Alan C.

Again, compared to the GT3 engine problems I can live with the GT4 issues. I don't regret the switch.

jphughan

Nah, I wouldn't be willing to let GT4 money sit tied up in a bubble wrapped car; I'd sooner sell it to buy something else that will give me some actual enjoyment for my cash. But I didn't stop driving my E92 M3 as a result of the Great Rod Bearing Scare, so I don't intend to change how I drive the GT4 as a result of these issues. I also have a 2015 production GT4, which so far at least has not had a report of a gearbox problem. At least that issue is being covered under warranty, although I definitely sympathize with owners who are having to wait forever to actually GET the replacement gearbox, especially since thus far there's no reason to believe that the replacement will last any longer. Sigh....

okie981

The 3rd gear problem doesn't concern me much at all, other than it's a major PITA to wait on the replacement gearbox and the shop work, and not knowing when the solid fix will be in replacement gearboxes and which cars will never need them.

Phil T

Oh no.....not the ghost of the rod bearings. I'm with you......I drove my E92 as if I had never heard of rod bearing failure (and that was damn near impossible). I intend to do the same with my GT4 unless these cases really start to show up with no clear cut explanation.........Phil

Track Junkie

Technology Porsche should use to help reduce this issue on all of their vehicles.

Pothole Detection available now on the $33,000 2017 Ford Fusion Sport.
Technology that can detect potholes and adjusts the active suspension damping to the affected shock that keeps the tire and wheel from dropping as deeply into the pothole.

https://www.youtube.com/watch?v=YK3U...ature=youtu.be

Window Cleaner

I think with the tower failing it saves damage to the rest of the chassis, if it didn't give, it would probably twist or break something more costly

jphughan

If that were true, I would expect this failure mode to be better known from experience with other cars, but it seems that what normally happens is the wheel absorbs the brunt of the impact to avoid passing it up into the chassis (or perhaps it DOES get passed up into the chassis and everything up there is just strong enough not to give). But yes I suppose if this area were reinforced and nothing else were changed, then theoretically something even more expensive would be damaged/broken, but even that doesn't address the issue that even if the strut tower were designed to be the sacrificial component, it shouldn't be failing under the circumstances that the ones in these cars have been.

Track Junkie

What are the circumstances?
Pothole depth, car speed, braking, angle of impact, tire pressure, modifications, etc. I haven't seen the specifics.
I don't think any similar aluminum chassis sports car made now can survive all potholes regardless of pothole size or vehicle speed.

Track Junkie

An interesting pothole impact study.
https://www.3ds.com/fileadmin/PRODUC...-impact-16.pdf

okie981

We do not know yet that just hitting a "pothole" will cause this failure. Joe Weinstein's failure on public roads at highway speeds after hitting a "small dip" in the road does not indicate these shock towers fail after one such event. Joe's car may have experienced a severe impact before he took delivery of the car. Cars experience all kinds of damage during factory-to-dealer transportation, so who knows? We simply just don't have enough information at this time to jump to the conclusion that a single pothole impact causes this failure on GT4 (or GT3 ) cars. Interesting study on potholes, yes, but that doesn't necessarily transfer as something that analyzes the issue we're seeing on some of the 981 (or 991) cars.

Think about it. How many 981 and 991 GT cars with the same camber plate and shock/strut have hit bumps, potholes, racetrack berms, etc., and never so much as missed a beat, with no shock tower rupture.

stout

I find this unlikely.

It's hard to imagine a repair more costly than a $25,000 or $30,000 structural replacement with collateral damage. The only thing worse would be irreparable damage to the structure, which this repair is dangerously close to due to associated costs. The repair would easily total a used 981 Cayman or Cayman S.

The road wheel should be first line in a line of sacrificial metal, followed by a suspension arm or the like—in other words, things that bolt to the car's structure.

A long line of Porsches and other automobiles sets a precedent that makes the failure seen in these GT4s hard to swallow. These cars probably aren't being used any harder out of the box than 996 and 997 GT2/GT3s were—and they should certainly fare better than 30-50yo Porsches being used on track and for autocross.

It's important to remember the we are still seeing only tiny numbers of these failures in terms of percentages. However, they are nevertheless alarming due to their nature, repair cost, and frequency within a short period of time in essentially new cars.

Joe Weinstein

I'm guessing it could be a quality control problem with the aluminum casting, occasionally putting one out with porosity etc.

4carl

What they have done is reduce the suspension travel by lowering the car. So now it bottoms out quicker and what it hits is a brittle piece of thin, inherently brittle cast aluminum They need to redesign the shock giving it more travel before it bottoms out . Its that simple. carl

okie981

Interesting theory, and it has some merit, but if that were it, that straightforward, I'd think we'd be seeing lots more of these ruptured shock towers.

Joe Weinstein

And if they'd approve a kit to allow a decent range of alignment so I could
get an honest 2.5 degrees of negative camber without lowering the car from
as-delivered ride height, I might have never had this happen.