Rollbar question for my 03 cobra vert

[CSCOBRA03]

Guys I'm interested in installing a roll bar on my Cobra vert and want to know what you guys recommend? I'd like something that is compatible with rules of SVTOA events and other race events that people do around here.

Thanks in advance

 

[David Hester]

SCCA Time Trials rollbar requirements
http://www.sccattse.org/images/Track_Trial_Rules.pdf
start page 148 Level 3


11.3.1. Basic Design Considerations
A. The basic purpose of the roll bar is to protect the driver in case the vehicle rolls over or runs into an obstacle such as a guardrail or catch fence. This purpose should not be forgotten.
B. The top of the roll bar must be a minimum of two (2) inches above the drivers’ helmet when the driver is sitting in a normal driving position
(as near the roof as possible on closed sedans) and shall not be more than six (6) inches behind the driver. In case of two driver cars, both drivers must be within the roll bar height requirement, however only one driver must be within six inches of the roll bar.
C. The roll bar must be designed to withstand compression forces resulting from the weight of the car coming down on the roll structure,
and to take fore-and-aft loads resulting from the car skidding along the ground on the roll structure.
D. The two vertical members forming the sides of the hoop shall not be less than fifteen inches apart (inside dimension). It is desirable that the roll bar extend the full width of the cockpit to provide maximum
bearing area in all soil conditions during rollovers. The roll bar vertical members on formula cars and other single seat cars with a center driver position must be not less than fifteen inches apart, inside dimension, at their attachment points to the uppermost main chassis member.
E. An inspection hole of at least 3/16 inch diameter must be drilled in a non-critical area of a roll bar member to facilitate verification of 11. Roll Bar / Cage Requirements
wall thickness. This should be at least three inches from any weld or bend.
F. It is recommended that steel gusset plates be used at all welds. Gussets should be at least two inches long on each leg and 3/16 inches thick.
G. It is recommended that roll bars be coated only with a light coat of paint. If, however, a roll bar should be chrome-plated, it is recommended
that the structure be normalized.
H. Post or tripod types of roll bars are not acceptable.
I. No portion of the safety roll bar shall have an aerodynamic effect by creating a vertical thrust.
11.3.2. Material
A. The roll bar hoop and braces must be seamless, ERW or DOM mild steel tubing (SAE 1010, 1020, 1025) or equivalent, or chrome molybdenum alloy steel such as SAE 4125 or SAE 4130. It is recommended
that mild steel tubing be used as a chromium alloys present difficulties in welding and must be normalized to relieve stress. Proof of the use of alloy steel will be the responsibility of the entrant.
Note: ERW tubing is not permitted in any GCR class car registered with SCCA after 1/1/2003. don't even consider anything but DOM drawn over mandrel. Most everyone is requiring it. Tad more, but safer with more uniform construction-no soft spots. DAVEB. For purposes of determining tubing sizes, the vehicle weight is as raced without fuel and driver. The minus tolerance for wall thickness
should not be less than .010” below the nominal thickness. Improved Touring roll cage tubing size is to be calculated based on the published vehicle weight minus 180 lbs.

Minimum tubing sizes for (all Showroom Stock, Spec Miata, Touring
and Improved Touring Category automobiles registered after June 1, 1994) for all required roll cage elements (All dimensions in inches):
Up to 1500 lbs. 1.375 x .095 DOM / Seamless / Alloy
1501-2200 lbs. 1.500 x .095 DOM / Seamless / Alloy
2201-3000 lbs. 1.500 x .120 DOM / Seamless / Alloy
1.625x .120 DOM / Seamless / Alloy
1.750 x .095 DOM / Seamless / Alloy
(American Sedans may construct to these specs regardless of weight.)
struct to these specs regardless of weight.)
3001-4000 lbs. 1.750 x .120 DOM / Seamless / Alloy
Over 4000 lbs. 2.000 x .120 DOM / Seamless / Alloy
Main hoop: 4 bends max., totaling 180º ± 10º
Front hoop: 4 bends max. or
Front downtubes: 2 bends max.
Rear hoop supports: No bends.
If any of the above bend requirements cannot be met, all components of the roll cage shall be fabricated from the tubing size(s) listed for the next heavier category of automobiles.
F. Where bolts and nuts are used, the bolts shall be at least 3/8 inch diameter SAE Grade 5 or equivalent aircraft quality.
11.3.3. Fabrication
A. One continuous length of tubing must be used for the hoop member

 

[brkntrxn]

Are you looking for racing or just HPDE types of events? Not sure about the groups in Cali, but there is a difference with most organizations.

As for a rollbar, give Autopower a call if you want to order a pre-built bar and install it yourself. You can get their typical 4pt roll bar with main hoop, rear down bars, diagonal cross bar and horizontal cross bar for a relatively good price.

 

[gcassidy]

Are you looking for racing or just HPDE types of events? Not sure about the groups in Cali, but there is a difference with most organizations.

As for a rollbar, give Autopower a call if you want to order a pre-built bar and install it yourself. You can get their typical 4pt roll bar with main hoop, rear down bars, diagonal cross bar and horizontal cross bar for a relatively good price.

What he said. That'll be fine for SVTOA/Track Guys.
But have the installer do anything he can to strengthen the mounting points.

 

[David Hester]

Just be sure to tell the folks at AutoPower what you want to use the car for (including future plans-don't want to have to do this twice, you really don't really want their "show bar" even though it is the cheapest) and they can get the correct bar to you.
Also note drag rollbars may not be legal on a road course. Two different sets of rules.

