*hit happens so don't get down on yourself since it can happen to anyone - I totalled a Viper years ago on the street and it was a learning experience. Make sure they really tear into the car to be sure all the damage is discovered, which I am sure they will since the more damage they find the more money they make. Personally I would not want a damaged car back since one would get killed on the resale value so it by chance it is close see push for totalling it and get another.

 

I think this formula will give you speed in knots, not MPH. Your formula would then give you 54 knots which is around 62 mph, but it doesn't matter because this formula cannot be applied to vehicles.

There are many contributing factors that influence hydroplaning on roadways. These are the numbers you need to calculate before being able to know hydroplaning speed:

Need to calculate water film thickness: for this you will need to measure length of flow path, rainfall intensity, pavement cross slope and roadway grade. The thicker the water film is, the lift force will be higher.
Need to calculate the contact force: for this you will need the weight of the vehicle on each tire, tire-pavement contact surface and instantaneous speed. To know each of these you will need to perform even more calculations.
Need to know the type of pavement: Concrete asphalt, Hot Mix asphalt, Open-graded friction course asphalt? They all behave different and offer different friction factors when wet.

Anyway... To the OP: It happens mate, get it fixed by a professional and sell it if you end up not liking it. I'm glad you are not seriously hurt.

 

I will repeat myself... The type of tire you use is probably the single most important factor in how your car handles in specific conditions.
Tread depth, tread pattern and type of rubber compound are all incredibly important. The Michelins are rated to be among the best in rain and dry.
The Pzeros are complete garbage in any condition. Not flaming you, I had them as factory on my GTS, but once I switched over to Michelins there was no going back ever..

Switch the rubber after you get it repaired and chances are this will never happen to you again.

 

So sorry to see this. I am glad you are ok. I dont believe this equation either, but it happened with many unfortunate conditions. I bet you could try that same road under those conditions and not hydroplane. Just a very unfortunate set of circumstances.

 

Glad you are ok. Hope you and your car are back to 110% very soon.

The airbag replacement costs alone will be BIG $$.

 

Just wanted to put some emphasis on the above, as it might save someone else here more than a little heartache, $$,$$$, or worse.

"Way back" in the 997.2 Turbo days, PAG had a press launch at Estoril and the conditions were abominable. Rain, and some parts of the track were "muddy/greasy" and about as grippy as ice. Those running the track component were clear: Use "Normal" mode, both for the reason you state above (which I have found to be true again and again while road and track testing in the rain) and because it's quite possible to spin a car in Sport Plus (and probably more likely in Sport). The more permissive PSM settings—which is what makes those modes more fun and still playful—mean less of a safety net.

PSM, as a safety net, was very good from the start and has only become better with each generation. But a lot of people think Please Save Me can fix anything. And, for all intents and purposes, it "almost" can. But not in certain situations (hydroplaning is one of them), and not when its interventions are intentionally limited by the driver. I tend to run Sport or Sport Plus often, as I like the way the car behaves. But I think twice about it in the wet…is that edge worth the added risk?

 

To OP.
im not familiar with Momentum. Collision Plus used to do all restoration work for Driver Source, they do work for Porsche West.
personally, they repaired Rear fender on a 997 4S, re-sprayed a bumper and fixed my wife’s Audi Q5 after two rear end collision. Always with great result.

I say call them both and see what you fell most comfortable with. Good luck.

 

Aside from the nautical/land mile point, I can see some of the reasoning behind the formula. It doesn't sound entirely bogus, but I'd like to do more reading to make sure I understand the idea. As the OP learned the hard way, it's not an abstract exercise.

The reasoning is that it's not all that important how thick the film is. Your tires are either rolling on incompressible, friction-free water or on the ground.

Here, again, it makes some sense that the leading edge of the contact patch is the only important part. This is where tire tread depth and pattern come into play. The key point is that any contributions from the tires are strictly second-order improvements, incremental at best.

Once you're on water, there is no friction. It doesn't matter in the least what the surface is, except to the extent that a rocky surface would need more water to develop a film than a smooth piece of asphalt would.

+1 to that for sure.

 

Thanks a lot for all your replies.

I went and checked the car today in sunlight. It seems that all the damage is concentrated in bumpers, plastics, and head and tail lights. All the gaps between fenders and doors and roof seem to be perfect.

The only worrying part is the muffler as the tips on both sides were destroyed.

I took it to Nick's workshop (Collision Plus II) upon Norge911 recommendation and he is an excellent guy to deal with. Let's hope that it's only the muffler that will need to be changed from the mechanical side and that the accident didn't affect the radiator or the engine or any other chassis components.

If that's the case, then I will be very luck for hitting two walls at 55 mph and ending up with only plastics and muffler replaced. However, I still feel from reading other threads that there might be much more to find once that rear bumper is disassembled.

 

To paraphrase Bernie Boom Boom Geoffrion, “they don’t call me Boom Boom for nothing.” Airbags don’t go off for nothing. It usually takes about 20Gs to set them off. Some bent up plastic isn’t going to generate 20 Gs. So I would prepare for some bent metal somewhere. Sorry. The good news is the airbags did their job. No injuries.

 

Airbags in the US deploy from 8-14mph. Not so significant to cause frame damage, thats absurd. You think every car that had an airbag deploy had frame damage?
I had some fool rear end me once in a parking lot (not in my Porsche) and the airbag deployed. Nothing but a crack in the rear plastic bumper, not even the tail light was cracked..

 

I actually tend to differ here. The airbags were deployed at the first impact with the left concrete barrier of the high way. As you can see from the photos, the front of the car is almost intact. I guess what happened is that I skimmed the barrier and hit the sensors of the airbags in addition to the vehicle sensors detecting the skidding of the car which may have triggered the car to go into "collision mode" and deployed the airbags. They airbag actually hindered me from being able to see anything, which made it more difficult to correct the car's direction.

 

Assuming no frame damage or headlamps, I think PTS-BRG is about right give or take a thousand dollars... the rear bumper cover can be had for $750... $500 to paint... front bumper is like 1200.... and on it goes. Glad you're OK. Doubt it gets totaled unless one or more of the wheel carrier assemblies took a whack that we can't see, then you'd be looking at upwards of 20K in total, not sure that would total it... I think it'll likely be repaired.

Make sure to hit your insurance up for a Diminished Value claim.

I've also heard that Michelins are better in the rain... I have the Pirelli on my 991 but the Michelin PS4s on my 997 turbo.... I don't drive in the rain too much.

 

FYI: These cars are very smart. If the car is traveling at 50mph starts to go sideways (which the car senses) and makes any sort of impact, the airbags will deploy. You dont need to hit a brick wall in order to be protected, the cars system sensors know pretty well when you are in trouble and do everything they can to keep you safe.

As far as the repair bill, these guys can go hog wild. They may say its 10k in damage if every airbag needs to be replaced and a scratches LED lens warrants replacement. You have insurance, they are going to cover it and the car will be as good as new. You are alive and the car survived too.

Now go change those tires

 

If your car is repaired, Nick will fight for you and make sure you get good parts.

make sure you order some Zunsport grill covers and have them installed before they put the new front bumper on.

good luck.