Dan Juday Posted October 14, 2001 Share Posted October 14, 2001 There have been threads lately conserning removing the rear bumper and smoothing the rear valance. This is what I plan to do, and many others have considered, or have done, as well. A consideration of safety came up as to how much protection the small, early type, bumpers actually provide. Some have talked about reinforcing behind the valance or other bracing simalar to what I have done. I want to offer this picture of a rear-ender. http://www.zparts.com/ads/new/Image012rw1.jpgThis is a car that Eric Neyerlin of Zparts is acquiring for parts. This pic is making me reconsider what I have done. Notice that the entire rear has accordianed and there is no apparent damage to the passenger area. It is obvious, in this case, that a bumper on or off would make little or no difference. My consern is that with the bracing I have done the energy of an impact would be transfered directly to that area. What do you guys think? Who has "been there, done that". Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted October 14, 2001 Author Share Posted October 14, 2001 Try this: http://www.zparts.com/ads/new/Image012rw1.jpg Quote Link to comment Share on other sites More sharing options...
Peternell Posted October 14, 2001 Share Posted October 14, 2001 Kinda like the short tail look. Looks a little like the Cheetas of the mid 60's, real long nose 327 set way back and the driver sitting nearly over the rear wheels. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted October 14, 2001 Share Posted October 14, 2001 A word of advice for those of you considering a cage in the rear. Make sure you still leave some crumple zone there, otherwise you'll be a milkshake. (but look fine on the outside) I don't think the small rear bumpers do anything at all, except distribute some of the force to the whole rear end in the case of being hit by a small object in the center of the bumper. (telephone pole, fire hydrant, etc) Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted October 14, 2001 Author Share Posted October 14, 2001 Thanks guys for your input. I had not considered a cage before now. Mine will be a street car only. But this has really made me think. I'd like to hear what others think as well. I'll be seeing Eric later this week and will ask him if he knows any specifics about this wreck, i.e. speed of impact, the size of the other vehicle. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted October 14, 2001 Share Posted October 14, 2001 Dan, a cage or an 8 point rollbar would be good insurance. SW makes a "kit" that fits the Z car. Davy Quote Link to comment Share on other sites More sharing options...
Guest John Adkins Posted October 14, 2001 Share Posted October 14, 2001 My understanding of crumple zones is that they are supposed to absorb the force of an impact so that the passengers and driver don't. Is that right? I guess this explains why when older cars big cars are in accidents the car survives better but the humans have more injuries/fatalities. When modern cars are in wrecks, the car looks horrible but the humans can walk away with minor injuries most of the time. Did the designers back in the '60s consciously design a crumple zone into the Z? from the picture it looks like the rear quarters crumpled but the area where the driver and passenger are looks intact.... Quote Link to comment Share on other sites More sharing options...
Drax240z Posted October 14, 2001 Share Posted October 14, 2001 John you have the reasoning behind crumple zones down. The 'crumpling' helps dissipate energy, and helps direct the energy from impact away from the passangers. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 15, 2001 Share Posted October 15, 2001 Yes exactly and this is the reason my cage does NOT extend fully to the rear of the car. I'm willing to sacrifice the rear of the car in order to save the passenger's lives. Side impact is actually one of the areas I'd urge many of us to consider. The Zs, especially the older ones like mine, have ZERO in the way of side impact protection This is mostly why I had a cage put in my car. I do NOT have removeable or swingout sidebars for this reason as well since it would be too tempting to take them out for convenience sake. I also worried that a swingout bar might give in an accident (shiver). ALL bars are padded (except rear crossbar) with SFI rated padding (covered too for UV protection) and passengers are REQUIRED to wear the racing belts. I'll be installing a crotch belt soon as I've noted the belts riding up without it but just haven't had time yet. Anyway, the passenger area is surrounded by the steel cage. Should the car be involved in an accident the passenger area is all I care about surviving, I can build another Z easily enough... Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted October 15, 2001 Share Posted October 15, 2001 quote: Originally posted by Dan Juday: My consern is that with the bracing I have done the energy of an impact would be transfered directly to that area. What do you guys think? Who has "been there, done that". I got put into a sping and my rear hit two jersey barriers and then I got hit dead on my right front corner by a speeder (can't say what speed...perhaps 30mph at impact..hard to tell at night with his headlights blinding you). My front 'crumpled' as intended (280ZX's have 'crumple' wrinkles in front fender intending them to buckel and twisted a bit but overall car from firewall rearward was basically straight. Entire rear of car required NO repair as the bumper took the force and absorbed it on both ends with no damage transmitted to rear of car. So rear bumper took the bounces as I deflected off jersey barriers and front crumpled OK. It had me leary of ever having frame rails extending past my crossmember as I got nailed sharply, car spun an instant 180 and stopped and I jumped out and wasn't too sore from the incident. I just wish we had more 'side' room for a side impact crumple zone in our z's....I'd keep my back rearward of strut towers and front fwd of xmember 'non trussed' if possible and when altering exhaust/fuel pump locations try to keep in mind the concept of shielding them from debris or hot areas.... Just my .02c. Too bad the 70-78 bumpers are so poor as my ZX rear bumer saved me a LOT of expense and headache. The front 'shock' absorber worked as intended but couldn't take all the force. Quote Link to comment Share on other sites More sharing options...
