strut tower failure
11-06-2019, 02:53 AM
#1156
11-06-2019, 08:47 AM
#1157
Rennlist Member
FWIW... I got rid of the helper springs, which allowed for longer linear springs (higher rate as well) which allows for more "work" to be done by the springs in reducing the possibility of bottoming out.
I have no data to suggest that this is effective, but my knowledge of suspensions, along with some bench talking with people waaay more knowledgeable that me on the topic, gives me some sense (imagined or not) of security.
YRMV...
I have no data to suggest that this is effective, but my knowledge of suspensions, along with some bench talking with people waaay more knowledgeable that me on the topic, gives me some sense (imagined or not) of security.
YRMV...
11-06-2019, 09:07 AM
#1158
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Thanks for that. Go Tarheels BTW. So what I find hard to believe is that aside from hitting something, the struts compress all the way even during hard use. My Cayman R never bottomed out. My 981 Spyder never bottomed out. The GT4 is stiffer in suspension than those 2 which are roughly the same weight, with the main difference being PASM in that it takes away the mechanical nature of the suspension by trying to fight compression based on its programming. Every time you travel over a crack in the road you can feel the lack of compression, and rebound which is strong. Just every day driving is a lot more force onto the chassis than X73 equipped stablemates. Does the helper spring somehow reduce travel making for an abrupt stop? That's the only other variable I can think of.
My theory is that the GT4 is so lowered in the front that it is blowing through all the travel and bottoming out and is doing so often. But I don't have one so there's no way for me to know. Someone who does have one *could* install some shock travel sensors and a data logger to see, but that's certainly an awful lot of work, not to mention requires some expensive sensors. Would be rare for someone driving around on a totally stock car to have access to that kind of thing already.
The other possibility I can think of is PASM. If there are bugs specific to some car models (assuming there is different software on different car models) *and* assuming the shock is capable of going to some near-infinite damping (I doubt it is, but maybe), then it could just be that the shock is going into that mode of operation (ie. super-stiff) at bad times (near bumps) and thus isn't bottoming out but is effectively putting the same stresses into the tower as if it were. I'm not sure that's even fundamentally possible on the hardware side, and if it WERE possible that's the ONLY situation I could see Porsche being able and willing to issue a fix for this. But if that were the cause, I'd bet they would have issues a fix already.
--Donnie
11-06-2019, 09:35 AM
#1159
Rennlist Member
Changing PASM coding, using stiffer springs, using lighter wheels and rotors, all good options.
I would like to see Porsche design and retrofit steel inner cups to the front strut towers, like is already done at the rear.
This would spread the load over a greater area and overcome the porosity limitations of the non pressure cast towers, for comparison the C8 uses pressure cast.
I would like to see Porsche design and retrofit steel inner cups to the front strut towers, like is already done at the rear.
This would spread the load over a greater area and overcome the porosity limitations of the non pressure cast towers, for comparison the C8 uses pressure cast.
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911F1 (11-06-2019)
11-06-2019, 04:08 PM
#1161
Rennlist Member
I have no experience with helper springs, so I can't personally speak to that.
My theory is that the GT4 is so lowered in the front that it is blowing through all the travel and bottoming out and is doing so often. But I don't have one so there's no way for me to know. Someone who does have one *could* install some shock travel sensors and a data logger to see, but that's certainly an awful lot of work, not to mention requires some expensive sensors. Would be rare for someone driving around on a totally stock car to have access to that kind of thing already.
The other possibility I can think of is PASM. If there are bugs specific to some car models (assuming there is different software on different car models) *and* assuming the shock is capable of going to some near-infinite damping (I doubt it is, but maybe), then it could just be that the shock is going into that mode of operation (ie. super-stiff) at bad times (near bumps) and thus isn't bottoming out but is effectively putting the same stresses into the tower as if it were. I'm not sure that's even fundamentally possible on the hardware side, and if it WERE possible that's the ONLY situation I could see Porsche being able and willing to issue a fix for this. But if that were the cause, I'd bet they would have issues a fix already.
