stony Posted June 22, 2007 Share Posted June 22, 2007 Need some advice on my chassis. My main concern is how the cage is attached to the body and if there need to be any more attach points. First question is on how the cage attaches to the from firewall. Right now it is only tacked. I'm not sure if there were going to be more tubing added.... My question is in this picture is just finishing the weld abound the tube to the firewall good structurally??? it is identical on both sides. myt biggest concern is how teh frame rails just kind of hang there not connected to anything. here is a pic. any suggestions are welcome. I was thinking that somehow the floor pan and frame rail should be connected to the cage somehow. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 22, 2007 Share Posted June 22, 2007 I'm not sure how to connect the floor to the cage. I don't think what has been done there is bad, I just don't know how to connect the two parts, although I'll be sure to check back and see, because I bet my attaching my dash is going to be very very similar... As far as the firewall goes, in my opinion they should have cut a hole in the firewall, slipped a single tube through it, welded it in, and then made a patch around the hole in the firewall. What they've done on your car is not good because you will have a weld joint right in the middle of a structural tube. If you don't want to cut that tube out and redo it I think your best bet is to weld a plate in at the floor that is cut to fit around the tube on both sides and make sure that the welder is set high enough to attach the plate to the tube and the tube to the tube fusing all the parts together fully. Quote Link to comment Share on other sites More sharing options...
stony Posted June 22, 2007 Author Share Posted June 22, 2007 The tube was never meant to go thru the firewall. The cage is being built not to go thru into the engine compartment. Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted June 22, 2007 Share Posted June 22, 2007 NHRA specs call for a 6 inch square piece of 1/8" plate at the junction of the body and the cage. FWIW Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 22, 2007 Share Posted June 22, 2007 The tube was never meant to go thru the firewall. The cage is being built not to go thru into the engine compartment. Oh, I thought the 2nd pic was showing a second tube protruding on the other side of the firewall. then I would plate around it with the 1/8" like dr hunt suggested and call it a day. Quote Link to comment Share on other sites More sharing options...
johnc Posted June 22, 2007 Share Posted June 22, 2007 SCCA spes are for a .083" or thicker plate, no more the 100 square inches, no longer then 12" on any one side, and no shorter then 4" on any one side. Plates must be welded all the way around to the sheet metal structure and the cage tubing is welded all the way around to top of the plate. The door hoop needs to be one continuous peice all the way to the floor right next to the rocker panel. Having it end on the bar running forward to the firewall is bad from a roll over perspective and will fail tech with most road race sanctioning bodies. An impact on the top of the driver's side A pillar will crush the cage down the distance between the bottom bar and the floor pan. Roll cage elements should be designed to take tension/compression loads, not bending loads. You might be able to fix it and pass tech if you create a plate box under that 3 tube junction connecting the junction to the floor pan and rocker panel. Gusset the tube(s) to the plate box. Quote Link to comment Share on other sites More sharing options...
stony Posted June 22, 2007 Author Share Posted June 22, 2007 SCCA spes are for a .083" or thicker plate, no more the 100 square inches, no longer then 12" on any one side, and no shorter then 4" on any one side. Plates must be welded all the way around to the sheet metal structure and the cage tubing is welded all the way around to top of the plate. The door hoop needs to be one continuous peice all the way to the floor right next to the rocker panel. Having it end on the bar running forward to the firewall is bad from a roll over perspective and will fail tech with most road race sanctioning bodies. An impact on the top of the driver's side A pillar will crush the cage down the distance between the bottom bar and the floor pan. Roll cage elements should be designed to take tension/compression loads, not bending loads. You might be able to fix it and pass tech if you create a plate box under that 3 tube junction connecting the junction to the floor pan and rocker panel. Gusset the tube(s) to the plate box. You cant really see it the way i took the pics but there is a plate behind where the 3 bars come together and it is welded to the horizontal tube. I will try to get some better pics. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 23, 2007 Share Posted June 23, 2007 I don't think Stony is too worried about SCCA rules. Seems like NHRA is going to be the sanctioning body... Quote Link to comment Share on other sites More sharing options...
