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I will ask for more pictures. There was some cosmetic damage reported on the lower control arm, and the body shop is noticing more collateral in-trunk damage, such as to the windscreen wiper components.
This is what the first body shop sent me to show lower control arm damage.
I'm looking at this photo on a phone and I can only see some minor indication of something marking the plastic brake cooling duct. Is this the damage they're referring to? If so, it's inconsequential.
I informed PNA of my intent to have the part analyzed, and asked if they could
ask their engineers whether they would have any interest in the criteria or
process used in the analysis, so they might be comfortable with the accuracy
of the results, but PNA responded that for them this case is closed. An impact
caused the failure, and that is their final position.
If your communication with PNA was by phone, you may want to consider having this dialog with PNA in an email (or a letter by email), and get their response back in written form. If it isn't on video or written down, the communication never happened. A courteous written notification with a request for a written response shouldn't cause any negative consequences.
If your communicstion with PNA was by phone, you may want to consider having this dialog with PNA in an email (or a letter by email), and get their response back in written form. If it isn't on video or written down, the communication never happened. A courteous written notification with a request for a written response shouldn't cause any negative consequences.
Thanks, yes, it's in email I have, and yes, that picture is all I have indicating any lower control arm damage...
This isreally too bad....having worked in the industry I understand the manufacturers need to play hard ball with consumers to protect their interests, but I really have been hoping Porsche would step up here. I've bought a ton of porsche product consistently over the years, and will continue to watch this thread to determine my future loyalty.
Good luck to Joe! I hope in a small way we can help him get the equitable resolution he deserves!
This isreally too bad....having worked in the industry I understand the manufacturers need to play hard ball with consumers to protect their interests, but I really have been hoping Porsche would step up here. I've bought a ton of porsche product consistently over the years, and will continue to watch this thread to determine my future loyalty.
Good luck to Joe! I hope in a small way we can help him get the equitable resolution he deserves!
Thanks. I really love Porsche. I have competed and won with other cars, but
have found a home with Porsche for the general quality and reliability. And
when things go wrong, they have stepped up without a hitch previously. They
replaced my 996 turbo's tranny, within weeks of the warranty running out.
They may be under pressure to cut costs because of the VW thing.
700 miles on my car to date and was suspect of future strut damage before seeing post
700 road miles on my car to date, the first 500 were on beautifully smooth California roads during vacation no issue.
Had the car shipped home to NJ, while we don't have the best roads here. Immediately heard what sounded like repeat harsh impact ( while avoiding any large road imperfections) sounds strut to body both sides of car driving on regular roads. So much so was going to bring the car into the dealer to have it checked out.
Took a friend for a ride who owns a body shop, just to experience the car in general. He was disturbed by the sounds as well, did not sound normal, like a bump stop was missing or something might have been loose.
No engineer here, but I own more than a handful of Porsche cars old/newer none of them sound like that.
My take ( didn't have time to read the threads) is that impact I am hearing over time could be a weakness in the design if intensified by track use or slightly harder road use heavy potholes the body will fail?
Put many many track miles on my 951 lots of curbs, potholes stress no strut brace, never considered this type of thing.
With my Alpina went thru 26 tire blow outs eight un repairable rims in four years, a few years back when roads were in worse condition, fortunately covered under wheel/tire warranty. While I felt bad for the car taking the abuse from these roads. Never experienced body failure and these were hard wheel/tire/road hits. It simply should not happen unless there is a serious collision.
Raises some concern as the 3rd gear thing, this was a small run of cars. Hopefully Porsche will address, haven't had the best experience with them with other recent admin matters, but hopefully they will step up if these things continue to occur. I am sure I will be on there black list for some of these posts.
Also perceived values of cars, repaired cars will undoubtedly will be worth less than un repaired car even if done perfectly.
Maybe jumping ahead here till issues are confirmed. But I think all of us will go to the track a little less confident knowing the failure is possible loss of steering etc.
Aftermarket modification is a temp solution, but with the possible safety risks it would certainly take Porsche out of the equation on a modified car in the event of any possible liability issue ( hopefully there are none).
^ I recommend you have your ride height checked and set to spec for GT4. Some have also found the monoball in the camber plates at the top of the shock/strut has slop and when replaced noises like you describe went away. It's a great car, nothing is perfect. We are learning more about the shock tower failures, stay tuned to this channel.
700 road miles on my car to date, the first 500 were on beautifully smooth California roads during vacation no issue.
Had the car shipped home to NJ, while we don't have the best roads here. Immediately heard what sounded like repeat harsh impact ( while avoiding any large road imperfections) sounds strut to body both sides of car driving on regular roads. So much so was going to bring the car into the dealer to have it checked out.
Took a friend for a ride who owns a body shop, just to experience the car in general. He was disturbed by the sounds as well, did not sound normal, like a bump stop was missing or something might have been loose.
