Big kudos to you for the honesty, and Porsche for handling this in the most gracious manner! Hope your car will be back on its feet soon!

 

Clarke: Overtorqued now I know the secret to your amazing speed on track

 

Car was in and out of shop in about 2 weeks. I have been to track many times since. I must say t is much easier torquing at 444fp than 600fp. Especially when taking them off.

Going to a FATT DE at SP tomorrow - traffic jam.

Thinking of hauling the rig (Dually & 40' trailer) and two cars down south for the winter, December - February. Looking for DE events in the south and any ideas on where I can leave the rig/cars between events that would be safe when I fly back to Virginia? And who down FL way would be good for any service on a track car? Would like to hit an event for 2 or 3 days every other week for those 3 months.

Thanks for any ideas.

 

Clarke for Florida service

Vortex in Tampa
Auto Quest in Ft. Myers
NGT in Miami
Orbit in Pompano just north of Miami/Lauderdale
BGB in Daytona

 

I work 4 beer

 

Hello from Germany:
Glad that things are clear now which is due to honesty from OP – thumbs up. Not easy to admit an own fault of “this dimension”. Also it seems that Porsche was up to the task (which is not always the case I think).
Anyhow it is still not all well with CL.
Here my CL story.
First car with CL was a GT3 in 2010. I did use if for autocross and occasionally track days and also did participate in the German Sports Cup with it.

When doing my first Autocross I notice some strange “ticking” noises from the front axle. Thought about all kinds of reasons for this noise. Did not hear it on the street so. Next Autocross same problem. People on the outside also could hear it (this was early in 2010). So it must have to do with the higher loads on the AX track compared to street driving.
Than I reported the issue to my Porsche Centre and finally had the car booked in. They checked everything and could not find any cause but certainly paid special attention to follow the procedure for the CL (at that time it was only the 500 Nm torque specified and also printed on the nuts). At this point also the 5 red stuts have been specially torque to spec since they where also under suspicion to cause the noise.

Next outing at Hockenheimring I first thought everything is fine but was not really hearing it due to the noises at high rpm. But it must have got worse during the day because later on I started hearing the noise again.
So car was booked in again at my PC (they are by the way experienced with track work, since they are the official support team for the Sports Cup in Germany – the PC is known as having formerly been Max-Moritz team). This time the wheel bearings have been changed (and later on I was told that the wheel bearing actually have been glued in to make sure they stay absolutely fixed!). Again mounting of wheels and CL was done with great precision.
This then finally seemed to have cured the problem – at least noises where mostly gone. Interestingly at that time a buddy from AX already had a 2010 RS which had the same problem.

During this time I heard that Porsche was starting to take care of this issue since more cars seem to have (developed) the same issue. One outcome of this was the special treatment for the wheel bearings …..

Then in 2011 I switched over to a GT3RS which did not have any of the issues with the CL. No noise nothing. Everything OK. I bought my own torque wrench to be able to change wheels by myself and to be able to work on the car. After learning on how to do this I think it is pretty much straight forward, even so sometimes inconvenient (needing another person to operate the breaks during installing of the wheels – even so this can be addressed with a simple tool). Everything seemed to be OK when all in a sudden I heard about the recall in order to exchange the CL nuts and also about the changed procedure with higher torque and instructions on how to use special grease and torque the nuts properly.

This was a big thing during the second event of the Sports Cup (was in May this year at Hockenheimring again). All times needed to have the CL nuts changed for the new ones and had to sing that they follow the new instructions. I was told that the only difference between the old nuts and the new ones is that the new ones do not show any torque printed on them. Also I was told that the Porsche lawyers insisted on this move (what every liability issues they where afraid of).

So what is the higher torque and grease and the whole new procedure good for? To have the wheel assembly properly preloaded to cope sufficiently with the higher stress on track (the procedure is called “CLW Additional Information When Driving On Race Circuits”). So obviously never an issue on the street but only on track with the higher loads and stress on the components.
Later on I also got more background on the story. The real problem of the CL not being tight (or preloaded) enough is actually some slight movements between wheel and hub (despite the 5 lock pins) which actually causes the noise I described above. These “relative” movements seem to bring additional stress on the hub assembly which has caused at least two failures and such cars loosing wheels (as far as I know in both cases one front wheel). One of the effected cars was actually one of the guys who is also using the services of the Porsche Centre during Sports Cup events that I am also using.