stony Posted June 23, 2007 Author Share Posted June 23, 2007 I don't think Stony is too worried about SCCA rules. Seems like NHRA is going to be the sanctioning body... But still concerned that that will still apply in my case if not for anything else but the right way to build it. In looking at my chassis and the way its put together it looks like the bar along the rocker is actually part of teh rocker the way it is welded. There is a professional chassis guy coming back to alaska in august and he is going to look at it. If it is up to his standards he will finish it. If he finishes it it will be done by the end of august. If i do it maybe next year :< Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted June 25, 2007 Share Posted June 25, 2007 I'm so disappointed that this project is taking so long due to "other" fabricators taking and enormous amount of time to complete such a simple project. By simple I mean that chassis builders do this all the time, welding shops do this all the time and you can never finish if you never work on it. I'm dismayed by the lack of progress like stony is but I also know that in the end it will be worthwhile. Quote Link to comment Share on other sites More sharing options...
stony Posted June 25, 2007 Author Share Posted June 25, 2007 NHRA specs call for a 6 inch square piece of 1/8" plate at the junction of the body and the cage. FWIW So in this pic all that is needed is for a plate to be welded in? Im starting to calm down a bit and getting more motivated to get this thing going. I WILL BE UP AND RUNNING BY NEXT YEAR!!!! shooting to have it running by the time the snow starts flying again this year Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted June 25, 2007 Share Posted June 25, 2007 So in this pic all that is needed is for a plate to be welded in? Im starting to calm down a bit and getting more motivated to get this thing going. I WILL BE UP AND RUNNING BY NEXT YEAR!!!! shooting to have it running by the time the snow starts flying again this year That is correct according to the new 2007 NHRA rule book. Running by the time snow starts flying again? I thought snow fall in Sept was normal?!! Quote Link to comment Share on other sites More sharing options...
stony Posted June 25, 2007 Author Share Posted June 25, 2007 Another concern i have is how the rear part of the cage is attached to the body. In the below picture the only thing added are gussets to each side of the tube. i can push on the rear 1/4 and get movement out of the body. This cant be good. should the rear part of the body be attached in more places to keep it from moving around. and anyone with pictures of examples would be great. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 25, 2007 Share Posted June 25, 2007 I used to work on a Porsche racecar which had a widebody kit that was something like 10" wider than stock and super thin fiberglass. What we did on that one was to take your standard aluminum fuel tube that you buy in a roll from the auto parts store and cut a length and pinch the ends. Then we drilled a hole in the flattened end, fiberglassed a nut to the bodywork and bolted it to the bodywork. The chassis end was attached with a sheet metal screw. I really liked this setup because the tube was easy to work with -- and talk about light! I don't know what you could do for the inboard end seeing as you have to attach it to the cage somehow. I think this is going to be the same answer as your floorboards. Maybe drill a hole in the cage and tap it (seems like a bad idea) or weld a nut onto the tube? Someone with more race experience that I will come up with the proper solution I'm sure... Quote Link to comment Share on other sites More sharing options...
stony Posted June 25, 2007 Author Share Posted June 25, 2007 I used to work on a Porsche racecar which had a widebody kit that was something like 10" wider than stock and super thin fiberglass. What we did on that one was to take your standard aluminum fuel tube that you buy in a roll from the auto parts store and cut a length and pinch the ends. Then we drilled a hole in the flattened end, fiberglassed a nut to the bodywork and bolted it to the bodywork. The chassis end was attached with a sheet metal screw. I really liked this setup because the tube was easy to work with -- and talk about light! I don't know what you could do for the inboard end seeing as you have to attach it to the cage somehow. I think this is going to be the same answer as your floorboards. Maybe drill a hole in the cage and tap it (seems like a bad idea) or weld a nut onto the tube? Someone with more race experience that I will come up with the proper solution I'm sure... I was thinking about something on the same lines and tiring it into the backside of the wheel tubs. Im also thinking along the same lines of basically just welding sheetmetal and just boxing in that area between the tube and framerails. Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted July 11, 2007 Share Posted July 11, 2007 Now, that you have it back in your hands I wonder if you've ever thought of sending it to one the guys in the lower 48 to have it finished? Seems like it would get finished right if it were in a shop that had some competition. Quote Link to comment Share on other sites More sharing options...
stony Posted July 11, 2007 Author Share Posted July 11, 2007 Im bringing a guy up from the lower 48 Quote Link to comment Share on other sites More sharing options...
MoNkEyT88 Posted August 7, 2007 Share Posted August 7, 2007 keep us updated.. Quote Link to comment Share on other sites More sharing options...
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