No engineer here, but I own more than a handful of Porsche cars old/newer none of them sound like that.
My take ( didn't have time to read the threads) is that impact I am hearing over time could be a weakness in the design if intensified by track use or slightly harder road use heavy potholes the body will fail?
Put many many track miles on my 951 lots of curbs, potholes stress no strut brace, never considered this type of thing.
With my Alpina went thru 26 tire blow outs eight un repairable rims in four years, a few years back when roads were in worse condition, fortunately covered under wheel/tire warranty. While I felt bad for the car taking the abuse from these roads. Never experienced body failure and these were hard wheel/tire/road hits. It simply should not happen unless there is a serious collision.
Raises some concern as the 3rd gear thing, this was a small run of cars. Hopefully Porsche will address, haven't had the best experience with them with other recent admin matters, but hopefully they will step up if these things continue to occur. I am sure I will be on there black list for some of these posts.
Also perceived values of cars, repaired cars will undoubtedly will be worth less than un repaired car even if done perfectly.
Maybe jumping ahead here till issues are confirmed. But I think all of us will go to the track a little less confident knowing the failure is possible loss of steering etc.
Aftermarket modification is a temp solution, but with the possible safety risks it would certainly take Porsche out of the equation on a modified car in the event of any possible liability issue ( hopefully there are none).
The odds for your GT4 surviving don't look very good considering your experience with the Alpina in your location. Your insurance company will likely refuse to insure your GT4 if you have multiple strut chassis failures. For your driving environment it may have to be a track only car.
Catching up here guys- I've been distracted by other things but a friend sent me a link to this thread.
Clearly there are a number of things going on here, but one point (and warning) jumps out at me.
Let me first say that this is educated guesswork- I don't have full suspension data from a GT4. That said: Porsche has been removing jounce (bump) travel from their cars steadily for a number of generations. A stock 997 Carrera has about 50mm of total travel up front before the spring rate goes off the chart (bump rubber completely squashed, chassis starts trying to flex). In the 991 they decreased bump travel to about 40mm. In sports suspension cars (that keep the shocks with shorter springs) travel is roughly that much less, so out of the box even the non-GT cars are running very, very low bump travel numbers. For comparison 3"-4" or 75 to 100 mm of bump travel was once the industry rule of thumb.
Now consider that the 30mm or so remaining plus your tire sidewall is all the space you have to effectively stop a "crash". Because once the suspension bottoms that's what you have, at which point the only question is "what breaks"? Does the chassis twist, the wheel bend, the strut to fail, etc.
My strong suspicion is that the GT4 is on the low end of Porsche's travel range, which means lowering it further could have serious unintended consequences of exactly the type we are seeing here. Pull out 10mm of ride height and you might unwittingly quadruple or more the severity of an impact.
My concern is that in order to dial in competition levels of camber we're doing exactly this, and given the clear lack of design margin it will lead to catastrophic failures. Ride height is almost certainly a far bigger variable than any part to part variation in casting or design factor of safety built in.
As I said this is only a suspicion currently, but it's a very strong one. We'd want to get suspension travel data (ideally from a K&C machine) and camber vs ride height numbers to confirm this...
Catching up here guys- I've been distracted by other things but a friend sent me a link to this thread.
Clearly there are a number of things going on here, but one point (and warning) jumps out at me.
Let me first say that this is educated guesswork- I don't have full suspension data from a GT4. That said: Porsche has been removing jounce (bump) travel from their cars steadily for a number of generations. A stock 997 Carrera has about 50mm of total travel up front before the spring rate goes off the chart (bump rubber completely squashed, chassis starts trying to flex). In the 991 they decreased bump travel to about 40mm. In sports suspension cars (that keep the shocks with shorter springs) travel is roughly that much less, so out of the box even the non-GT cars are running very, very low bump travel numbers. For comparison 3"-4" or 75 to 100 mm of bump travel was once the industry rule of thumb.
Now consider that the 30mm or so remaining plus your tire sidewall is all the space you have to effectively stop a "crash". Because once the suspension bottoms that's what you have, at which point the only question is "what breaks"? Does the chassis twist, the wheel bend, the strut to fail, etc.
My strong suspicion is that the GT4 is on the low end of Porsche's travel range, which means lowering it further could have serious unintended consequences of exactly the type we are seeing here. Pull out 10mm of ride height and you might unwittingly quadruple or more the severity of an impact.
My concern is that in order to dial in competition levels of camber we're doing exactly this, and given the clear lack of design margin it will lead to catastrophic failures. Ride height is almost certainly a far bigger variable than any part to part variation in casting or design factor of safety built in.
As I said this is only a suspicion currently, but it's a very strong one. We'd want to get suspension travel data (ideally from a K&C machine) and camber vs ride height numbers to confirm this...
$.02
You have a point. So all of us who keep the stock ride height (because we actually drive on real roads with the occasional driveway), but get our camber through shims and toe arms, are OK?