Also I have heard that Porsche used different hub assemblies for the RS (stronger) than in the regular GT3 but that this was then changed and all GT3 versions got than the same stronger parts.

So I have been running my car this year without any problems. I am used know to the new procedure and also the 600 Nm are no real difference to the 500 Nm. The new procedure is now well known and not a real issue. The locking mechanism is always quite easy to bring the out and locked position and for ease of checking things also during the events I leave the plastic caps off.

My personal statement to the CL is: it is a marketing gimmick. No real benefit for this type of cars (total different story for Cup cars, but there the mechanism is totally different!). A 5 bolt standard configuration would be easier to handle and after market wheels would be easier to get (and probably be cheaper as well). At the beginning there have been some (serious) issues but these seem to have been sorted out (Porsche should have done this before selling it one could say …).

Also based on the problem the OP had you can see that things can easily go wrong – and being confused between Nm and lbft is “easy”. In another post one poster also wrote 600 lbft at which point I was commenting and correcting this not knowing what could happen if constantly over-torqueing .

Actually I would wish that the margin of error would be bigger but it is as it is.
I hope this gives a little insight in the mystery of CL and also it may help to regain confidence in the CL and at the same time it focuses the view on the fact that proper working routines are important (after all the German engineers are not dummies )

So everyone take care and have the Castrol Optimol Paste TA in your reach

Peter

 

LOL;

NGT is too far, the nearest are Auto Quest, BGB, vortex and Orbit.
Orbit is not in pompano, it is in North Palm Beach. I know they have a lot of indoor storage room, will bring service trucks to the events at Sebring (As will Votex I think), they will invite you for some evenings mid week at PBIR (10 mins) and are about 1 1/2 hours south of Sebring. Not sure if that is closer or not to Vortex, Auto Quest or BGB.

And he has the tools with him. No really. Just hand him his tools and your beer and all will be maintained and replaced at the track :-)

 

OK I take back everything I said in the other thread. Maybe I was just over torqued like your wheels.

First I am glad you are OK from this incident. Second, glad you shared it.

Now go buy a cup car, be safer, and dont worry if it has been dinged a bit.

 

Okay, you knew someone was going to do what I'm about to do.

Knowing as little as we know, I question whether it was actually overtorquing that caused the wheel-off failure. An overtorqued fastener will tend to yield (and not reach the desired torque) and/or will fail (fracture) at the time it's being torqued. It's hard to imagine how an overtorque would have a) not been noticeable as it was being torqued and b) caused a wheel to come off later. It's *undertorqued* wheels that tend to cause insidious fatigue failures that manifest as wheels coming off later.

Just sayin'...

 

wow I read this entire thread as im thinking about a GT3. Im getting sleepy!

 

DO IT!! mancation III ;-)

Bring car and leave all your stuff at Orbit and fly in and out or PBI ir FLL for beer drinking. uh I mean DE's.

I will be drining at:
Dec 10 www.chinmotorsports.com
Dec 11 PBIR Orbit day

January to Winterfest at Sebring 4 days www.pbocflorida.com

Feb 48hours at Sebring, but it is sold out.

There are many other groups to run with NASA, SAFE, HOD, but I have not looked at the calender. Pertty sure there are several events to choce from every weekend except the last 2 of the year.

 

that's what I'm doing! Orbit has been helpful in the process. At VIR now: fun track!

 

Dings and this OP are no strangers

I was there too. Quite a few 6,7.1 and 7.2 3's out there and Caymans.......

 

That track is a blast. Love that back straight. The compression through that roller coaster...150mph then 6th, 5th, 4th, 3rd, brake brake, turn, gas! awesome....never figured out turn 1 though. brake early, brake late, apex, big arc, didn't matter. any time I tried to go fast I was basically going sideways (maybe it was the 22nd day on those tires...or it was just the driver). A great weekend.

Did you see that 1970s something turbo'd 911 parked by the GT3s? 800hp. I have video. Spit fire at Oak Tree then left me standing still on the back straight. Nuts.

There was a very fast Boxster in white too. Purple. Seemed normal, until he told us about the 3.4 liter 911 engine in there. He was very fast though. Never broke.

Great event.

 

Yup, saw both those cars. Both were pretty tricked out.

VIR is a blast! Great weather except Friday morning was crazy cold! It was a busy event for instructors because they gave most of us two students.