PDK 987.2 Overheating Issues
10-22-2014, 07:32 AM
#31
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Alright folks...we are all ready for Daytona. For Phase II we installed the same trusted PWR radiators that we used to contest 2 professional endurance racing Championships, run the Rolex 24 hour and have installed on all cars we add engineering support for in the IMSA series. These radiators are on almost every professionally built/engineered endurance Porsche raced today and have been proven in 24 hour competition for nearly half a decade now. Trusted for use in NASCAR, F1, IRL and other, it's all we use.
As mentioned by Spencer and myself, the 2nd part of the approach was to fully open up the radiator intake grills but what you can not see is that we have added nearly 50% more airflow thanks to a revised radiator shroud made by Dougie at ITC racing. When the bumper is removed, the factory radiator shroud covers up half the radiator. This fix adds a ton more air flow to the radiator via his modifying your OE shrouds. ( he sends you upgraded ones and you send him yours). That was the first half of the job to increase flow and the 2nd half was to remove all black plastic grates. We think we have almost 50% more flow going into a more robust, bigger radiator with better cooling cores and fins than the OE design. The fact that these radiators drop in with zero fabrication, withstand a frontal impact and last for 3 seasons is just an added bonus!!
@CSF - I have seen your product and one of your reps keeps reaching out to me; this thread though is about PDK temperatures and cooking them and as far as I know the 2 cars you mentioned are not PDK. Thanks for the intel tho!
Cheers everyone!
As mentioned by Spencer and myself, the 2nd part of the approach was to fully open up the radiator intake grills but what you can not see is that we have added nearly 50% more airflow thanks to a revised radiator shroud made by Dougie at ITC racing. When the bumper is removed, the factory radiator shroud covers up half the radiator. This fix adds a ton more air flow to the radiator via his modifying your OE shrouds. ( he sends you upgraded ones and you send him yours). That was the first half of the job to increase flow and the 2nd half was to remove all black plastic grates. We think we have almost 50% more flow going into a more robust, bigger radiator with better cooling cores and fins than the OE design. The fact that these radiators drop in with zero fabrication, withstand a frontal impact and last for 3 seasons is just an added bonus!!
@CSF - I have seen your product and one of your reps keeps reaching out to me; this thread though is about PDK temperatures and cooking them and as far as I know the 2 cars you mentioned are not PDK. Thanks for the intel tho!
Cheers everyone!
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Kinderelk (12-16-2022)
10-24-2014, 07:12 PM
#33
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I am going to have to post pics of the modified shroud but the new radiator grill setup and the new PWR radiators were worth every penny! While it does not count because it's Daytona and has way more air flow than a short, tight track, we went from 235 on the coolant and 260 on the oil to 190 on the coolant and 215 on the oil temp. Again, the goal is to be at 210/215 on coolant and 240 degrees on the oil and Daytona flows way more air than Palm Beach but thus far, things look very promising!!
10-26-2014, 10:35 AM
#34
Hello,
I have to say, I am happy I found this thread. I have been battling the same problem all year and I was starting to think something was wrong with my car.
I have a 2012 Cayman R which was 'prepared' by a builder near where I live. I have had the car since May (I am the third owned, second owner as a track car). It is a 3.4 PDK. I have had ongoing, continuous heat problems in the car, seeing over 275 EOT and 240 ECT after only about 10 laps at almost any track (MMC, Lime Rock, Thompson, Pocono, NJMP). Ambient temp doesn't seem to matter too much as I have seen this overheating problem even in 75* F ambient.
Being a total motor head and having built a couple LS-based race cars, I started researching this on my own. Here is what I have found thus far, and what my plan is.
The first major thing that was done was a lower temp thermostat was put in. I had little belief this would do anything because the temperature rise I was seeing would be characterized as a creep. As in, every lap, the temperatures would go up a little by little, until I let off. This clearly indicated to me that the cooling system was inadequate to reject the amount of heat created by the heat sources (more on this later). But I entertained the idea and it was put in. No change in the problem at all.
