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help with design of roll bar

hymodyne

Senior Member
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I'm interested in suggestions, photos and any other assistance in designing a single hoop rollbar and supporting structure to install in my GT6 MK III. the tub is off the chassis at the moment and during this time I'd like to put in a SCCA compliant rollbar.

James
 
Go to scca.com and look up the rules under the cars section. Basically the main hoop needs to be bent in one plane. You will need a diagonal from one top corner down to the opposite side lower. You will also need a horizontal bar at about shoulder height, and rear facing down tubes at no greater than 30 degree angle. The website will list the materials and all of the nuances you will need to know. Pretty easy to follow.
 
As Todd mentioned, you need to look at the SCCA-GCR

~Click Here~ to see it.

Generally, to be SCCA compliant for racing would require a full cage (not just a single roll bar). But if you're using the car for autocross, a single bar is probably OK. In that case it's probably best to go to your local autocross club and check out the legal cars before commiting to welding anything.

The Autopower catalog mentione above has some good illustations:

https://www.autopowerindustries.com/
 
Please be sure that you vehicle is listed in the SCCA's book for the events that you are planning on attending.
 
Look at the pictures of the Grassroots Motorsports restoration of the ex-Group 44 GT6 - they have had several segments over the past months on this project. Last month's dealt with the rollbar (the GRM crew is backdating to like 1970 specs for historic racing purposes). Plus, you'll likely pick up a lot of good GT6 info from this series of articles. Sorry I can't give you date and issue # cites, my wife makes me keep the number of back issues of car mags down to the minimum.
 
On Spitfires and GT6s with the frame and chassis being separate you mount this main hoops a bit differently, you'll need flat pads on the bottom the main hoop that serve as attachment plate that sit in the floorboard, with a suggested (4) 3/8" grade 8 bolts securing them to,and thru the floorboards with thick back up plate the same general size as the maouting palte on the top side used below the tub where the bolts from the mounting will be nutted, this is required by the SCCA so the cage will not pull thru the floorboard, you can also weld the mounting plates along the edges to the tub on the top side to give addtional security and still have a tub that is removable from the chassis if needed for futrue work or repairs. Hope this helps.
 
I have my roll bar components now, and I'm looking at the best way to fit it in the car. The single hoop will sit nicely on the outer edges of the rear seat area, specifically on the small area right in front of each rear wheel well. This is where I would like to install this hoop, but this area sits right on top of an I beam that the rear suspension links attach to. I'd like to drill through and attach my support plate to the underside of the I beam and run long bolts of the appropriate grade through to attach.

suggestions would be appreciated,

Hym
 
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