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So I am getting sick of overheating (going into limp mode where car puts the dreaded "engine overheating" message on the DIC) during my HPDE events with my 2016 Z06 A8. I end up overheating at about 16 minute mark of a 20 minute so I dont have a huge problem and I dont have gobs of money to throw at this so I am hoping some of you guys got actual experience with a few of the low cost options. So here is some of the things I was thinking about and see if anyone tried and saw any gains.
1. Remove all coolant from radiator and go with water and water wetter. I live in AZ so no freezing could ever occur.
2. Remove all coolant from the supercharger cooling system and go with water and water wetter.
3. Add one of the after market expansion tanks for the supercharger cooling system
What year car and is it a M7 or an A8? What ambient temperatures are running in and what is the track length and what gears do you use?
M7s with the secondary radiator can run very fast laps throughout a normal HPDE session without over heating in temps up to 95 degrees. I know I have been able to do it for three seasons without coming close to over heating.
What do you consider over heating? I typically see mid 220s coolant and mid 270s oil temps on those hot days and those temps are far below the over heating range.
So I am getting sick of overheating during my HPDE events. I end up overheating at about 16 minute mark of a 20 minute so I dont have a huge problem and I dont have gobs of money to throw at this so I am hoping some of you guys got actual experience with a few of the low cost options. So here is some of the things I was thinking about and see if anyone tried and saw any gains.
1. Remove all coolant from radiator and go with water and water wetter. I live in AZ so no freezing could ever occur.
2. Remove all coolant from the supercharger cooling system and go with water and water wetter.
3. Add one of the after market expansion tanks for the supercharger cooling system
No, and No. Can't answer 3rd question. Do not know about the particulars. Having a 50/50 mix of coolant and distilled water are your best options. The coolant in the water raises the vapor pressure of the working fluid and also increases the boiling point of the working fluid as compared with just plain water. This is a good thing as boiling fluid reduces the amount of heat transfer the radiator can transfer from the engine. I am not a big believer in water wetter. It has a minimal effect on enhancing heat transfer from the radiator. The solution you seek is somehow you need to add a larger radiator to your ride. More fins are the solution to increasing the cooling.
What year car and is it a M7 or an A8? What ambient temperatures are running in and what is the track length and what gears do you use?
M7s with the secondary radiator can run very fast laps throughout a normal HPDE session without over heating in temps up to 95 degrees. I know I have been able to do it for three seasons without coming close to over heating.
What do you consider over heating? I typically see mid 220s coolant and mid 270s oil temps on those hot days and those temps are far below the over heating range.
Bill
The car is a 2016 Z06 A8. The car goes into over heat mode and throttle wont go higher than 20% or so and the dash has the Engine Overheating warning (see image below for example). Oil is 320 but not sure on the coolant but it is sky-rocketed I am sure. This last track is only 1.2 and is highly technical and was in 3rd and forth all the time, ambient temp was 85, but have overheated at all the tracks in the phoenix area. Arizona Motorsports Park is 2.2 with lots of high speeds, using 3rd, 4th and 5th. So that should give you an idea of the wide range of tracks.
For the race track, if you want to drive fast,
You need a perfect cooling.
Katech, for example, can help very well.
If you do not want to spend money:
-Disassemble the complete air conditioning system
Drive your machine always in manual mode and switch at the latest at 5700RPM
For the race track, if you want to drive fast,
You need a perfect cooling.
Katech, for example, can help very well.
If you do not want to spend money:
-Disassemble the complete air conditioning system
Drive your machine always in manual mode and switch at the latest at 5700RPM
Cölestin
I got some money to spend, just not a lot. Katech would be waaaaay to much obviously. I do already manually shift but seems like I will have to shift early since it seems my 3 ideas r not worth anything.
No, and No. Can't answer 3rd question. Do not know about the particulars. Having a 50/50 mix of coolant and distilled water are your best options. The coolant in the water raises the vapor pressure of the working fluid and also increases the boiling point of the working fluid as compared with just plain water. This is a good thing as boiling fluid reduces the amount of heat transfer the radiator can transfer from the engine. I am not a big believer in water wetter. It has a minimal effect on enhancing heat transfer from the radiator. The solution you seek is somehow you need to add a larger radiator to your ride. More fins are the solution to increasing the cooling.
Actually, that's not true. Water and water wetter will move heat away from the engine far better than a 50/50 mix of antifreeze and water. The boiling point increase is almost 100% due to the systems being pressurized and not any function of the antifreeze. Yes, it's antifreeze, not coolant and antifreeze has less of a heat carrying capacity than water. Why do you think GM changed the mix to 60/40 for the intercooler? Because more water cools better. Water wetter works, but only on water, it has no effect on antifreeze. Water wetter and the other similar products act as water softeners and reduce the water's surface tension. This allows the water to reach areas in the rough cast cooling jackets that it couldn't before. This reduces hot spots around the combustion chambers and generally cools better.
