GT4 strut top failure - Page 3 - Boxster/Cayman - PistonHeads UK

Picture from social media. Apparently on track and kerb hopping!!!!!!! Not that we would ever do that obviously . More info please

is that for real ?

Flippin eck. God only knows how the race car will cope, if that's a road car.

The race cars will be seam welded and strengthened with roll cages and box sections I would have thought so that won't be a weak area. There had to be a fault there though for it to give like that.

Evolved said: The race cars will be seam welded and strengthened with roll cages and box sections I would have thought so that won't be a weak area. I doubt it, the section of the bodyshell that has failed is formed from what looks to be an aluminium casting or forging that has possibly failed due to a forging/casting or adhesion/bonding fault. http://european-aluminium.eu/media/1543/1_aam_body... (page 79) The race car rollcage has a tubular section which protrudes through the front bulkhead to the strut top/inner flitch to provide some additional (maybe much needed...) strength and support. But no obvious seam welding or additional box sections. Edit to add, the strut top mount on the GT4 clubsport race car looks to be a bespoke (991 Cup car ? ) mount too. Edited by Slippydiff on Thursday 11th August 00:01

The biggest load points on the chassis are the front suspension turrets. The designers aim will be to prevent the loads from translating themselves through the chassis causing twisting or bending. This would prevent the cars suspension from functioning correctly and the chassis would effectively become a giant torsion bar. The cage extensions to the turrets in the race version of the Cayman are located to counter the additional torsional loads created by slicks and the much stiffer suspension fitted to the car. A flexible chassis is one thing but a turret failure is something far more serious. I have never seen a turret fail like this before. I would see this as more worrying than the engine failures associated with the 991GT3 as the implications are far greater. Very odd given the loads that the turrets are designed to endure and the structural significance of that area of the chassis. The Caynan and especially the GT4 has a particularIy stiff chassis which makes this event even more unusual. I suspect there is a hidden story behind this event. Hopefully Porsche will give the market some comfort by explaining it.

That race car picture shows a black strengthening plate mounted over the top of the original strut? I wonder if that could be a mod fitted to the road car. A serious issue for sure and a weak spot recognised by the factory judging by the change to the race cars.

Is it really about chassis or suspension? I remember reading somewhere, a tiny discussion about GT4 and 911's rear suspension difference. (GT4's completely new)

A strengthening plate would be welded not bolted if it were a real issue. The problem is most certainly chassis. The chassis should hold together even with the stiffest of spring/shock combinations. It will probably flex a fair bit but it should hold together. The GT4 has bushes and is not rose jointed which will absorb a fair bit of load and prevent it from passing up to the turret. Very odd failure.

Ha! True.

What is the actual material on that area? Specs say "Intelligent lightweight construction with aluminum-steel composite" Would be nice to see a cross-section of the chassis only, checking the surface and thickness. (Have not seen before, apologies if its too ignorant) Responding my own question , I guess the affected area is the green ? - "mikrolegierte stähle"- (If GT4 also shares the same material of 981 body as this illustration below?) Edited by ooid on Thursday 11th August 21:59

The area that's failed is blue (aluminium). It looks to be a cast or forged part as the underside of the turret has strengthening webs and is a thicker section than the surrounding metalwork.

It would be interesting to see what state the wheel and tyre are in on this car

This happened to Jari-Matti Latvala in Rally Argentina. http://www.wrc.com/en/wrc/news/april-2016/latvala-... But he was going very fast (for a rally car) and hit a massive rock, which gives you an idea of the forces involved. If this happened on track, there would have to be something seriously wrong with the design.

Excuse my ignorance, but how would they go about repairing damage like that?

It looks like a catastrophic fatigue failure to me. I'd be amazed if the strut mount was cast, but I agree the ribs underneath would suggest that. Failure mode is similar to bending and straightening a spoon. Do it enough times and it'll break as microscopic cracks propagate. Presumably on this car the kerb fatigued the part beyond its elastic limit until it failed. All speculation of course, but perhaps indicative of the risks of cutting edge materials and manufacture (over good old pressed steel).

What is the full story behind failure? Was it an accident? It just seems a bit random as the gt4 chassis is mainly the same as any 981 which have been built for 4 years and of which a few have seen track action over years especially across the pond yet this is the first case to hit the net!

FrankCayman said: Excuse my ignorance, but how would they go about repairing damage like that? I am curious too. They could cut it out and weld a good dome in (not sure how comfortable I would be with that?) or reshell the whole car. Yikes.

EricE said: FrankCayman said: Excuse my ignorance, but how would they go about repairing damage like that? I am curious too. They could cut it out and weld a good dome in (not sure how comfortable I would be with that?) or reshell the whole car. Yikes. I would imagine they would replace the complete inner wing which of course incorporates the strut tower.

Hi the strut support is shown as a separate part for £222.00. I would want Porsche to explain why this cant take the load, as some of the potholes are huge. Chris

Interesting to see who ends up paying for that...

