I doubt there is actual data. But just consider the geometry: most NASCAR bars have little to keep them from creasing and bending inward. On the other hand, the pyramid X distributes force outwards towards the four corners. This allows the front and main hoop sections of the cage to help out.

Again, I want what the Porsche factory welds into their cars (with carbon fiber doors). When a GT3 Cup comes over from Germany with NASCAR bars then maybe I'll change my mind.

 

Porsche is not famous for looking out for the safety of their drivers so I would not hold up their cage design as a paragon of safety.

NASCAR, with their "rubbin' is racin'" attitude, have to build structures that will protect drivers from heavy cars and heavy collisions at greater speeds than what you normally see in sport car racing. There is a lot more energy in a typical NASCAR crash than a typical ALMS crash.

That "pyramid X" structure you are touting is too shallow to provide much force distribution and would likely cave in easily during a side impact of any consequence.

That's why I would like to see some numbers. I don't have any answers either but what I see from Porsche is not confidence inspiring for side impact protection.

Scott

 

I would recommend that you take a second look at the belt routing on the pass side as well. If you don't have manufacturer's information to suggest your current routing, you should probably change it up.

Also, it looks like you are missing a required element if you plan on competing in SCCA events. See as follows:

2. One tube must extend, from each front down tube, forward
to the firewall or through the firewall except in vehicles in
Improved Touring, Showroom Stock, Spec Miata, and Touring.
This tube, one on each side, must connect to the chassis at a
point not more than 12 inches forward of the front axle centerline.
3. Cars competing in Improved Touring, Showroom Stock, Spec
Miata, and Touring may extend one tube, from each front
down tube, forward to the firewall, bulkhead or wheel well,
but not penetrating any panel.

Depending on how the rest of your car is configured you may be able to argue that you car is in Improved Touring "E", to get a regional Logbook as the element is optional for that category.

Or obviously, you may not be interested in SCCA's rules... Just thought it was worth mentioning.

 

Danny Boy, those pics are soooo pretty, great job and I'm sure very safe, wish I was going down and playing with you guys, nice job to an already great GREEN race car, good luck. Glad to see they finally are starting to put E, F and G together, should be some great fun!

 

well since everyone is showing off..

 

My cage builder is saying a similar thing re the X bars. His feeling is that people are turning away from this design and that they can cave with a perpendicular impact. fwiw.

 

What is the purpose of the holes in the door bar gussets?

 

I'm afraid I have to agree with winders on this one. Wasn't it Porsche that built magnesium framed 917s (one of which nearly killed Mark Donohue, before he actually died as a result of an F1 accident), and 935s with aluminum roll cages until they were outlawed?

Don't get me wrong - I'm a die hard Porsche fan - but just because Porsche does something doesn't mean it's the safest way to do it.