Actually, that's not true. Water and water wetter will move heat away from the engine far better than a 50/50 mix of antifreeze and water. The boiling point increase is almost 100% due to the systems being pressurized and not any function of the antifreeze. Yes, it's antifreeze, not coolant and antifreeze has less of a heat carrying capacity than water. Why do you think GM changed the mix to 60/40 for the intercooler? Because more water cools better. Water wetter works, but only on water, it has no effect on antifreeze. Water wetter and the other similar products act as water softeners and reduce the water's surface tension. This allows the water to reach areas in the rough cast cooling jackets that it couldn't before. This reduces hot spots around the combustion chambers and generally cools better.
Pure nonsense bud. 100% !!! I am laughing so hard that my side is hurting. You do not know what you are talking about other than maybe what you read in some BS market literature. I know what watter wetter is and capable of. Think of it as snake oil. It is a mere band-aid. The thermodynamic properties of a 50-50 blend of coolant-distilled water will yield the highest possible boiling temperture which is as good as you're going to get. Pressurizing the cooling system also raises the boiling point further. This solution will increase the vapor pressure of the fluid which increases the boiling temperature. You want to increasure the boiling temperature as you want the fluid in your coolng system to remain as a fluid and delay any onset to becoming a vapor. Why you ask? Liquids are much more capable of transferring heat away than pressurized vapor is. If you disagree then you know absolutely nothing about science. Sorry bud, but the Laws of Thermodynamics are on my side on this one. You're not a water wetter sales person perchance?
We are local to you sir and I have quite a few c7z's that do full road racing not HPDE stuff and they have zero overheating issues with our setup's. If you want to discuss your options shoot me a pm, email me, or come down to the shop.
We are local to you sir and I have quite a few c7z's that do full road racing not HPDE stuff and they have zero overheating issues with our setup's. If you want to discuss your options shoot me a pm, email me, or come down to the shop.
Wow, that is hot.
Did the DIC tell you to change the oil after that high temp?
Using 15W-50 oil or something different?
Did you get any coolant boil?
No I did not get a change oil warning. I did not see any boil but it is possible I am sure with the temps I get to. Since it overheats early I drive a lap and half in 5th gear to cool down and then get 1 more lap or 2 in. I get this every event except for the ones where we stay under 60 degrees for the day. Using the same oil as always.
We have a few options that you can pick from, including a dual oil cooler setup that does not alter the bumper, and retains the brake ducts. In addition to that, we are finally happy and ready to release our blower reservoir that we use in our big cooling packages for the last two years- only catch is that it retains the OE heat exchanger, but changes the flow and removes the air from the system. The engineering has been done for some time, and should hit the market in the next two weeks.
These two systems combined will lower coolant temp 30* and lower oil temp 65* and can be installed in a long afternoon with normal hand tools.
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We have a few options that you can pick from, including a dual oil cooler setup that does not alter the bumper, and retains the brake ducts. In addition to that, we are finally happy and ready to release our blower reservoir that we use in our big cooling packages for the last two years- only catch is that it retains the OE heat exchanger, but changes the flow and removes the air from the system. The engineering has been done for some time, and should hit the market in the next two weeks.
These two systems combined will lower coolant temp 30* and lower oil temp 65* and can be installed in a long afternoon with normal hand tools.
This is the one I would check out OP. That's coming from an an engineer. Snake oil doesn't work.
Pure nonsense bud. 100% !!! I am laughing so hard that my side is hurting. You do not know what you are talking about other than maybe what you read in some BS market literature. I know what watter wetter is and capable of. Think of it as snake oil. It is a mere band-aid. The thermodynamic properties of a 50-50 blend of coolant-distilled water will yield the highest possible boiling temperture which is as good as you're going to get. Pressurizing the cooling system also raises the boiling point further. This solution will increase the vapor pressure of the fluid which increases the boiling temperature. You want to increasure the boiling temperature as you want the fluid in your coolng system to remain as a fluid and delay any onset to becoming a vapor. Why you ask? Liquids are much more capable of transferring heat away than pressurized vapor is. If you disagree then you know absolutely nothing about science. Sorry bud, but the Laws of Thermodynamics are on my side on this one. You're not a water wetter sales person perchance?
You need to restudy thermodynamics my friend! Ethylene glycol (the major portion of antifreeze) has a heat index of 2.78, where water has a heat index of 1.0. The lower the number, the better the fluid transfers heat. Start by reading that carton of antifreeze (yes, that's what it is, NOT COOLANT.) You will see that as the percentage goes up the boiling point doesn't change much at all, but the freezing point does go down with increased percentages, that's why it is ANTIFREEZE. The major reason the boiling point is raised is due to having the fluid under pressure. The OP was on the right path with ditching the antifreeze, water with waterwetter or similar, will cool better than with antifreeze. Antifreeze is used for two reasons, to keep it from freezing (naturally) and as a lubricant for the water pump. The waterwetter provides the lubricant needed as well as helping the water move the heat out.
You seem stuck on the idea of vapor pressure. What you should think about is keeping the fluid "fluid", and not vapor. That is done by having a pressurized system, not by using antifreeze. Most importantly, water has a higher heat capacity (the ability to take heat away from the engine) than antifreeze.
I, my friend, have studied thermodynamics. Why don't you do the same before attempting to educate others on the subject.
