RichFL

Thanks for the advice. I do have grills and I've been looking into Water Wetter using distilled water although I'm concerned about the loss of corrosion inhibitors. I guess some people have used it with coolant. This isn't a dedicated track car so I'm running Motul 5 W 40 and changing it every 15 track hours.

Cloudspin

I haven't either but I've only done one event since mid - April. Registered for the Chin open track day at Sebring in September and am looking for some other dates as well.

RichFL

I can't make that event as I'm out of the country. Have a great time.

Rich

mgent

BGB / GTGears / Miek and others -

I recognize that this is now a really old thread, but was curious if there is any further thinking around cooling - both engine oil and PDK/Dif fluid for the 981 platform? I have a 981 Cayman S w/PDK, and at my last DE I was running 260+ oil temps... I'm planning on adding the center radiator after this season at a minimum, but had some additional questions:
- The car is still dual use (Street/DE), should I switch fluid seasonally between water/ww and coolant/antifreeze?
- Is using the factory center radiator sufficient?
- Any benefit switching to aftermarket side radiators instead of adding center? How much benefit in addition to center w/ 3 aftermarket radiators as well?
- How significant is the difference between aftermarket options - CSF and PWR? almost 2x cost difference between them for all 3 replacements...
- For DEs, is a PDK or diff cooler required if the radiator changes reduce coolant temps?
- If so, what a preferred/recommended cooler system? Front mount or in the rear?

I know some time has gone by, and with that hopefully lots of experience gained that hopefully we can leverage!

Thanks

Mark

mikew968

This is my experience: I have a 987.2 and have the after-market radiators and and center radiator as well as the trans oil cooler. I have GT3 upward wending over the center radiator and the rear bumper area has been opened up. My water is staying under 220 but my engine oil is getting to 250 in a 30-40 min race. I think the oil heat exchanger is not large enough for racing.

From what i read adding the center radiator seems to be enough for the 981. I think you already have a diff cooler on your car.

djm68

Hi Mark,

I have a 987.2 (Cayman R) PDK; I've spent a lot of time on the phone talking to various shops, including BGB. My car is still street legal and I mostly take part in time trials and DE's. My car came equipped with the center radiator and I've added a BGB PDK *diff* cooler.

My advice is to make your mods in stages. Start with the center radiator and watch your temps at your next DE, both your water and oil. What you are likely to see is reduced water temps and a slower progression in rising oil temps. As mikew968 pointed out the oil heat exchanger is too small to dump enough heat into your cooling system. You can increase your cooling system capacity 10x but the oil-water heat exchanger is still not able to utilize the additional cooling capacity.

With my setup, I've not fully mitigated high oil temps, but I've been able to slow down the progression and thus extend my time out on the track. As you car is already equipped with a PDK cooler, I'd just try the center radiator and measure the results.

It would be fantastic if someone offered an bolt-on heat exchanger with increased capacity.

Cheers,
DJM

mikew968

DJM:

Do you have a PDK cooler or a diff cooler?

djm68

BGB's diff cooler.

RichFL

I'm not an expert by any means, but I think you also have to consider where your race and time of year as these influence outside temperature. Also, whether or not you have a LSD.

PUNKT2

Reviving a very old thread, but I’ve just come back from my second track event with a new-to-me 987.2 PDK.

Had the BGB PDK cooler added and unfortunately saw limp mode twice (90 degrees and running double sessions at Sebring - my wife and I share the car). The shop that installed the cooler had very good things to say about it, and I’m very hard on the car so I’m sure it would’ve been much worse without it, so I’m glad to have purchased and installed it, but obviously need to do more.

Next stop will be a call to RS1 and I’ll try to remember to update this thread with next steps as I progress along...

