Sleeper-Z Posted October 14, 2005 Share Posted October 14, 2005 just doing a little thinking and it is possible that i'd go ahead and tube the front and mid-sections of the car. i've searched various race sanction rules but all goes towards the thickness and diameter for roll cages. my question is, what would you [the educated reader] would recommend (as far as mild steel 1020 DOM tubing width and diameter) for a fairly low torque, about 225-275 ft. lb., non-neck braking 280z. keep in mind i have all fiberglass panels (fully gutted with a 14-point cage), no dash, nothing except for steering shaft, seat, gauges, and fire system; and will be using an engine/transmission setup lighter than stock. car is non-street driven. i am aiming for 1700-1800 lbs if not lighter... note: everything is going to be tied into each other correctly and is going to be done right. i was thinking of matching the cage diameter, but if i could get away with using smaller diameter tubing (weight purposes) safely i will go ahead and do that. 4130 is not an option because a. don't have a tig welder b. not cost efficient. but it would be nice to get the weight benefit of using 4130 over mild steel, maybe later in life. thanks! steven m. Quote Link to comment Share on other sites More sharing options...
tube80z Posted October 14, 2005 Share Posted October 14, 2005 i've searched various race sanction rules but all goes towards the thickness and diameter for roll cages. my question is' date=' what would you [the educated reader'] would recommend (as far as mild steel 1020 DOM tubing width and diameter) for a fairly low torque, about 225-275 ft. lb., non-neck braking 280z. keep in mind i have all fiberglass panels (fully gutted with a 14-point cage), no dash, nothing except for steering shaft, seat, gauges, and fire system; and will be using an engine/transmission setup lighter than stock. car is non-street driven. i am aiming for 1700-1800 lbs if not lighter... i was thinking of matching the cage diameter, but if i could get away with using smaller diameter tubing (weight purposes) safely i will go ahead and do that. 4130 is not an option because a. don't have a tig welder b. not cost efficient. but it would be nice to get the weight benefit of using 4130 over mild steel .095 1.5 inch tubing should be fine. I have seen many cars built that way at a shop near me that have won many championships. For your weight target be prepared to bolt in weight. My project is an EMOD V8 powered autoxer. All the pieces (complete frame) and everything else piled on the car weighs 1640 pounds. It is built with .095 for the outer sections and main cage tubes and a lot of .064 and .049 used as bracing for sections that showed low stress in simple FEA tests. You will need to check on materials if you plan to roadrace. I'm pretty sure all the tube needs to be the same thickness in GT and DOM. Cary Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted October 14, 2005 Share Posted October 14, 2005 I built my tube front end with two criteria: First, I wanted it to be light and strong. Second, I wanted to use the stock (sort of) suspension attach points. Here is my take on it as stated in this thread: http://forums.hybridz.org/showthread.php?t=102715 " My strut bar and the two tubes connecting the main hoop to the strut bar are 1.625 x 0.083. The main hoop, the diagonal, and the bars from the top of the main hoop to the strut bar are 1.625 x 0.120. All of the tubing is 4130N (normalized chromoloy) and is TIG welded. My door bars are 1.625 x 0.120, the hoop at the firewall is 1.625 x 0.083, and most of the front end tubing is 1.625 x 0.065. My subframe is 2.5" square x 0.085 mild steel. All of the tube not specifically designated in this picture are 1.625 x 0.065 " I like to use several thin wall tubes arranged in triangles rather than put a thicker tube in bending. When I cut off the front of the car, I weighed all of the pieces (frame rails, inner fenders, strut towers, radiator core support, etc.). The stock pieces minus the fenders, hood, and headlight buckets weighed 95 lbs. The structure that I replaced it with weighs 45lbs, and is much stronger and stiffer than the stock front end. If you are interested, there are more photos of my cage/front end in my album. By the way, I was inspired by the work of tube80z when I began my tube chassis design. I have since lost the link that showed pictures of his tube chassis. Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted October 14, 2005 Share Posted October 14, 2005 I used 2-1/2" .120 wall square tubing for the front of my car and 1-1/2 x 2-1/2 rect. .120 wall tubing for the under the car. Instead of doing tube supports up front, I welded the tubing to the stock inner fenders. I do have a tubular radiator support and tubular spreader between the frame rails. Quote Link to comment Share on other sites More sharing options...