You need to restudy thermodynamics my friend! Ethylene glycol (the major portion of antifreeze) has a heat index of 2.78, where water has a heat index of 1.0. The lower the number, the better the fluid transfers heat. Start by reading that carton of antifreeze (yes, that's what it is, NOT COOLANT.) You will see that as the percentage goes up the boiling point doesn't change much at all, but the freezing point does go down with increased percentages, that's why it is ANTIFREEZE. The major reason the boiling point is raised is due to having the fluid under pressure. The OP was on the right path with ditching the antifreeze, water with waterwetter or similar, will cool better than with antifreeze. Antifreeze is used for two reasons, to keep it from freezing (naturally) and as a lubricant for the water pump. The waterwetter provides the lubricant needed as well as helping the water move the heat out.
You seem stuck on the idea of vapor pressure. What you should think about is keeping the fluid "fluid", and not vapor. That is done by having a pressurized system, not by using antifreeze. Most importantly, water has a higher heat capacity (the ability to take heat away from the engine) than antifreeze.
I, my friend, have studied thermodynamics. Why don't you do the same before attempting to educate others on the subject.
You have studied Thermodynamics but you do not know that coolant and anti-freeze are the same? 🤣😂🤣You're a knuckle head. Anti-freeze and coolant are both Ethylene glycol. If they were not the same then car manufacturers would recommend everyone in colder climates flush their cooling system every 6 months. Water wetter is snake oil. All water wetter products do are reduce the surface tension properties of the water molecule so that it reduces the dynamic viscosity of water. This will allow water to flow marginally more smoothly across the internal surfaces within the engine's cooling system. This effect is marginal in it's ability to enhance the conductive heat transfer effects of water in a cooling system. In fact, the total effect it offers is nowhere as benefical as the effect of having coolant (aka Anti-freeze) as a 50-50 mixture in solution in your car's cooling system. This ratio has been experimentally determined to provide an optimal and beneficial effect of increasing the boiling point temperature of this solution. This is a well established incontrovertible fact. All car manufacturer's fill their cooling system with a 50-50 mix of coolant and distilled water. They all recommend this. No engine manufacturers are shipping their products with water wetter absent Ethylene glycol. In fact manaufacturers would more than likely void your warranty if engine problems developed as a result of you swapping out coolant from your cooling system and found you switched to water wetter only. I'd recommend you go back to school if want to learn more about thermal sciences and chemistry. Let me know when you receive your doctorate in engineering and have spent your entire career working in this field as I have.
The car is a 2016 Z06 A8. The car goes into over heat mode and throttle wont go higher than 20% or so and the dash has the Engine Overheating warning (see image below for example). Oil is 320 but not sure on the coolant but it is sky-rocketed I am sure. This last track is only 1.2 and is highly technical and was in 3rd and forth all the time, ambient temp was 85, but have overheated at all the tracks in the phoenix area. Arizona Motorsports Park is 2.2 with lots of high speeds, using 3rd, 4th and 5th. So that should give you an idea of the wide range of tracks.
Originally Posted by ktoonsez
I do have the PDR, totally forgot that there was a free program (if it is still around) to open that up and get all the embedded information.
EDIT:
Using Cosworth app, oil got up to 320 and coolant was at 264.
Just to clear up something mentioned in an earlier post: GM uses a 40/60 mix of coolant to water in the C7s. You could drop to 30/70 but I don't think I would drop any lower.
I think one of your issues is you are running the engine at higher rpms without a lot of speed due to the short tracks you are running on. I would try driving the tracks without using third gear and see if that delays the temp increase. Instead of gearing down to exit lower speed corners use the engine torque to pull out of them by opening the throttle sooner on corner exit while keeping overall revs down while moving at slower speeds. High rpms at low speed will pump a lot of extra heat into the cooling system. One of the reasons the M7 drivers don't see as many overheating problems is they choose to run in 3rd and 4th and maybe 5th. A similar gearing profile with the A8 would be 4th, 5th and maybe 6th if it isn't too tall.
The other issue is you don't have the extra engine cooling the M7 cars have with the Secondary Radiator. That radiator drops temps about 14 degrees. I don't think you can get 14 degrees reduction by reducing the coolant to water ratio. Even if you went to straight water with some Water Wetter and water pump lubricant I don't think you could gain that much drop.
Some of your problem may be driving technique. Can you improve your corner entry speed and speed coming off the apex of a turn? If you lose less speed in a turn that is less speed that has to be made up driving off the corner. Try driving without using 3rd gear and apply more throttle sooner in 4th to power off a corner. Sure 3rd gear raises the rpms and on the standard power diagrams that seems to indicate you would have more power to the rear wheels but at part throttle that diagram doesn't mean much. When the tires are limiting the power you can put down having the rpms high with less throttle opening to produce X HP isn't helpful if you can produce the same X HP by opening the throttle more at lower rpms in a higher gear. The other thing that happens is using the higher gear you can get smoother throttle application which helps you apply power sooner so you can be wide open sooner. The idea is to keep rpms down at the lower speeds without losing time on the track.
10-13-2018, 06:33 PM
Need to coooooooool down
