Ronan

Minor update fact: roof of the RS is definitely magnesium. Subcontracted out and being constructed currently. I got this from someone close to it who is credible to me.

consolidated

Mg, interesting choice. It'll be a giant sparkler when sliding on it's roof.

Zeus

Benefits of Magnesium over Carbon Fiber or Aluminum? Anyone know?

New ZO6 will have a Carbon Fiber roof option. Hmm...

race7117

Porsche uses magnesium for the roof of the Cabrio and Targa, I assume they have invested heavily in its production and thus decreases cost for them, making it more cost effective as a company. Also Magnesium not as brittle yet still very light, I think light as aluminum but still stronger more stiff without being brittle. There is currently a battle between Mg and Carbon wheels for motorcycles

Tre

Race, it's from my understanding from motorcycle wheels is that cf is much lighter (~50%) and stronger than magnesium. It's just that magnesium is more "flexible" hence more forgiving with potholes compared to cf. But in the case of a car's roof, I'd think that scenario is irrelevant and you'd want the lightest and strongest material, hence the use of cf. There's a reason why high performance cars use cf tubs and/or components and not moving towards magnesium. Maybe this is a cop out for Porsche to go after profit margins vice making the lightest possible RS.

race7117

Completely agree, more than likely a cheaper alternative

Macca

Mg is typically alloyed with Au. Infact many alloy wheels have a small Mg component. I cant see any structural or weight benefits of a higher content Mg alloy for the roof over CF or alloy other than perhaps a benefit when producing the double bubble pressing and a margin weight benefit which may offset what I believe to be a higher roof line (for the bubble components) from what I have studied from the patent drawings which could be a measure to offset what would be a fractionally higher COG if in fact my observations are true. Of course there is also the marketing angle in using a "more exotic" manufacturing and material process. Infact too high Mg component will made for a more "brittle" and fracture prone end result so I guess they will be alloying with something clever to counter this....just my 0.2 on the subject.

Nizer

I suspect the choice was more engineering than cost driven given location as structural component of the tub/passenger cell (unlike bolt on hood and front fenders).

Magnesium is more expensive than aluminum but has well established advantages over the latter. See this comparison from bike building website: http://www.precisiontandems.com/cat_...amagnesium.htm)

The issues of connecting mg and steel - a factor in this location - also seem to have been solved. See: http://www1.eere.energy.gov/vehicles...eng_2011_o.pdf

nash

In all honesty I consider my "roll bar" to really just be a harness bar for this reason. It may provide some relief in a roll situation, but you can imagine the seat belt mounting points are probably pretty easy to shear. I'd say it has some benefit, but certainly nothing like a true welded-in cage. And it's certainly not providing much in the way of extra rigidity...

Bottom line, if you are putting in harnesses then absolutely get one, but otherwise I'd probably skip it. Just extra weight and squeaks otherwise

24Chromium

I tracked my RS for 3 seasons with just a harness bar. I'd seen first hand how well a 911 survived a nasty head-on and roll over without a roll bar. The fact that both driver and passenger walk away unscathed was quite comforting to me.

SamFromTX

Thanks. The car is very fast and it wants to be driven very hard so I'm always worried that something can happen and I'm not adequately protected. I certainly need a harness and a Hans so I'll get it done. I also learnt of a 911 that flipped several times at MSR a few years ago and both passenger and driver walked afterwards. It had a bolt on cage, FWIW.

SamFromTX

Wow, I just posted a similar scenario, just because I missed your post.

SamFromTX

Thank you for posting this, very informative. I knew Mg is stronger than Al but your post elaborates on many more aspects that I didn't know about. I did not believe Porsche would use Mg vs CF for maximizing profit (they're jacking the price to achieve that) so this makes sense, provided this bit of info about the RS roof material is indeed factual.

TrackFan

If you're going to track your car, and drive at your limit. You should set it up like a race car. Which means a roll bar. One guy walking away from a roll without a roll bar doesn't mean you'll be as lucky.

mooty

at min., I put a rear roll bar in with hans