WizardBlack Posted September 22, 2007 Share Posted September 22, 2007 My 280Z came with a mildly beat up lower radiator core support and some areas cut away on the sides and whatnot. I am getting ready to go turbo with the huge ebay intercooler with 3" outlets so I need some more room on the sides, too. Let me describe the core support in my own words and then I will describe what I want to do and leave it up to everyone to comment on safety and feasibility. The upper and lower pieces run horizontal (obviously) and are tied in with the side pieces which are not much more than a thin strip of sheetmetal running along the inner fender sheetmetal. The side pieces have holes in them at the top for the intake pipe, etc. They also have the mounting points for the radiator. The upper support is a ovalized tube of sheet metal and has a triangular gusset on each end where it connects to the inner fenders. My guess is it is mostly for compression support to keep the fenders at the proper width. It basically is tack welded to the sheet metal of the inner fenders and doesn't have the attachment to provide a serious amount of chassis support. The lower support is a beefy 2"x2" square tube beam that tapers lower (closer to the ground) in the middle. It is tack welded via spread out sheets of metal to the chassis beams. My guess is this puppy is a significant chassis support and provides support in several axes. Ok, what I want to do first of all is eliminate the sheet on the sides so I can open up enough for 3" intercooler piping. They were essentially cut enough already to basically be moot as far as tying the upper and lower together. I then want to use 2"x1.5" square tube to replace the rusty, chewed up upper support and weld the proper support webbing back to it. I suspect that really won't cause any issues. It also gives me a better support for the dzus fasteners for the hood and to mount my intercooler to. Finally (and this is the part that I am wondering about) I want to replace the smashed up lower support with new steel square tubing of equal size (about 2.5"x2.5") and decent thickness to essentially do an "as stock" replacement as far as shape goes. Perhaps it'll be made of a bit thicker material if that seems useful or prudent. I have enough equipment to do it (big Wilton bandsaw, Lincoln TIG, Miller MIG, etc.). I haven't torn it apart enough to get an extremely comfortable idea of how the lower is attached to the car, yet. So what do the chassis guys think on here? I have seen uppers replaced with chassis tubing, etc. on other cars. I figured with the gusseting on the S30 and the fact that they are basically tied into the frame via L-shaped pieces of sheet metal that square tubing is the prudent choice. As far as the lower support goes; I am doing it for more cosmetic reasons rather than fitment or severe rust, etc. This portion I may drop if I get the feeting that it's risky. Thanks for reading my long-winded post. Mark Quote Link to comment Share on other sites More sharing options...
johnc Posted September 22, 2007 Share Posted September 22, 2007 Think of the engine compartment as a big rectangular box with the core support as one end of that rectangle. Tie the top corners of the core support into the upper frame rails that extend from the cowl, tie the bottom corners into the lower front frame rails, and then add a diagonal brace or an X across the opening with small diameter (3/4") round tube. The wall thickness on all the materials you will use to build this core support doesn't need to be anything thicker then .063". Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted September 22, 2007 Author Share Posted September 22, 2007 Think of the engine compartment as a big rectangular box with the core support as one end of that rectangle. Tie the top corners of the core support into the upper frame rails that extend from the cowl, tie the bottom corners into the lower front frame rails, and then add a diagonal brace or an X across the opening with small diameter (3/4") round tube. The wall thickness on all the materials you will use to build this core support doesn't need to be anything thicker then .063". The X-brace is during removal of old and installation of new parts; yes? It sounds like it's doable then; sweet. It's one of the very few rusty and mangled sections on the entire car; believe it or not. Thanks for the info! Quote Link to comment Share on other sites More sharing options...
Jeff Posted September 23, 2007 Share Posted September 23, 2007 The X-brace is during removal of old and installation of new parts; yes? The X brace is a permanent part of the new installation. Here is how mine sits at the moment and I will be adding an X brace to mine. Right now the top member is a bolt in but I don't think this is going to be torsionally rigid enough so I'm going to weld it in and add the X bracing. My frame rails & lower core support member are all 2 1/2" tube steel. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted September 30, 2007 Author Share Posted September 30, 2007 Hmm, more stuff to think about.. Thank you! Quote Link to comment Share on other sites More sharing options...
Careless Posted September 30, 2007 Share Posted September 30, 2007 hey at least having it bolted in makes the welding process much easier when you've squared it all up looks really nice. what process did you use for designing the frame rails Quote Link to comment Share on other sites More sharing options...
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