Rollcage discussion
#16
Rennlist Member
My 993 GT2 chassis is being built as we speak by a pro. He has built cages for over 400 race cars and strictly follows FIA regulations.
He has mostly done rally cars (a lot of WRC stuff too) and boy those cages need to be rigid!!
You may want to take a look at it...maybe you will get some ideas.
Photos of the build here (chassis photos are at the bottom and I update it almost daily as the work progresses):
http://m3supercar.1g.fi/kuvat/993/GT2+EVO+MOTORSPORT/
If you want room for proper door bars, why not put in Carbon/Kevlar doors and shave 140lbs while at it??
Hahn GFK sells these doors (same manufacturer who made these for the race cars back in the day). 800eur/door. So good bang for the buck!
He has mostly done rally cars (a lot of WRC stuff too) and boy those cages need to be rigid!!
You may want to take a look at it...maybe you will get some ideas.
Photos of the build here (chassis photos are at the bottom and I update it almost daily as the work progresses):
http://m3supercar.1g.fi/kuvat/993/GT2+EVO+MOTORSPORT/
If you want room for proper door bars, why not put in Carbon/Kevlar doors and shave 140lbs while at it??
Hahn GFK sells these doors (same manufacturer who made these for the race cars back in the day). 800eur/door. So good bang for the buck!
#17
Burning Brakes
Thread Starter
My containment seat (Racetech 4000HR) will be on sliders. From just looking at it, I think it will work - but we'll have to see!
#18
Burning Brakes
Thread Starter
The rules consideration is an important thing. I was originally worried about PCA rules, but I've started to think about other series that I might want to eventually try (NASA GTS, for example) and will need keep them in mind. For example, I won't be able to well the sill bar to the chassis if we go down that route.
I came across this cage in an E46 m3 last night while reading up on FIA rules; its almost exactly what I envision (minus the rear subframe reinforcement that's necessary on those cars).
#19
Rennlist Member
In 5 years of racing with PCA, I have never seen an "old" 911 with one of those FIA bars. Maybe there are a few? I have seen gussetting there but not a separate bar that intrudes into that very limited and critical space. I haven't paid enough attention to the 944s, but I do think the lower angle A pillar on a 944 would allow more room for such a thing.
An FIA bar will only work if the bar is positioned in such a way that it does not extend into the window opening past the vent window (the fixed quarter window on older 911's), which can't be removed according to PCA Stock rules. (I think the rule is silly myself, but ...).
#20
Addict
Rennlist Member
Rennlist Member
A couple pics of my cage (964 tub) done a few years ago. I don't have a 'knee' bar so much as a dash bar - it supports the steering column and the dash (original dash removed for weight reduction). The cage had no damage, and most importantly, no damage to me when I hit a wall at 63 mph and then ended the crash upside down.
#21
This thread seems an appropriate place to ask a question that has been in the back of my mind for some time...
Question: Why would Porsche cages not tie the seat to the cage? Are Porsche chassis/seat mount welds seen as stronger than others so as not to be concerned about this as a potential weak point? Or am I overlooking some aspect of Porsche cages?
There appears to be a difference in Porsche cage design in that I have yet to see one incorporate seat mounting as some others prefer. While I very much trust the professionals behind the cup car design, I question why is the seat still mounted to the stock mounts, rather than tied into the cage.
Point of reference: When I built my BMW E36 ITS/JP race car professional team wisdom dictated that the seat should be tied into the cage rather than the stock floor mounts. This would prevent the risk of the seat moving separately from the cage and causing problems with the harnesses (tied to the cage) and the seat that would otherwise be mounted to the chassis. It could be all myth, but I recall stories of seats breaking from the stock mounts in severe impacts or potentially the chassis crumpling in a different manner than the rigidity of the cage would otherwise not.
I have included two images of my prior BMW's cage to illustrate the question. With this cage, the seat was tied into the cage and essentially floated over the stock mounting location so the seat would move with the cage should an impact be encountered.
Thank you!
Question: Why would Porsche cages not tie the seat to the cage? Are Porsche chassis/seat mount welds seen as stronger than others so as not to be concerned about this as a potential weak point? Or am I overlooking some aspect of Porsche cages?
There appears to be a difference in Porsche cage design in that I have yet to see one incorporate seat mounting as some others prefer. While I very much trust the professionals behind the cup car design, I question why is the seat still mounted to the stock mounts, rather than tied into the cage.
Point of reference: When I built my BMW E36 ITS/JP race car professional team wisdom dictated that the seat should be tied into the cage rather than the stock floor mounts. This would prevent the risk of the seat moving separately from the cage and causing problems with the harnesses (tied to the cage) and the seat that would otherwise be mounted to the chassis. It could be all myth, but I recall stories of seats breaking from the stock mounts in severe impacts or potentially the chassis crumpling in a different manner than the rigidity of the cage would otherwise not.
I have included two images of my prior BMW's cage to illustrate the question. With this cage, the seat was tied into the cage and essentially floated over the stock mounting location so the seat would move with the cage should an impact be encountered.
Thank you!
#22
Addict
Rennlist Member
Rennlist Member
Whoops! Nice compliments in this thread on your cage and builder though