Trev450 said: I would imagine they would replace the complete inner wing which of course incorporates the strut tower. ^ This.

Further details in this rennlist thread http://rennlist.com/forums/gt4/948382-strut-tower-...

gtsralph said: Further details in this rennlist thread http://rennlist.com/forums/gt4/948382-strut-tower-... Thanks for the link that is what I was hoping for. Clearly an issue for sustained track use. memo to brain avoid the big kerbs

GT3 does it also on the road after hitting a curb !

Porsche911R said: GT3 does it also on the road after hitting a curb ! Is that a 991 GT3?

Its not the first http://rennlist.com/forums/gt4/925084-first-salvag...

Curbs like these at Rockingham are best avoided....

A car designed for occasional track use should be easily able to handle rumble strips. I suspect that these failures were caused by substantial impacts.

It's an issue that should not happen whatever the impact. I would expect wheels and suspension arms to bend or break but never the top mount. Very worrying from a longevity standpoint.

Inclined to agree. I'd expect to see a wheel failure before a chasis failure. I've seen some very big accidents with 996 and 997 race cars but never seen the chasis break at a load point through an impact. Sometimes a wishbone can punch through a pick up point but if its a race car, the spherical joint normally collapses and takes energy from the impact first. I drove for a racing car manufacturer at the start of my racing career, he was a brilliant designer and taught me a lot about chassis design and the theory behind it. The load point of the front suspension are 'the' critical points of the design. They transfer loads backwards into the space frame or monocoque where they would disperse with the minimum of flex or disortion. Obviously in these cases the load/shock has not been successfully transferred backwards into the chasis resulting in the failure of the load point.

This ^. In a previous life, I spent a good bit of time attempting to master the art of forest rallying in a MK11 Escort. I blew front struts, bent front struts, broke TCA's, etc, but never did I see this sort of failure on anything both at club and international level.

I heard the vehicle in question has been sent to Struggart for further analysis

gbrown2014 said: I heard the vehicle in question has been sent to Struggart for further analysis Only one, or all three that have been pictured in this thread? ETA d'oh missed the (miss-spelt) Strutgart! Edited by AW111 on Monday 15th August 14:35

Steve Rance said: A car designed for occasional track use should be easily able to handle rumble strips. I suspect that these failures were caused by substantial impacts. Beyond the rumble strips... Is the elephant truck curb

I could be wrong but I am pretty certain that the strut top failures are because Porsche are using aluminium. Steel would not do this.

According to the link above, the part labeled "11" is failing . Coming from a completely different design/engineer background, I would be curious to know why is that part failing from the racing/engineer experts? Geometry? material? both The white Cayman accident image also shows, there is a very strange bonding agent on the edge of the struts? (might be image accuracy or my lack of visual knowledge in the area)

Trev450 said: This ^. In a previous life, I spent a good bit of time attempting to master the art of forest rallying in a MK11 Escort. I blew front struts, bent front struts, broke TCA's, etc, but never did I see this sort of failure on anything both at club and international level. As you'll know all too well, the rally prep boys don't p*ss about when they do shell prep, they build the cars properly to withstand massive jumps, ruts, potholes etc. My old S5 Impreza WRC after an expensive altercation with a bridge parapet on Mull (the chassis leg was bent up nearly 3") : |http://thumbsnap.com/1RBROmOq[/url] Bulkhead split : It cracked the alloy strut top mount, but it remained in it's correct position (ie didn't punch through the bonnet) Strut seen here with new replacement top mount plate and strut casing. Repairs underway : Note the new turret top is formed from 10mm thick steel blank Tig'd in place .... And the finished job : There was some nice/clever fabbing work on those first Impreza WRC cars, but fast forward 5-6 years and the game had well and truly moved on : But a rally cars has to do things that racecars couldn't even contemplate, and everyone knows rallying sorts the men from the boys ....

Wow that was some impact. Superb rebuild job though.

The issue Paul is the use of aluminium within the construction of the car. The only thing on my Hellcat that is aluminium is the bonnet. That I can live with. Aluminium cars do not crash well

Porsche seem to be making road cars you can't track hard When did this new turn around occur Utter sh te that seems to be bad engineering, a shoddy design that they engineer out if you pay considerably more for a racing model Awful Used to be that you could track your road car. It's how they sold them in the US Edited by stuttgartmetal on Friday 2nd September 09:03

Any further update on this failure? Just seen one of the you tubers with a yellow GT4 has experienced the same issue

ratty6464 said: Any further update on this failure? Just seen one of the you tubers with a yellow GT4 has experienced the same issue Just watched that video. 5k miles on the clock and 3rd gear, clutch then strut top failure!

