Clarification of Factory "Roll bar" acceptance

[Dinoracer801]

This issue came up this year at at least one event, and I'd like to get a rule change/clarification in the book for next year. Since I don't have a dog in this fight myself, I'm really hoping to get some input from members on where COM should stand. <br>
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I'll throw out what I've got so far...please add your knowledge or opinions freely.<br>
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Section VI.F.4 requires roll bars in all open cars. The factory bars in some cars (Specifically looking at Honda S2000 and Porsche Boxster, although others may also be out there) are billed as rollover protection, that by our current rule book is not accepted. <br>
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Looking around online, I found that some other organizations allow these cars to run as is in their HPDE events, as long as they pass the "broomstick " rule. That is, lay a broom stick across the winshield and bar, and as long as your helmet doesn't touch, you're in.<br>
I found that there is a "roll bar extender" available for the Porsche that raises the top of the bar an inch or two to meet this requirement. I didn't see anything like it for Honda. <br>
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(EMRA states flatly that these two cars the factory stuff is no good. PCA says the factory Boxster roll bar is fine by them..)<br>
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I'm looking to propose a rule change that states clearly what the car needs to play in our sandbox. I'll start by advocating for a "broomstick requirement" plus added padding (which the factory bars seem to lack) for SS and ST cars. SP and P need a real roll bar preferably a cage.<br>
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Thanks for your input. <br>
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Tom C, club scribe<br>
'65 Mustang # 801 <br>
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[boltonite]

I was involved in a high-speed incident at WGI in 2004 in a convertible and I can tell you that as the car approached the armco (backwards) at ~ 80 mph I became acutely aware of the factory belts. When we hit the wall backwards those factory belts may not keep me from being thrown from the car, or so I thought. Maybe I'm being a wimp, but I did not feel secure w/ one diagonal torso belt.<br>
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If I were to lobby for any change for convertibles, as an instructor I'd prefer that these cars have full harnesses. And a windshield to keep bugs from flying into one's face (one kit car had no passenger-side windshield or wind deflector - it was a long day...but at least it wasn't raining).<br>
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Fred F

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[kfoote]

The Honda S2000 roll bar is held in by 8 6mm bolts. That should be enough right there to say it's no good, as that's barely enough to hold it in place as a decorative item.<br>
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The Porsche Boxster/Boxster S/993/996 convertible system isn't any good either. Basically, there's a pop-up lock feature on them that's very fragile.<br>
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There are a couple of Targa-top cars that have a structural integral roll bar that is sufficient for SP. The two cars I have come across are the C4 Corvette T-top and the Acura NSX. Both of these cars have a bar that meets the roll bar requirements built into the c-pillar structure. The Lotus Elise may also fit this category, though how it is attached to the chassis concerns me.<br>
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When I was Chief of Tech, I treated all of these on a case-by case basis, and I have not yet seen an OEM convertible roll bar structure that is strong enough and well enough designed to pass what COM is looking for.

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[Christine D]

Kevin,<br>
Have you seen the 2006 Miata? What did you think of its rollbar?

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[Subw00er]

I would love to use my s2000 at the track, but the rollbar rule keeps me from being able. I know many other clubs allow the s2000 without modification, some require hardtops. I do see a Boxster on the track from time to time with no visible modification. Personally, I feel it should be up to the discretion of the driver - similarly to how its the driver's preference as whether or not to use a full harness, or racing seat.

Also, many owners like myself have factory hardtops - perhaps s2000's with hardtops can be allowed?

I would personally love to see this rule changed as my s2000 would be great on the track (An added bonus is that it is much cheaper to maintain than my z06. Do you know that rear tires on my z06 are over $300 a piece?!)

[kfoote]

I would love to use my s2000 at the track, but the rollbar rule keeps me from being able. I know many other clubs allow the s2000 without modification. I'm especially annoyed that the Boxster is allowed and the s2000 is not. I do see a Boxster on the track from time to time. Personally, I feel it should be up to the discretion of the driver - similarly to how its the driver's preference as whether or not to use a full harness, or racing seat.

