well there has always been those that state that the teq. equipment rollbar which bolts in is for show. first, I was never one to buy this argument. Porsche wouldn't hang themselves open for liability that easily. Anyway I was at Orbit racing and saw a 996 that rolled over and the bar kept the roof up 100 percent.

 

that's good to know... I have had one in the car for a couple of years now but everytime somebody "serious" sees it they say it's a nice piece of "jewelry". Knew it couldn't be all that bad

 

4 or 6 point bar?

 

Thats good to hear... about the rollbar holding not the rolled 996. Hopefully the occupants fared as well.

 

it'd be also interesting to see what it would of done w/o the bar. There was a pic of a 996 cab that flipped at a good clip and the cabin looked perfect!

 

I have installed a bunch of these bars. They are very rigid, stainless ( go figure )!
I am also Porsches harshest critic, the bars are meant to augment, the structure of the car,not to be the save all that a proper cage might be in a serious shunt. However the design and construction would pass tech, (were I the inspector ) for anything but, a full on race car. I think they are great for everything else. Porsche seems to agree.
Happy holidays, Jayster

 

Anyone who has personally installed this rollbar by themselves knows it is not cheeze whiz based on the physical stuggle to get it bolted in...

 

Any pictures?

 

Is that code for........"it doesn't fit real well, and half way through the effort I was wondering if it had been made for a slightly different car"....

 

That is a great point. each and every time i install one of these "roll bars" i catch myself letting out a small nervous laugh, when i think about the 4 small barely 1/2 bolts that are supporting the load of this rollbar.
I suspect the structural rigidity in the construction of the 996 has much to do with it surviving a roll.

Erik

 

 

exactly, and personally for me, if I put a cage in a car it's welded in, none of this held on by bolt crap.



How much does the porsche bar help the rigidity of the car?


cars today are built w/ roll cages in them basically w/ support beams etc. The vast majority should be able to handle a good roll over. And that's another one of teh reasons NHRA, IHRA etc are lowering their times required for roll cages.

 

Erik,
you guys don't ever weld those rollbars in?
I know in the 914s, that the bolted-in rollbars are damn near just added weight, whereas the welded-in units also really strengthen up the chassis.

just curious....


Scott
Modesto Ca

 

Bingo!

 

Erik,
As you know I have one of these "wedge in place, squeeze, pull, push, torque, porta-power, sweat, cry, bleed and curse" rolbars in my car. To address your load concern......
Assuming the bolts used are in fact 1/2" diameter and they have a yield strength of 36,000 psi.....

• The allowable load, in shear, on each bolt is 2,830 pounds.
• The yielding load, in shear, on each bolt is 7,070 pounds.
• The ultimate load, in shear, on each bolt is approximately 11,390 pounds.

Definitions are in order......
In structural engineering.........
Allowable load is a safe percentage of the yielding load.
Yielding load is the load that permanently deforms the bolt.
Ultimate load is the load the breaks the part into two pieces.

And remember, there are four of these bolts.