Yeah, a black, translucent roof would look wicked with your headlamps and wheels

[QUOTE= I want a clear roof![/QUOTE]

 

Really ?

And, just where did you perform the tests for longitudinal and torsional body stiffness ?
Care to share your before and after test results ?

Or, maybe you arrived at your "bolted and glued panel" has no effect
conclusion using FEM analysis ? As in Finite Element Analysis.

Or, maybe you just pulled your conclusion out of your a . . ?

Sorry, don't take it personally.
I'm just in kinda of a pissy mood.
Like usual.
And, this still keeps coming up after all the endless but real technical discussion threads.

 

So what's your opinion,, hhuumm?

That's why I posted this question......

 

Howdy!

This is what appeared in an article Written by Hib Halverson (supported and quoted to reference GM engineers):

1) Stiff structure: backbone construction with enclosed driveline tunnel and hydroformed outer frame rails make the car’s structure one of the stiffest in the world. Hardtops are the stiffest of all C5s because they have both the Coupe’s "top bow" and the Convertible’s extra crossbar behind the seats. Bodywork behind the windshield and above the belt line is bolted to the windshield header and is bolted and bonded to the rear deck. The underbody structure, the fixed roof and the lack of the big hole in the back for the Coupe’s hatch make the Hardtop about 12% stiffer in torsion than a Coupe with its roof in place. Rocket scientists out there will be interested to know the convertible’s first torsional frequency is 20hz. Coupes with the roof out are at 20.5hz and, with the roof on, jump to 22hz. The Z06 is a stout, 24hz.

The underlined passage seems to suggest that the primary stiffness contributors are the combination of the halo bar and (vert) x-brace. Also the roof in Coupe vs. Z06 is -2hz difference, but some of that is the x-brace/crossbar, so it would seem like the roof portion of the difference is minimal.

I'm certainly not an engineer (well of sorts, but not for this sort of thing), but I've seen a few knowledgeable people claim this as well.

BTW, I read in another thread about your loss - I know it's a little late, but my sympathies go out to you and your family.

 

OK, I'll bite.
I'm a sucker for people who are really interested in a subject.
So, you asked for it, and you'll get my usual long post.

You say you are not interested in tracking the car. That is fair enough. So go ahead and do it.
I don't think you are in a "safety problem" area.
( warning: hey, all you trial lawyers, I am not qualified to back up that statement ).
But,

"Some things" in the handling department are not going to be optimized as well as the factory development end result.
Such as spring rates, shock calibrations (velocity ranges, compression and rebound), sway bar, bushings
(both lateral and longitudinal calibrations), etc., etc. and probably stuff I forgot to include off the top of my head.

All that said, I really doubt you are going to notice much difference in normal driving,
or even as you push up to the "7/10ths" or "8/10ths" range.
Maybe you don't even drive your car that way. Or, maybe you do.

The people that can immediately notice "changes" like this are few and far between,
and have legendary "seat time", and spend their lives "agonizing" over "optimizing".

John Heinricy is probably the most famous in this category.
See his fantastic Touring 1 and A/Sedan SCCA National runoff winning records ( "near stock" vehicles ).
Thanks John, for making my Z far more capable than I am.

Race drivers are the other category where "this" is all important.
However, plenty of them are not wizards at the "optimizing" process.

Here is the article DT refers to above. It's about the 2001 Z, but a very worthwhile read on the "process", including good details.
http://www.idavette.net/hibz06/

I repeat this quote from the second page.
12% stiffer in torsion IS HUGE over a coupe with the roof "in" that is already pretty good.
As always, given the vehicle weight. Anyone can get good stiffness by "adding iron". A lot of iron.

But, until you start tracking it, and start adding DOT R tires, and start adding T1 suspension components,
and start playing with suspension alignments, and spend time agonizing over how to reduce lap times by tenths of a second,
who cares.

Have a good time letting the wind blow your hair around.
And, hopefully, your partner's skirt up.
There is more to life than lowering your lap times. For some of us.

 

Thanks for pointing to the link. Everyone with a Z06 should read this.

Thanks.
It was time for him to go. When you have no quality of life left, let it go. Another WWII vet bites the dust.
But, of course, he fought for three months after the doctors' said, "He's Done". Typical fighter pilot stuff.

BTW, soldiers from Fort Riley (The Big Red One) traveled clear across Kansas to do "the honors" at graveside.
And fold and present me his casket flag. I'll aways remember and appreciate that.

 

I thank people like your father and the brave folks who put themselves in harms way everyday in service to our country.

A gentleman I work with had a mother who passed recently - he had the same situation, where her quality of life was gone (and he's a physician, so he's always ready to help someone fight it as long as they can). Interesting lady, did volunteer work in support of the war (WWII), really contributed alot to medicine and medical research as well.

Take care buddy!

DT

 

Retired GM Engr, I am interested, and thank you for the input.

 

I do miss my the open air of my old 98 C5 Roadster powered with its MTI built 427 C5R Motor. That having been said, i know its more expensive but ifi kept my 02 Z long term I would love to make it a complete Z06 full convertible and I know this can be done also but for a steeper price than the targa top conversion for Z06s!