spotfitz Posted October 15, 2001 Share Posted October 15, 2001 Thats a shame. Besides the little bit of rust I can see on the rocker, it appears to be a clean car. Looking over all the bumpers in todays cars and realizing the regulations of "5mph bumpers" is a joke, I don't think with our Z cars there are many options to protect us against a hard impact. Even a full blown cage and reinforcements to the bumpers connecting to that cage, our Z's will suffer significant damage. I would estimate the impact that it took to make this Z look the way it does, did not exceed 35mph. With that said to be true, who on this board thinks their Z could withstand a 5mph impact in a parkinglot and still drive away? Probably, most everyone, bumpers or not. Now, how many of those people think their Z could withstand a 35mph impact and still be willing to repair it after you get it towed home? Protecting ourselves and our loved ones is the main concern here. The car is just that, a car(except in Petes case ). Whether it is a Z car or what have you. It's the carbon based lifeforms inside that we have to consider the most. Cage it and don't worry about what happens to whats going to be left of the car. Reinforce if your inclined to do so. I am more worried about what that reinforcement can do to the passengers, as Dan suggested. Crumple zones in new cars are there for a reason. I'll be caging mine and reinforcing where I have to, just to keep flex down to a minimum. Other then that, a harness. What else can we do? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 15, 2001 Share Posted October 15, 2001 Rather than putting side bars in your rollcage you could try putting a bar in the doors, theres plenty of room for it, ive done a couple of jap import GT-Rs for australian compliance, we had to use a 50x20 rhs tube (or there abouts) running the length of the door at waist level and welded to the outer of the door frame. Also if your doing a cage it should'nt go past the front and rear shocker towers, anything beyond is in the major crumple zones, and a waste of time anyway, because it wont dramaticaly increase the rigidity of suspension and handling. Quote Link to comment Share on other sites More sharing options...
Guest Zpeed Posted October 15, 2001 Share Posted October 15, 2001 I can get a rollcage made for the Z for around $275 australian.... do you think its worth it, 8 point... made for racing Quote Link to comment Share on other sites More sharing options...
Andrew Bayley Posted October 15, 2001 Share Posted October 15, 2001 If the Oz dollar compares to the U.K. lbs. than $275 is a good deal. In the U.S. a generic 8 point cage starts around $750 professionally installed. -Andy Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 16, 2001 Share Posted October 16, 2001 I'm gonna put a directional charge in the rear of my Z (like reactive armor). That way if some idiot hits me, it'll blow their car back and away and leave me unscalthed, sep for some burn marks. J/K I think the installation of subframe connectors, since they are under the passenger compartment, will help keep that area intact. I still have the stock frame rails and likewise in the back for the crumple effect. IMO a cage is a great idea. I think it's a good idea to reinforce the doors but have yet to figure out the best way to do that (like will the door just give out when it gets hit and smash the S**T out of me?) Anyway, anything my wife rides in damn well better be safe. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.