living with a rollcage on dual purpose 911

[zotman72]

This year I decided that it is finally time for me to taste the world of PCA club racing. My '72T quasi-DE track prepared vehicle will be the ride. However, I am reluctant to throw a switch that prevents me from regularly driving this enjoyable car on the street. The custom rollcage from DART Auto will be very much permanent by nature. How many of you live with your rollcages on the street? What are biggest dangers? Head bonking during entry/exit?
Thanks for your insight.

[jpnovak]

I have a bolt-in (to welded plates) cage from OG Racing. I don't have any problems getting in/out. The side bolsters on the seats are at least as high as the door bars. The downside is that the rear cross bar and diagonal really prevent any use of the back seat area when traveling to the track. Packing will be tricky.

I have not hit my head on it yet and I am 6'3".

[IROC]

I think that head bonking during an accident would be the biggest concern. Everything else boils down to how much inconvenience you want to put up with.

There are alot of opinions out there on this, but the potential safety dangers when not wearing a helmet led me to installing a roll bar instead of a cage (albeit for a DE/street car).

Mike

[Todd Simpson]

I'll second Jamie's comments on the rear seat area. Lots of cargo area is lost, through with some careful design of the diagonal you could minimize it. Fixed racing seats make it worse as well.

I'm guessing this is a welded cage? If so, excellent, you will really feel the increased stiffness in the chassis. If it's custom think about the stuff you may want built in from the beginning, harness loops, seat back brace mount, camera mounts, etc.

Door bars are a bit of a pain, but can also help with getting in and out of a tight seat. I've just taken out my soft rollbar padding and upgraded to the proper hard SFI rated stuff. I use it everywhere there's even a remote chance I could come in contact with the cage.

Consider the door panels and window winders. My upper door bar prevents me from opening the windows. Also look into a large rear view mirror. Race seats, harnesses and bars all around cut your vision. A 17" clip on panoramic mirror is nice on the track and even better on the street.

[Jim Richards]

Is there a wife or g/f that needs to weighed in to your plans, Bill?

[Britain Smith]

I just recently added a full cage for my project, part safety and part strenght. I went with the lower street style door bars and everything else is tucked away nicely. Check it out.





-Britain

[peridotian]

Damn Britian, looking good? Was that a TC fab roll cage?

[Grady Clay]

Bill,

Make sure it complies with all the rules of the various sanctioning bodies – SCCA, PCA, RMVR, etc. Go look at all of Dave’s roll cages and talk to the owners. You will find more details that no one thought of at the time. Talk to the guys at 3R and there are several other skilled roll cage fabricators – go pick their brains.

I agree with Tod, think through every stinking little detail. One that comes to mind is the bolt attachment to the original seatbelt upper attachment. You want the fittings for a window net – both sides.

Most well designed cages make it easier to pry my lame o’l bod into a track car. A higher door bar lets me sit on it and slide over and down into the seat.

Consider the upholstery – you don’t want it damaged or else remove and carefully store it.

Are you going to use competition seats for events and original seats for street? Think through the swap.

A great deal of thought should go into the 5-point or 6-point seatbelt mounting. The angles and positioning are critical. Consider your arms and legs. If you did a multi-endo, what are they going to hit? See if DART has a junk factory knee pad you can mod with SFI padding. Use arm restraints with your harness. Don’t preclude the addition of a HANS Device or similar.

Don’t forget the passenger side. You want your instructors and passengers to be safe.

For a racer, the side bars need to go out to the outside door skin. I know several people who have their original doors resting quietly and use gutted doors to clear the cage.

A welded-in cage is not as permanent as you think. With a saw, it can be out in minutes. Some grinding and put the upholstery back and you’re done. I don’t know anyone with “bolt in” that takes them in and out.

The criteria is:
Be as safe as reasonable.
Comply with the rules.
Don’t overweight the 911.

Best,
Grady

[widebody911]

I did mine relatively low with a slight kink outwards for better ingress/egress

[Jack Olsen]

There are a lot of differences of opinion on this.

You definitely want to put high-density SFI padding (not the nerf stuff) on the cage anywhere your head might travel in an accident.

Britain's cage looks great, with only one thing that I wouldn't do. There is no way I'd put a cross knee bar in there unless your sitting position means your knees are down below it at all times (which is not the case in my car). That bar will make for some very ugly knee and leg fractures in an accident.

