Planet-9 Porsche Forum banner

1 - 20 of 29 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
This is a cross post from Rennlist...and sounds similar to an issue that Jerseydevil posted (though he was running a manual w/ RE71's)

I have a 2014 (981) Cayman S that I track fairly frequently. It has about 40k miles – recently changed air filter and PDK flush*, along with oil changes every 3-5k miles and brake fluid changes, and already had spark plugs changed. Using Mobil 1 0-w40*. Using Pzero tires and always use PSM. Issue only appeared recently.

On the last two sessions of a recent 3-day track event (high 80’s and sunny), I was driving the car in sports plus and allowing the car to do the shifting. Half way into the second to last half hour session, it felt as if the car went into sort of a limp mode. No fault codes/CEL, but car wouldn’t rev to redline before shifts – was short maybe 500 – 1000 RPM before shifting. I ended the session early, let the car rest, and then went back out the last session, and after 5-10 minutes laps, it “limping” again.

I was advised by someone to do a PDK/transmission flush*, which I did along with an oil change, and brought it out to the track the following week for a test (fresh PDK/transmision fluid and oil). Temps were about high-80’s / 90 degrees – on the first day, I was able to drive 3 sessions without issue, then every session afterwards, started “limping” after 10 minutes or so – when I noticed this, I did a cool down lap and pitted in. The next day, it started “limping” after 10 minutes of the first session. Called it quits and went home.

Brought the car to a Porsche dealer the next day – and they concluded that it was because I overheated my brake fluid (likely because that’s the only code they saw).

A few questions come to mind:

-I question the conclusion the dealer came up with, since I use RBF600 fluid, which was flushed beginning of the year, and bled prior to the 3-day event when the “limping” started to occur. Also, seems far fetched associating these two together…and even if I upgrade to SRF, wouldn’t the fluid still get just as hot, but not necessarily boil - setting off the high temp brake fluid sensor?

-Someone suggested it might be a cooling fan or thermostat/sensor issue, but dealer didn’t (or couldn’t) see that.

-I spoke to a very knowledgeable Cayman guru who said to get a third radiator, use Driven DI-40 oil and PDK cooler. I would have done this, had I not found out that there are other 981 Cayman S owners in the area that drive their cars harder/faster than me (at the same event), and do not have these modifications. My concern is that these modifications cost real money, and I cannot test if this would be successful unless I invest additional time and money into a track event to test it out (I can't replicate this problem safely on public roads)

-I understand alot of people don't like Mobil 1, but I've always used it in the past with no issue (and know others that are faster than me using it), and used fresh Mobil 1 oil on the test event to no benefit. I have also tracked the car in 90+ weather many times in the past with no issue.

CPO warranty is running out soon, and I’m getting frustrated throwing money and time into troubleshooting and testing the car. Was curious if anyone else had this same issue and what resolved it. Very close to selling my car and moving on in life to another hobby.

Thanks everyone!
 

·
Registered
Joined
·
57 Posts
I had this same problem with my 2011 Boxster S. Several years ago, first time out with this car, I was driving at Gingerman Raceway - at that time a 1.9 miles mile track with 11 corners - I was letting the PDK shift for itself in sport mode. After about 10 minutes of track time it went into the limp mode. I let it cool off and tried again, same problem after about 10 minutes. I sensed that it was an overheating problem probably maybe by the PDK auto shifting. I went out much later after a big cool down but this time I shifted the PDK manually. No problems.

I did a little test and counted the number of shifts in auto mode for one lap and then did the same for my manual shifting. I can't remember the numbers but I do recall that in auto mode there were at least 50% more shifts. Let me give you an example, going into one fast corner I am close to the shift point in 3rd gear just before I brake and downshift. I notice that in PDK auto mode it will shift into 4th gear just before the brake point. I would not have done that manually. No advantage in upshifting 50 feet before my brake point. That means that it went from 3rd to 4th unnecessarily (1 upshift), then it downshifted to second as I braked (2 downshifts), as I exited the corner it upshifted to 3rd. That is 4 shifts in that corner. If I did it manually, I would have stayed in 3rd, downshifted to second (1 shift) and did another upshift to third at exit. So, manually I did that corner in 2 shifts, instead of 4 shifts in auto PDK.

