Roll bar, cage, street or street/track car build?

[RAAMaudio]

Edited, I forgot about my plans before I moved


Just a bit of info to consider if you are contemplating roll over "protection" in your street driven or even track only car.

I feel this is very important info some may not of been exposed to as I have researched and practiced this for a very long time including reading every rule there is and designing and building my own systems which have all passed inspection the first time. I also have personally known several race car inspectors, builders, etc and discussed all these issues with them.

A caged car on the street is a royal pain in the ass even on a car with big doors and the design optimized for the best entrance and exit which I know from personal experience. Removable door bars are sometimes allowed with the proper mounts but can be dangerous in not padded properly when the bar is in or out of the car.

A roll cage also requires a race harness and fixed back seat and you really should be wearing a helmet and using the very best dual density padding properly placed, single density in less critical areas.

Make a few errands in a caged street car and it ends up a garage queen as just not much fun

A proper roll bar makes the rear seat useless in this car, even for our doggies to get in and out as I wanted to build on for my very fast street/track car, just not viable for our needs. Roll bar still requires fixed back seats, main hoop bar as far up and to the rear from your head as possible and then you will might need a helmet to be safe in a hard hit. Of course proper padding is also needed.

Bolted in roll bars: Most simply are bolted into sheet metal and are often allowed on road course cars which make no sense to me at all, a huge debit in the safety area and in some cases more dangerous than no bar at all. I had a car taken to probably the biggest company in that market to prototype one and then the first production unit sent to me. I did not even install it, sold it to a guy building a show car that promised me he would hardly ever drive and never race it.

Drag race rules were if not still are quite different than road race rules, removable door bars allowed but most I have seen are not really very effective for anything other than helping the main hoop stay upright in certain impacts, most have the front of the side bars bolted to sheet metal, etc...a side impact could render them a very dangerous thing to be near.

At least these little cars are superbly engineered to be very solid in a roll over, the smaller the shell the stronger it becomes which helps as well. Side air bags though sometimes dangerous can help in a side impact though.

1)Roll cage = race car, welded in
2)Roll bar = two passenger, semi race car, welded in
3)Door bars = bad news unless properly gusseted, track use only
4)Bolted in roll bar = Show car only unless the chassis is properly gusseted
5)No bar = street/track car and accept the risk and avoid the dangers and hassles of the above.

My vote: #4 a real roll bar, bolt in so I can use the car when needed to haul the doggies, left in the rest of the time or just for the track. I was considering ideas for a back brace to use the stock seats, lots to consider there, or just bolt in a real race seat when the roll bar was in the car. I was just starting on the design when our house sold before expected, no shop now, tools all in storage.

I am stuck with #5 for now but will be looking around for a competent shop to build what I design or I might just fill the chassis with foam as in my next post. I do not have the expertise to figure out how much safer it would be but I know it would be far more stiff thus less prone to caving in.

Rick

Any questions, clarifications, help with sorting out rule books, etc...let me know, glad to help

Rick

 

[meFiSTo]

Man, you nailed it. I had a 6-point welded-in cage with comparatively minimal door bars on my old heavily modified SVT Focus. What a horrid car to drive on the street. It's why I got rid of it (even after taking it back to a 4-point cage and removing all the hardware in the front of the cockpit). it was stiff and just unpleasant to drive. Never again..which is also why i'm committed to dialing back a click or two from full on 10/10ths running on track days.

 

[RAAMaudio]

I did not even mind the stiffness all that much, it was crawling in and out, sliding and then sitting in a tight race seat, hooking up the 6 point harness and having less than perfect shoulders, knees, back.....it sucked!

This is the only way I would add strength to a street car now but likely not happening as a huge job, take out the whole interior, side sills off, rear bumper cover, etc......tape everything exposed, double the tape and coverings....spray in expanding foam in all the voids possible with the exception of the very rear of the car and the firewall forward(I would probably do the "frame rails" up to the suspension mounting points)

The foam I have used is PurFil from Germany, far better than Home Depot stuff, far more costly, nasty stuff to clean up, if dried impossible....360liquid oz in the Scion TC my son and I built, took a whole week of long hours, $100 in blue masking tape, had to wear off my hands and finger nails had to grow out.

The car was so stiff it felt fully caged, almost hurt your hand to shut the doors it was so solid, then we caged it and barely could tell it was stiffer than just the foam.

We also were the first to replace the glass roof with a carbon/kevlar roof, dropped 45 lbs off the top and it also made the car stiffer.

Since the ST has a sunroof, needed for air flow for the dogs, it is a bit less solid than one without it. I might just take the car apart and do the foam job and add a bar or two on the roof as near the B pillars as possible unless it has a good factory element on the front and rear of the sunroof, I could just fill them if they look strong enough.

 

[RAAMaudio]

I made the mistake of not looking into manf claims of track approved roll bars for the convertible vette until after spending hundreds of hours and $30k on mods to a C6 convertible, the roll bars were completely illegal and unsafe. I called all the vette race shops, nobody made one or wanted to....I spent at least 50 hours on a design but always came to the conclusion I would have to hack up the car to much, top would not work, could not make it removable and strong enough and get to the points without many hours of work to take it out or put it in so I could use it as a street car.....

Though a couple of orgs would let me track the car without a roll bar there was no way in the world I would take a very fast car made into a super fast car on track without one so I parted it out to stock and traded it on our dually

One very cool thing I learned, I actually like the FiST far more than the Vette, really

 

[AMontgomery]

Subbed.

At some point in the future, I'd like to have some semblance of a cage or bar, if for no other reason than to have a place to mount a true 4 point or 5 point harness for aggressive track use. The safety aspect is great but the ability to really strap in actually gives performance benefits as your arms can focus on steering and shifting and your feet can focus on dancing across the pedals instead of holding your body in the seat.

Granted, there may be a better way to accomplish that but having the added safety of a cage/bar is worth the hassle.

 

[RAAMaudio]

I had good results with reclining Recaro seats like SRD and speed used with Schroth DOT approved 4 point harnesses. They are designed to loosen at one side on the shoulder strap and allow your body to twist just enough to prevent submarining. I had a set in the FiST, both front seats, installed them then found NASA would not let me use the ones made for the BMW I had them in

The were far easier to use than a 5 or 6 point, did not need a roll bar, kept all the safety systems working as the stock belts still function when doing errands, etc...

 

[AMontgomery]

I'm looking them up now. I think having lockable belts for both shoulders would really make those stock Recaros shine on a twisty back road or Auto-X track.

 

[AMontgomery]

Looking at their Web page, I'm having trouble picturing how the shoulder straps mount in the stock locations. Do they go on either side of headrest on each shoulder and run down to the floor while leaving the stock retractable belt in place?

 

[meFiSTo]

I have to figure out if the clubs/orgs that run the track days around here will accept those 4-point harnesses. I'm conditioned to avoid them for non-caged cars, but could be these will pass inspection.