PTS-BRG

Ok, so as many of you know, I have a tuned Targa AWD GTS and had it tuned by COBB. Great power, The Handheld is also very convenient. However, since tuning I have had a persistent problem with shifting at redline sometimes in 3rd and sometimes in 4th. The engine flutters at redline and doesnt "snap" shift into the next gear. Trying to isolate why this is happening. Thought it could be snow tires and Turbo S wheels. Thought it needed to have the PDK just re-calibrated with Pwis from Porsche. Thought the tune needed to be tweaked. No solution. Finally, uninstalled the Cobb completely and returned car to stock. Now it shifts normally.

To those of you reading this who are on the fence about doing a tune, do not be discouraged by my story. The tune is the best mod you can do to this car and even if I have to live with the flutter at redline forever, I will be returning the car to a modified tune very soon. Just do it, as I am the only one experiencing this issue from any Tune from any company, so don't blame Cobb. I am also confident that the problem will be solved with some of the great minds on this forum and my tuner and maybe even Cobb themselves.

So, here is my question to those of you with tuned 991.2's... Does anyone have a tuned All wheel Drive car? If I recall correctly, every single one of the members who I have read about with tuned cars all have rear wheel only vehicles and no one has an AWD car. I ask because I am now thinking that the cars AWD system is what is messing with the tune and that this is the problem.

Wanted to create a poll but, no one ever reads them so I wrote this post. Please comment below if your car is tuned and if you have RWD or AWD variant,
And if you have any thoughts on a solution I would appreciate your input. Thanks Guys!

Fcassells

I’m not tuned but I have a 18 GTS4 that I will be tuning shortly.

having said that , my previous 997tt was tuned by Softronic and I had a very odd similar situation that occurred during WOT highway runs. The car would “hang” slightly when I shifted flat out. very much like a dead spot in the tune I imagined, obviously not related to PDK as it was a manual but similarly it went away when I removed the tune.

I hope COBB sorts this out prior to me having Softronic flashbacks. ��

cjjones

I am running Cobb Stage 2, 93 octane on my 4GTS. However, I have a manual not PDK. I am not experiencing the same issue as you.

erko1905

I'm running a Cobb pro-tune on my C4S but it's also manual so I can't comment on PDK issues unfortunately.

You might benefit from having a tuner put your car on the dyno to see what exactly is happening up top that's confusing the PDK.

PTS-BRG

I should have also specified that this is a PDK issue, not manual.

Anyone have a tuned 991.2 that is AWD with PDK?

As far as putting it on the dyno, it has been on several times and the problem has even been data logged with the Cobb Handheld AP. No one can figure it out..

reacher

Are you driving it in auto mode or shifting manually? I have a stage 2 tune on my RWD, but I also have shift manually 99% of the time (the remaining 1% I have a coffee in my hand), so I'm not sure I would experience the same thing. Mine has been running super smooth and I've had zero issues.

PTS-BRG

This is really only an issue when starting in launch mode and mashing the pedal from 0-150.
Like a quarter mile or half mile run. It will get to red line and just bounce for a second before engaging, which of course destroys any chance of having a good run.
Frustrating when you have all of these performance goodies and you cant see the true benefits because of a mis shift.

4 Point 0

This is going to sound strange, but what tyres are you running?

fastforddriver

Have you talked to anyone from Cobb about it?

Sounds like the shift point is just off a tad at wot under some conditions. Incorrect tire diameter could be a culprit. I assume the flutter is the rev limiter kicking in?

PTS-BRG

Not strange, it was one of the issues we thought could be the culprit.. I am currently on Michelin Alpin's on Turbo S wheels for winter.
Just purchased PS4's for summer and waiting for HRE Lightweight wheels to mount them on.. Factory sizes on Summer tires (not yet installed) and winter sizes as recommended by Porsche on currently.

Psorcery

I experience the flutter once on a beta tune test. PDK near 4th gear redline going into 5th. It happened about 1k RPM before redline.

Never happened again and since I've had the map changed.

Do you have any CEL codes that are hidden? You could have a hidden PDK fault.

PTS-BRG

FFD: It could be the tires. I don't know for sure if it is the rev limiter or not. Shift points are determined by the PDK software not the Cobb tune.
When I removed the tune completely with the winter tires on the car it shifted perfectly. Possible that the additional torque and HP on incorrect tire diameter "could" be it, but I dont think so..

PTS-BRG

Psorcery: that is very interesting. If I had any codes they are probably gone as I have removed the Cobb tune completely and whatever may have been there is probably overwritten.
I never saw anything pop up as an error. Do you have an AWD car? If not, then it may be something with just the PDK cars or just PDK with AWD..

4 Point 0

AWD are super sensitive to tyre size. When you run winter tyres, are you changing the TPMS to winter? I think its your tyres.

PTS-BRG

Changing the TPMS to winter? The sensors are in the wheel and calibrated to the computer. Never knew there was a setting for winter or summer..