Pete Sprenger Posted November 30, 2007 Share Posted November 30, 2007 I got my Bad Dog SFCs today! I haven't given them a test fit yet, but they look good! I am pleased. They don't weigh all that much, but I was wondering if drilling lightening holes in them would make them weaker. I tried to attach a picture of what I have in mind. Hopefully it will work. I don't think the SFCs in the picture are Bad Dog parts, but it gives you the idea. In case the picture doesn't come through, I was thinking of using a 1.75" hole saw to drill a hole every 4 to 6 inches or so. Would this weaken my new pieces? Pete Sprenger 1972 240Z Quote Link to comment Share on other sites More sharing options...
Guest TeamNissan Posted November 30, 2007 Share Posted November 30, 2007 That is one area that would be last on my list for lightening. There are lots of other areas you can lighten with out compromising stiffness or structural integrity at all. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted November 30, 2007 Share Posted November 30, 2007 Yes, cutting any holes will weaken the rails. Maybe not enough to make a difference. Rather than drilling smooth holes, you want to flange the edge of the hole making a lip. That will bring back rigidity. But the metal is pretty thick, I think it would be hard to do. Plus you will now have all these holes for water and road debris to get in. Not worth doing in my opinion. Quote Link to comment Share on other sites More sharing options...
EvilC Posted November 30, 2007 Share Posted November 30, 2007 But the metal is pretty thick, I think it would be hard to do. Plus you will now have all these holes for water and road debris to get in. Not worth doing in my opinion. I was thinking the same thing. Now you give a place for water to sit right under your floors. After you drive in the rain or wash the car, you won't be able to dry that area. Def should have look else where to save the pounds....unless you have an idea you are not telling us. I have BD stuff on my car also. Quote Link to comment Share on other sites More sharing options...
Bartman Posted November 30, 2007 Share Posted November 30, 2007 The picture you posted looks like complete subframe connectors made from rectangular steel tubing. It also looks like most of the holes are in the top part of the connectors. If you go this route, it would probably be fine to add holes to the top (something like Pete's frame rails http://alteredz.com/structuralmods.htm), but the Bad Dog units are slip on and I don't think you want to put holes in them. Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 30, 2007 Share Posted November 30, 2007 I wouldn't lighten them in any way, there is...as mentioned above...plenty of other non-structural areas on the vehicle to take weight from. Seriously, how much weight will you save? I have seen a 240Z where the fenders were reproduced from Nissan FRP pieces...only in Carbon Fiber because the fabricator thought they 'weighed too much'. After he got the CF pieces, he realized the aluminum bolts that attached them were now about .5mm longer than they needed to be. So he then cut all the bolts to length. While they were in the lathe, he also gun-drilled them...and then touched the heads with a ball mill to scallop extra weight out of non-structural pieces. The same car also had Titanium A-Arm pivot bolts manufactured, which were similarly gun-drilled to save weight. It's all a matter of where you look to save weight, curiously on the car above, the frame rails under the car were untouched in lightening efforts. If he skipped 'em, that tells me something... Quote Link to comment Share on other sites More sharing options...
locodrftr Posted December 1, 2007 Share Posted December 1, 2007 I think what you're trying to do is what u see on the a pillars and such on roll cages where it appears like flat piece of steel with holes in it...but its from using dimple dies.... read here http://tool.off-road.com/tool/Fab+101+-+Compliments+of+DIRTsports/Fab-101---Dimple-Dies---Compliments-of-DIRTsports/ArticleStandard/Article/detail/322511 i hope this link works... Quote Link to comment Share on other sites More sharing options...
BWRex Posted December 1, 2007 Share Posted December 1, 2007 I would think to lighten the Z at the front and/or rear.Weight and strength on a Z in the center is never a bad thing... Quote Link to comment Share on other sites More sharing options...