Link: https://www.youtube.com/watch?v=O_HyXLsdOw0

Mad Scientist said: I’m sure they will be watching his kerb hopping over zealous recent track footage with interest. Including the trip into the litter. Whilst I’ve not seen that footage you allude to, one needs to remember this is a car that should be equally at home on track as it is the road (and some would say that’s precisely what it was designed for) Plenty of Porsche GT cars end up in the kitty litter and go on to leave normal healthy lives. I tend to think that when a company such as Porsche builds a car such as the GT4, it should be able to take some kerb hopping action in its stride without the front suspension top mounts punching through the turrets... Edit to add, I’ve watched a few minutes of the video you alluded to, if a BMW 4 door saloon can withstand the rigours of some sprightly track action, a purpose built car such as the GT4 should be able to also, especially when it’s publicity video shows it’s well known chief test driver doing just that. https://m.youtube.com/watch?v=_F91GMna_c0 Edited by Slippydiff on Friday 15th February 09:18

Link to previous track action before the strut failure: https://www.youtube.com/watch?v=z_WpLON3VSk Apart from a fast off into the kitty, nothing particularly out of the ordinary when track driving imo. Edited by boxsey on Friday 15th February 10:17

One at copart as well.....

No way should the owner have to remove any videos. Obvious design fault that needs sorting. Not as if Porsche told buyers that track use was not advised...:-) quite the opposite.

Ran plenty of brrrrr kerbs in the two race Cayman GT4 and neither ever did that! Edited by 88racing on Saturday 16th February 22:16

Wilmslowboy said: One at copart as well..... Is this another recent failure or was it a while ago?

Hello, link to video, outcome should be interesting...! https://www.youtube.com/watch?v=O_HyXLsdOw0

Holy s t. Shall I be concerned for my 981 CGTS x73? I guess high mileage and non GT4s value is going to be affected? Definitely Porsche should provide full repair and courtesy car. I wouldn’t be in Porsche Body Structure Chief Engineer job right now. That’s very sad...

WORRALL. said: Is this another recent failure or was it a while ago? Not sure when it failed (it was taxed until Dec 2018), the car is currently for sale at the link below (not corpart, the other site) https://auctions.car-transplants.co.uk/vehicle-lis...

Has any of the owners complained this to DVSA yet in the last 2 years or any proper investigation yet? Obviously, this is a pure design issue and Porsche A.G. allowing these cars with this defect is not road-safe. I would not want to be around one of these while cruising around 70mph on busy m25!

Olivera said: ratty6464 said: Any further update on this failure? Just seen one of the you tubers with a yellow GT4 has experienced the same issue Just watched that video. 5k miles on the clock and 3rd gear, clutch then strut top failure! Having seen that recent video. My buying lust for a GT4 is officially...now over!!! Great shame, but I just couldn't fathom the thought of a failure like that, especially when loading up the car whilst cornering. Tyres and structural integrity are paramount to being confident, when utilising the performance of a car like that.

Would insurance cover this? It is not an accident. The Black car advert attributes the damage to "a pothole" which seems more likely than curb hopping. Does the Clubsport have the same construction?

gtsralph said: Would insurance cover this? It is not an accident. The Black car advert attributes the damage to "a pothole" which seems more likely than curb hopping. Does the Clubsport have the same construction? You’d think an insurance company would say “manufacturing defect” ? Especially with a quick google search. Maybe not, I am guessing very policy specific.

Over seventy days on track in my very early build GT4, which is now fitted with slightly stiffer springs and reworked Bilstien Dampers, no issues to report. Having seen the first photographs of a strut top failure some two and a bit years ago I concluded I’d make a real effort to tidy up my track driving and avoid putting high stresses through the chassis by absolutely avoiding damaging curbs - its a worthwhile discipline to adopt from every aspect !

gtsralph said: Does the Clubsport have the same construction? Believe the Clubsport also has some additional caps - but these do not protect against this happening. Its something that can happen to any car... but it does appear to be a venerable part of the 9x1. This issue has also affected GT3's. It just we don't hear about as many of those. According to RL - Strut Top failure is unheard of in Germany...and Manthey, which looks after the race car have not seen it either. So might be a bit of an echo chamber issue here. As Tim says - try stay off the aggressive curbs on track, and keep a keen eye out for potholes on our decaying UK roads.

LotusMike2 said: Hello, link to video, outcome should be interesting...! https://www.youtube.com/watch?v=O_HyXLsdOw0 Looks like Glasgow OPC. Potentially not painting themselves in glory.