So after that, I went down my own road, and the first thing I did was put in the three CSF 2.125" radiators. I was going on the theory that there wasn’t enough heat rejection capacity in the factory radiators. This turned out to not be the case, and this made no difference at all. I will say though as an aside, the CSF radiators are a work of art and went right in the car. No issues on the install at all.
Next theory was a bad water-pump, not moving enough water. Maybe the impeller was spinning on the shaft. This was not the case. But perhaps at high RPM, the pump cavitates? Not sure on this, but another possibility.
Then I modified the front bumper cover to allow more air exhaust from the center radiator, this made no difference at all either. It should be noted that the car already had the fans removed.
So then, I stick the car up on the lift and start poking around, taking a complete fresh look at things. First thing I wanted to do is see what the entire cooling system looks like in this car and see what has deviated from stock. I hadn’t gotten any build information on the car, so I really had no idea.
Stock, the car comes with two plate-fin heat exchangers. Coolant passes through the engine block, then on to the first plate-fin which cools engine oil and power steering fluid; then on to the second plate-fin which cools PDK fluid. There is no differential cooler on a stock car, from what I can tell.
My car had been modified with a third plate-fin heat exchanger, hosing, and a pump, to circulate additional PDK fluid through that third cooler. So, effectively, we are cooling PDK fluid twice but never touching the differential fluid.
My personal belief is that the cooling system (fore to aft cooling pipes, radiators, gpm of the water pump, etc.) is inadequately sized to handle the current setup, and barely sized to handle a stock setup on the track.
So, what am I doing about it? Normally, I’d sell the car when I get to this point. The problem is, I love driving this car. It’s my first Porsche ever (I’m traditionally a GM or BMW guy),
First thing we are doing is adding a secondary air to fluid cooler for engine oil. I know that EOT is almost always over 260 and approaches 280 from time to time, and that is just to dang hot. We are adding a decent sized cooler in hopes of bringing down the EOT from the stratosphere to a more manageable 200-220. This will be accomplished by going to a spin-on filter with adapters to bring lines out on the pressure side of the oil pump.
Secondly, I plan on completely removing the third plate fin heat exchanger that was added by the builder for the PDK fluid, and adding another air to fluid cooler for that. And last, I will most likely add a third air to fluid cooler for differential fluid. I am highly confident that this will completely solve the problem. In summary, I believe too much heat is being dumped into the coolant system, and I am going to remove as much of that heat as possible by adding other coolers.
Hopefully much of this work will be done this week and I plan on testing the car at NJMP a week from tomorrow (Monday at Jeffapalooza). Since the car has an AIM MXL, I’m also adding a bunch of temperature sensors for telemetry; I am going to measure coolant temps to and from the front radiators (which I had this before), and hopefully temp probes in the differential fluid and PDK fluid as well.
I will gladly report back.
I have to say, I am happy I found this thread. I have been battling the same problem all year and I was starting to think something was wrong with my car.
I have a 2012 Cayman R which was 'prepared' by a builder near where I live. I have had the car since May (I am the third owned, second owner as a track car). It is a 3.4 PDK. I have had ongoing, continuous heat problems in the car, seeing over 275 EOT and 240 ECT after only about 10 laps at almost any track (MMC, Lime Rock, Thompson, Pocono, NJMP). Ambient temp doesn't seem to matter too much as I have seen this overheating problem even in 75* F ambient.
Being a total motor head and having built a couple LS-based race cars, I started researching this on my own. Here is what I have found thus far, and what my plan is.
The first major thing that was done was a lower temp thermostat was put in. I had little belief this would do anything because the temperature rise I was seeing would be characterized as a creep. As in, every lap, the temperatures would go up a little by little, until I let off. This clearly indicated to me that the cooling system was inadequate to reject the amount of heat created by the heat sources (more on this later). But I entertained the idea and it was put in. No change in the problem at all.
