mom'sZ Posted December 26, 2006 Share Posted December 26, 2006 I purchased an Autopower bolt in roll cage for my car. I am trying to install it and have some questions. Please see picture below This picture shows the main hoop positioned roughly in place. The seat is a MOMO start. It is FIA approved and will therefore not need a seat back brace. My problem is that the shoulder harness, when run through the holes in the seat and wrapped around the crossbar ends up at a sharp angle. Much discussion on another thread and reading mfg's documentation has come to the conclusion that the harness should be no more then around 15 degrees up or down from the holes. When I am seated in the seat, the holes line up with the tops of my shoulders pretty well. I could and may lower the seat some, maybe an inch or so, but the harness would still be at a bad angle. Compounding the problem is that I'm not a short guy, six foot, so the seat is back quite a ways and is almost against the main hoop. There will be very little room for the three bar adjuster on the harness between the bar and seat. One solution I have considered is welding another crossbar between the rear brace bars to attach the harness to. You can see one of the rear braces in the picture. What do you think of that or maybe a better idea? I don't need advice on how the cage could have been better constructed or where the bars should attach. It is what it is, and I'm trying to make it work. See below for why I chose this cage. Also please answer only if you have direct experience with race prep or cage construction. Why I got an Autopower cage I purchased this cage because I would like to get this car on the race track. It is constructed from the proper size bar and has passed tech for SCCA competition many times. I have purchased a spare 280z body shell and plan to strip it down, blast it, do the metal work and then have a proper custom roll caged welded in. The parts would then be swapped onto that car from this one. This cage is a short term solution so I can race. I will be happy to answer anyone's questions about how it fits ect. just ask Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 26, 2006 Share Posted December 26, 2006 One solution I have considered is welding another crossbar between the rear brace bars to attach the harness to. You can see one of the rear braces in the picture. What do you think of that or maybe a better idea? That's one option. I had done this to my Autopower roll bar when I had it. I sold it to Auxilary, he might be able to show you a picture if you ask him. The other is to weld a bar across the strut towers, and run your belts off of your welded in strut tower bar. A third option is to weld a loop onto the strut tower on each side and use the clip on connectors for the seat belts. John B (gramercyjam) did this on his autox car, I searched but could not find the thread. Maybe PM or better yet email him. Haven't seen him hanging around as of late. Quote Link to comment Share on other sites More sharing options...
Jeff Posted December 26, 2006 Share Posted December 26, 2006 I cut off the seat brace bar and welded a harness bar on the diagonals instead of the main hoop. My Autopower unit did not have a horizontal bar from the factory though. I bought it used so I have no idea how old it is. Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted December 26, 2006 Author Share Posted December 26, 2006 ...The other is to weld a bar across the strut towers, and run your belts off of your welded in strut tower bar... Jon, that is not an option as the car is being prepared for improved touring and would be illegal. Quote Link to comment Share on other sites More sharing options...
2ManyZs Posted December 26, 2006 Share Posted December 26, 2006 I'd cut the flat bar out and do like Jeff did and add a tube between the rear diagonals so you'll be ITS legal and you can put it at the height you need for your belts once you get the seat at the height you want. With an extra tube back there, you'll actually benefit a bit by having a legal rear strut tower bar because of where the rear legs mount and it will be legal. You can also weld a thick flat plate to that bar and mount the shoulder straps with either a bolt thru mount or an eyebolt and clip on, or just do a wrap around on the bar itself. By the looks of the seat height, you're probably going to want to bolt that seat as close to the floor as possible or you may end up with your helmet against the main hoop. The Autopower cage I had in my car, I had to mount my aluminum seat on 1 inch square tubing on the floor for head room. My question is, where is the diagonal in the main hoop? Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted December 27, 2006 Author Share Posted December 27, 2006 My question is, where is the diagonal in the main hoop? It just out of the picture, here's another shot Quote Link to comment Share on other sites More sharing options...
katman Posted December 27, 2006 Share Posted December 27, 2006 Sorry to say, but the top of the inner fender is not a safe place IMHO to mount the main hoop. And how are you going to do door bars? There was a time, like 1983, when just a roll bar was legal for IT (Z's were in ITGT back then), and I raced one just like this (but with a crossbar between the aft legs as previously mentioned to attach the harness to at the right angle), but I wouldn't use this as a foundation for an ITS cage today. Not after what I've seen. I think this Autopower rollbar was originally certified for SCCA Solo I and showroom stock a really long time ago. It really isn't what they have in mind for ITS. The main hoop really needs to mount to the floor, in front of the inner fender, so it can shear the vertical loads into several load paths. That also gives you something to mount your door bars to. http://www.izzyscustomcages.com/ZCageArticle.html for the discussion on ITS cages. Quote Link to comment Share on other sites More sharing options...
2ManyZs Posted December 27, 2006 Share Posted December 27, 2006 OK, I figured it was just out of the picture. Hmm, they kept the diagonal the same all these years. I was under the "ass"umption that they were going to make it a full width diagonal but obviously they didn't One word of caution, when you are fitting your forward tube, take a little extra time and make sure you have it mounted to the main hoop as high as possible for as much headroom as possible while your sitting in the seat. Mine was so close to my helmet, that after installing the roll bar padding it ended up as a headrest in a right hand turn and it got annoying really fast. Quote Link to comment Share on other sites More sharing options...
