okie981

That's a great question. Even if you include the 991 cars and the one I found on the Pistonheads forum, and those that had a severe crash-like impact are included, i think the total reported is around 5. But I have not done an exhaustive search and count, so caveat with that.

I had written off the other failures months ago as crash damage. But when Joe Weinstein reported his occurring while driving on public roads, I can't write it off any longer, at least not until we understand what caused Joe's to fail.

There's always the possibility that Joe's car suffered a suspension whack before it was delivered to him. There is just too much we don't know right now to make any conclusions.

Buteo

Agreed.

I feel like we all are searching for issues with this car. Some concerns are definitely warrantied (3rd gear issues) but im not completely sold on this strut problem. In fact, statsicially speaking I'm sure with all the cars (991/981/Gt3/4) with issues (say 5 or 10) I'm sure they would be viewed as outliers.

But with that said, I'm going to avoid pot holes!

stout

Good perspective above.

The nature (and consequences) of this failure make it one to take seriously, especially since we didn't see this failure in previous Porsches using steel strut towers. With that said, there are a lot of GT4s without this problem, and a looooooot of 981s and 991s without the issue. It may be a GT4 thing. It may be a 981/991 thing. It may be user error in some cases. It may be a bad batch of strut towers that will only affect a small group of cars. It may be a combination of all of the above, or none of the above. It may be a time bomb.

It's too early to know—but it's good to do what we can to find out more and maybe help prevent future failures at speed. Hopefully, this thread can become an "unsticky."

Track Junkie

It will be very difficult to determine what is actually causing this issue.
Drivers are likely to deny knowledge of what happened since that could exclude warranty coverage and become a very expensive insurance claim.
Since drivers are not going to admit hitting anything, we may never find out what actually caused the failure, at least until the warranty is over.

4carl

The GT4 doesnt have what they call the extra"spring" #6 on the PET (bump stop)that the 981 does. See post #62..I think what happens is the shock bottoms out and cracks the tower. There is less free travel on the GT4 because of the lower ride height. Thats probably why no bump stop. If you ever put shorter springs on a car they always tell you to cut the bump stop. carl

Yargk

delete

okie981

If it's true there's no additional spring, a.k.a. snubber, on the GT4, then by taking the PET at face value, neither does the GT3. I have to think there's some type of snubber on the GT cars but without seeing all the parts disassembled, I can't tell for sure.

Even so that would still leave potential differences in spring and damping rates as differences between GT3 and GT4 cars, as far as potential contributors to increased shock tower stress.

stout

Also different weight distribution and considerably different mid/rear body structure. 981 coupe has a much smaller passenger cavity between its A- and C- pillars vs 991 coupe.

4carl

They all my be factors. My gut is the GT3 has a stiffer front spring. The stiffer the less the chance to bottom . A simple bump stop may be all thats needed to reduce the chance for the tower breaking if the shock bottoms out. The cast aluminum tower is very brittle not a great thing for absorbing sharp un-dampened impacts

May not totally eliminate it but would probably greatly reduce it. So in a situation like Joe's it wouldn't have failed?? carl

okie981

Yes, all good points.

Joe Weinstein

I am going to have to react to this... This is like saying "Yes, the entire passenger compartment has collapsed, but we'll never know what the cause is, because there is no other damage to the chassis or fender or even the bumper, so if the driver had survived, he might have denied hitting anything so he didn't have to pay his insurance deductible."

I will gladly deduct or pay whatever the equivalent to what would have been my deductible and any possible rate increases and more, for this incident in exchange for a repair that removes the possibility of this casting being a brittle first failure.

I am surprised to hear that our car has no bump stops on the shocks. If there was one, even a sacrificial one-use crushable one to absorb one beyond-expected impact, there would simultaneously be a tell-tale and a protective crush zone for the core chassis of the vehicle. Maybe even wire it so the dash lights up if it's been crushed.

Joe

MVEED3

I've trimmed internal bump stop on inversely-mounted monotubes. I've never come across internal bump stops on a twin. Does anyone know if the GT4 comes with mono or twin tube struts?

I'd like to believe I can keep tracking this car safely. It seems the only preventatives we can do for now are to:

1. Avoid suspect (and especially known) killer berms. Failure locations would help here.
2. Increase mating surface area of strut mount (aftermarket plate or mount).
3. Increase front spring rates without sacrificing bump travel.
4. Routine strut tower inspection.
5. Become intimate with checking ride height in a controlled setting that yields repeatable tolerance. Measure at similar conditions. Monitor ride heights for any unknown drop.

JPR

How has the factory responded to the owners who have had these failures? I don't know to what extent they can bring it back to factory condition.

Jpr

okie981

Hopefully Joe Weinstein will have a report for how Porsche responds and it will be positive news. Not aware of any other "factory" responses so far. Someone earlier on this thread reported crash damage that was repaired back to like new, indistinguishable from before the damage, but at a reported cost of $30k.

Joe Weinstein

I can only give a minor update for now. PNA is sending an expert to examine the car to decide about the warranty claim, but needs two weeks or so to get someone here. In the meantime, it sits at the approved body shop, taking up rack space for the poor owner who has been instructed not to touch it till then. I visited to bring him my battery charger for it so the battery is not degraded while we wait.