BGB Motorsports

Ladies and Gents,

Who here has tracked their 987.2 PDK car to the point of limp mode or overheating? Can we get a show of hands and how many of you are already running transmission coolers, center 3rd radiators and any additional cooling?

Thanks in advance.

John

djm68

Reviving this ancient thread as I am currently researching cooling solutions for my '12 Cayman R PDK. ECT temps really soar (240) during DE's on warm days; I always back-off and allow temp to reduce, but this is rather frustrating.

Car is currently stock, but planning, at the very least, to replace OEM radiators with CSF aluminum units. Considering the Bilt Racing deep sump oil pan as well, but for $2500 I wonder if this money would be better spent on trans cooler or perhaps an external oil cooler.

Thanks,
DJM

BGB Motorsports

I am literally on track right now with a customer car trying to get water temps and oil temps a bit lower. The car is running our PDK gearbox, LSD and power steering coolers. You need coolers for going on track for longer than 20 minutes. Please email me or call the shop.

John

mikew968

John, I am running a 2010 CS with nasa gts-4. I had limp mode kick in at road America but am not sure if it was from curb or high temps. My water temp is getting to around 216 on an 80 degree day and engine oil temps are at 253. I have a trans cooler and of course a 3 rd rad. I also have the side radiator areas free from lights etc. even on a 45 degree day the oil temps get into the 230's. I believe the engine is reducing power as oil temps get into the 250's although I have no real hard evidence. I believe the car needs a larger oil cooler not just a water to oil heat exchanger. The pdk may need a larger cooler as well but I have no way to determine the temp of the pdk fluid.

Paseb

I dont know if we have the same problem as you guys do, but again today(monticello) the car acts funny and trans goes in neutral or get stock in gear.

We ´re unsure about the problem at all

We dont have any additionnal cooling parts

We will add a trans cooler on the pdk next week for daytona

djm68

Sending you a private message now, John.

Thanks,
DJM

GTgears

The factory has installed a couple of oil to coolant heat exchangers on these vehicles. They are inadequate for all but the most basic track usage. If you are going to track the car hard or racenit you must add an additional air based cooler.

Furthermore there are two gearboxes. The "open" diff gearbox has a smaller diff. When we designed an LSD for it we were forced to make a smaller LSD. The smaller LSD runs hotter.

If one is serious about building a racecar, spend the extra money up front. Get the LSD version of the gearbox. The LSD for racing we designed is do much more robust and able to better distribute loads and heat. If you are spending 6 figures on a racecar, don't cut corners. Pay a little extra on the front end. The guys who have paid $7500 for a crate LSD gearbox (core exchange) and then had to buy another proper Motorsports LSD have an extra 5 figures in the car. This is not isolated to my LSD. My competition claims their LSD is good to go for your PDK. It's small and will wear out your gearbox, if not overheat things, much more quickly.

Heat is the enemy. Bigger is better and more cooling increases lifespan.

mikew968

Are you referring to cooling the diff oil, the pdk fluid or the engine oil? Seems like all of the stock heat exchangers are too small.

GTgears

There's been a lot of debate about that. Personally I favor cooling the differential oil. It is my personal belief that the diff is too hot. Basic physics suggests that things are going to attempt to equalize temperatures across the reservoirs. The hottest fluid will transfer its heat across the case halve/reservoirs to the cooler side. I think the diff oil is overheating the clutches.

How do we prove this? Put temp sensors on all of them and track them. Then it's not just an educated guess. Then it is empirical.

ExMB

If I remember correct Napleton developed this, an LSD cooler, that is used on several PDK equipped Rs. It increased the fluid capacity and added an additional fan whose operation could be set up 3 different ways: owner switch control, temp control and always ON.

BGB Motorsports

We have just done about 10 sessions down here, almost 200 miles now since Wed and the only things I'm battling are the usual run of the mill 230 degree water temps and 255 degree oil temps. This car has the stock engine cooling fans, stock radiators, screens and grills. Those are causing the water and oil temps to be high because we stole frontal area to make brake ducts. We return Monday to remove that stuff. I wanted to see what was the worst it would be considering that it's 92 degrees here now with 90% humidity. Those water and oil temp issues will be resolved when we remove that stuff. I wanted to replicate what you more stock folks are running, not prove that a race car is thermally more efficient than a street car.

The transmission stack temps are fine. The LSD fluid is fine. Our coolers work. It also has a power steering cooler of the same size snd style. I have track tested this application in a 3 hour Enduro at Sebring. I have never seen any of our cars with coolers throw a Trans Emergency Run fault for trans temp. The wet clutch PDK system needs to be insulated and the gearbox and LSD side need an air to oil cooler. Our GX Cayman which was 987.2 never went higher than 210 degrees on any fluid temperature during the Rolex 24. People may make fun and call me stubborn but Caymans run hot. I don't like using the coolant to "cool" anything nor do I believe in fan operated coolers that sit next to a gearbox, an engine and exhaust headers that have zero hopes of engine bay heat dissipation. We have 4 sessions today. It's hot down here! More to report. I have video and photos of the car on our facebook and instagram pages.

We can send you a cooler and have any shop install it. It's $750 for the cooler and you should expect someone to spend 6 hours labor installing it. I can drop **** it to you. We don't mark the unit up very much because we usually install them and we can't imagine charging someone $2000 to install a gearbox cooler - even though it will allow you to make every single session that weekend, and then some!

spencercox

I have run 5 PDK Caymans with 3.4 and 3.8 motors. Never a limp mode. I have air to oil diff coolers in each and I feel wrapping the headers are equally as important. I have Data and sensors everywhere. I use the most expensive gear driven oil cooler pump as I have melted everything else. I also agree that having steering fluid, oil cooling, the pentosin from the gear box all heating the water is a very poor design. The coolant doesn't stand a chance. Also the Cayman has a very small oil cooler. My water temps are always 215 to 240 and oil 230 to 269. I have checked my sensors and it is right.
I also run the cup car lower thermostat to help.
I believe the factory plastic radiators are more efficient than the aluminum. I remove one fan for better flow and cut open the fender liner to get the heat out." Put mesh in place"
My cars have run for years without issue but it is unsettling. BGB makes some great alternatives to install. He is spent thousands of hours testing everything on the market to find what works.
Spencer ***
Speed Sport Tuning

aero997c2s

A lot of fantastic info in here, thank you John and Spencer. My 987.2 is a manual so obviously the PDK cooler is not needed, so other than 3rd radiator what is the next most important cooler for my application? It certainly isn't a full race car yet, but temps can be very similar heat and humidity wise to south Florida here in the Mid Atlantic.

djm68

Great to see this thread taking off and providing much needed info for those of us who are trying to address cooling issues. Thanks for jumping in John, we know you are busy, greatly appreciate your expertise.

Spencer,

Besides adding the third radiator, the next thing to do is to cool the engine oil. You can install an air-liquid cooler and/or install a much larger sump, such as this:

http://lnengineering.com/25qt-deep-s...1-engines.html

2.5 additional quarts of oil, plus a bit more cooling surface area for the engine oil, though the price is fairly steep for an oil pan, IMO.

Cheers,
DJM

mikew968

What is the "proper" target for water and oil temps? Will the engines have longevity with 240-260 oil temps? Has LN made the adapter that allows for you to bypass the engine oil heat exchanger and add a proper air to oil cooler?

Thanks, Mike