It’s a nonesense Porsche not picking up the tab for this. For the relatively small cost (ie their actual cost) they could have a happy advocate in the owner and a whole heap of current and potential owners thinking warm fuzzy thoughts about them. Instead of that we have this and many other bad smell threads spread out all across the globe. Well done Porsche, how short sighted can you possibly be.. You can argue the toss all day long about how and why. Personally I think it’s so obviously unfit for purpose or a clear manufacturing defect for a car marketed as a track toy that to blame the owner, just because you can, is incredibly disingenuous. But, this is how these folks operate, for reasons known only to themselves.

ttdan said: It’s a nonesense Porsche not picking up the tab for this. For the relatively small cost (ie their actual cost) they could have a happy advocate in the owner and a whole heap of current and potential owners thinking warm fuzzy thoughts about them. Instead of that we have this and many other bad smell threads spread out all across the globe. Well done Porsche, how short sighted can you possibly be.. You can argue the toss all day long about how and why. Personally I think it’s so obviously unfit for purpose or a clear manufacturing defect for a car marketed as a track toy that to blame the owner, just because you can, is incredibly disingenuous. But, this is how these folks operate, for reasons known only to themselves. This ^ It just shouldn’t happen Steve. Period. The forging, stamping, casting or whatever it is, should NOT fail. Personally, and from a layman’s (ish) perspective, aluminium isn’t the right material for the job, or it needs reinforcing to ensure it doesn’t fail. Though one wonders if you strengthen the turret top, whether something in the chassis leg then fails. Maybe the turret top is “sacrificial”, but if it is, the whole chassis leg/glitch/turret is a poor design. That should read flitch, but glitch probably isn’t too far off the truth ... Let’s flip this on it’s head. If the front or rear subframes “occasionally” failed after a “heavy” impact/abuse, would that be in any way more acceptable ? Personally I’d say categorically not, both are critical components that should not fail under all but the heaviest impact (think huuuge accident). Edited by Slippydiff on Thursday 2nd May 20:53

Well it certainly won't stop me using my GT4 as intended. If this system is good enough for the highest performance GT cars --- it must be good enough for the GT4. Regarding failure rates, the cost of engineering zero failures in all circumstances would create a product that nobody could afford to buy .... over-engineering put Porsche into very deep water in the 3.2 to 964 era ... What is the inflation linked cost of a 964 in 1990 with the current cost of a 718 ? Then compare what they can each do ... performance / accommodation / economy / toys /

ChrisW. said: Well it certainly won't stop me using my GT4 as intended. If this system is good enough for the highest performance GT cars --- it must be good enough for the GT4. Regarding failure rates, the cost of engineering zero failures in all circumstances would create a product that nobody could afford to buy .... over-engineering put Porsche into very deep water in the 3.2 to 964 era ... What is the inflation linked cost of a 964 in 1990 with the current cost of a 718 ? Then compare what they can each do ... performance / accommodation / economy / toys / I’m not suggesting every component in every car they build should be engineered to be zero failure Chris, but body shells (and specifically a turret top) should not fail in this manner. Period. You’ll most likely be aware of BMW’s floor/rear subframe mount cracking issues ? Mine cracked on my CSL some 8-9 years and 60k miles into the car’s life. The car had a full BMW service history and a BMW AUC warranty. BMW sent their representative out to inspect the car at my local dealership. Having done so they sanctioned the replacement of the boot floor/rear subframe mounting points. This means the removal of the fuel tank and all the rear suspension and the interior trim in the rear of the car. The finished job was indistinguishable from original. That is the way manufacturers should address issues such as failed turrets. Neither you or I have owned a 996/997 variant with a chocolate engine, had you suffered engine failure such as many have, perhaps your views of Porsche would be less rose-tinted ??

You only need to do a quick Google to find plenty of pictures. Even GT4 cup cars are cracking, as well as 991 GT3's. Porsche have since upgraded the tower on the 992, so what does that tell you.

WOW! Can't think anyone can argue with that collection of images. We will never know what the circumstances were of each of these failures but the simple fact is that it is obviously an integral weakness in the bodyshell and if Porsche aren't accepting any responsibility as seems the case then I would be looking at preventative measures to remove (or reduce) the risk. I believe there are now options of chassis braces available which owners should be considering. Then the issue arises of OPC failing the car on a pre-warranty 111 point check as its modified......

chrisABP said: WOW! Can't think anyone can argue with that collection of images. We will never know what the circumstances were of each of these failures but the simple fact is that it is obviously an integral weakness in the bodyshell and if Porsche aren't accepting any responsibility as seems the case then I would be looking at preventative measures to remove (or reduce) the risk. I believe there are now options of chassis braces available which owners should be considering. Then the issue arises of OPC failing the car on a pre-warranty 111 point check as its modified...... You mean the chassis brace in pic 1? Which is also on a clubsport race car... I think a dye pen inspection of the strut towers should be part of the buying process.

To be fair, it looks like a lot of those images are from the same vehicles. In reference to the yellow GT4, whilst I do think it is a design fault and Porsche need to hold their hands up, I can understand Porsche not paying out or even contributing to the 10k bill. If they did, this would be an admission of fault and open the flood gates, even a contribution would blur the lines of responsibility and surely cause confusion with regards to insurance payouts.