I would personally love to see this rule changed as my s2000 would be great on the track (An added bonus is that it is much cheaper to maintain than my z06. Do you know that rear tires on my z06 are over $300 a piece?!)

To my knowledge, the Boxster has to run a roll bar with COM. See my earlier post. I have never seen a Boxster run without a proper roll bar, and if it has, it certainly shouldn't have.

That having been said, the roll bar on the Boxster will at least do a little bit in the event of a roll over, as it is designed to be somewhat structural and has sufficient attachment points, but still not nearly what COM is looking for. The roll bar in the S2000 is 100% decorative ant has no structural strength at all. If it was designed to be more than decorative, it would be FAR more solidly attached than it is, and the attachment points that the 6mm bolts go through would be reinforced a lot more than they are.

In a best case scenario, assuming that Honda used at least the metric equivalent of a grade 8 bolt, the failure of the bolts holding the roll bar in is about 26,900 lbs of force. Assuming the car weighs 3000 lbs, that means the maximum g-forces that the bolts holding the roll bar in could sustain in the event of a rollover is just under 9 g's. As another way to look at it, if the roll bar has to support the entire weight of the car in the first 0.01 seconds of a rollover, and in that time the mounting points deform 3/8 of an inch, all of the mounting points fail. Keep in mind that these calculations are based on a best case scenario, all of the mounting bolts sharing the load perfectly evenly, and best case scenario force loading. For any load off perfectly vertical or perfectly horizontal (with the design of the bar, a force impact angle of 45 degrees is the worst angle), a good approximation of how little force can be sustained is to multiply the above numbers by the cosine of the angle.

If you really want to run the S2000, for the cost of a set of tires on the Z06, you could have a roll bar put in the S2000. Frankly, this is a HUGE safety and liability issue, and a place where I feel COM should not compromise.

[kfoote]

Kevin,<br>
Have you seen the 2006 Miata? What did you think of its rollbar?

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I haven't seen an 06 Miata in paerson yet, and haven't looked at the design enough to make an informed comment. My initial gut reaction is that it's probably better than the S2000, but not as good as the Boxster, meaning it's insufficient.

[Stynger]

I'd agree the '06 MX5 "roll bars" are unacceptable. Too low to begin with.

http://www.miata.net/news/nc_debut_file ... _0779.html
http://www.miata.net/news/nc_debut_file ... _0689.html

[dinoracer]

Thanks all for your input


I have submitted a proposed rule change that includes clarifying language regarding factory roll bars and harness/sport type bars.

We have had an unwritten understanding that anything not definitely a roll bar (ie; solidly and substantially mounted to the car, padded, and 2" above the helmeted head) does not count. The proposed change is to get this down in the rule book.

As such, the S2000, Boxster and a few others would not make it.

I did not include language regarding these same cars with an added hardtop, if they were available. I'm concerned that sticking a lightweight (fiberglass or aluminum) hardtop would skirt this rule, we'll have to discuss Wed I think

thanks

Tom Cannon

[Subw00er]

If you really want to run the S2000, for the cost of a set of tires on the Z06, you could have a roll bar put in the S2000. Frankly, this is a HUGE safety and liability issue, and a place where I feel COM should not compromise.

Thanks for the info. I do understand it is all about safety, but I (personally) still think it should be up to the discretion of the driver as the driver is the one that is at risk by not having a rollbar, not other drivers.

Can someone explain the liability issue to me? How does not having a roll bar make the club liable?

I have looked into roll bars, and besides having to cut the interior up quite a bit, it will cost $1500 when all is said and done (no one local to me does this sort of work). But the real reason I stopped looking at the roll bar is that it makes the driver's seat lose some ability to move backwards and this would create a horrible driving position for me.