The moral of the story is that on a short track the auto mode shifts too much and that must have an effect on PDK temperature. Also on a short track the corners come up quickly, there is a lot of shifting and not much distance between corners to cool down the PDK. I notice that at Road America - 4 miles 14 corners - I do not have a problem in PDK auto mode. Probably because there is more time for the PDK to cool between corners. In any case I always use the manual PDK. I thing you would be surprised at how much unnecessary shifting is done in auto mode. Maybe Porsche has cured this problem since 2011. At the time my dealer checked everything and said the PDK was fine. But, on track in auto mode it was crap.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #4
Thank you Dannov. Makes sense. I was on a 2 mile track with 12 turns and uneven flow of traffic definitely caused the car to shift more. I think I will take the car out on a bigger track with less turns to try out!

Did you try adding in a PDK cooler or third radiator to remedy the issue?
 

·
Registered
Joined
·
57 Posts
Thank you Dannov. Makes sense. I was on a 2 mile track with 12 turns and uneven flow of traffic definitely caused the car to shift more. I think I will take the car out on a bigger track with less turns to try out!

Did you try adding in a PDK cooler or third radiator to remedy the issue?
No, never considered that modification, but it could not hurt. I just never use auto PDK anymore on the track. Even on long tracks it does unnecessary shifting. On track, I like to decide when to shift and I want to choose what gear I am running. Auto PDK eliminates thinking about gears and RPM, I'm not sure that is good when you are on a track. When it come to transmissions we have a choice of straight manual, manual PDK or auto PDK. On the track, manual PDK is the best of all for quick shifts and control.
 

·
Premium Member
Joined
·
833 Posts
... When it come to transmissions we have a choice of straight manual, manual PDK or auto PDK. On the track, manual PDK is the best of all for quick shifts and control.
I'd argue there is a another choice next to straight manual: Manual with Sports Chrono package. Gives you perfect rev matches without heal toe, and gives you a warning before a money shift, since the rev match starts before you get the gear engaged (saved me once on the 3 track days I did with the 981 GTS).

OP if I were you I'd try again using manual mode PDK before throwing in the towel or making modifications that might not solve the problem. Good luck.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #7
Yes, manual with rev match would have been ideal, but the car I currently own popped up when I needed one

Yes - going to a track event in 3 weeks at a larger track. Curious how PDK holds up with less autoshifts in those conditions - then start doing manual shifts. I was close to throwing in the towel on the car, but giving it another shot thanks to you guys!
 

·
Registered
Joined
·
8 Posts
Discussion Starter #9
Ledbette - yes, running oem size tires - pzeros n1. Been running on them for about a year with no issue
 

·
Registered
Joined
·
498 Posts
Interesting. My friend and I run 981 "race" cars but I have the 3rd radiator and his does not. The first race we realized that cooling is insufficient as we both had some issues with PDK overheating in moderate ambient temps. After that we added an extra air-to-oil cooler in series with the stock PDK heat exchanger to help out (This was a tip from a German racing team that runs lots of Caymans) and with fresh fluid too.

My car was fine the next race where it was really hot (but lots of straight lines) but his car also started doing the early upshifting all on its own after a couple of laps. This was with the gearbox in manual mode by the way. It didn't care, still shifted around 7K by itself. There were no error codes, but turning the car off in the pits and going out again cleared it for a little while.

Pretty weird.
 

·
Registered
Joined
·
2 Posts
No, never considered that modification, but it could not hurt. I just never use auto PDK anymore on the track. Even on long tracks it does unnecessary shifting. On track, I like to decide when to shift and I want to choose what gear I am running. Auto PDK eliminates thinking about gears and RPM, I'm not sure that is good when you are on a track. When it come to transmissions we have a choice of straight manual, manual PDK or auto PDK. On the track, manual PDK is the best of all for quick shifts and control.
When you say shifted PDK manually means using gear Knob in manual mode? Or steering wheel paddle or both consider manual shift?
 