--Donnie
My theory is that the GT4 is so lowered in the front that it is blowing through all the travel and bottoming out and is doing so often. But I don't have one so there's no way for me to know. Someone who does have one *could* install some shock travel sensors and a data logger to see, but that's certainly an awful lot of work, not to mention requires some expensive sensors. Would be rare for someone driving around on a totally stock car to have access to that kind of thing already.
The other possibility I can think of is PASM. If there are bugs specific to some car models (assuming there is different software on different car models) *and* assuming the shock is capable of going to some near-infinite damping (I doubt it is, but maybe), then it could just be that the shock is going into that mode of operation (ie. super-stiff) at bad times (near bumps) and thus isn't bottoming out but is effectively putting the same stresses into the tower as if it were. I'm not sure that's even fundamentally possible on the hardware side, and if it WERE possible that's the ONLY situation I could see Porsche being able and willing to issue a fix for this. But if that were the cause, I'd bet they would have issues a fix already.
--Donnie
Last edited by 911F1; 11-06-2019 at 04:12 PM. Reason: duplicate
11-06-2019, 04:10 PM
#1162
Rennlist Member
I have no experience with helper springs, so I can't personally speak to that.
My theory is that the GT4 is so lowered in the front that it is blowing through all the travel and bottoming out and is doing so often. But I don't have one so there's no way for me to know. Someone who does have one *could* install some shock travel sensors and a data logger to see, but that's certainly an awful lot of work, not to mention requires some expensive sensors. Would be rare for someone driving around on a totally stock car to have access to that kind of thing already.
The other possibility I can think of is PASM. If there are bugs specific to some car models (assuming there is different software on different car models) *and* assuming the shock is capable of going to some near-infinite damping (I doubt it is, but maybe), then it could just be that the shock is going into that mode of operation (ie. super-stiff) at bad times (near bumps) and thus isn't bottoming out but is effectively putting the same stresses into the tower as if it were. I'm not sure that's even fundamentally possible on the hardware side, and if it WERE possible that's the ONLY situation I could see Porsche being able and willing to issue a fix for this. But if that were the cause, I'd bet they would have issues a fix already.
--Donnie
My theory is that the GT4 is so lowered in the front that it is blowing through all the travel and bottoming out and is doing so often. But I don't have one so there's no way for me to know. Someone who does have one *could* install some shock travel sensors and a data logger to see, but that's certainly an awful lot of work, not to mention requires some expensive sensors. Would be rare for someone driving around on a totally stock car to have access to that kind of thing already.
The other possibility I can think of is PASM. If there are bugs specific to some car models (assuming there is different software on different car models) *and* assuming the shock is capable of going to some near-infinite damping (I doubt it is, but maybe), then it could just be that the shock is going into that mode of operation (ie. super-stiff) at bad times (near bumps) and thus isn't bottoming out but is effectively putting the same stresses into the tower as if it were. I'm not sure that's even fundamentally possible on the hardware side, and if it WERE possible that's the ONLY situation I could see Porsche being able and willing to issue a fix for this. But if that were the cause, I'd bet they would have issues a fix already.
--Donnie
I suggest having a good auto insurance policy that replaces with original parts.
07-22-2020, 05:16 PM
#1166
Rennlist Member
07-24-2020, 11:16 AM
#1167
https://rennlist.com/forums/718-gts-...-spyder-7.html
07-24-2020, 06:15 PM
#1168
Rennlist Member
Good thing it's not true and misinterpreted as being a strut tower top hat issue. Whew.
https://rennlist.com/forums/718-gts-...-spyder-7.html
https://rennlist.com/forums/718-gts-...-spyder-7.html
. I hope we get more details soon.
07-24-2020, 06:17 PM
#1169
Always sad when something major like this happens to a Porsche of any kind. Just making sure everyone isn't mislead to that strut tower issues factually continued to 718 ...maybe it will...but not yet.
