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Ever since I took my GTS racing I've been dealing with getting temps under control. Even on the 3.4L with mostly water coolant (+ MoCool) I was seeing 270F on the oil, a bit more even if it was warm out (warm being a relative term in Russia). And being a GTS I already have the 3rd radiator.

When swapping to the 3.8L I made sure that we also upgraded the water to oil cooler. It's from a 718 (not sure which model exactly) and a lot bigger than stock. I've driven it on track now in very cool ambient temps and saw just under 260F. Which is I think similar to what the 3.4L would've done with the smaller cooler in similar conditions. So given that the cooling system is now dealing with cooling a bigger engine with 80+ horsepower extra I guess it's doing OK. But I'd like to have a solution that sees no more than 250F ideally.

I haven't been able to log the actual water temp but ever since I switched to a mostly water coolant (which has a slightly lower boiling point than a 50% glycol mix) I start to smell some of the coolant by the time the reported temps have maxed out. Which takes a while. Oil temps go up to 250-ish pretty quickly but then they seem to stabilize there for a little while, perhaps because the high specific heat capacity of water or because the gearbox doesn't heat up as quickly and takes a bit longer to start dumping lots of heat into the water. Then a few laps later the oil temps will move up the last notch and I start to smell the coolant inside the car a little. The car is stripped so there isn't much between the pressure cap of the cooling system and my nose. I drove like this all last year and the coolant level doesn't actually drop but there must be enough pressure being built up to push some past the cap.

So, would CSF rads solve my problem or are they a marginal improvement? Do I need all three or worth trying just an upgraded center rad? I'll also move to a GT4 bumper with top vent and also putting on vented RS style front fenders which might increase efficiency of the side rads a bit.

Just looking for opinions.
 

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Normally I don't think you're going to see a change in coolant temp since that's really controlled by the thermostat unless you're exceeding the cooling capacity of the system. If you're on the edge and running with the thermostat open (on track anyway) most of the time the increased cooling of the CSF radiators is significant and should help bring your oil temps down. Based on the coolant needle, you really need to log the OBD2 coolant temp, it sounds like you're on the edge of the cooling system. The oil system does a lot of the engine cooling and is going to take a beating when the water cooling system is overwhelmed.

We use CSF radiators and intercoolers in our race cars and really like them.


The combo of venting and radiators upgrades should really help. Feel free to message me with any questions, we can ship these for free in the US too.

Josh


Ever since I took my GTS racing I've been dealing with getting temps under control. Even on the 3.4L with mostly water coolant (+ MoCool) I was seeing 270F on the oil, a bit more even if it was warm out (warm being a relative term in Russia). And being a GTS I already have the 3rd radiator.

When swapping to the 3.8L I made sure that we also upgraded the water to oil cooler. It's from a 718 (not sure which model exactly) and a lot bigger than stock. I've driven it on track now in very cool ambient temps and saw just under 260F. Which is I think similar to what the 3.4L would've done with the smaller cooler in similar conditions. So given that the cooling system is now dealing with cooling a bigger engine with 80+ horsepower extra I guess it's doing OK. But I'd like to have a solution that sees no more than 250F ideally.

I haven't been able to log the actual water temp but ever since I switched to a mostly water coolant (which has a slightly lower boiling point than a 50% glycol mix) I start to smell some of the coolant by the time the reported temps have maxed out. Which takes a while. Oil temps go up to 250-ish pretty quickly but then they seem to stabilize there for a little while, perhaps because the high specific heat capacity of water or because the gearbox doesn't heat up as quickly and takes a bit longer to start dumping lots of heat into the water. Then a few laps later the oil temps will move up the last notch and I start to smell the coolant inside the car a little. The car is stripped so there isn't much between the pressure cap of the cooling system and my nose. I drove like this all last year and the coolant level doesn't actually drop but there must be enough pressure being built up to push some past the cap.

So, would CSF rads solve my problem or are they a marginal improvement? Do I need all three or worth trying just an upgraded center rad? I'll also move to a GT4 bumper with top vent and also putting on vented RS style front fenders which might increase efficiency of the side rads a bit.