Name that Porsche: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. Edited by jimPH on Friday 3rd May 10:47

RevsPerMinute said: To be fair, it looks like a lot of those images are from the same vehicles. In reference to the yellow GT4, whilst I do think it is a design fault and Porsche need to hold their hands up, I can understand Porsche not paying out or even contributing to the 10k bill. If they did, this would be an admission of fault and open the flood gates, even a contribution would blur the lines of responsibility and surely cause confusion with regards to insurance payouts. I've deleted 10 and 14, two duplicates. Ask the rest are seperate cars. I only searched for a few minutes, this isn't all of them. I'm sure you can find plenty more.

If the strut top part used is also used in the 911 GT and RSR models, why aren't there failures there too? Is it part of the production process?

jimPH said: chrisABP said: WOW! Can't think anyone can argue with that collection of images. We will never know what the circumstances were of each of these failures but the simple fact is that it is obviously an integral weakness in the bodyshell and if Porsche aren't accepting any responsibility as seems the case then I would be looking at preventative measures to remove (or reduce) the risk. I believe there are now options of chassis braces available which owners should be considering. Then the issue arises of OPC failing the car on a pre-warranty 111 point check as its modified...... You mean the chassis brace in pic 1? Which is also on a clubsport race car... I think a dye pen inspection of the strut towers should be part of the buying process. https://www.spmsracing.com/shop/strut-tower-support-bracket-for-gt4

chrisABP said: jimPH said: chrisABP said: WOW! Can't think anyone can argue with that collection of images. We will never know what the circumstances were of each of these failures but the simple fact is that it is obviously an integral weakness in the bodyshell and if Porsche aren't accepting any responsibility as seems the case then I would be looking at preventative measures to remove (or reduce) the risk. I believe there are now options of chassis braces available which owners should be considering. Then the issue arises of OPC failing the car on a pre-warranty 111 point check as its modified...... You mean the chassis brace in pic 1? Which is also on a clubsport race car... I think a dye pen inspection of the strut towers should be part of the buying process. https://www.spmsracing.com/shop/strut-tower-support-bracket-for-gt4 Yes it is then. Unfortunately it doesn't stop it breaking as you can see in pic 1.

TDT said: Porsche has clearly determined this as an acceptable risk vs the reward in performance benefits they have been able to make wrt profit margins, weight saving, dynamics. If we think about the total number of 9x1 architecture cars that have been produced vs the number of reported failures - this is still negligible and Porsche won't say anything about it, unless there is a major case - and maybe not even in that case dependant on the circumstances. Ideally you'd want Porsche to just underwrite these items and the repair in the case of a failure or provide a strengthening kit as has been mentioned above. I mean, are we really saying that all 9x1 cars are now untenable as a ownership proposition because of this? Absurd really. Yes......stop playing around and buy a Radical

JayK12 said: Yes......stop playing around and buy a Radical Lol - leave me alone!!

chrisABP said: https://www.spmsracing.com/shop/strut-tower-suppor... All this part does really is limit how much of the impact is transferred into bonnet damage? It braces against another part of the chassis - we then don't know want load is transferred elsewhere at that point. Something crucial to note....for these multi-material chassis - Porsche tolerance for chassis measurements is 2mm. So if there is an impact that transfers load to the chassis, and when they measure the chassis, if it is more that 2MM out then a new chassis is required. Big problem being that 981 chassis are not longer available.... so it's a write-off. https://youtu.be/yvnVSTTPvkY Translated German from the description: This video shows a modification of a Porsche Cayman GT4 body shell. The GT4 got a new body shell because he had a small accident on the racetrack. The body has warped by more than 2 mm, which exceeds the tolerance range of the manufacturer (2mm). Since the body is a multi material mix, the bodywork must not be straightened. So we had to build a new one. For the rear of the GT4, looks like Porsche actually added reinforcement cups/hats not sure why they don't just have a similar solution for the front.. if that is stamped steel Edited by TDT on Friday 3rd May 12:54

Point now taken Slippy ! I'd like to believe that my KW 3 way Clubsport dampers offer better handling in extremis because they do a better job of absorbing track undulations and kerbs. I also hope that there is so little weight on the inside wheel when I'm running a kerb that the impact is modest ... However. if chassis are no longer available I would be concerned about the cost of a significant track-day off ... this does make a very good case for always having track-day insurance ... As far as the mount supports are concerned, spreading the load should minimise the chance of failure and help to avoid significant collateral damage ... I must find out more ... Cx. P.S. I got involved in a McLaren gearbox failure where a leaking oil seal resulted in an £18k replacement gearbox on a 4000 mile 40 month old MP4-12C ... (that had been McLaren serviced three times) ... contrast that to the current GT4 gearbox replacements. Maybe P haven't had enough failures ? Or maybe they will propose a reinforcement (which I guess I will have to pay for due to my mods !) Edited by ChrisW. on Friday 3rd May 15:48

The legendary reliability of Porsche is slowly turning into a myth.. quite disappointing really.. - 997.1 and 987 boxster engine issues.. - 997 RS 4.0 engine issues - 991.1 GT3 flammable engine.. - A/C issues on pretty all models (including some of mine) Now the suspension strut issue on GT cars that looks MUCH more serious.. quite worrying trend.. might be b/c they produce exotica in larger numbers which means more chances to uncover design faults.. but tbh you don't hear these horror stories from Ferrari.. the worst being the F430 manifolds that could easily be cured.. disappointing..

