Dr.Bill

This past weekend I had the Cayman R out for another track weekend. It's starting to get a bit warm here - the temperature was in the mid-90's.

With the car in Sport Plus mode, the coolant temp would get close to 250 after several laps. Switching to manual mode and shifting early, around 6k rpm would solve the problem. However, I never had an issue with the 997.2 PDK I had and it's not even really hot here yet.

The sport plus mode keeps the engine pretty high in the rev range - maybe it just can't handle it?

Any suggestions? I've been told it will run cooler using just distilled water and water wetter. Will that work? I'd hate to have to drive like an old lady whenever it gets warm out.

Thanks for any insight!

orthojoe

Bill, there is the option of adding a 3rd center radiator like Steve did on his car, but, I've heard that it should not be necessary.

I had problems with coolant overheating in my Evo in the past, and it turned out that there was some air in the system. Even after 'burping' the system, it still had some issues and it finally took a true flush/fill to get all the air out. Maybe start with something simple like that first before getting a 3rd radiator.

My coolant temps have stayed very stable on the spyder, but it's 6MT and hasn't been driven in 90+ weather at the track yet. I've had tranny overheat and coolant overheat problems on my dual clutch Evo X, but that's obviously apples and oranges.

Joe

orthojoe

btw, Bill, 250F for ECT is dangerously high. Definitely get this sorted out before your next event. My money is on air in the coolant system

Dr.Bill

Thanks Joe.

It's a PDK, so it has the center radiator for the transmission already.

orthojoe

Ah, didn't realize that. I don't think it's a PDK issue. Bensf's spyder is PDK, and I don't believe his car has run into overheating issues. Given how frequently he runs his car at the track, I'm betting he's run in some 90+ degree days. I'll let him chime in.

Let us know if you figure it out. The car should not be overheating, IMO.

2slow2speed

FWIW: Issues with high coolant temp with PDK equipped Cayman (S/R) have been documented, as the OP mentioned running the vehicle in Sports Plus seems to be one of the triggers.

On my 6 speed CR if I kept the engine at the top of the powerband the coolant temps would start creeping up on long sessions with high ambient temps, ended up adding the PDK/tiptronic 3rd radiator to get around the problem.

Napleton Porsche is supposed to be working on a solution to address the high coolant temp on PDK equipped vehicles since they are starting to prep track cars that are equipped with PDK. The last I heard they were supposed to have something available by Summer. Their race cars use a larger 3rd radiator along with a tranny cooler, so would not be surprised if they decide to follow a similar route for the PDK vehicles.

cvazquez

Replace high temp with Low temp thermostat and add wet-wetter.

orthojoe

I don't think thermostat or water wetter will change the temps that drastically. 250F is head warping temp, from my understanding. Bill, how long are you running out at the track?

Dr.Bill

They are only 20 minute sessions. Probably closer to 15 minutes of driving before they throw the checkers. With as few as 3 laps the temp would start climbing in sport plus mode. Never an issue with a PDK 911 - maybe just another way Porsche handcuffs the 987 platform.

orthojoe

Overheating that quickly and easily can't be 'normal'. Have someone take a look at the cooling system. Good luck and let us know what you find

bensf

I've attended track days in 90+ degree weather using Sport + mode without issue. I did a track day in 100+ degree weather using just Sport mode without any issue either. On that particular day, the cooling fan would turn on and stay on whenever the engine was off.

orthojoe

Bill, I went back through my datalogs from my last track day and found the peak ECT temp I hit was 206F, and average was 200F. Ambient temps from that day was about 60F, but I figured this might give you a data point for reference to

Dr.Bill

Thanks Ben & Joe.

Seems there is a TSB on the issue. From what I understand, they reprogram the DME to run at lower rpm's. Not sure if it's just a Cayman issue or not.

I guess it's time to either buy a real race car or just hang it up. Should have kept the GT3. . .

2slow2speed

To the OP, is your car running any kind of radiator guards?

In some of my previous track cars, adding a radiator guard would cause coolant temps to increase. Based on some quick testing, I've noticed that the PorscheMesh radiator guards do block some of the airflow.

Wonder why the TSB is not better known? Reducing RPM's kind of sounds like cheating your way out of a problem

bensf

Bill - I see a lot of the Caymans at the track running without the carpet and padding over the engine cover. Not sure if this would help your situation but might be worth a shot. I agree with 2slow2speed. Reprograming the DME to reduce the revs seems like a half *** solution from Porsche to me.