heavy85 Posted April 10, 2004 Share Posted April 10, 2004 I am trying to decide what to do with my seat belts and need some advice. I dont want two sets of belts (one for street and one for track) but at the same time I want a harness for autox and other events while maintaining street legalness (is that a word?). A Schroth harness seems to be the way to go to fit best of both worlds but in another thread someone mentioned NOT attaching the shoulder harness to the strut towers because the towers would deflect too much in a crash. Seems to me the towers would be one of the strongest parts since they hold the structural load generated through the struts? I dont have a cage yet and probably wont for a couple years so I need a shorter term solution and was wondering if it is acceptable to tie the shoulder harness into the strut tower? Also, is the Y type acceptable because I've read a lot of oppinions but little or no facts on the matter? Obviously there is one less belt to hold you in but at the same time as long as the one is strong enough that should be all you need - still a lot stronger than stock or am I missing something? Lastly, if I need to use factory bests can a three point belt from a later model Z fit a 240Z? Thanks Cameron Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 10, 2004 Share Posted April 10, 2004 I used to install a lot of harness bars for Porsche guys who were just hitting the track. They were not very big or strong looking. I would think that you might be able to find something similar for a Z. The one thing most people screw up is the angle of the harness. The harness should NOT angle up a lot to the top of the seat. If it does, and you crash with the harness on, it will compress your spine. BAD!!! I used a Y type for a couple years, never really USED it though. Next time I'll go with separate shoulder straps, but the Y didn't worry me. The end of that Y is pretty thick. I think the recommended angularity is 5-15* to the back of the seat. Hopefully someone with more direct knowledge will give us the official word on that. I honestly don't know if attaching the seatbelts to the strut towes is a bad idea, but I know I've seen a couple Z's that had the belts attached there. The original 3 point from the early Z is probably the best stock seatbelt to use, because you can crank it down really tight, which you can't do with a retractable belt. When I was autoxing my Toyota P/U, I used to fold the belt in half and pull it through the loop so that it wouldn't loosen during a run, but it never really worked that well. The Z setup allows you to make it tight and not have to worry about it coming undone. Jon Quote Link to comment Share on other sites More sharing options...
rc's240z Posted April 11, 2004 Share Posted April 11, 2004 Attaching a rear strut bar and looping your shoulder harnesses around the top bar would eliminate the spine compression issue. G-force makes a very economical belt that is SFI and FIA rated, and should pass any tech inspection when you add a roll bar or cage be sure to add or include a seatbelt bar as well as a support to the cage if your seat is not already designed to tie into the cage. http://www.driversupply.com/ is a good resource. Talk to John and he will get you set up. Ron Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted April 11, 2004 Share Posted April 11, 2004 It is not that big of a deal to install both belts. I have a 70 240 that originally had the non-retractable, separate lap and sholder belts. The PITA with those was the catch part would fall down between the seat and the trans tunnel. I searched a JY and found a set of belts out of a Mazda 808 that had the catch on the end of metal rod. This holds it up over the side of the seat. Mounted the retractable part up on the stock sholder belt bolt. Woks fine for the street. Interestingly, the stock sholder belt mount does not give you the 5-10 degree downangle mentioned above. I also have a simpson 5 point harness bolted in. Only used that for auto X. I have it bolted to the shock tower, as did probably 90% of the guys I use to auto X against. Maybe not the best solution, but definitely better than the stock belts alone. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted April 11, 2004 Author Share Posted April 11, 2004 I have seen those harness bars and I agree they dont look very effective in an accident - only good for autox IMHO. Anyway, I do have a rear strut bar now so I could either wrap the belts around them or use the rod-end bolt which is what the PO did. I used to have a GTI that I installed both the factory belts and a Simpson harness that I used for autox but the Simpson ended up getting wadded up, dirty, rattled around, etc on the street. That's why I would rather have a single solution that would be street legal and safe while also be able to use in competition. My car had the drivers seat belt removed (except the latch) and the recess where it normally mounts had a seat bracket welded over it. I've since cut the bracket out but am not sure what the stock belts all entailed. The passenger side has a lap belt only arrangement - was there originally a should or can one be added? It was built in 2/72 so what other years factory three point could be used? Finally, does anyone sell new replacement factory belts since if I find a junkyard one it would be ~30 years old. If I remember right my 74 260Z had a shoulder belt but that was 10+ years ago so my memory is not real clear. Thanks Cameron Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted April 12, 2004 Share Posted April 12, 2004 The really early vehicles (like my 12/70) do not have the pocket behind the seat for the retractable mechanism. So whether that pocket is there or not should not be an issue. And like you said, it is not like you can find something that will work in those pockets that isn’t past it’s useful life. Most vehicles with retractable belts have a one piece lap/shoulder belt with the retractor mounted off the shoulder part. So any J/Y solution will not make use of the pockets. But it sounds like you don’t want a retractable mechanism at all? Sounds like something out of a 70 with the solid belts would be exactly what you want. Might be a tougher find. Also since you had a 5 point in a street car, I assume you realize how unacceptable a solid type belt is for day to day driving. Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted April 12, 2004 Share Posted April 12, 2004 Well for starters. 1: 280z's for sure had the stock belt mounted to the top of the shock towers. 2: find a harness that is DOT legal. It should not be a problem. Our cars are getting old, and I would rather trust a new harness to an old 3 point belt from a 25 year old Z. 3: Make sure your strut brace is very strong if you are going to mount it to it. The adjustable one from places like MSA I would not hook my seat belt to. My rear bar is 1.5inch chromemoly with 1/4 inch plates that the strut bolts to (like a giant washser so to speak sitting on the top of the strut.) Quote Link to comment Share on other sites More sharing options...