rosino said: The legendary reliability of Porsche is slowly turning into a myth.. quite disappointing really.. - 997.1 and 987 boxster engine issues.. - 997 RS 4.0 engine issues - 991.1 GT3 flammable engine.. - A/C issues on pretty all models (including some of mine) Now the suspension strut issue on GT cars that looks MUCH more serious.. quite worrying trend.. might be b/c they produce exotica in larger numbers which means more chances to uncover design faults.. but tbh you don't hear these horror stories from Ferrari.. the worst being the F430 manifolds that could easily be cured.. disappointing.. buy a Cayman R with no AC,, job done, drives better than all the others you posed also ;-) 430 also kills front end ball joints etc and the manifold issue is only after marklet fixable so touchy subject come inspection time. as I said in the 992 Audi thread, 987.2 cars and 997.2 911's are the sweet spot not only for driving but for having little to no issues.

I see that PCA Club Racing have issued a notice allowing fitment of the strut reinforcement plates for GT4s It’s a pity the weakness in design is not acknowledged by Porsche themselves and of course these plates will only minimise damage caused by strut tower failure. Further comments on this post: https://rennlist.com/forums/gt4/948382-strut-tower...

Doesn't look like it's going away.. certainly puts me off buying along with the massive engine issues on GT3's.

gtsralph said: I see that PCA Club Racing have issued a notice allowing fitment of the strut reinforcement plates for GT4s It’s a pity the weakness in design is not acknowledged by Porsche themselves and of course these plates will only minimise damage caused by strut tower failure. Further comments on this post: https://rennlist.com/forums/gt4/948382-strut-tower... But this is only available for LHD cars ...

As these failures are likely to lead to total failure of the steering and brakes, hence leading to total loss of control of the vehicle on the road, these failures ought to be brought to the attention (in the UK) of the Driver and Vehicle Standards Agency (DVSA) for investigation by them. The same ought to be happening in the USA with their appropriate vehicle authority. Details of the postings on this site together with those on Rennlist should suffice to highlight the situation.

That's what I can't understand. Just how many failures does it need before they take action, on the front steering wheels no less.

Thread resurrection. Does anyone know if the new GT4 has the same strut tops or have Porsche re-engineered them?

Same structure I believe as the core shell is the same.

Twinfan said: Same structure I believe as the core shell is the same. Very reassuring - not! Must say I do wonder what the long term holds regarding these failures, it’s not beyond the pale to imagine metal fatigue as the cars age and hence more failures. But hey, I’m not a metallurgist!

For info the top strut supports are only available for LHD cars ... I guess for the Clubsort GT4 race series. As for top mounts .. they are the same for GT4 and GT3 cars ... the GT3 being both heavier and more performant than most GT4's ... Most have not failed ... it's gone very quiet on here, which I guess is good news !

ChrisW. said: For info the top strut supports are only available for LHD cars ... I guess for the Clubsort GT4 race series. As for top mounts .. they are the same for GT4 and GT3 cars ... the GT3 being both heavier and more performant than most GT4's ... Most have not failed ... it's gone very quiet on here, which I guess is good news ! Also, all the strut supports do is stop the strut going through the bonnet. They don't stop the failure. I believe basically all cases of this were down to kerb strikes at some point in the cars history weren't they? Like the yellow car in Scotland, someone highlighted he'd sent it heavily across a huge sausage kerb at Knockhill in one of the videos he'd posted a few months prior.

RacerMike said: Also, all the strut supports do is stop the strut going through the bonnet. They don't stop the failure. I believe basically all cases of this were down to kerb strikes at some point in the cars history weren't they? Like the yellow car in Scotland, someone highlighted he'd sent it heavily across a huge sausage kerb at Knockhill in one of the videos he'd posted a few months prior. I'd be interested in seeing this vid if anyone knows the location of the heavy kerb strike. If it's the kerb I'm thinking of the car will be unloaded (usually both kerbside wheels airborne) and pretty much every car that goes around Knocky will use at least part of this kerb. I wouldn't expect any structural damage from this on any car. Having not read this entire thread (I probably have seen most of it before) it seems that "kerb hopping" isn't acceptable with GT4's but I'm fairly sure any other car could handle it no problem. I'm not in any way anti GT4 as I'm currently shopping for one but this aspect of them has never sat easily with me, saying that I realise there will be plenty of track used GT4's that won't have this problem. Would the same happen on a heavy pot hole where you'd usually expect to get a burst tyre or bent wheel at most? Dunc.

I think the fact that we haven't seen more on this says that it really isn't an issue. The early cars are now 7 years old ....