Pete Sprenger Posted December 1, 2007 Author Share Posted December 1, 2007 Ok, thanks for the feed back. I am not going to drill any lightening holes. How about this idea? I was thinking that an X brace between the frame rails would really help stiffen the car. The drive shaft and exhaust pose the most immediate challenge, but then I thought of an X brace with an integrated drive shaft / exhaust hoop. What do you guys think of that idea? Doable? Pete Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 1, 2007 Share Posted December 1, 2007 I was looking at that myself, but I think the issue preventing it is the exhaust hanging down. I had my exhaust tucked up really high and tight, and I don't think I could make it work. Sloppy exhaust would be damn near impossible I think. I haven't actually mocked it up, by the way. I just looked at the Bad Dog SFCs and the location of the front diff mount crossmember and figured it was a no go. You might want to take a close look before you rule it out. Quote Link to comment Share on other sites More sharing options...
janaka Posted December 2, 2007 Share Posted December 2, 2007 somewhat off topic: can someone post a link to where to find these sfc's? I did a search on google and didnt come up with anything some how. on topic: IMO something used to stiffen the chassis shouldn't be the first place to look to take material away from in efforts to loose weight on the car. thanks Quote Link to comment Share on other sites More sharing options...
COZY Z COLE Posted December 2, 2007 Share Posted December 2, 2007 somewhat off topic:can someone post a link to where to find these sfc's? I did a search on google and didnt come up with anything some how. on topic: IMO something used to stiffen the chassis shouldn't be the first place to look to take material away from in efforts to loose weight on the car. thanks http://www.baddogparts.com/ LARRY Quote Link to comment Share on other sites More sharing options...
johnc Posted December 2, 2007 Share Posted December 2, 2007 I was thinking that an X brace between the frame rails would really help stiffen the car. Just adding weight. Quote Link to comment Share on other sites More sharing options...
Guest TeamNissan Posted December 3, 2007 Share Posted December 3, 2007 Just adding weight. This thread went from maybe risking structural integrity to save 5lbs? To adding 10+ in bracing in only 2 days. Nice lol. Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 3, 2007 Share Posted December 3, 2007 Just adding weight. John, you would really like Ad (the guy with the aluminum bolts for the CF fenders.) You sound just like him! Quote Link to comment Share on other sites More sharing options...
johnc Posted December 3, 2007 Share Posted December 3, 2007 Sometimes I'm a freak about adding lightness. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 3, 2007 Share Posted December 3, 2007 Lightness vs stiffness seems to be the issue. I think the correct answer depends on how hard the car turns and what spring rates are going to be used. The more g's and the more spring, the more stiffness you should have. That's the theory I'm using to build my car. Quote Link to comment Share on other sites More sharing options...
Pete Sprenger Posted December 5, 2007 Author Share Posted December 5, 2007 The one time I borrowed a friend's G-Tech Pro, my car reached 1.20 lateral gs in a sweeper on an autocross course. I use 225 lb springs and 225 mm wide tires. Since I use the car for autocrossing and track days, I don't think an X brace is "just adding weight," especially since you can literally hear the car creak if you jack it up at the stock jack locations (near the tires). If I was building a drag car then, yes, an X brace would be useless weight, but then so would sway bars, strut tower braces, 225 mm wide front tires, and basically anything that helps the car actually turn. My original question was just asking if to find if there was extra weight that could be removed without sacrificing strength. If I could remove a pound or two of weight without sacrificing strength, then that weight would have been truly useless weight (every little bit helps, its what enabled me to pass an 07 Vette at the last track day). That doesn't seem to be the case though. Pete Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 5, 2007 Share Posted December 5, 2007 Careful there Pete. John knows his road racing, and had an INSANELY fast 240z that didn't have subframe connectors at all. I think there are better places to lose weight than from subframe connectors. Focus on weight up high. John sells nice CF hood and hatch replacements through his motorsport business http://www.betamotorsports.com. You might take a look at bjhines's project. He went a little crazy with a flared hole punch. Don't know how much weight he saved though, and again, I think I can guess accurately that John's opinion is that both bj's and my own cages are overkill and unnecessarily heavy. I believe the ROD had a roll bar, not even a full cage... Quote Link to comment Share on other sites More sharing options...
Guest TeamNissan Posted December 5, 2007 Share Posted December 5, 2007 I own a gtech and would take its readings with a grain of salt. Esp when it says your pulling 1.20 lat with 225 springs. Don't get me wrong I like the gtech but its far from accurate. Sorry to sidetrack the thread, it was pertinent. Quote Link to comment Share on other sites More sharing options...
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