rc's240z Posted April 12, 2004 Share Posted April 12, 2004 A rear strut bar like the one from PDK should be fine for your application, see http://www.pdkfabrication.com. Eventually I would recomend a roll bar with a seatbelt bar. I would suggest a seatbelt bar that is 1.5 DOM 90 wall. As far as seatbelts are concerned: there is DOT legal (street legal) SFI (SCCA) and FIA legal. SFI belts will only be legal in your race car for two years according to the SCCA where as FIA would be legal for up to eight years. SFI and FIA are far more stringent than DOT. I doubt that police officer would give you trouble with FIA/SFI belts. BUT that depends on the laws in your state. Quote Link to comment Share on other sites More sharing options...
johnc Posted April 12, 2004 Share Posted April 12, 2004 Make sure that whatever 4 point harness you install is designed and certified to be used as a 4 point harness. DO NOT install a 5 or 6 point harness and leave out the crotch straps. In a hard front end accident you will submarine under the lap belt and jam your knees real, real hard into the firewall. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 12, 2004 Share Posted April 12, 2004 Interestingly, the stock sholder belt mount does not give you the 5-10 degree downangle mentioned above. Yeah, but it only goes over one shoulder and has connects very high, so there is no way that it could force your body down in an accident. I was referring to 4 point and better real harnesses, not OEM seatbelts. Very common scenario in Honduh wannabes: They'll get a 2" wide "race harness" with a Y strap that plugs into the back seatbelt. They then have a 30* or more angle down from the back of the seat to the seat belt connection. If they crash, when the seatbelt pulls tight it will force their body down. If the crash is hard enough, you're talking spine injury. That's the type of scenario I was trying to warn against. Haven't seen anyone in a Z running the shoulder belts to the floor right behind the seat, but it wouldn't surprise me if there were someone out there driving around like that, and it is not a good idea. Jon Quote Link to comment Share on other sites More sharing options...
gnosez Posted April 12, 2004 Share Posted April 12, 2004 I should have harness bars like those mentioned above, in the next 60 days, for those people who don't have rollbars or cages installed in their Zs yet. During the restoration of my 240 I had to have a series of parts made (and ended up with a bunch of new and used parts too) so I've started up a small business called "Bad Dog Parts". A dog helped me wreck my other 240, hence the name. We're finishing up on replacement seat brackets (needed when you do your floor pans), g-nose hinges, frame rail plates, single point jacking plates, etc. Next week the site will go official with pics, etc. A harness bar is in the works and will fit 70-78 Zs. Later model bars will come out in July/August. We'll be at MSA and the ZCCA convention at Orange County. Quote Link to comment Share on other sites More sharing options...
rc's240z Posted April 13, 2004 Share Posted April 13, 2004 gnosez, you've got mail. Will see you at the MSA show. Quote Link to comment Share on other sites More sharing options...
z-ya Posted April 13, 2004 Share Posted April 13, 2004 Nobody actual saw the dog BTW Quote Link to comment Share on other sites More sharing options...
Guest Chez Roban69 Posted December 26, 2004 Share Posted December 26, 2004 ...DO NOT install a 5 or 6 point harness and leave out the crotch straps. In a hard front end accident you will submarine under the lap belt and jam your knees real, real hard into the firewall. Jamming your knees would be the least of your worries. The real reason for the anti-submarine strap(s) is to prevent decapitation. The same reason for not reclining your seat too far while driving. Robin Quote Link to comment Share on other sites More sharing options...
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