hei83

Hi people

I am currently in the market of buying a track car to replace my current one (2012 honda fit, front wheel drive, as fast as an electric wheel chair) that I can drive on the track and go back home. Can someone please share your experience on both a Cayman S with PDK vs the 991 GT3?

There are a few things I want to know. The shift differences to a driver in between the PDK and PDK-S. Also the maintenance differences on those 2 units. I have heard stories when someone had to pay 14k to get the pdk repaired.

As a track toy, 991 GT3 is out of my budget. I want something I can drive on the track without worrying about the repair bill. I attend 15-20 track days a year so I want to keep my cost down. I am only deciding in between the 987.2 vs 981, stick or pdk. I don't plan to track my 997.2 as no 3rd party extended warranty covers GT cars any more so I would just keep it off the track.

I appreciate your input. Thanks

Paseb

we race a pdk cayman and we havnt found a fix for the pdk trans yet. We are with the shop BGB and BRS

every event we have trouble.... car stalls in neutral

so far, nightmare!!!

my dad has back problem, so its pdk or no race!

hei83

Thanks Seb, glad to have your 1st hand experience. A fix wasn't found but have you guys found the cause? Over heating etc?

It will be a DE car, 5-6 20 min sessions a day.

Paseb

we havnt found the cause yet.

next step is to put the new part from porsche in the transmission.
i will also cut the rear bumper to get some of the hot air out.
im installing csf rads within a few days.

We do run a trans cooler.

i dont think its a problem of hot/cold outside temp

we got the problem many times at road atlanta and it was like 5 celcius during the race,,, and at Sebring we had only 1 failure during complete weekend.. its inconsistent

hei83

That makes me worry Seb, it sucks to have a weekend ruined.

djm68

I track my '12 Cayman R, same as Cayman S for the purposes of this discussion. I did 10 track days last year and did not experience problems with the PDK gearbox. However, I did experience overheating issues that are exacerbated by the heat generated by the PDK, in particular if it is equipped with an LSD.

The cooling issues with the 987.2+PDK are well documented on a number of forums. John and BGB has developed a PDK cooler that I feel is a must if you track your PDK car; John also suggests upgrading to PWR radiators.

In order to address my cooling issues, I am adding a Mantis deep sump pan which increases oil capacity by 2.3 quarts; I will also add the BGB PDK diff cooler. I will try the car with these mods and see how my water/oil temps look before diving into the PWR radiators ($3000+ for all three).

I can not address PDK vs PDK-S as I've never driven a PDK-S.

Other than the cooling issues, I love the PDK -- it is amazing. Would I but PDK again? Tough question. It is more expensive to purchase, you will need to add a cooler and perhaps upgrade radiators. Then again if you do 15-20 track days you probably should have a gearbox cooler even with a 6-speed manual.


Cheers,
DJM

hei83

Thanks DJM, i ve been following bgb's offerings. I figured i would need some pieces from them eventually. I m leaning toward to a pdk cayman s. Appreciate the input!!

golfnutintib

another data point for u...i have tracked my 997.2 CS w PDK ~15 vigorous track days in NorCal (but never over 100 degrees ambient)...never had a problem with PDK. i did change my pdk gear oil after roughly 10 track days...my car does not have lsd <-----------------------------see pic on left

... i do not know if there is something inherent about a 987.2 w pdk that makes the tranny more prone to overheat on track than in a 997.2 application... (i do also have a pdk cayman r but i have never tracked it)

the 991 gt3 pdk-s is an another league of shift-speed but the original pdk is very very nice in sport/sport plus modes, and gives you the right gear at the right times flawlessly... you would need to be a truly superb manual shifting expert to come close to the regular pdk on track imho... even then you would still need to lift to clutch and shift while i stay on the throttle...

GTgears

Just speculating based on our experience with manual gearboxes, but the overheating issue appearing to afflict Caymans more than Carreras may be engine location based.

The Carrera, when you accelerate hard on track, has the oil pool towards the differential. The Cayman is the other way around. On manuals it makes the differential run really hot and a cooler is mandatory.

Now while there is a separate reservoir of fluid for the wet clutches on the PDK, if the differential is running hotter, it will act like a heat sink that raises the temp of the clutch fluid across the wall of the gearbox. I speculate that this is the root cause of them running hot.

John at BGB has also told me the PDK is really sensitive to fluid levels. Somehow the sensors know when the level isn't right and will get finicky. I think some of the assumed hot run issues may also actually be fluid level issues. I'll ping him and maybe he will comment in more educated detail than I can provide.

hei83

Might be able to figure out a fix for that oil level issue with more input! Cayman + PDK seem like a fun and fast combo on track. Looking forward to it!!

PCA1983

I've never been involved with racing, but as an engineer observing these things for years, can say it does seem that everything needs extra cooling for racing, and some parts and fluids need more additional cooling than others. It would be interesting to know what Porsche is doing differently in the race GT4s with the PDK tranny, if that's what it is, vis a vis the regular production PDKs in the S and GTS.
This is just a guess but those 2 clutches probably do generate substantially more heat in racing, and it's likely there has to be more cooling added somewhere to keep that from affecting the transmission.

GTgears

Porsche hasn't built a PDK based racecar since the 962 a couple decades ago. All inside information I have been shown says the GT4 racecar is a manual. A 6spd synchtonized manual.

DrPhil Gandini

I drive a Cayman GTS with PDK, and drove a 991 GT3 with PDK-S a few weeks ago. The only thing they have in common are the letters P, D and K. I presume there are gear ratio differences due to the very different nature of the engines, and power-bands, but there seems to also be a difference in the software. The PDK-S is far more engaging and "mates" far better to the engine than the PDK does in the GTS. The clutches seem to be tuned to engage harder as well as faster. The PDK seems to have an amount of slip tuned into it, whereas the PDK-S doesn't have any of this "mushy" feel to it. The PDK-S feels like a manual gearbox with a fancy clutch, whereas the PDK feels like an auto gearbox with a fancy shifter...

djm68

Phil,

The GTS Cayman comes by default with 'Sport Mode' software, correct? I have '12 Cayman R with PDK and 'Sport Mode' software, so I have 'Sport' and 'Sport Plus' modes. Driving in Sport delivers clearly more crisp shifts, while in Sport+ the changes are positively 'hard' -- you can clearly feel the clutches 'slamming' shut during heavy throttle shifts. I've take friend for rides in my Cayman, who've never in and a dual clutch car before, and they immediately could tell the car had a clutch based on the noticeable clutch engagement.

I've head the PDK in the 981 was made smoother; perhaps the PDK in the 987.2 is 'less smooth'?

Cheers,
DJM

jcastle

I think PDK cayman is a terrific street/track car. I tracked my 987.2 before converting it to a track focused car. Biggest issue was brakes overheating. For street/track, I would recommend more air to cool front/rear brakes, race brake fluid, pagid pads.