tube80z Posted November 12, 2013 Share Posted November 12, 2013 The interesting thing to me is the DOM is made from ERW. And I've seen a few autopower bars that looked like they were built from it, which I thought was odd since they are approved. I'm thinking for a street car if you wanted to make the car safer and perhaps better handling a rear brace hooked to the sills would be good. And like new cars a brace across the dash/cowl area. And lastly some bracing in the floor since our cars are weak there compared to new models. But I wouldn't want a cage in the car my head could it. Well that's my thinking anyway, Cary Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted January 5, 2014 Share Posted January 5, 2014 (edited) Just to add to this. I know a fellow that bought a retired rally race car. Don't know the series, but the cage was legit, but expired/old. I don't know if its just rally cars and there is eventually too much work hardening in the pipe, but I bet a poorly made cage would do the same thing the expired cage did to him. He got in a side impact and the cage broke apart and impaled his thigh all the way through. He lost 50 pounds by the time he was mostly rehabbed from the impalement. My Z has a cage but its OK install-wise but not great. As soon as I get the floor pans and such redone it is coming out and custom bracing only is going in. This is just for harnesses and frame rigidity but nothing near my head. Edited January 5, 2014 by WizardBlack Quote Link to comment Share on other sites More sharing options...
johnc Posted January 5, 2014 Share Posted January 5, 2014 I don't think a cage work hardens over time, but I could be mistaken. I do know, from the folks at the Lincoln Electric Welding School (took their basic and advanced Motorsports Welding classes back in 2002) that if you use .023 or .025 wire in your MIG welder on tubing with a greater wall thickness then .083 the weld itself will work harden as it cools. I forgot what the exact process is but they said .030 wire up to .118 wall and .035 wire up to .150 wall. Quote Link to comment Share on other sites More sharing options...
m1ghtymaxXx Posted January 7, 2014 Share Posted January 7, 2014 I don't think a cage work hardens over time, but I could be mistaken. I do know, from the folks at the Lincoln Electric Welding School (took their basic and advanced Motorsports Welding classes back in 2002) that if you use .023 or .025 wire in your MIG welder on tubing with a greater wall thickness then .083 the weld itself will work harden as it cools. I forgot what the exact process is but they said .030 wire up to .118 wall and .035 wire up to .150 wall. Interesting info. I installed a Custom Cages T45 Chromoly cage in our rally evo. Custom cages sent the appropriate MIG wire, which was about the equivalent of 0.30" (it was a metric diameter, can't recall exactly). It seemed a bit thick for the thin wall chromoly, and I thought I might have been able to get a slightly nicer bead with thinner wire, though in the end I was still pleased with my welds. I suppose that could explain why they provide the thicker wire. Quote Link to comment Share on other sites More sharing options...
Avernier Posted January 7, 2014 Share Posted January 7, 2014 Actually, chromoly does crack over time. To stay legal chromoly cages have to be replaced every 3 years, and they cant be mig welded if you expect it to pass tech. Tig only. Quote Link to comment Share on other sites More sharing options...
johnc Posted January 7, 2014 Share Posted January 7, 2014 To stay legal chromoly cages have to be replaced every 3 years What racing sanctioning body has that rule? 4130 weld cracking has much more to do with welding technique then material choice. Quote Link to comment Share on other sites More sharing options...
LLave Posted January 7, 2014 Share Posted January 7, 2014 Actually, chromoly does crack over time. To stay legal chromoly cages have to be replaced every 3 years, and they cant be mig welded if you expect it to pass tech. Tig only. Right.... and the aerospace 4130 parts that are mig welded together? Quote Link to comment Share on other sites More sharing options...
m1ghtymaxXx Posted January 8, 2014 Share Posted January 8, 2014 (edited) Actually, chromoly does crack over time. To stay legal chromoly cages have to be replaced every 3 years, and they cant be mig welded if you expect it to pass tech. Tig only. T45 ≠4130. We were offered a free upgrade from CDS to T45 because of a production delay, and at first it seemed like a mixed blessing in that we'd be saving a ton of weight, but at the severe expense of not being able to weld it ourselves (no TIG or experience using one). Custom Cages insisted that T45 has similar welding properties to mild steel, but with physical properties like 4130. To be sure we called a few other shops that build Cutom Cages kits, inlcuding 4 Star Motorsports, arguably the best rally shop in Canada, and said they MIG all their cages unless by requested by the team (at a significant premium), and no heat treating/stress relieving necessary. Apparently this material is uncommon outside of the UK, however 2 other friends have Custom Cages T45 cages in their Targa Newfoundland tarmac rally cars. Weld examples: http://www.flickr.com/photos/87466467@N04/9456377968/ http://www.flickr.com/photos/87466467@N04/9456363326/ http://www.flickr.com/photos/87466467@N04/9456370190/ http://www.flickr.com/photos/87466467@N04/9456385428/ Edited January 8, 2014 by m1ghtymaxXx Quote Link to comment Share on other sites More sharing options...
johnc Posted January 8, 2014 Share Posted January 8, 2014 4130 and T45 are medium carbon steel. The only sanctioning body, or any other organization, that requires stress relieving after welding this steel in thicknesses under .125" is NHRA. FIA, SCCA, IMSA, the FAA for experimental aircraft, and more all are fine with properly welded medium carbon steel tubing. None that I know require a cage replacement after 3 years. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted January 9, 2014 Share Posted January 9, 2014 I cannot say for sure on the details but I remember it was an Evo 4~6. One of that CN9A series that wasn't available in USA. It had a link ECU, anti lag and full carbon brakes which was my first experience driving with those. I didn't know it had them until I was mildly hot into a corner on a street test. The cage was out of date and he wasn't worried about it which raised my eyebrow. I remember he wanted to have me ride nav seat for pikes peak. I can't recall if that was the race he had his crash in or not. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted January 9, 2014 Share Posted January 9, 2014 I wonder if this "out of date" concept is a misrepresentation? Perhaps you have to have the cage re-certified every 3 years and a new sticker applied? I simply can't imagine having to cut out your cage every 3years to have a new one out in. I could see how it might need to be re-inspected by an official just to check if it has been modified, damaged or if the rules have changed...but not replaced due to wear and tear. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted January 11, 2014 Share Posted January 11, 2014 I wonder if this "out of date" concept is a misrepresentation? Perhaps you have to have the cage re-certified every 3 years and a new sticker applied? I simply can't imagine having to cut out your cage every 3years to have a new one out in. I could see how it might need to be re-inspected by an official just to check if it has been modified, damaged or if the rules have changed...but not replaced due to wear and tear. Maybe so. I guess I should explicitly say out of date and not... Expired? It has been a while. Something was not right because it was an ugly wreck. Quote Link to comment Share on other sites More sharing options...
johnc Posted January 11, 2014 Share Posted January 11, 2014 No recertification required for SCCA or NASA. They do get inspected every year as does any DOM cage and after a big wreck they typically pull the logbook for the car and require a full inspection after the repairs are done. But nothing unique is required for 4130. Quote Link to comment Share on other sites More sharing options...
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