RacerMike said: ChrisW. said: For info the top strut supports are only available for LHD cars ... I guess for the Clubsort GT4 race series. As for top mounts .. they are the same for GT4 and GT3 cars ... the GT3 being both heavier and more performant than most GT4's ... Most have not failed ... it's gone very quiet on here, which I guess is good news ! Also, all the strut supports do is stop the strut going through the bonnet. They don't stop the failure. I believe basically all cases of this were down to kerb strikes at some point in the cars history weren't they? Like the yellow car in Scotland, someone highlighted he'd sent it heavily across a huge sausage kerb at Knockhill in one of the videos he'd posted a few months prior. Sausage kerbs are designed to be driven over, they are driven over regularly and cars are not supposed to have terminal damage caused by them. They are there to keep cars within track limits. Porsche has designed in a major flaw to the structural strength of the chassis that cannot be undone. Poor design, nothing more.

Oilchange said: RacerMike said: ChrisW. said: For info the top strut supports are only available for LHD cars ... I guess for the Clubsort GT4 race series. As for top mounts .. they are the same for GT4 and GT3 cars ... the GT3 being both heavier and more performant than most GT4's ... Most have not failed ... it's gone very quiet on here, which I guess is good news ! Also, all the strut supports do is stop the strut going through the bonnet. They don't stop the failure. I believe basically all cases of this were down to kerb strikes at some point in the cars history weren't they? Like the yellow car in Scotland, someone highlighted he'd sent it heavily across a huge sausage kerb at Knockhill in one of the videos he'd posted a few months prior. Sausage kerbs are designed to be driven over, they are driven over regularly and cars are not supposed to have terminal damage caused by them. They are there to keep cars within track limits. Porsche has designed in a major flaw to the structural strength of the chassis that cannot be undone. Poor design, nothing more. The very rare cases of front strut tops failing only happened on GT4s which had been lowered. Basically the lowered car resulted in the damper running out of travel and nowhere to go except straight through the subframe supporting the strut tops. Will get my GT4 an alignment more suited for track use however will no lower it apart from it being lowered by adding negative camber.

Taffy66 said: The very rare cases of front strut tops failing only happened on GT4s which had been lowered. Basically the lowered car resulted in the damper running out of travel and nowhere to go except straight through the subframe supporting the strut tops. Will get my GT4 an alignment more suited for track use however will no lower it apart from it being lowered by adding negative camber. My 718 GT4 ex factory Axle Ride Heights were 113mm/134mm F/R and after CG alignment for track use were 102mm/125mm. No issues on clearance or kerbs, so far.....

gtsralph said: My 718 GT4 ex factory Axle Ride Heights were 113mm/134mm F/R and after CG alignment for track use were 102mm/125mm just to add some data to the discussion. No issues on clearance or kerbs, so far.....

Taffy66 said: The very rare cases of front strut tops failing only happened on GT4s which had been lowered. Basically the lowered car resulted in the damper running out of travel and nowhere to go except straight through the subframe supporting the strut tops. Will get my GT4 an alignment more suited for track use however will no lower it apart from it being lowered by adding negative camber. Correct, this is simply all there is to the subject. Not sure why it’s still a topic. 991.x GT3 and 3RS have the same vulnerability…

Sausage kerbs are designed to be driven over, they are driven over regularly and cars are not supposed to have terminal damage caused by them. They are there to keep cars within track limits. Porsche has designed in a major flaw to the structural strength of the chassis that cannot be undone. Poor design, nothing more. And what has the failure rate been ? Is this worth the argument ?

And what has the failure rate been ? Is this worth the argument ? [/quote] Well, it's interesting isn't it? Had Porsche made their brake discs out of cheese instead of metal/ceramic and heavy use had caused the cheese to melt on track, one could argue that it's only under extreme conditions etc and brushed this nonsense under the carpet. Everyone else wouldn't be having this most basic problem because, well, metal/ceramic. But Porsche have made an issue, an issue nobody else appears to suffer because of a most basic design flaw*. Might as well made the bloody strut tops from chocolate, at least you'd have a large chunk to nibble on while wondering how to fix it. The question is, was the flaw engineered in?

Engineering is a trade-off ... price / weight / normal use + (what percentage ?) / life / market-customer segmentation / What is the best-cheapest ? Often asked, but obviously impossible to answer ... my answer would be a Honda Jazz or Toyota Yaris ! If you want to pick up on something, the 981 GT4 was sold with fully adjustable suspension ... but this didn't stop front tyre shoulders wearing very badly on track unless the fully adjustable suspension was modified to adjust more ... designed in ? I think the fact that these turrets are the same on GT4 and GT3 would suggest that it was not designed to be a problem ... and in any event if it was it doesn't appear to have been much of a money spinner. Of note is that the Clubsport racing versions were only available for LHD cars and the turret supports (that only save the bonnet from damage) are only available for the LHD cars ... Edited by ChrisW. on Sunday 16th October 12:09

dunc_sx said: I'd be interested in seeing this vid if anyone knows the location of the heavy kerb strike. If it's the kerb I'm thinking of the car will be unloaded (usually both kerbside wheels airborne) and pretty much every car that goes around Knocky will use at least part of this kerb. I wouldn't expect any structural damage from this on any car. If that's the video I'm pretty sure it is, the video is no longer up. The video was uploaded by "Vehicle Villains" who decided to go to Wales for one of their videos and then post footage of them at 3 figure speeds on the public road. Not entirely surprisingly the Welsh police took issue with this and a court case resulted in them getting bans/fines. All their old content was taken down. I am pretty sure the video in question here was one of theirs when one had a GT4. That car also left the track at Knockhill and went through a gravel trap. Apologies for the "mail" link. https://www.dailymail.co.uk/news/article-10297105/...