Just looking for opinions.
 

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I've been talking to LN Engineering a bit about track cooling solutions. I'd email them and see what they have to say for your application.

I also think logging your coolant temps is a smart first step. If you're bouncing off the tstat upgrading radiators won't do anything. If you can see your temps are well above the tstat open point then maybe they would.
 

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Thanks guys - yeah guess I have to log it. I'm pretty sure coolant temp is higher than tstat temp but I don't know by how much exactly.

I noticed that in normal use oil temp is a lot lower than it used to be. In sport/sport+ it's down to 85C on the highway where it was 90C before upgrading the hear exchanger. As the coolant smell only happens around the time I start seeing max oil temp I think it's a reasonable assumption that the coolant must be above its ambient pressure boiling point with the pressure inside the cooling system stopping it from actually boiling. Hence some of vapour getting pushed out through the safety cap.

Still got a couple months till the season starts so I'll try logging at the next test in a few weeks.

On the Tarett site I saw a claim of 12% increase in efficiency from CSF rads which is significant but may not be quite enough... looking at the formulas I guess the increase in efficiency means we could more or less drop the delta T by that percentage as the heat output and water flow are unchanged. I'd need a bigger drop to get down to the water temp the car wants to run if it's over 100C now. Guess more air flow through the rads will be necessary. Maybe opening up the fender liners could help a bit too.
 

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LNEngineering thinks adding their 2qt larger oil sump is worth a lot for lowering oil temps. They have lots of experience racing and designing parts for Caymans, i'd start there.
 

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[QUOTE="JCviggen, post: 2144207, member: 37851 And being a GTS I already have the 3rd radiator.

So, would CSF rads solve my problem or are they a marginal improvement? Do I need all three or worth trying just an upgraded center rad? I'll also move to a GT4 bumper with top vent and also putting on vented RS style front fenders which might increase efficiency of the side rads a bit.

Just looking for opinions.
[/QUOTE]
I may be telling you things that you are probably already aware of. I did a lot of research before installing a center radiator in my 2014 CS with PDK and went with all the Porsche parts but went with the CSF radiator for additional cooling efficiency over the Porsche radiator. Porsche and CSF makes a wider (larger) radiator for the GT4 bumper for additional cooling for the 3.8L and additional air flow with the top venting. The stock GTS center radiator has four small square downward vent openings. The GT4 complete bumper package has the wider radiator bracket which tips it in the opposite direction for upward venting and the necessary ducts to connect to the upward smile vent. This system appears to be larger and more efficient with increased air flow and downforce. I don’t have any hard data but the CSF center radiator seems like a no brainer.
Jim
 

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LNEngineering thinks adding their 2qt larger oil sump is worth a lot for lowering oil temps. They have lots of experience racing and designing parts for Caymans, i'd start there.
There's no doubt adding volume with help but only for so long. If you don't have enough heat rejection those 2 quart will get just as hot as the rest eventually. We run 10-15 quarts in our drysump systems and as much oil cooler as we can.

The GT4 complete bumper package has the wider radiator bracket which tips it in the opposite direction for upward venting and the necessary ducts to connect to the upward smile vent. This system appears to be larger and more efficient with increased air flow and downforce. I don’t have any hard data but the CSF center radiator seems like a no brainer.
Jim
(y)
 

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There are a number of coolant and oil temps available that are merged together to get what you have on the display. I have been able to see at least a half-dozen temperature sensor readings using an Autel MD-802. If I recall, the readings were for intake, engine compartment, ambient at radiator, radiator outlet, engine outlet, PDK coolant, engine oil, PDK oil. Looking at those together will give you a better understanding of how efficiently the cooling system is working vs. how much heat your engine and PDK is dumping into the system.

Aside: I wonder where Autel got all the CAN bus address/calibration info to provide these readings. That thing can probably access over a hundred different CAN-bus measurements from a dozen different subsystems on this car alone. That thing supports probably a hundred different models of cars from various manufacturers. I've been searching for this type of info to no avail. I'm not sure if they paid for it, or they reverse-engineered it.
 
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