·
Registered
Joined
·
57 Posts
When you say shifted PDK manually means using gear Knob in manual mode? Or steering wheel paddle or both consider manual shift?
I have shifted PDK both ways, with paddles and using the PDK knob in manual mode. I really prefer to use the PDK knob in manual mode. It is faster and more intuitive for me, i.e. push forward to go up a gear and pull back to go down. When I'm are on the track going fast I don't want to have to think about shifting, except for when and where to shift. I am sure I can learn the paddles so that it is automatic, but sometimes I do it wrong. I never screw up using the PDK knob.
Let me say something else about using PDK in auto mode. This is a good way to learn the shifting points on a new track provided you are aware that in auto mode it often upshifts too late when going into a corner. It is pretty obvious when it makes a stupid upshift too close to your brake and turn-in point. But knowing that fault, it does help you in learning a new track, just be aware that too much of that dumb PDK auto shifting may cause overheating. I sometimes do it in auto mode for a few laps just to get a feel for a new track without the bother of shifting.
 

·
Registered
Joined
·
156 Posts
I have shifted PDK both ways, with paddles and using the PDK knob in manual mode. I really prefer to use the PDK knob in manual mode. It is faster and more intuitive for me, i.e. push forward to go up a gear and pull back to go down. When I'm are on the track going fast I don't want to have to think about shifting, except for when and where to shift. I am sure I can learn the paddles so that it is automatic, but sometimes I do it wrong. I never screw up using the PDK knob.
Let me say something else about using PDK in auto mode. This is a good way to learn the shifting points on a new track provided you are aware that in auto mode it often upshifts too late when going into a corner. It is pretty obvious when it makes a stupid upshift too close to your brake and turn-in point. But knowing that fault, it does help you in learning a new track, just be aware that too much of that dumb PDK auto shifting may cause overheating. I sometimes do it in auto mode for a few laps just to get a feel for a new track without the bother of shifting.
Interesting to me the paddles make sense and the stick is backwards, coming from a shifter kart I think of towards me as up-shift (accelerating pushes you back) and away from me as down (braking moves you forward in the seats) so I can't use the stick at all, plus if I keep my hands in the same place I always know which hand is up and which is down and don't remove my hands from the wheel.
 

·
Registered
Joined
·
57 Posts
Interesting to me the paddles make sense and the stick is backwards, coming from a shifter kart I think of towards me as up-shift (accelerating pushes you back) and away from me as down (braking moves you forward in the seats) so I can't use the stick at all, plus if I keep my hands in the same place I always know which hand is up and which is down and don't remove my hands from the wheel.
Whatever works is fine. I am 70+ years old and have never been in a shifter cart so your logic doesn't really register with me. I screwup the paddles too often when pushing hard. Maybe you can't teach an old dog new tricks, that could be my problem. In the past I have watched European sedan racing on TV and noticed in the in-car shots that they used sequential shifters, i.e. straight forward for upshifts and back for downshifts. I'm not sure what the logic is of setting it up that way, but I suspect it is something like forward is for faster and back is for slowing down. I suspect that in shifter carts things are so fast that paddles are a necessity because you can't readily take your hands off the wheel, but that is rarely true on a road course.
 

·
Registered
Joined
·
156 Posts
Whatever works is fine. I am 70+ years old and have never been in a shifter cart so your logic doesn't really register with me. I screwup the paddles too often when pushing hard. Maybe you can't teach an old dog new tricks, that could be my problem. In the past I have watched European sedan racing on TV and noticed in the in-car shots that they used sequential shifters, i.e. straight forward for upshifts and back for downshifts. I'm not sure what the logic is of setting it up that way, but I suspect it is something like forward is for faster and back is for slowing down. I suspect that in shifter carts things are so fast that paddles are a necessity because you can't readily take your hands off the wheel, but that is rarely true on a road course.
Interesting, I never thought about it, that way, but I also never internalised why I felt like the shifter was backwards, based on your statement I went to look at some in car video and found this one where they pull back for up shift: https://youtu.be/SCNEOQS42KU?t=82 and another https://youtu.be/kk0OcAPs61k?t=31