So after that, I went down my own road, and the first thing I did was put in the three CSF 2.125" radiators. I was going on the theory that there wasn’t enough heat rejection capacity in the factory radiators. This turned out to not be the case, and this made no difference at all. I will say though as an aside, the CSF radiators are a work of art and went right in the car. No issues on the install at all.
Next theory was a bad water-pump, not moving enough water. Maybe the impeller was spinning on the shaft. This was not the case. But perhaps at high RPM, the pump cavitates? Not sure on this, but another possibility.
Then I modified the front bumper cover to allow more air exhaust from the center radiator, this made no difference at all either. It should be noted that the car already had the fans removed.
So then, I stick the car up on the lift and start poking around, taking a complete fresh look at things. First thing I wanted to do is see what the entire cooling system looks like in this car and see what has deviated from stock. I hadn’t gotten any build information on the car, so I really had no idea.
Stock, the car comes with two plate-fin heat exchangers. Coolant passes through the engine block, then on to the first plate-fin which cools engine oil and power steering fluid; then on to the second plate-fin which cools PDK fluid. There is no differential cooler on a stock car, from what I can tell.
My car had been modified with a third plate-fin heat exchanger, hosing, and a pump, to circulate additional PDK fluid through that third cooler. So, effectively, we are cooling PDK fluid twice but never touching the differential fluid.
My personal belief is that the cooling system (fore to aft cooling pipes, radiators, gpm of the water pump, etc.) is inadequately sized to handle the current setup, and barely sized to handle a stock setup on the track.
So, what am I doing about it? Normally, I’d sell the car when I get to this point. The problem is, I love driving this car. It’s my first Porsche ever (I’m traditionally a GM or BMW guy),
First thing we are doing is adding a secondary air to fluid cooler for engine oil. I know that EOT is almost always over 260 and approaches 280 from time to time, and that is just to dang hot. We are adding a decent sized cooler in hopes of bringing down the EOT from the stratosphere to a more manageable 200-220. This will be accomplished by going to a spin-on filter with adapters to bring lines out on the pressure side of the oil pump.
Secondly, I plan on completely removing the third plate fin heat exchanger that was added by the builder for the PDK fluid, and adding another air to fluid cooler for that. And last, I will most likely add a third air to fluid cooler for differential fluid. I am highly confident that this will completely solve the problem. In summary, I believe too much heat is being dumped into the coolant system, and I am going to remove as much of that heat as possible by adding other coolers.
Hopefully much of this work will be done this week and I plan on testing the car at NJMP a week from tomorrow (Monday at Jeffapalooza). Since the car has an AIM MXL, I’m also adding a bunch of temperature sensors for telemetry; I am going to measure coolant temps to and from the front radiators (which I had this before), and hopefully temp probes in the differential fluid and PDK fluid as well.
I will gladly report back.
10-26-2014, 06:26 PM
#35
Nordschleife Master
Porsche did figure out that the diff needed a cooler and has added one to the more recent vehicles. However it is still inadequate for track usage of any sort.
10-26-2014, 11:39 PM
#36
Rennlist Member
Arubenstein,
Please keep us informed. I too believe the CS needs an oil to air cooler for engine oil. I have an oil to air cooler for the diff. I am awaiting the new mxl2 and plan on putting sensors on engine oil, diff fluid and possibly the pdk fluid.
Please keep us informed. I too believe the CS needs an oil to air cooler for engine oil. I have an oil to air cooler for the diff. I am awaiting the new mxl2 and plan on putting sensors on engine oil, diff fluid and possibly the pdk fluid.
10-26-2014, 11:47 PM
#37
Former Vendor
As I have been working since 2010 to develop my 4.2L engine for these cars, I have also dealt with oil cooling arrangements on a day to day basis. Air to oil has been most efficient, but we have had to manufacture our own units to facilitate this being an effective fitment.
Internal mods have proven to reduce oil temps more than anything else, these engines are simply too tight internally, and thats why they shear oil so badly.
Internal mods have proven to reduce oil temps more than anything else, these engines are simply too tight internally, and thats why they shear oil so badly.
