Yorgee Posted February 25, 2008 Share Posted February 25, 2008 Finally got around to designing my front strut bar after making my rear one a while back. Got some ideas from you guys on hybrid, pulled out the welder and the ideas started flowing. Think it came out pretty good. After I finished the strut bar I decided to go ahead and fab up a roll bar. I was planning on just buying the MSA street roll bar but then I found some nice 90 degree bends and decided to try and make my own. First I just made the cross bar and thought it was a little too simple, and decided to add 2 more bars connecting to the fire wall, kind of like the pdk roll bar set up. Still have to sand the strut bar down and paint it, same with the roll bar, needs another coat and still needs to be installed. Quote Link to comment Share on other sites More sharing options...
Guest 280ZForce Posted February 25, 2008 Share Posted February 25, 2008 i'll be 1st to say, can't wait till we build my strut tower bar! and i'm really impressed w/ you building it and your roll bar man! thanks again for the times you help me out. Quote Link to comment Share on other sites More sharing options...
Yorgee Posted February 25, 2008 Author Share Posted February 25, 2008 I'll make you a deal, when I hear your car running, we can build you a strut bar =). Probably have to change up my design quite a bit to make room for your intake too... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 25, 2008 Share Posted February 25, 2008 I really don't want to tear you down, but here is some constructive criticism: The strut bar is OK, but the straighter the bar is the stronger it will be in tension and compression. It would have been better to make the brackets taller or at least mount them all the way at the top of the strut tower, as this would have required less bend in the bar itself and also attached the bar right at the strut top, where the chassis is actually going to flex the most. The bars to the firewall aren't doing anything useful. Theoretically they could try to prevent the strut towers from flexing forward, but they would be a lot more effective if they actually connected to the strut towers, and not to the middle of the strut tower bar. On your rear strut tower bar the bars that intersect in the middle would be stronger if they hit the floor than hitting the stock braces in the middle. It's kind of the same problem as the front bar. Load paths are not taken into account and it would be stronger if you attached to the frame rail than the braces. Roll bars should not be welded at the corners, they should be one solid tube bent to the correct shape. In my opinion what you have there should be removed for your own safety. If you crash and the tubes come apart at the welds you could have some serious problems. Roll bars are made from DOM tubing (drawn over mandrel). DOM tubing is stronger than plain welded tubing or pipe and is required by almost every if not every racing sanctioning body. I am guessing what you have there is not DOM. I'm sorry I can't give you a big thumbs up, but I'd rather you know what the potential problems are. Quote Link to comment Share on other sites More sharing options...
Yorgee Posted February 25, 2008 Author Share Posted February 25, 2008 Thanks for your criticism Jmortensen, I really didn't know much of the rules or regulations of a general strut bar. I was just experimenting and I had no real way of bending a pipe in that manner. It's completely removable which is a good thing. I just don't like buying stuff I could make, but since I probably can't make one properly, might have to head towards that direction. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted February 25, 2008 Share Posted February 25, 2008 looks good.. but the roll bar looks very unsafe.. Quote Link to comment Share on other sites More sharing options...
Yorgee Posted February 25, 2008 Author Share Posted February 25, 2008 I do believe the welds are definitely strong...the same welds are holding up my car. And if i did get hit or hit something at speeds to break those welds, I'd have to worry about other things hitting me in such a fragile car, the other car or what ever I hit for example. Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted February 25, 2008 Share Posted February 25, 2008 it's not the welds that aren't safe, it's the mounting point for one. You mounted it to the fender well correct? the correct way to mount it, would to have it tie into the cars frame rails, or a stronger point. If the car were to flip, instead of the energy being transfered into the strongest points of the car, the energy would transfer into the fender well, which would then buckle under the weight and become crushed. That is of course, if the welds don't break under stress and the thing comes apart. There's a reason why the main hoop is a single peice of steel. the strut bars look nice, but like someone said earlier, they are MUCH stronger when perfectly straight, and mounted to the plate up at the top. not really claiming to know anything either. I've never built this kind of stuff. More or less i'm going based of observations of other cars, and my dad's 66 VW. all the mounting points mounted to the strongest points of the pan, and the rear mount went through the body, and bolted to the transmission horns (another major structure point) The way i kinda think of things for mounting stuff like that, is if i can dent it with a hammer, it's probably not strong enough. Quote Link to comment Share on other sites More sharing options...
Shift Posted February 25, 2008 Share Posted February 25, 2008 Its not only that, welding mutiple pieces together that could be done with a single piece is more dangerous. With the loop being made from a single piece, you don't have to worry about the metal "around" the welds sheering off and stabbing you. Its not the welds themselves (if done properly) its the metal base metal around the welds being treated differently then the unaffected base metal and the welds themselves. I believe that it would fail SCCA inspection (just a guess) because of that and where/how its mounted. (admins chime in to tell me if I am wrong). Quote Link to comment Share on other sites More sharing options...