2ManyZs Posted December 27, 2006 Share Posted December 27, 2006 Katman, there have been rumors in the Tech shed for the past couple seasons about the Autopower cages and the fact the main hoop doesn't go to the floor/rocker panel. There's only one problem, the Autopower cage is the spec cage for Spec-RX7. Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted December 27, 2006 Author Share Posted December 27, 2006 ...how are you going to do door bars? ... Keith: the door bars are included in the kit. The kit has not been updated to 07 specs yet for the double door bars on both sides requirement but autopower sent me two extra door bars and the weld on stubs (already fish mouthed) to weld on myself at no extra charge. At first I didn't think there was any way the second bars would work but after a quick trial fit, it looks like they will. The original door bars come off the main hoop right at the bottom, just above the mount pad maybe an inch or two up. They angle down and curve right where the seat back is and then a straight shot forward to the front down tubes. (I can snap a pic if anyone cares to see) They end up a few inches above the rocker, about thigh hieght. I plan to attach the secound bars about 4" - 6" above the first ones. This would have them originating right about where the horizontal in the main hoop is. Quote Link to comment Share on other sites More sharing options...
jmark Posted December 27, 2006 Share Posted December 27, 2006 Good stuff Keith. Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted December 27, 2006 Author Share Posted December 27, 2006 ...there have been rumors in the Tech shed for the past couple seasons about the Autopower cages and the fact the main hoop doesn't go to the floor/rocker panel... I have heard rumblings to that effect as well. But I have read and reread the 07 GCR and not found anything making this cage illegal. Don't get me wrong, I'm not thrilled about where this thing attaches. Being a former collision tech, I know the wheel houses to be one of the strongest parts of a unibody. But that doesn't give me a whole lot of confidence that in a roll over it won't punch right through the sheetmetal. I plan to round the edges of the pads to help prevent that. I'd feel a lot better if the rear stabilizers ran to the tops of the strut tower where the stock shoulder harness attaches. Obviously a lot of compramises were made to accomidate installing it with full interior (a throw back to it's showroom stock origins) When you get the whole thing inside the car, it gets down right clostraphobic (sp?) in there. The door bars are against your thigh, the foward tube is against your head and in a roll over, if the roof is crushed down any at all it will make egress about impossible. I raced motorcycles about ten years ago and considered this 'safer'. The first time I mocked it all up and crawled inside, I thought about going and buying a new GSXR. Suddenly getting thrown clear seemed not that bad. Like stated in my first post, I'd like to get through driver's school and get my license. I have another shell and will put a real cage in ASAP. Quote Link to comment Share on other sites More sharing options...
frank280zx Posted December 27, 2006 Share Posted December 27, 2006 Not that safety was a HUGE issue back in the day.. but the factory cars had similar cages mounted And another pic Alan used in one of his threads( Alan where did you get this as i could swear i have seen the exact same picture in a book i have, or is it yours there aswel ) and another pic from the same thread. A friend of mine has a Factory car that even has the panels prepped to accept the cage So i guess back then this was the rule of law .. so my bet is that is safe enough to do something. Some of the drivers hated a full cage so removed it .. as it blocked sight! Quote Link to comment Share on other sites More sharing options...
bjhines Posted December 27, 2006 Share Posted December 27, 2006 They ALL have the weld nuts and stampings to accept the factory style cage.... I brought this up.. I was removing ALL of the unused weld nuts in my chassis to reduce weight... all of them... This area came up as a mystery... I posted the pic with the green circles and I was informed that EVERYONE knew about this 30 years ago... How quickly we forget.... In any case... The areas that the factory cage bolted to are some of the thinnest metal in the entire car... I would not rely on these areas to save you in a crash... and the comment was made that that was never intended for use on track in wheel to wheel racing... It was a rally car "safety bar" back in the days when people died on course regularly... Quote Link to comment Share on other sites More sharing options...
frank280zx Posted December 27, 2006 Share Posted December 27, 2006 i know they all have it.. his car however has all the 'special padding' aswel i know this came for the tread you started, but it was easy linking it from hybridz site..Thanks for the green markers it pointed it out in this case again .. that mounting a cage there is not such a bad idea i agree on safety concern however .. as in those days the even just drove around in tshirt LOL but even for piece of mind i would rather tie it to the floor... Quote Link to comment Share on other sites More sharing options...
bjhines Posted December 27, 2006 Share Posted December 27, 2006 oohhh..... post some pics of the padding please... Quote Link to comment Share on other sites More sharing options...
frank280zx Posted December 27, 2006 Share Posted December 27, 2006 haha i dont have any.. but im sure they will be on line soon enough It has the panels cut out to accept the cage .. but the cuts are pretty fluent so not really cuts . it is really interesting to see a real works car with your own eyes once .. so many little things different .. i cant even begin to sum em up Quote Link to comment Share on other sites More sharing options...
bjhines Posted December 27, 2006 Share Posted December 27, 2006 Knowing what I know now... I would love to pour over a Works car with a camera.... Quote Link to comment Share on other sites More sharing options...
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