10-28-2014, 04:12 PM
#40
Rennlist Member
981S ??
I don't mean to intrude in a thread that is clearly focused on the 987.2 with PDK but I have questions about my 981S PDK. I would be happy to start a new thread for that if necessary, but if not, here is my question:
Anybody with the 981CS PDK install a Guard LSD that sees significant track time? By significant I mean fast driving, but not racing for an hour. I'm a DE'r who drives somewhat fast but no plans to race. I'm considering adding the Guard LSD but I'm told to expect higher diff temperatures.
Interested to see what your experience is and how you handled it.
Additionally, anyone do detailed before and after mod temp measurements?
How about measuring gearbox temps before and after?
Thanks
Anybody with the 981CS PDK install a Guard LSD that sees significant track time? By significant I mean fast driving, but not racing for an hour. I'm a DE'r who drives somewhat fast but no plans to race. I'm considering adding the Guard LSD but I'm told to expect higher diff temperatures.
Interested to see what your experience is and how you handled it.
Additionally, anyone do detailed before and after mod temp measurements?
How about measuring gearbox temps before and after?
Thanks
Last edited by futurz; 10-28-2014 at 08:17 PM. Reason: More questions
10-28-2014, 09:57 PM
#41
Rennlist Member
While I'm not sure how effective it is your 981 CS PDK does have a diff cooler. Do you know what kind of oil temps you are seeing?
10-28-2014, 10:04 PM
#42
Rennlist Member
Yes I am aware of the diff cooler. To be honest, I haven't been concerned about it until I began to contemplate changing out the diff. Guard informed me that I should expect an increase in diff temperatures, but since there has been so little analysis done on the 981S, until someone installs a sensor, or at least gets an infrared reading, we're a little in the dark when it comes to actual operating temps and whether the OEM is up for the job or whether some kind of aftermarket or 3rd radiator is necessary. And assuming that some kind of mod is required, we still haven't seen any kind of data that tells us just how much lower the diff temps are after adding various kinds of cooling mods. With the growing popularity of the 981, especially for DE type tracking, I think this would be useful information to have.
10-29-2014, 10:31 AM
#43
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Mr. Futurz,
I feel a little bit strange addressing this stuff when you and I email every week and I would have gladly answered this for you but it's fine...more info for the discussion for others to soak up:
1. ) Matt is just being honest and is saying that with additional locking and friction comes increased fluid temps.
2.) The % of my 987.2 customers that run the PDK LSD on track and DO NOT run a cooler is 0% because I won't let them. They all have installed a cooler for track usage to help with the fluid temps in the LSD and gear stack so that the PDK does not heat soak itself. If I did not relay to you properly that we install coolers and data acquisition systems and have designed these cooler approaches following extensive temperature testing of fluid in and out of the gearbox, then I am sorry; I should have told you. Our air-oil cooler kit that we sell takes average trans/LSD temps from 260 to 220. I probably failed to include it somewhere so I am sorry.
3.) Given that your car already has some type of cooler on its transmission/LSD, of the 981 folks that have LSDs, we have not installed aftermarket air-oil coolers for the gearbox fluid and LSD fluid. So those customers have not purchased the cooler kits because you already have some sort of cooling. I guess if you understood how I do not agree with using coolant everywhere to cool fluid for gears, engine oil and the entire motor you would understand why I can't see the sense in fighting the center 3rd radiator. In theory I want you to get a center 3rd radiator to make your existing gearbox cooler more efficient.
4.) You don't have to start a new thread and we can use this one to expand it to anything about PDK/981s/987s, etc since we addressed above that the 981 does NOT have the ECT/Engine Coolant Temp issues that were present in the 987s, .1 and .2 and already has some sort of cooler so no one will fault you because 981s didn't exist when I started it.
