If I remember correctly, 1 3/4" x .095" DOM tubing weighs about 1.5 lbs per foot; .125 is about 2 lbs per foot. What are you using Aaron?

Don't forget that you've removed maybe 15 lbs of stock roll hoops and trim, so subtract that from your 30 - 40 lb Bitterbar and it is really not an issue.

 

"This bar does not need to be as thick as the main bars. Your thoughts on this would be welcome"

I am talking from memory...so forgive me if I am wrong.

I think according to SCCA rules, all the bars have to be the same diameter and thickness. I do not have the rule book handy, but I think that is what it says. Someone correct me if I am wrong. This is for Solo II rules.

Chip

 

I believe that all required elements have to be the same specified diameter and thickness; additional reinforcements may be of different diameter and thickness.

 

Judging by the weight figures provided by Allan, the bar would way 40lbs at most. subtracting 15 for stock comonents gives an increase of roughly 25lbs. I'll have exact figures next week.

I'll keep everyone posted.

Aaron

 

It looks like a pretty good piece, but I can see one major problem concerning the rear braces. The following is taken from the SCCA GCR, but similar wording is also included in the PCA's (Porsche Club of America) 2002 Club Racing Rules, whose rollbar/cage construction guidelines must be adhered to by any open-topped car running a PCA sanctioned Driver's Event in anything higher than the Green run group. As follows:

SCCA GCR Section 18.2.6 Bracing: The main roll hoop shall have two braces extending to the rear attaching to the frame or chassis. Braces shall be attached as near as possible to the top of the main hoop not more than six (6) inches below the top and at an included angle of at least thirty (30) degrees.

Although the rear braces may indeed be at a thirty degree angle from a vertical plane, they most definitely are not at a 30 degree included angle to the main hoop. Nor is the main hoop in a vertical plane. Although I couldn't find any specific wording prohibiting this in my brief skim of the GCR, I have never seen an integral roll structure in which the main hoop was not mounted in the vertical plane, and I would be willing to bet that some sanctioning bodies might take issue with this.

At any rate, in its current form, it is my opinion that this bar would not be considered legal for either Solo I events, or PCA DEs, at the very least. I'm not trying to dissuade anyone who is interested in it from purchasing it or pursuing it further, but just offering some input for those who may considering this as a bar for use at any track event.

 

Altiain,

The rear kicker angle is definately the primary problem (thus the Z3's I've seen with holes cut in their trunk for the rear kickers to go through!), I'm not sure that the vertical plane issue is a problem. I'm going to take this bar to an SCCA tech to see what they say, but that being said, people should know that it was designed with three goals in mind:

A) to make the bar as high as possible
B) to make the bar as strong as possible
C) to make the bar fit under/with the soft-top

Obviously I believe the bar achieves these goals in the best possible way. That being said, other than for my peace of mind knowing I'm safer on the track and on the street, I also installed the bar to be able to run in events where I normally wouldn't be able to. It may be that it doesn't pass SCCA inspection, in which case those of you interested in SCCA competition shouldn't get this solution. However, the bar does enable me to run with almost every group and on every track that previously wouldn't let me run. This includes the POC (Porsche Owner's Club) and other competitive time trial groups.

It may end up that this bar is for everyone EXCEPT those looking to run SCCA, PCA, and with other organizations that strictly adhere to SCCA guidelines.

dt

 

dt - I agree. I think your roll bar is great for non-competitive track days! I would give me more peace of mind when trying to push the car harder. Since it is removable (big plus ) those running SCCA club racing events can bolt in their roll cage.

altiain - If you are doing Solo II events, I think you can run with your stock roll hoops. If you are doing club racing, you need a full roll cage. If I read section 18 of the GCR correctly, the requirements apply to Club racing and not Solo II. My guess is that Aaron's bar would be legal for Solo II and SCCA driver schools.

 

Gil,

Also, I believe groups like TCRA, which run races and competitive time trials, and which have aftermarket rollbar requriements will approve this bar. I look forward to attending my first TCRA event just to find out.

Of course the S2000 Challenge Series (www.speedventures.net) allows the stock roll hoops in our time trial series .

dt

 

Gil,

Thanks, but I don't even own an S2000 (check my signature line). However, my particular roadster is equipped with a bar that meets all of the GCR specs.

I'm well aware of what is or isn't necessary to run Solo II, club racing, and the DEs put on by the organizers in my area of the country. You guys in California have a lot more tracks and event organizers to choose from. Where I am, we get mostly NASA, PCA, BMWCCA, and Driver's Edge events. I was just speaking from my experience that the bar in question would most certainly not be legal in anything beyond the Beginner's run group at any PCA-sanctioned event in 2002, as they are now all being required to follow national guidelines for scrutineering, whereas previously they had been left to make up their own rules Region by Region.

As for the GCR rules, doesn't it bother any of you in the slightest that the bar wouldn't meet them? It's not like the SCCA threw a bunch of acute angles into a hat and drew 30 degrees at random. The rules are the way they are for a reason. That reasoning has been developed through years of crash data analysis, and countless hundreds of hours of engineering research. In plainer terms - the rules are there for your own safety. Just because a local sanctioning body will allow you on the track with this particular bar is in no means an indication of its ability to protect you in a rollover. Due to some of the constraints of its design, it would appear (to me, at least) to be potentially susceptible to failure should a car be rolled while travelling backwards at a good rate of speed - a distinct possibility on a racetrack.

Again, I'm not trying to convince anyone to use or not to use the particular bar in question. Nor am I trying to imply that the aforementioned product is inherently unsafe. Heck, living is inherently unsafe. I'm just raising some questions I haven't seen addressed here.

 

Altiain,

You're right, except for the fact that this bar has strengthening/reinforcement features not required by SCCA. It may actually be stronger and safer than a bar which meets the minimum SCCA requirements. It is in fact designed and built by a person who has been building cages and rollbars in the racing community for 20 years, not someone who throws random pieces of metal and acute angles into a hat.

Either way, as stated before, the question is whether it's safer than stock, not safer than an SCCA approved version. The solution is designed to enable an S2000 to be a roadster; both a daily driver, and a performance car for the circuit.

As far as it's strength in a situation where the car is travelling backward and upside down, I think it's just as sturdy as it would be if the car is traveling forward and upside down. The two large single plate mounting points are probably the weakest link and they would rip off the body of the car just as readily going forward as backward, in fact probably more readily going forward given that one of the two vertical side mounts is on the foreward portion of the bar.

BTW, Bitterman Time Trials, Inc. does not hereby condone, implicitly or explicity, the driving of cars upside down. Passengers located in cars travelling upside down, forward or backwards, are subject to potential risk and physical danger.

dt
Bitterman Time Trials, Inc.