aigle836

HIHIHI !
.
.
.
.
.
.
.
.
DONE !

okie981

Looking closer at that schematic, the shock tower is attached to stamped metal made out of aluminum, but it's pretty much irrelevant to the shock tower rupturing under impact.

Spyerx

I heard same but I thought it was an orange FIA curb "JUMP"??

DONT HIT ****

consolidated

I have a similar hehe story. My college girlfriend at the time had a low coolant light on her new Audi, a nice car for a 19 year old. So after opening the hood she carefully unscrews the cap on the valve cover and fills the crankcase with a garden hose...and then goes for a drive, a short drive.

Of course it stopped running, steam everywhere, and I thought terminal. But, the motor was flushed out and miraculously saved. Yes, blond...and she never appreciated me repeating the story, which how can you not?

okie981

On pages 60 and 61 of this Service Information Technik book for the GT4: https://rennlist.com/forums/gt4/8869...l#post12492702

It describes how the GT4 rear shock towers were reinforced over the base 981 car design. No mention of the front shock towers being reinforced.

d00d

I see what you mean, looks like the vertical piece under the horizontal sheet steel is sheet aluminum.
From pealing back the plastic in the frunk, and also looking up into the wheel well, it's riveted to the sheet steel.
It's also welded at the bottom to the aluminum frame rail.

okie981

In addition to that, the document at the link I posted above says in it somewhere the shock towers are installed with two-part adhesive and rivets. I think it's in the beginning of the section on repair methodology for the body structures.

okie981

Now that's funny. Logic is a wonderful thing. Engine is low on coolant. Water cools things. Open the engine and add a lot of water. Done! It's amazing how engines can recover from being totally submerged in water if they are flushed properly and all electrics properly dried out or replaced. Another buddy of mine let his dad's V8 (Ford) powered ski boat accidentally sink in shallow water to where only about 6 inches of the boat was sticking out above water. The transom plug had a not too slow leak. Anyway, the engine was drained, flushed with kerosene several times, filled with oil, ran a few minutes, oil changed again, and she was back pulling us around on skis and inner tubes the next weekend. That boat ran for many years longer with not a sign or odd noise from the engine.

4carl

Cast aluminum is very brittle not a good application for a shock tower

d00d

Good information in that document, here's another (page 78), and it shows that some sheet aluminum Boxster pieces have been replaced by stronger deep drawn steel in the Cayman;
http://european-aluminium.eu/media/1...structures.pdf

The CS has some additional bracing, but not for vertical impacts like this;
http://www.pistonheads.com/gassing/t...=231&t=1613839

savyboy

I just dropped a note to TH mgt asking them to take a look at T6 track-out.

I've bent wheels dropping off berm edges three times: Buttonwillow, RFR, and TH. Each of those three times it felt like the strut tower was going to break. It's common for the back edge of a berm to have a suspension-killing sharp drop off (and tall edge to hit upon reentry, if able to).

"Using all the track you paid for" for is a fine platitude for those who don't have to pay for their own repairs I now save most apex and track-out berms for "emergency" use.

I saw the poor wounded GT4 when he limped back to the paddock, from talking to the driver it was a momentary lapse of attention/precision where he was trying to accommodate / making room for a driver passing on the left.

Spyerx

:-(

Resolute1

^^this

It's apparent that there was some type of impact or serious external stress put on the wheel/suspension on that corner that was beyond the design criteria. Porsche runs FEA and stress analysis on all of these parts and I'm not sure what the safety factor they use is - but it was clearly exceeded by an exponential factor. They design these cars to deal with some curbing, but not straight impact or drop off I'm guessing.....

OR

The casting had a void, which is fairly common in aluminum casting processes. Depending on design and casting technique it's not unusual to se a 15% rejection rate in aluminum due to voids, porosity, and seams. Curious if they use x-Ray or a magnetic particle or "other" process on cast components for inspection.

Either case it's an anomaly and I wouldn't think too much cause for concern.

Quickly looking at the component it looks as if it could be made better by machining the part out of an aluminum forging or bar stock.

Hopefully the owner is back up and running quickly and we don't see any more of these issues.

electron mike

This brings back bad memories as this happend to a 991 GT3 I was buying when the tech did the PDI. He hit a curb on the test drive and did significant damage... I didn't take the car as it was messed up pretty badly, and they couldn't get another GT3 allocation.

trebien

Funny, considering the impacts & loads that this part must endure over and over from a 3000+ lb projectile hurtling down the asphalt... I was thinking the opposite. What, about 1/8" thick?

Especially since it looks like cast aluminum... a material known to be brittle, whereas steel would flex and give a bit, absorbing some of the shock.

Interesting, nonetheless.

Other than a formed/molded steel "cup" insert that could go up under the shock mounting and maybe bonded... not sure what else can be done for reinforcement.