You have to remember that a lot of this stuff that we designed was engineered for endurance racing and its applications are being requested because every single 981 customer in America that tracks their car has at least one concern or another about the temperature of some sort of fluid. The 981's thermal engineering and ability to keep Engine Coolant Temps around 200 degrees when the 987.2 could not is a real feat and I think that you only see your 198 degree coolant temp or 210 and think that it's not a concern and I think it's misleading because it's what you see and that is why you don't think you need a center 3rd radiator. I wouldn't think a 3rd center radiator was necessary if my coolant temps were only 210 tops or 220 but you have to remember that more water in the system for cooling is a good thing with a car that uses coolant to cool the oil in your PDK, your gearbox, crank case, etc; if I failed to make those points and why I am concerned about temps and why I don't want you to fight the whole center 3rd radiator thing, I screwed up!
I bet we could do a bunch of analysis that shows that your car in stock form across 20 minutes might very well behave the same as something with coolers or a center 3rd radiator, etc. but these guys are looking for insurance/safety/longevity and they're freaked out about temps after 25 minutes. We took a 987.2 Cayman race car to the track 3 weeks ago and it couldn't last over 25 minutes in 98 degree temps without seeing 235 on the coolant and 265 on the oil temp. I was embarrassed to have built a race car for club racing that couldn't do 25 minutes. These cars DO NOT run cool and we just try and do whatever it takes to alleviate that. The only thing that did run cool was the fluid in the transmission at about 215. 240 degrees on the ECT and 260 on the oil?!?!? I was like
!!!!
I feel a little bit strange addressing this stuff when you and I email every week and I would have gladly answered this for you but it's fine...more info for the discussion for others to soak up:
1. ) Matt is just being honest and is saying that with additional locking and friction comes increased fluid temps.
2.) The % of my 987.2 customers that run the PDK LSD on track and DO NOT run a cooler is 0% because I won't let them. They all have installed a cooler for track usage to help with the fluid temps in the LSD and gear stack so that the PDK does not heat soak itself. If I did not relay to you properly that we install coolers and data acquisition systems and have designed these cooler approaches following extensive temperature testing of fluid in and out of the gearbox, then I am sorry; I should have told you. Our air-oil cooler kit that we sell takes average trans/LSD temps from 260 to 220. I probably failed to include it somewhere so I am sorry.
3.) Given that your car already has some type of cooler on its transmission/LSD, of the 981 folks that have LSDs, we have not installed aftermarket air-oil coolers for the gearbox fluid and LSD fluid. So those customers have not purchased the cooler kits because you already have some sort of cooling. I guess if you understood how I do not agree with using coolant everywhere to cool fluid for gears, engine oil and the entire motor you would understand why I can't see the sense in fighting the center 3rd radiator. In theory I want you to get a center 3rd radiator to make your existing gearbox cooler more efficient.
4.) You don't have to start a new thread and we can use this one to expand it to anything about PDK/981s/987s, etc since we addressed above that the 981 does NOT have the ECT/Engine Coolant Temp issues that were present in the 987s, .1 and .2 and already has some sort of cooler so no one will fault you because 981s didn't exist when I started it.
You have to remember that a lot of this stuff that we designed was engineered for endurance racing and its applications are being requested because every single 981 customer in America that tracks their car has at least one concern or another about the temperature of some sort of fluid. The 981's thermal engineering and ability to keep Engine Coolant Temps around 200 degrees when the 987.2 could not is a real feat and I think that you only see your 198 degree coolant temp or 210 and think that it's not a concern and I think it's misleading because it's what you see and that is why you don't think you need a center 3rd radiator. I wouldn't think a 3rd center radiator was necessary if my coolant temps were only 210 tops or 220 but you have to remember that more water in the system for cooling is a good thing with a car that uses coolant to cool the oil in your PDK, your gearbox, crank case, etc; if I failed to make those points and why I am concerned about temps and why I don't want you to fight the whole center 3rd radiator thing, I screwed up!
