Quote:
Originally Posted by Chris@WheelsDirectOnline.com
Its been said in many places that the z, has almost no supports in the roof line. Most of them around around the doors apparently and lower in the vehicle. Its been said all BY NISSAN, that instead of making the car, and then modifying it for a roadster like they did for the 350z, they built the car, the coupe from the go with all the supports so that they convertible would not gain a huge amount of weight and still be almost as rigid as the coupe.
I am not calling you a liar, but I am not making this up and I have read it in a ton of places when the convertible was about to come out. It was specifically from Nissan saying they thought ahead this time pretty much.
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I said anybody doing this needs to make sure they fully check into this and make sure that the assumptions they are making are correct. Even if the roof line effectively carries zero force for 100% of your driving, it will ABSOLUTELY do something in the event of a crash, particularly one where you are rear ended into somebody. Having the car buckle in under your seat
could be a huge problem.
Quote:
Originally Posted by ZTarga
We don't have an answer for you about the year earlier. I am not sure what the difference in the supports are either, but how can you guarantee something when you don't know the differences? I'm not attacking you. I am sure you do know way more about this Z34 than me and my wife put together. This seems to be a huge unknown for us, and everyone I spoke to. Our builders say it is the same if not better than the z33, from their research. What exactly is the difference in the underbody? Can anyone tell us? Is the z34 more rigid than the z33? From what we understand it is. Nissan did make structural improvements to the z34. If we are wrong, let me know. So, removing a section of the roof will naturally diminish some structural aspects, but will it be diminished so much as to revert even lower than a z33? We don't know for a fact. There goes the test. We want to prove it is as strong as or stronger than a stock z33. If it is not, then we will stand corrected, but we feel secure and safe with our builders that it is. When it is proved without a doubt it is - line-up t-top and targa fans because a ton of tops will be coming off. lol  If it proves it is not, then we can always add 100-150lbs of reinforcement to compensate so it will be. Then, we all will know what it will take to have a targa top. We are here to find out the facts, and have fun. Win - win.
As far as selling the car, which we will never do. Ok, maybe one day we will. We still would feel safer in a targa than in a convertible. I am not a lawyer by any means, but I think “as-is” speaks for itself? I do agree that it will not react the same way a stock car would, but does any car react the same as a stock vehicle with any huge modification?
This is a huge modification- maybe over the top. All your points are very logical and noted with respect, and we are not poo pooing them at all. It is the unknown or the lack of raw data that is troublesome for us all. We are willing to spend our money to be the guinea pigs and really test this modification out, and have that raw data we all need. Even after that, this modification will always take away some safety features of this car. Is it worth it? Heck yeah! We are just some Z fans pushing our car to the edge - don't most of us do that anyway? ~ Dean and Amy |
It's not so much the weight you add, but the added thickness of structural members increasing the ability of those bottom rails to resist bending moment, as well as the added compressive force in accidents since the roof would no longer be there. In short, of course there is the possibility Nissan builds them the same, but my intuition tells me that they are not structurally identical since their weights are so different. There is no need to have that extra weight of a large structural member when you can resist those bending forces with several times smaller & lighter members simply by putting them up higher...i.e. in the roof (where the convertible can obviously not do).
Anyways, I said I'm not sure what, if any differences there are and don't think I ever claimed that I knew. I was just suggesting something from a structural engineer's point of view that you may have not considered, ultimately just trying to ensure your safety in the event of an accident.
I LOVE that targa top. I'd do it to my car. But relying on a statement from Nissan that most likely doesn't fully explain whether they have thicker frame rails on the convertible could be a deadly gamble. Example: They may be talking about the frame in general is the same, but maybe the bottom rails are larger in the convertible (I can't imagine this would be a big change in mass production).
Side Note to you two: I am impressed by the fact you guys would actually undertake this project. You guys have done an amazing job and it's going to be an awesome finished project