Yorgee Posted February 25, 2008 Author Share Posted February 25, 2008 Hmmm, really?? I believe the MSA and Autopower Roll bars are mounted in the same area? I could be mistaken though but thats what I remembered. Yeah, found this picture with an MSA roll bar mounted. Which is what I was basing mine off of. If those mounting points are unsafe, they shouldn't be selling those in the first place. That is strange. Quote Link to comment Share on other sites More sharing options...
Guest 280ZForce Posted February 25, 2008 Share Posted February 25, 2008 you guys, the mounting point is fine, msa makes a couple roll bars, even 1 of them is for scca racing and they mount in the same spots. the only real main concern here w/ the roll bar is the main hoop not being 1 piece and outta DOM tubing. he is going to redo the main hoop properly, but the mounting points are fine. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 25, 2008 Share Posted February 25, 2008 The problem with the fenderwells as the mounting points is that using them doesn't stiffen the chassis as much as attaching to the frame and the strut towers. Some people think that it's not a good mounting point, but I think the fenderwells are plenty tough. It's just not utilizing the roll bar to really strengthen the chassis. Quote Link to comment Share on other sites More sharing options...
johnc Posted February 25, 2008 Share Posted February 25, 2008 Unfortunately, becuase of the multi-piece construction of the main hoop of the the roll bar, you will not be allowed on track or at an autocross with pretty much any sanctioning body. You might be able to sneak it by the tech inspectors if they are lazy. If you don't intend to track or autocross the car, then you don't need to worry. Quote Link to comment Share on other sites More sharing options...
z or bust Posted February 25, 2008 Share Posted February 25, 2008 You didnt weld those with that easy mig did you?? Quote Link to comment Share on other sites More sharing options...
Yorgee Posted February 25, 2008 Author Share Posted February 25, 2008 You didnt weld those with that easy mig did you?? Yes, I've been doing all my welding with one since I got it. Thanks though for all the input. I'm definitely going to research some places and get the correct DOM tubing bent. As long as its cheaper than 300 bucks ill definitely do it. If it is more expensive, I'll just go with the MSA roll bar. It will be easier now because I can just take what I have made and have someone copy the bends with the right kind of tubing. The problem with bolting/welding to the chassis, is that for the pipe to be in the correct angle, I've noticed that you would have to cut into the fender walls, and I'm really not looking to do so. Especially if I am planning on making it removable. I also really want to try and track/auto cross my car, so if installing it is going to disqualify me from entering any events, It's not going to hold me back. Thanks again. Quote Link to comment Share on other sites More sharing options...
doublexl240z Posted February 25, 2008 Share Posted February 25, 2008 I don't believe the mounting points are safe whether MSA or anybody else uses them. As far as chassis stiffening, the middle of the fender well won't flex. As far as rollover protection, it would get punched through the well, or if the welds where not too hot it would just bend until it hit your head. And in the case of side impact, you would be protected from the shoulders up. Its too easy to build them to be protective and chassis stiffening. and as soon as I figure out how to resize a pic, I'll post some pics. Quote Link to comment Share on other sites More sharing options...
johnc Posted February 25, 2008 Share Posted February 25, 2008 I don't believe the mounting points are safe whether MSA or anybody else uses them. They are safe. I know of two people who rolled their 240Zs at speeds in excess of 60 mph with the Autopower/MSA bars in place and one person who went end-over-end 4 times. All walked away from the wrecks with minor injuries. Ask Tony D about what Hiten Patel did at LVMS... Quote Link to comment Share on other sites More sharing options...
Yorgee Posted February 26, 2008 Author Share Posted February 26, 2008 I don't believe the mounting points are safe whether MSA or anybody else uses them. There was probably research, I hope, done before putting those roll bar in the market. There had to have been, or else there would be nothing but law suites involved if they were "unsafe". Quote Link to comment Share on other sites More sharing options...
junglist Posted February 26, 2008 Share Posted February 26, 2008 this thread has some good info. i'm relieved to read more confirmation that the autopower roll bar mounting points are "safe". I was lucky enough to find the SCCA one unused for $200. I plan on cutting the harness bar off of it and probably going to fab something welded up between the struts with some DOM to use as a harness bar. Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted February 26, 2008 Share Posted February 26, 2008 It isn't a factor of the welds breaking. The welds are VERY strong. The problem is the heat affected zone(or HAZ) which is where the base material is reduced in strength. The combination of a very hard area of metal(the weld) next to a weakened area(the HAZ) will cause any break to happen inside the HAZ. If you only plan on using the car on the street, then it may give you some mild crash protection if you get T-boned. The lower horizontal bar will not help you at all though in a side-impact. It will snap off right by the 90* bend next to the weld. The shape overall is fine but just should be made with some proper DOM tubing for safety. Quote Link to comment Share on other sites More sharing options...
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