I bet we could do a bunch of analysis that shows that your car in stock form across 20 minutes might very well behave the same as something with coolers or a center 3rd radiator, etc. but these guys are looking for insurance/safety/longevity and they're freaked out about temps after 25 minutes. We took a 987.2 Cayman race car to the track 3 weeks ago and it couldn't last over 25 minutes in 98 degree temps without seeing 235 on the coolant and 265 on the oil temp. I was embarrassed to have built a race car for club racing that couldn't do 25 minutes. These cars DO NOT run cool and we just try and do whatever it takes to alleviate that. The only thing that did run cool was the fluid in the transmission at about 215. 240 degrees on the ECT and 260 on the oil?!?!? I was like
!!!!
10-29-2014, 10:40 AM
#44
Rennlist Member
John, I appreciate your response. I was just wanting to find out what kind of response these questions might generate and to create a wider dissemination of knowledge if possible. I'm still digging.
Further....
Since John has graciously invited comments on the 981 I will try to add to what I have already said.
Even though I have track temps for coolant and oil that are too high by many people's standards or comfort level, to date, I have not been able to verify that the 3rd radiator in the 981 significantly lowers oil temps. I do have a track buddy with a 981s PDK who did install the 3rd radiator. Since he does not use a data logger, we can't tell how much his coolant temps have come down, but the oil temp gauge shows a drop of 10 - 15 degrees. One would have hoped for more. It is interesting to note that Porsche has decided to make the 3rd radiator standard in the GTS. Wonder why?
Having said all this, I am in agreement that heat is the enemy of all things mechanical, and on ounce of prevention should be worth at least a pound of cure, especially in a Porsche. Therefore, I will likely install the center radiator this winter.
What has not been established, at least it has not been made public if it has, are the gearbox temps before and after installing the LSD in the 981? Furthermore, assuming the LSD raises temps as Matt has stated, how much cooling of the gearbox specifically, has the extra cooling from the center radiator provided? It is entirely possible that the extra cooling does a good job on coolant and engine oil, but the gearbox temps may still be running too high. Not high enough to cause a fault, but perhaps high enough to shorten the life of the diff. If that is the case than additional cooling specific to the gearbox may be useful.
Finally, I understand there is a big difference between racing these cars over longer periods of time, and doing what I do (and likely most people) which is 4 - 5 25 minute sessions a day at OL or DE events. Obviously, any solution that allows a track car to run at race speeds for an hour at a time (or longer) will make life a breeze for the DE'er.
Thanks
Further....
Since John has graciously invited comments on the 981 I will try to add to what I have already said.
Even though I have track temps for coolant and oil that are too high by many people's standards or comfort level, to date, I have not been able to verify that the 3rd radiator in the 981 significantly lowers oil temps. I do have a track buddy with a 981s PDK who did install the 3rd radiator. Since he does not use a data logger, we can't tell how much his coolant temps have come down, but the oil temp gauge shows a drop of 10 - 15 degrees. One would have hoped for more. It is interesting to note that Porsche has decided to make the 3rd radiator standard in the GTS. Wonder why?
Having said all this, I am in agreement that heat is the enemy of all things mechanical, and on ounce of prevention should be worth at least a pound of cure, especially in a Porsche. Therefore, I will likely install the center radiator this winter.
What has not been established, at least it has not been made public if it has, are the gearbox temps before and after installing the LSD in the 981? Furthermore, assuming the LSD raises temps as Matt has stated, how much cooling of the gearbox specifically, has the extra cooling from the center radiator provided? It is entirely possible that the extra cooling does a good job on coolant and engine oil, but the gearbox temps may still be running too high. Not high enough to cause a fault, but perhaps high enough to shorten the life of the diff. If that is the case than additional cooling specific to the gearbox may be useful.
Finally, I understand there is a big difference between racing these cars over longer periods of time, and doing what I do (and likely most people) which is 4 - 5 25 minute sessions a day at OL or DE events. Obviously, any solution that allows a track car to run at race speeds for an hour at a time (or longer) will make life a breeze for the DE'er.
Thanks
Last edited by futurz; 10-29-2014 at 01:05 PM.