About the Boxster, I saw it at Watkins Glen with no roll bar (I'm fairly certain of this, I could be wrong). I also actually took some video of it at Mt Tremblant. http://www.r1150r.org/temp/mt/boxster.MOV Looks like hes using a hardtop here. The video is not real clear, but I dont see a roll bar in there.

Its just a shame that I have this wonderful handling car and cant use it on the track without spending a a lot of money and ripping apart the car.. This is a daily driver, not a race car.

Maybe we can follow the lead of SCDA and allow factory hardtops?

[Subw00er]

I just came across this info about the s2000:

The windshield surround is specially strengthened by a tubular brace. The driver's and passenger's integrated roll bars are made of 1.5-inch diameter high-strength steel pipe with a .080-inch wall thickness. The roll bars are securely anchored to the high X-bone floor frame. The reinforced door pillars, and reinforced windshield posts and windshield frame all contribute to the car meeting the Federal standards for occupant protection in a rollover accident – even though open-topped cars are exempted!

If it meets federal rollover guidelines for enclosed cars, cant it meet COM?

[therooster]

I do not want COM to follow the lead of any other club except to err on the side of safety.

Have you ever seen a car roll? A factory hard top for a convertable does little more than increase the comfort of the passangers (or in our case the speed of the car on a race track). It is not a safety item. A bolted on peice of fiberglass is no more structural than a peice of canvas.

As "it should be up to the discretion of the driver ". That is not a good reason. The club as a whole depends on the safety of each member. If we stop thinking about that then the price of insurance goes up and then the price of events go up and then the reputation of the club gets hurt, then we have trouble getting events, then we need to start charging more for each event.....you get the idea I hope.

Also, if we allow a car that we know has a substantial risk of harm with no safety measures and someone gets hurt, the club becomes liable for all injury. This will increase the cost for all member.

As for the car at the Mt Trem event, if that was at a COM event it should have been required to have a roll bar. It also does not appear to have a rear window. I was not at the event, but if I was I would have pointed out to that participant that in addition to the required roll bar, that a rear window would be required for SS. ( Now before anyone gets on me for this. SS is a restricted class. Rules state that factory hard tops are allowed. Nothing says that they may be modified.)

If you want to discuse this further please PM me.

[therooster]

"1.5-inch diameter high-strength steel pipe with a .080-inch wall thickness"

This is still less than any "race" acceptable roll bar set up including COM's own rules(VI.F.4). Please explain how we could do this and not expose the club to liability.

Chris A.

[kfoote]

The factory hardtop is useless for anything except intrusion protection. Fiberglass does not support very much weight.

Also note that in ALL of my calculations, the strength and size of the roll bar itself was not questioned. The same reasoning I used works for an infinitely strong roll bar. A stiffer roll bar will theoretically make it worse as there will be less impact absorbed by the bar, transferring more to the bolts that hold the bar in place.

If I was still Chief of Tech, a Boxster with just the factory roll bar would have been sent home with no refund. IIRC, I did this in 2002 at Summit Point.

The liability is with the insurance company that COM uses. I don't know all the details of the policy, but the policy rates are based on the club rules and by-laws. If the safety rules are changed to be less stringent than what we currently have, the insurance rates will go up, and probably by a lot given the number of convertible cars that would be likely to show up if there was no roll bar requirement.

The forces that a car is likely to see on the street are FAR less than what is seen on the track. Having seen the results of a couple of rollover incidents that the driver had a fully welded cage in where the driver probably would not have survived, never mind walked away from if the car had a SCCA legal bolt in cage rather than a full welded cage, I'm totally against ANY rules that would reduce the safety standards of COM.

For an example of what can happen in an 80 MPH multiple rollover crash in a car with a full cage if the cage fails, there is some very dramatic in-car footage floating around on the internet form the 2004 Rally Deutschland of a Subaru rollover.

[brucesallen]

SCDA should NOT be considered as a good example.