The positives of a cage are usually overlooked in these discussions. Having one significantly increases your car's ability to withstand a side impact or a rollover. That's huge.

Look at the pictures some time from SWBSAM's impact with a stone wall.

On the negative side, a cage reduces some of the car's ability to crumple (and absorb energy) in a crash, especially if the cage extends beyond the cabin to the suspension points. This increases the likelihood of whiplash-type injuries.

And as is often pointed out, a cage also brings big steel bars into the vicinity of your head.

But there are a lot of goofy (and scary) realities of cars in crashes when the cars are kept stock. Guys who make a big fuss over SFI high-density padding on cages often forget about the folded steel edge of the roof near the driver's head in a stock car that's protected by... a vinyl headliner. The A- and B-pillars are also hard steel, just waiting to crack some bone.

It's a shame the way legislation forces the auto industry to be very good about 2.5-mph impacts, but not be so good about toxic gasses produced by car fires or particularly meaningful cabin safety and side-impact protection. Airbags are finally addressing some of this, but most of our cars don't have airbags.

[doozer]

I want to do one for street use but with no cross bar behind the seat.

What I want is a weld in cage for my cab that does not interfere with the back seat use.

Is this possible??

Is it safe??

[Britain Smith]

Yes, my cage was built by Tony at TC Design in the bay area.

Jack,

I designed that cross-bar to be higher than the knee pads would normally be in a stock 911. I am tall (6'3") and with the position of my seat, my knees are far from the underside of the dash. I understand your concerns though, I have been in some 914's where my knees hit the cage due to the tight space and a low bar. I also had the roll bar area in the back moved slightly farther back to clear my seat due to my height. I made the whole cage out of PVC before I took it to the fabricator to be made out of steel.

-Britain

[Todd Simpson]

There is no way I'd put a cross knee bar in there unless your sitting position means your knees are down below it at all times (which is not the case in my car). That bar will make for some very ugly knee and leg fractures in an accident.

Unfortunately this is not the case with my car...my knees bend right in front of that bar.

It's SFI padded, but do I need more?

[widebody911]

I don't see how you'd prevent lateral moment of what would basically be a simple roll hoop.

Originally posted by doozer
I want to do one for street use but with no cross bar behind the seat.

What I want is a weld in cage for my cab that does not interfere with the back seat use.

Is this possible??

Is it safe??

[Jack Olsen]

You're right, Britain. The new picture makes it clear that your bar is nice and high up.

[doozer]

Originally posted by widebody911
I don't see how you'd prevent lateral moment of what would basically be a simple roll hoop.

I would tie it together under the front of the dash and some gusseting but I really dont want the cross bar in the back seat.

Any Ideas?

[kary993]

http://members.rennlist.com/kary993/cage2new.JPG

Here is pic of my car that had a new custom cage installed. I use it on the street and the track. The picture does not have the recently added BSCI SFI 45.1 rated padding as it does now, but I do not see any issue with hitting the roll bar as long as there is padding in locations that your head or body might contact the car.

Having done a lot of research about cages and their strength I am somewhat surprised by some fo the door bars that I have seen in this thread as they are not that strong in an impact and do not really protect the driver very well given the position and structure. Though they are easier to get in and out of the car. Not much of a trade off in my mind.

Not pictured in my pic is the roof cross bar. I think this is a good idea for additional protection in the event of a roll over, street or track. The knee bar is a must, it also provides added rigidity as well as added protection in a side hit on one of the door. Without it, the a pillar bars will just collapse inward by your legs. Not a good thing at all!


Just my 2 cents....

[Jack Olsen]

Doozer, you don't want anything lower than (or even equal to) the height of the kneepad. I don't think the factory puts anything there.

For a rear diagonal, you might want to think of a piece that can bolt in and out. That's the way I have my door bars. If I need easy access, it zips right out.

[doozer]

Originally posted by JackOlsen
Doozer, you don't want anything lower than (or even equal to) the height of the kneepad. I don't think the factory puts anything there.

For a rear diagonal, you might want to think of a piece that can bolt in and out. That's the way I have my door bars. If I need easy access, it zips right out.

Is this a saftey issue or a structural issue?

Thanks Jack, thats a great idea..

[KobaltBlau]

sorry I missed this on the first round... Jack, do you wear 3-pt belts on the street at all?