Rear Engine & Rear End Shunts

[Aggi]

Just about to start my search for a 911 (993) having decided thats definately what I want. However have just read the "Bad Accident" thread on "General Gassing" and got be to thinking. My kids will go in the back of the 911, in my current jallopy (Subaru, awaiting chav jokes) if i get shunted, theres a meter or so of space and chassis filled with triathlon gear (soft and smelly) to absorb the impact and deform. In a 911 theres a big lump of metal there! What would happen in a 911, would the engine break its mounts and enter the rear cabin at say 35 mph?

[domster]

The kids will be sitting effectively over the engine, so it shouldn't enter the cabin. I haven't seen many impacts into 911s from the back, most tend to be damage at the rear three quarters because of spins, or frontal damage because of lack of braking because of a light front end.

911s aren't particularly unsafe, but for max kiddy safety you ought to get a Hummer

[iguana]

Subaru maybe more space for impact, but built of an old kitkat wrapper.

993, less colapsable space but built of iron left over from building the Bizmark.

One even Steven Hawkin can crumple up & throw in the bin, the other took half the british fleet to sink.

[Aggi]

iguana said:

993, less colapsable space but built of iron left over from building the Bizmark.

Thought rigidity in an accident was a bad thing? Id rather strap a box full of kit kat wrappers to my head and run into a wall than a box full of iron:-)

[domster]

Err, not if you're INSIDE the box of kit kat wrappers.

I'd rather be in an iron box thrown at a wall

Of course, you are right to talk about dissipation of energy in a crash, but 911s still deform. The point is that they deform rather than end up completely destroyed. You still need some rigidity to hold the thing together in an impact.

A normal scooby isn't overly rigid chassis-wise, as Bluesatin could tell you - he kept cracking his windscreen on trackdays when running slicks as there was so much chassis flex.

[Aggi]

So to prevent this turning into a physics thread my kids are probably safer in the back of a 911 than a Scoobie cos the 911 is stronger, i.e. the crumple zone in the scoob is made entirely of air so the incoming missile will get further into the car and nearer my kids?

[domster]

Errr, I'm not sure where this is going, but basically I would suggest that:

1) a 911 is built better/stronger than a scooby
2) but a 911 is NOT necessarily safer - it is smaller, exit is more difficult from the back, and without a full cage, 6 point harnesses and helmets, it is going to deform in a crash and even if it didn't the decelerative forces could blend your insides

Like I said, if safe kiddies is an overriding priority, get a Hummer - a 911 is a sports car, and one that really doesn't need any extra weight over the rear axle

Most 911s in crashes that I've seen have survived well in the circumstances, albeit the rollovers aren't so good, but cages are a whole can of worms anyway

Hope this helps
D









>> Edited by domster on Wednesday 16th June 12:25

[Aggi]

Yes that helps, thanks for humoring me!

The overriding requirement is not safety, (I agree safety questions about 911s might seem to miss the point). I wanted to canvas opinion on whether a 911 is much more dangerous than a front engined car, to the rear passengers, cos of the location of the engine. If it was then they'd have to travel in wifeys BMW

[Melv]

Don't worry -have seen hundreds of crashed Porsche pix on both road and track, and the safety cell, i.e. the passneger compartment, has never been compromised.

Mel

[veewhy]

Dom, For what it's worth (and hopefully our poster will never need to find out) the rear passengers will be sitting over the gearbox, not the engine. In fact the engine is completely behind the rear seats, albeit low slung. I seem to remember seeing a cutaway drawing of a modern 911 detailing the types of metal used,apart from the bodyshell being made of unit steel, they use 'Boron' in the most vulnerable places, and various other extra strenghtened steel in descending order.

[domster]

Yup, in reality the passengers are not directly over the whole engine, but in a classic air cooled 911 rear seat passengers do sit over and alongside the gearbox and some of the engine.

The point is that the lump isn't right behind a passenger waiting to brain them in a crash. I imagine it will either exit below the car, or possibly out to the side, before choosing the bulkhead. In reality, of course, a car crashing heavily into the rear of a 911 is likely to ride up it - which may be even scarier.

I'm not sure 911s are particularly safe, but neither are they particularly unsafe.

ATB
D

[iguana]

Dr Dom 'Badger' Domster- is indeed the worlds acknoledged expert on Porsche crashing, his work is much respected by others in the area of Porschacrashology, mainly because he tends to favour a more 'field work' based approach and uses his own vehicles, rather than more lab based or computer model based experiments

[bluesatin]

I agree with the Lizards wise words about badgers and the domster.

[Aggi]

veewhy said:

... use 'Boron' in the most vulnerable places, ...

Sh1t thought that was a gas!
arrrgghh cant type edited

>> Edited by Aggi on Thursday 17th June 09:58

[cyrus1971]

I am ashamed to say I completely wrote off my 993C2 skidding on some diesel exiting a large Basingstoke roundabout at about 80 mph, spun 360, clipped a storm drain, flipped on the roof, rolled the car fully twice before coming to rest. To get out I had to open the door vertically and climb !

I literally did not have a scratch on me. One bruised rib (and pride) from the sports seats bolster and that's it. I noticed at the time how well deformed every panel was and that the engine bay was rigid and intact.

I totally rate their safety, from all angles. See pictures of crashed 993s at www.wreckedexotics.com/ and form your own opinions. Of course in a Scuby I would never have had that accident in the first place - but then that's another story !