gasongasoff

Sounds like the Porsche launch control is designed to be used repeatedly with minimal wear. It's nothing like dropping the clutch on a manual.

See here:
http://www.examiner.com/european-spo...dk-first-drive

"When Stephen Schwartz was explaining this feature on the PDK my first question was “how many times can you use it before you either fry the clutch or void the warranty”? Stephen said that since the PDK uses a wet clutch transmission it can withstand repeated use and will not void the warranty or cause excessive wear on the clutch. He went on to describe the PDK in the new Panamera Turbo that they had been receiving their sales training in at Firebird Raceway. Stephen said that the car had over one hundred launches in the two days and the one hundredth launch was just as smooth as the first."

Edgy01

Since I don't have a PDK tranny I truly do not know what is going on inside the system when launch control is used. But I can suspect that it does some wear. When we use Military Rated Thrust (MRT) on our jet engines in the USAF we can only go to MRT for a certain amount of time before we wear things out too much. Is there such a correlation to the Launch Control?

Macster

Using LC stresses the car probably not as much as tracking. But full throttle blasts up through the gears clearly stresses the engine more than not doing this.

My info is that in the case of Porsche cars the drive train computer does *not* monitor the number of times LC is used.

As an aside, I watched a Porsche tech demo LC to a owner of a PDK car -- the car was in for service and broken in and warmed up -- and the car took off like a scared rabbit. Man what a launch! I can't recall ever seeing a street car launch so quickly with so little fanfare and so little drama. Just a whoosh and gone. I want PDK!

One of these days...

Sincerely,

Macster.

Macster

Generally wet clutches experience very little wear and those controlled by a computer -- as is the case with the PDK clutches -- even less wear since the clutch's engagement is controlled by computer vs. some ham fisted err footed human who at least once in a while will slip the clutch excessively.

Of course, I dare say that two otherwise identical cars one LC'd a lot and one not LC'd at all we almost certainly can say which one will have a PDK problem sooner (provided something else doesn't happen first).

Frequent use of LC I think at least calls for a more frequent PDK fluid/filter (and engine oil/filter) service schedule and how more frequent depends upon the frequency of LC use.

Sincerely,

Macster.

Mike in CA

I wouldn't say that LC stresses a car "far more so" than tracking it, and in general using LC may not be particularly harmful; PDK was designed for it. I don't mean to go all philosophical and judgemental about this, but in general I don't like to abuse my stuff without a purpose. Autocrossing my car means using full throttle, heavy braking, etc. So does flooring the accelerator at stoplights and racing to the next one. But one activity has "purpose" and the other doesn't, at least from my perspective. I can understand being curious and trying LC once or twice, but doing it repeatedly falls into the racing-between-stoplights catagory, IMO.

I have a respect for mechanical things and If I'm going to "use up" my car (for want of a better term) I want it to be for a good reason. If I were going to buy a used car from someone, it would be nice to know they shared my mechanical sensibilities, which is why I made my original comment. Just my $.02.

Carrera Jack

Thanks everyone for your inputs and comments, I guess I can summerized in the following....
1. LC puts stress on the car
2. Tracking puts stress on the car
3. LC doesn't void warranty
4. Tracking voids warranty
5. tracking has a "purpose"
6. LC doesn't have "purpose"

Guys, come one, what are you all saying??? If stressing a car is such a bad idea, then why buy a Porsche? Might as well get a Miata!!!! Warranty only applies when the car had defective issues or problems, not for people when they do irresible thing such as racing, that's why Porsche dealer voids the warranty for car that goes on track!!! My purpose here is to find out the car I bought lives up what Porsche claims. I'm not into tracking or street racing (nor draging racing) as I've mentioned in the first post.

I'm merely asking if 1. there is something wrong with my car or 2. I'm doing something wrong. That's my purpose. If you have differences of opinion, please post in other thread and I'm sure others will follow.

Scott997, thanks for standing up, at least I know there are people who is willing to help. I do suspect it is the hill climb assitant that's causing the delay as Gasongasoff's post.

PS. I would never buy a used Porsche.

Mike in CA

My apologies for going off topic with my opinion. As I posted earlier, the thing that jumps out at me is that the manual and C&D both indicate that the launch should occur at around 6500rpm. You said that you were launching at 4500rpm which is not going to give you the optimum balance between power and traction. If you are following the correct procedure as described in the manual, and it still launches at only 4500, then there may in fact be something wrong with your car. I don't know if the hesitation is related, but if you're looking for a problem, I'd start with finding an explanation for the difference in revs.

rodsky

Like I said before, I've done 2-3 launches, just to see what it was like, then haven't done it since. I did not experience what you are experiencing. If you follow the instructions, it should work pretty much as advertised. 4500 RPM? There's an issue right there. If you are following instructions and it doesn't work, take it in..

utkinpol

dropping clutch at 6500rpm with any sort of internal mechanism does cause at enourmous amount of stress on clutch and gears, no matter what.
on aisin 6sp gearboxes it was not uncommon simply brake off a tooth from 1st gear which would resullt in complete gearbox replacement. 6500 is a max power spot, 4500 would be close to max torque spot, i usually launch from 3500-4000 rpm at autocross, it is a less damaging than launching from 6500-7000 rpm with quite negligent time diff (unless you do real drag on a dragstrip).

i would think it would be wise if porsche actually altered default LC logic in PDK to 'beep' at 4500rpm, it would be much better for gearbox and clutches.

i would only guess that 'hesitation' may come from a park assist or whatever new 997.2 cars get to keep on brakes on an uphill. more computer crap you get - more unpredictable results you get. and pdk got too much computer control anyway...

PS. BTW the result of this is: i got my car with 38L miles and it was only street driven before it so i would assume clutch had its original life expectancy (100K miles or so). At 53K miles now i had to pay to get a new clutch, old one was totally done. so nothing comes free when you get from a car all it can give.

duke92

...and the chorus says " remind me not to buy YOUR car when you decide to sell it"

j/k. Appreciate all your input--always informative.

RED HORSE

From page 175 of my owner's manual. "CAUTION. Stress on components increases dramatically when starting with maximum acceleration in comparison with normal driving off. Use of Launch Control will inevitably reduce the life of the engaged engine and transmission components."

Carrera Jack

Hi guys, thanks for all your inputs. I went to the dealer this afternoon and asked them about the hesitation that I'm experienced with me GTS. Immediately, they told me "launch control" is not recommended, BUT it is cover by the warranty. Again, tracking or racing is not cover!!! One of the mechanics was really helpful and explained to me what could've happen.

1. 4500rpm setting is for the new car (2011 GTS) to protect both engine and transmission.
2. The hesitation that I felt is due to the hill claimb assist when I fully depressed the brake. I should brake normally ie. stop at red light.
3. He suggested to reset computer for the transmission, this would help to renew the hill climb assist???

Point 3 is where I'm having the trouble to understand, what do you guys think?

Anyway, my heart has rested as I thought I was doing it wrong or there is something wrong with my car.

Mike in CA

I don't really understand what he means by number 3 either. Very interesting about the new rpm limit for LC on the 2011 GTS. That is a definite change from my 2009 S. What does your owner's manual say on the subject?

Carrera Jack

Mike, surprising that the owner manual is the same as any Carrera, it is not specialized for the GTS. As matter of fact, there is nothing mention of GTS in the manual at all!!! I guess Porsche doesn't make an extra manual for the GTS. I do get a supplement manual for the center lock wheel, but it looks like for GT3, not specific for GTS......

utkinpol

several people complained about hill assist in different ways that is why i suggested it was it.
they will figure it out, hopefully. i think this stuff was acting up not only during LC but all the time on your car.