Catching up here guys- I've been distracted by other things but a friend sent me a link to this thread.
Clearly there are a number of things going on here, but one point (and warning) jumps out at me.
Let me first say that this is educated guesswork- I don't have full suspension data from a GT4. That said: Porsche has been removing jounce (bump) travel from their cars steadily for a number of generations. A stock 997 Carrera has about 50mm of total travel up front before the spring rate goes off the chart (bump rubber completely squashed, chassis starts trying to flex). In the 991 they decreased bump travel to about 40mm. In sports suspension cars (that keep the shocks with shorter springs) travel is roughly that much less, so out of the box even the non-GT cars are running very, very low bump travel numbers. For comparison 3"-4" or 75 to 100 mm of bump travel was once the industry rule of thumb.
Now consider that the 30mm or so remaining plus your tire sidewall is all the space you have to effectively stop a "crash". Because once the suspension bottoms that's what you have, at which point the only question is "what breaks"? Does the chassis twist, the wheel bend, the strut to fail, etc.
My strong suspicion is that the GT4 is on the low end of Porsche's travel range, which means lowering it further could have serious unintended consequences of exactly the type we are seeing here. Pull out 10mm of ride height and you might unwittingly quadruple or more the severity of an impact.
My concern is that in order to dial in competition levels of camber we're doing exactly this, and given the clear lack of design margin it will lead to catastrophic failures. Ride height is almost certainly a far bigger variable than any part to part variation in casting or design factor of safety built in.
As I said this is only a suspicion currently, but it's a very strong one. We'd want to get suspension travel data (ideally from a K&C machine) and camber vs ride height numbers to confirm this...
$.02
Great write up and excellent points brought up. Well done!
Hearing your comments gave me the urge to try my Porsches and see if they feel or sound differently over bad roads......so I took rides earlier today back to back in 6 different Porsches I own over a very rough road close to home. I kept my speed steady around 50 mph and I tried to follow the same line. Without a question GT4 definitely sticks out of the bunch and especially with stock PASM module. The impact noises are much much loader and impact feels much harsher. I have installed DSC module a while back on GT4, but for this test I put back the original PASM module. Some of the impact noises sounded like hitting metal on metal and come through the shock towers and especially the back. Really awful sounds.
Interesting observation after reinstalling the DSC module back, I did one more run on the same road. Wow what a difference most of the noises if not all are gone and could not feel the harsher impacts, even when I selected the stiffer shock setting. GT4 felt like it was running on air suspension. Not sure why the DSC module is able to do that and not sure if it would even save the shock tower in a harsher wheel impact but at least it makes the GT4 sound & feel normal again, even if it is a false sense of security! Mark
Catching up here guys- I've been distracted by other things but a friend sent me a link to this thread.
Clearly there are a number of things going on here, but one point (and warning) jumps out at me.
Let me first say that this is educated guesswork- I don't have full suspension data from a GT4. That said: Porsche has been removing jounce (bump) travel from their cars steadily for a number of generations. A stock 997 Carrera has about 50mm of total travel up front before the spring rate goes off the chart (bump rubber completely squashed, chassis starts trying to flex). In the 991 they decreased bump travel to about 40mm. In sports suspension cars (that keep the shocks with shorter springs) travel is roughly that much less, so out of the box even the non-GT cars are running very, very low bump travel numbers. For comparison 3"-4" or 75 to 100 mm of bump travel was once the industry rule of thumb.
Now consider that the 30mm or so remaining plus your tire sidewall is all the space you have to effectively stop a "crash". Because once the suspension bottoms that's what you have, at which point the only question is "what breaks"? Does the chassis twist, the wheel bend, the strut to fail, etc.
My strong suspicion is that the GT4 is on the low end of Porsche's travel range, which means lowering it further could have serious unintended consequences of exactly the type we are seeing here. Pull out 10mm of ride height and you might unwittingly quadruple or more the severity of an impact.
My concern is that in order to dial in competition levels of camber we're doing exactly this, and given the clear lack of design margin it will lead to catastrophic failures. Ride height is almost certainly a far bigger variable than any part to part variation in casting or design factor of safety built in.
As I said this is only a suspicion currently, but it's a very strong one. We'd want to get suspension travel data (ideally from a K&C machine) and camber vs ride height numbers to confirm this...
$.02
Hey Pete,
Excellent post, and welcome back!
Almost certainly a contributing factor, and 20-inch wheels and tires probably don't help. On the other hand, the failure mode and $$,$$$ repair cost seen in multiple and nearly new GT4s is alarming after 50+ years of thousands of people lowering Porsches and putting hundreds of thousands of hard miles on their cars without widespread steel tower failures, no? Those cars had the same challenge as outlined above. I've got one that's 44 years old with 250,000 miles on its chassis—with most of those miles logged at a very low ride height—and its steel strut towers look perfect and the car drives very right.
12-21-2016, 04:18 PM
