :thumbsup:
 

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