Papamurphdog

Call LN Engineering and ask about their 3XL PDK heat Exchanger. Much larger than stock and those I've talked to who run them seem to have no issues. I'm working on adapting their kit to work on my 997.2 in the next couple of months. I'll report the news here if we get it working. Doing it as "preventative" measure for hot DE days. FYI, I added the LN deep sump oil pan and their deep sump PDK pan (hydraulic side), and it certainly helps the motor oil run cooler. Did the 3 day PCA Road Atlanta event this weekend and happily saw max oil temps spike to 240 but mostly hovering in 225-230 range with a lot of hard driving. (note, previously did the CSF race rad + center rad upgrade, but motor oil was still spiking at 250 to 260 -- not good). With the pans installed it's running noticeably cooler. I hope to get the 3XL HX installed, then see if any more improvement. Perspective note: I ran my PDK is Sport+ mode while paddle shifting manually, which the PDK and I both liked. Tried Sport+ in automatic just to see how it worked, and the PDK didn't seem to like that as much -- was holding the upshifts too long and would do it in weird places on track. Downshifting was cool, but not always leaving me in the right gear as it couldn't see all the hills and valleys!! :-) [On a flat track it would probably work great]. So, I plan on keeping mine in Sport+/Manual for track use. I think manual shifting contributed to keeping the heat build down a bit. We'll see as the season progresses.

PUNKT2

I try to upshift manually a little early a few places at Sebring, as I really don’t need the couple of extra tenths saved by wringing it out on the backstretch, for example.

Mrhobbiest

Hey Papamurphdog, any updates on the retro-fit into the 997.2? Thanks

Papamurphdog

Hey there MrH! So, been tracking the car, and so far so good with current upgrades. With that baseline intact, we're going to focus on making the LN 3XL PDK HX work on my car during the month of July. Just got back from Road Atlanta, and I'm doing the Barber PCA event on Father's Day weekend (thanks family). Then I'll be taking her to ATL Speedwerks for a little R&R and R&D. Will be taking photos and documenting for the LN folks (thanks Charles), and all of you here. All are hopeful we can make it work well.

Sadly, this is likely a needed fix as 4 different cars at RA this weekend had PDK "limp" issues. Key points, (a) none had any other cooling upgrades of any kind, and (b) all were running in "automatic" either in standard or sport mode, none in sport + mode (ATL Speedwerks let me paddock with them, so I was there to witness). One was a very recently serviced PDK by a shop unknown to any of us (nothing personal). The rest were original miles PDK's. I'll report more as I learn what happens with each repair (names withheld to protect the innocent).

I am forming a thesis: I only ran three days of track event time in auto mode since I had the car, in Sport mode and Sport+ (per various recommendations), and that is when I was experiencing all sorts of over heating issues, but the PDK still worked. After a lot of reading and research, I believe the PDK loves to be in Sport+ mode for the track, and, ALL the remapping it does also works in MANUAL as well as auto. I then noticed that in Sport+ every up-shift was basically at redline (about 7200-7300 RPM on my 3.6L NA DFI motor), and that's about 400 to 500 past the HP curve (depending on what one reads), so, that's a waste of revs and making more heat too. I also noticed that the PDK can't "see" what is ahead on track, and will tend to be a gear higher or lower than I'd like on hilly tracks like Barber or Road Atlanta. My "ah-ha" moment. Thus, I've been running it in Sport+ mode and manually shifting ever since! What a difference!! I can better manage the max revs when flat out on the straits (keeps everything a tad cooler), and I can be in the gear I want, and in the powerband, on command (just like a "real" manual :-)). Here's my trick so far... since the PDK spins up the gears on both sides of the gear you are already in, to anticipate up-shifts and also down shifts -- partly because of which pedal you are using and how much you are using that pedal, as well as accelerometers, an actual altimeter, and lots of other sensors -- I try not to downshift unless I am on the brake pedal. That lets the PDK brain do it's thing so the revs are more easily matched with much less excess revving stress = less heat, I think. I don't downshift "on the gas" very often -- unless I'm lugging a bit, which it handles very nicely. Up shifts are now in the HP band and like "buttah" as they say. Moral? I think manual shifting the PDK makes less heat, as long as one is not abusing the privilege and mindful it is not bulletproof. I believe tracking a PDK in auto creates excessive heat while downshifting (it's working really hard to help you slow down) and also while upshifting (attempting to get every last drop out of the jar, every shift). We'll see what happens as the saga unfolds... Stay tuned.

Papamurphdog

Ha! See my post below. Very much agree that the PDK tries to "wring-out" every last bit of Revs. NOTE: In my reading, the PDK takes from 3 to as much as 8 seconds (depending on your source) to reset back to "auto" when you make a manual shift in any direction. I confused my PDK more than a few times at Barber, and it was weird. I was in the wrong gear a few times, which could have been painful. Just sayin. I am REALLY liking manual paddles now that I have a few tracks days behind me. It's very cool and I don't think I could go back to auto now. Not a "manual snob" thing. For real. It's a blast.