Then I found this site where they sell kits to make manual boxes into sequentials and they also pull back to shift up: https://www.s1sequential.com/product/sequential-shifter-t-5/

"The simple pull back to up shift and push forwards to down shift is much easier to coordinate all movements under racing loads than the H-pattern shift. "

Also the new 991.2 cars have reversed this movement now, and it's pull back for up shift, push forward for downshift (look at pictures of their consoles, it's quite obvious)

Then being a UX Geek I started thinking about why does the upshift on the right and downshift on the left make sense to my brain? I think it's because you move a manual to the right to up shift and to the left when downshifting.

I'm not saying you're wrong about this you should use whatever works for you and prevents you from making mistakes, but I'm trying to illustrate it's far from decided which direction does what.
 

·
Registered
Joined
·
57 Posts
Interesting, I never thought about it, that way, but I also never internalised why I felt like the shifter was backwards, based on your statement I went to look at some in car video and found this one where they pull back for up shift: https://youtu.be/SCNEOQS42KU?t=82 and another https://youtu.be/kk0OcAPs61k?t=31

Then I found this site where they sell kits to make manual boxes into sequentials and they also pull back to shift up: https://www.s1sequential.com/product/sequential-shifter-t-5/

"The simple pull back to up shift and push forwards to down shift is much easier to coordinate all movements under racing loads than the H-pattern shift. "

Also the new 991.2 cars have reversed this movement now, and it's pull back for up shift, push forward for downshift (look at pictures of their consoles, it's quite obvious)

Then being a UX Geek I started thinking about why does the upshift on the right and downshift on the left make sense to my brain? I think it's because you move a manual to the right to up shift and to the left when downshifting.

I'm not saying you're wrong about this you should use whatever works for you and prevents you from making mistakes, but I'm trying to illustrate it's far from decided which direction does what.
I don't think there is any right way or wrong way about sequential shifting. I see now that these boxes can be setup both ways. I did not realize that. My 2011 Boxster S came from the factory with PDK setup for manual upshifts forward and downshifts back. My 2016 Macan is the same. To remember that pattern and create an automatic reaction, I just developed my own mental trick. That was also true in my old 1985 911 with manual box. If I were to use the shift paddles more often I would develop another mental trick to remember the proper pattern. Porsche sent the car to me setup this way and I just have to train my brain to use the the shifters properly. Now, some may think this conversation is not very meaningful and if you just drive on the street that is probably true, i.e. there is a lot of room for error on the street. But on the track it is a different story. When you are going into corner #1 at Road America at 140+ mph you have to brake and downshift automatically - no time to think because a lot of stuff is happening all at once - these mental tricks come into play at that point and the successful downshift is achieved without thought. If you screw up the downshift on corner #1 at RA - ops, how does this work again? - you can get yourself into deep trouble in a flash.
 

·
Registered
Joined
·
156 Posts
Absolutely no right or wrong I was just exploring the reason for the unconscious bias I had that back means up and forward means down

I don’t think there are settings to reverse them but Porsche decided a year or two back to align them with the race cars, and I agree for sure the track is nowhere to discover the right and wrong way. Interestingly I think the paddles feel correct to me because of watching f1 for years




Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
1,056 Posts
The GT3 PDK has always been pull back to shift up. I never understood why they made the 981 the opposite, however Cobb Tuning has a PDK file for the 981 that will reverse the function for you if happen to own a Cobb device. Its an expensive upgrade if that is all you really want to do once you factor in the cost of the device plus PDK tune, but may be be reasonable option for those that have already purchased one for an ECU tune and just need to purchase the PDK file. I guess the good news for anyone starting from scratch is you would also be getting the ECU performance tunes on the device for the price, and the Cobb device is a really great data logger for all sorts of things on the car and can also read fault codes.
 