Sleeper-Z Posted October 14, 2005 Author Share Posted October 14, 2005 .095 1.5 inch tubing should be fine. I have seen many cars built that way at a shop near me that have won many championships. For your weight target be prepared to bolt in weight. My project is an EMOD V8 powered autoxer. All the pieces (complete frame) and everything else piled on the car weighs 1640 pounds. It is built with .095 for the outer sections and main cage tubes and a lot of .064 and .049 used as bracing for sections that showed low stress in simple FEA tests. You will need to check on materials if you plan to roadrace. I'm pretty sure all the tube needs to be the same thickness in GT and DOM. Cary the existing cage in there is 1.5 but not sure on the thickness. have to research more on rules and see what's the thinnest and safest i can go but .095 sounds good. i'll be using SAE 1020 DOM tubing. do you have any pictures of your car? (not going to copy it but would like more ideas. BTW' date=' is 1640 including motor, drivetrain? maybe i should be aiming for 1450-1500 lbs! When I cut off the front of the car, I weighed all of the pieces (frame rails, inner fenders, strut towers, radiator core support, etc.). The stock pieces minus the fenders, hood, and headlight buckets weighed 95 lbs. The structure that I replaced it with weighs 45lbs, and is much stronger and stiffer than the stock front end. If you are interested, there are more photos of my cage/front end in my album. when i searched around before this z you were my main inspiration for tubing. great pics. yeah triangulation is key for strength, or that's what the motto is for tubing my car. 50 lbs under stock and stiffer sounds great! I used 2-1/2" .120 wall square tubing for the front of my car and 1-1/2 x 2-1/2 rect. .120 wall tubing for the under the car. Instead of doing tube supports up front' date=' I welded the tubing to the stock inner fenders. I do have a tubular radiator support and tubular spreader between the frame rails. [/quote'] thanks, i'll keep that in mind. i was wondering if there are any draw backs if i replace the front frame rails instead of using square tubing to go ahead and use that 1.5x.095 from the rear frame all the way to the front (replacing/eliminating the front square tubing) boxing and tieing it in with the outer frame rails and roll cage. i know i can do it, but would it be adviseable? this way instead of the mid frame rail eliminating at the end of the floor pan, it'll tie into the rear frame; and being supported and boxed and traingulated by the frame rails in the mid sections, firewall section and the roll cage will extend tubing to the front and misc. points from there to each other. damn, i love this website! so easy to ask a good question and get great answers! thanks guys, cheers. steven m. Quote Link to comment Share on other sites More sharing options...
Sleeper-Z Posted October 16, 2005 Author Share Posted October 16, 2005 on the rotisserie now... have about 4mm between the drip rail and the floor while turning! i think i'll raise the mounts... cheers, steven m. Quote Link to comment Share on other sites More sharing options...
tube80z Posted October 22, 2005 Share Posted October 22, 2005 the existing cage in there is 1.5 but not sure on the thickness. have to research more on rules and see what's the thinnest and safest i can go but .095 sounds good. i'll be using SAE 1020 DOM tubing. do you have any pictures of your car? (not going to copy it but would like more ideas. BTW' date=' is 1640 including motor, drivetrain? maybe i should be aiming for 1450-1500 lbs![/quote'] Just back from Mexico, sorry for digging this back up. The car weight was a wet estimate as it isn't finished. I piled everything on that would be needed for it to run and that's the weight we got. So I'm confident that a lighter weight could be done. I'll post a lot more details about the car when it really runs and works. I see too many internet success stories that never seem to be finished. It's easy to write how fast a car is. It's another matter to back it up. I'll put some pics in my gallery. I have yet to figure out how to get pics to attach to a post. I know it can be done as I see others do it all the time. Cary Quote Link to comment Share on other sites More sharing options...
preith Posted October 24, 2005 Share Posted October 24, 2005 .095 1.5 inch tubing should be fine. I have seen many cars built that way at a shop near me that have won many championships. For your weight target be prepared to bolt in weight. You will need to check on materials if you plan to roadrace. I'm pretty sure all the tube needs to be the same thickness in GT and DOM. Cary Be sure to check your sanctioning body's rulebook. The last time I read the SCCA GCR, it listed a minimum of .120 wall, 1.5" tubing, and .095 wall for 1.75", and I believe that may, or already has changed to .120 as well. Quote Link to comment Share on other sites More sharing options...
Sleeper-Z Posted October 24, 2005 Author Share Posted October 24, 2005 Be sure to check your sanctioning body's rulebook. The last time I read the SCCA GCR, it listed a minimum of .120 wall, 1.5" tubing, and .095 wall for 1.75", and I believe that may, or already has changed to .120 as well. preith, in the scca rule books as far as solo 2005, the 1.5x.120 is for roll cages. i believe it states nothing about chassis. Cary: Thanks for all the info! you're a real help and inspiration. I'll be hopefully ordering the tubing bender soon ($600; ouch) and start practicing with spare tube before i start mocking and making the whole bottom frame, suspension, and then the cage. Thanks, Steven M. Quote Link to comment Share on other sites More sharing options...
preith Posted October 24, 2005 Share Posted October 24, 2005 preith' date=' in the scca rule books as far as solo 2005, the 1.5x.120 is for roll cages. i believe it states nothing about chassis.[/quote'] My bad, after I posted that I realized you weren't talking about the roll cage, which should've been obvious by the pics, and look good BTW. Quote Link to comment Share on other sites More sharing options...
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