I had a buddy that bought a supposed NASA legal car. Turned out the gage used too small tubing (obvious through the window at 20 feet -well made, just not legal-big enough to support 3000+ lbs. Miata, maybe.) for SCCA or NASA. Ended up paying for 2 cages.

 

[pkwest]

maximum motorsports roll bar. Theirs has much larger mounting pads and thicker wall dom tubing than autopower.

 

[FX-Man]

So far the Autopower bar I got with the bolt in harness bar and diagonal bar has passed tech at SVTOA, various other HPDE events, and hillclimbs. Unless you plan on doing some wheel to wheel racing you should be fine with an Autopower.

 

[CSCOBRA03]

Thanks for your help. We are going to install it ourselves maybe the MM one.

 

[cobraracer46]

Guys I'm interested in installing a roll bar on my Cobra vert and want to know what you guys recommend?

I recomend the Convertible roll bar from Griggs Racing as it is the best one on the market. In my opinion, the Autopower and MM units are a very poor design.

I welded in the Griggs bar my self and the big thing that sets it apart from Auto power and MM is that main hoop points go right into the bulkheads and not the paper floor pan, plus there is more passanger room with this set up as you dont have a big roll bar hoop in the passanger compartment. I think it looks cleaner as well.

 

[mu22stang]

...plus there is more passanger room with this set up as you dont have a big roll bar hoop in the passanger compartment...

I hope you don't mean you are putting people in the back seat with a roll bar. oke:

 

[gcassidy]

Yea, that's not a real good idea.

But I do like the idea of attaching somewhere stronger than the floorpan.
Do you have any pics of the attachment points?

Is the Griggs convertible bar wider than the coupe bar? I have a friend with a Griggs bar in his Bullitt coupe, and it doesn't go into the sides like that.

 

[GR-40 Pat]

Yea, that's not a real good idea.

But I do like the idea of attaching somewhere stronger than the floorpan.
Do you have any pics of the attachment points?

Is the Griggs convertible bar wider than the coupe bar? I have a friend with a Griggs bar in his Bullitt coupe, and it doesn't go into the sides like that.

The main hoop mounts to the top of the B-Pillars in the convert. version, a much stronger mount point vs the floorpan or rear bulkhead that the coupe and most other roll bars mount to. This does however require cutting on the interior plastic to fit.

 

[firemanmike]

op:op:op:

 

[mu22stang]

I'm trying to find this bar, but I only see 05+ rollbars on Grigg's site. Maybe I'm looking in the wrong place?

 

[GR-40 Pat]

I'm trying to find this bar, but I only see 05+ rollbars on Grigg's site. Maybe I'm looking in the wrong place?

They might not have it on the website, give them a call

 

[NJ 03Mach1]

That Griggs bar will not pass SCCA tech if I remember correctly... it MUST have a diagonal bar that runs from the main hoop down to the opposite floor area such as, guess what!? The MM bar. The MM bar is a great product, very well built and when installed PROPERLY will work perfectly fine. I love mine, and have no doubt it will work if ever needed.

I hope it never happens, but that Griggs cross bar would be a missile if those bolts fail in a rollover. I'd much rather have my life welded together then bolted.

ArtsPerformanceParts.com can get you anything MM sells, at a cheaper rate.

** Just looked up the rules, SCCA does not require it, but "recommends it"

My hillclimb rules require it, always mixing up the books...

 

[David Hester]

For anything above level I time trials requires the diagonal. Griggs shown won't cut it. You need the diagonal and the rear kickers.
Meets many club rules for roll bars in open track cars. um, open track days only- no competition rule. You can install race harness while retaining the OEM seat and shoulder belts for the street. Powder coated Satin Black. Requires minor modification to interior trim panels near floor level below B pillars.

For race car use, simply weld in and add two tubes to rear frame section and it will meet most 4 point roll bar requirements, or become the foundation for a full 6 or 8 point roll cage meeting SCCA/NASA Spec....

For $1,000 + you could have a legal bar.

 

[cobraracer46]

That Griggs bar will not pass SCCA tech if I remember correctly... it MUST have a diagonal bar that runs from the main hoop down to the opposite floor area such as, guess what!? The MM bar.

I hope it never happens, but that Griggs cross bar would be a missile if those bolts fail in a rollover. I'd much rather have my life welded together then bolted.



.

Not quite.:lol: The SCCA defines a "roll bar" as a main hoop supplemented by two additional bars/ attachment points so as per the rules, the Griggs roll bar is legal. The Griggs roll bar must also be legal in NASA as well sine I've seen it used in NASA time trials.

If you read the SCCA rule book, you will see that a roll cage is defined as a main hoop with a diagonal brace supported by 4 or more bars/ attachment points and since the Griggs bar is not a roll cage then the diagonal requirement does not apply because the part on my car is a roll bar and not a roll cage.

In my opinion, I think the autopower and MM convertible roll bars( not to be confused with a roll cage) stink and that is why I went with the Griggs convertible roll bar.:beer:

 

[David Hester]

Autopower does make a SCCA/NASA legal enry level rollbar, just tell them what you want and not that expensive...
Again for $1,000 be sure you won't move up past entry level events in the future and have to start all over again with a rollbar or cage.
The SN197 hoop, I don't think would make it. SCCA wants kicker front or back. The B piller seatbelt anchors aren't going to cut it in anything about level one.

 

[Jowsik]

Hey guys, I have one for sale if anyone is interested. It was made by Phoenix CMR which runs events at the Glen. It was my neighbors and when he moved he gave it to me to get rid of. Let me know if your interested and I'll get you the rest of the details and some pictures.