PaulD86 said: If that's the video I'm pretty sure it is, the video is no longer up. The video was uploaded by "Vehicle Villains" who decided to go to Wales for one of their videos and then post footage of them at 3 figure speeds on the public road. Not entirely surprisingly the Welsh police took issue with this and a court case resulted in them getting bans/fines. All their old content was taken down. I am pretty sure the video in question here was one of theirs when one had a GT4. That car also left the track at Knockhill and went through a gravel trap. I recall all their videos, including the Knockhill ones, and I don't recall the owner ever hitting a kerb in one. Yes he ended up in the gravel after overcooking a corner, but again nothing that would damage the suspension.

Yes you can lower it, of course you can, and I'm sure the odd pot hole has caused a bump stop to be used. What folks are saying is that if you lower the car and then clatter it over sausage kerbs you're going over and above what the car was designed to do so it's no surprise parts break.

Manthey lower the car as part of their tweaks..

Yes, the car comes with height adjustable coil overs…. Porsche have a recommend range of adjustment for heights…. The PRIMARY reason is to allow for corner weight balancing. There are also some other side benefits of roll center control that come from moving the car down a little within the recommended range, front-rear. Upon investigation…Most of these strut tower issues have occurred with a combination of the car being outside of these parameters AND the car being run into a high kerbing or road defect, or object at speed. They don’t just randomly explode whilst driving down the street. If you lower the car excessively … then you are reducing the operating range of the spring and damper…. So will hit that bump stop quicker. If you are running so low, as to effectively be riding on the bump stops… you have no suspension and no capacity to absorb bumps or lumps. Of course… you can have this issue even if you are at the top of the recommended range and hit something too big, too quickly. That shock will be dissipated somewhere….. It’s called physics. Take responsibility for your actions, your driving and your car… keep the vision up, and drive according to the conditions and your ability. Edited by TDT on Wednesday 19th October 08:59

MannyLon said: Manthey lower the car as part of their tweaks.. Which is fine until you start driving over big kerbs. It's the combination of the two, not the lowering alone.

Manthey will operate, and potentially lower the car, within the recommended ranges.., particularly for N’ring set up, and allowing you to take those kerbs, if driven properly… so would not expect any issue there. As aforementioned …their primary reason for height adjustment is corner-weight balancing.

It's curious that people lower all manner of cars on cheap coilovers, run over potholes and kerbs, for years and years on end, yet the damper punching through the strut top is pretty much unheard of. It's clear to me that this is either a design or manufacturing defect.

Olivera said: It's curious that people lower all manner of cars on cheap coilovers, run over potholes and kerbs, for years and years on end, yet the damper punching through the strut top is pretty much unheard of. It's clear to me that this is either a design or manufacturing defect. Maybe you more know than Porsche do… give them a call! For this generation of 911 and Cayman/Boxster, this approach was taken for weight saving… and also for increasingly stringent safety standards… the materials have been chosen to absorb and dissipate energy away from the passenger compartment. Other cars will take that energy and have it unloaded out through other components and/or put it into the passenger compartments or into the passengers. Strategic fail-safe of these parts particularly the front end also allows for a pretty ‘easy’ repair, and allow the passenger compartment body structure to be unimpaired. The parts are just bonded and riveted in, without having to make cuts or welding which is tricky when working with a multi-material body, from a chemical reaction pov.

TDT said: Strategic fail-safe of these parts particularly the front end also allows for a pretty ‘easy’ repair, and allow the passenger compartment body structure to be unimpaired. The parts are just bonded and riveted in, without having to make cuts or welding which is tricky when working with a multi-material body, from a chemical reaction pov. Hi TDT, Thanks for your input, it's good to hear it's a fairly cheap easy repair. That certainly puts my mind at rest to some extent when considering a purchase. Cheers, Dunc.

I say easy…. Lol…. I didn’t say cheap! Lol It’s easy for a Porsche centre, as they are supported by a fully documented process and repair strategy.

As usual great insight and extremely knowledgable input from our resident expert TDT which dispels the internet folklore some like to spout about this non issue.

Ha! I’m not an expert, but I have looked into this subject a lot, and I just have an issue with myths being endlessly repeated in the echo chamber, particularly when absent of context.