·
Registered
Joined
·
156 Posts
You may be on to something there, I remember reading something about either the 991.2 or the 992 that specifically said they had "Finally flipped the shifter" I've searched a little on-line for some interior pictures of cars where you could see the shifter, and this 2016 Carrera is forward up: https://www.porschebellevue.com/used/Porsche/2016-Porsche-911-dc7653d60a0d0cc768c9d340338c20ab.htm although this 2016 GT3RS definitely shows it flipped: https://www.dupontregistry.com/autos/listing/2016/porsche/911--gt3--rs/2010011 and this 2014 GT3 shows it flipped: https://www.edmunds.com/porsche/911/2014/vin/WP0AC2A99ES183107/

So I wonder why they flipped it for the GT3 cars from the street cars? I'd guess again to align more closely with the race cars.

Unfortunately Cobb doesn't offer a little more flexibility in their maps, for a bit more, I'd love to be able to flip the shifter, have it hold a gear when in manual mode instead of kick down, and shift at the Sport + settings for speed and clutch firmness, but they don't let you do this you basically have to take the most aggressive maps to get those features. I understand this sort of programming is complicated so it's probably not worth the time for them to do this sort of Ala Carte setting.
 

·
Registered
Joined
·
1,056 Posts
You may be on to something there, I remember reading something about either the 991.2 or the 992 that specifically said they had "Finally flipped the shifter" I've searched a little on-line for some interior pictures of cars where you could see the shifter, and this 2016 Carrera is forward up: https://www.porschebellevue.com/used/Porsche/2016-Porsche-911-dc7653d60a0d0cc768c9d340338c20ab.htm although this 2016 GT3RS definitely shows it flipped: https://www.dupontregistry.com/autos/listing/2016/porsche/911--gt3--rs/2010011 and this 2014 GT3 shows it flipped: https://www.edmunds.com/porsche/911/2014/vin/WP0AC2A99ES183107/

So I wonder why they flipped it for the GT3 cars from the street cars? I'd guess again to align more closely with the race cars.

Unfortunately Cobb doesn't offer a little more flexibility in their maps, for a bit more, I'd love to be able to flip the shifter, have it hold a gear when in manual mode instead of kick down, and shift at the Sport + settings for speed and clutch firmness, but they don't let you do this you basically have to take the most aggressive maps to get those features. I understand this sort of programming is complicated so it's probably not worth the time for them to do this sort of Ala Carte setting.
Yes it would be nice to be able to check a few boxes with which features you would have the Cobb PDK map apply.

I've had the PDK maps since they first came out and my main reason for investing in them was because a few of the beta test guys claimed that it removed the PDK dead stop throttle delay when suddenly applying hard throttle from a standstill. It does not! I shift manually 100% of the time so I'm already in control of when the cars shifts, so the higher shift points the PDK tune applies dont really help me. I can certainly see the value for those guys that run in full auto mode though.

I tried the reverse shifter mode because I too feel like it makes more sense the way the GT3 operates, but that mode also removes the usual automatic "creep" from the tranny as well as the kick down feature. I'm fine with the kick down being gone and even the creep being gone, but removing the creep caused the car to lurch when trying to do things requiring finesse such as moving into the garage up closely to the wall, or in a parking space with a concrete front lip killer in it.

The car will act like a full manual without the creep so this means it will roll backward on an incline if not steep enough to trigger the hill hold. That took a little getting used to but was no big deal in the end. It was just too harsh for me when pressing the accelerator in confined areas as this would trigger the tranny to engage and it was like dropping the clutch on a manual too quickly. I could deal with this in normal driving on the road, but it made it damn near impossible to move the car just a few inches at a time very slowly when needed so I removed that particular map.

Ironically I had become used to the new shifter direction and kept dropping the car down a gear instead of up and had to retrain my brain to go back to the factory direction again:)
 
1 - 20 of 29 Posts
Top