Update on the new C4 frame braces

[dmd]

Anyone who does track day events, autocrosses or just drives hard on the street in a C4 coupe without a roll cage and says there is no difference is either unwilling or incapable of driving car close enough to the car's handing limits to feel the difference.

As for C4 convertibles...the problem is even worse. The structure in those cars is so weak that its frequency in torsion and bending approaches the its ride frequency. That's one reason the car shakes lot. It's, also one, reason C4 convertibles were never offered with Z51 or Z07, ie: the structure is so weak that when you start increasing roll stiffness (increased spring rates or stabilizer bar rates) you end up with the structure deflecting just as much or more than the roll stiffness increases. When the structure starts bending the car becomes unpredictable at the limit.

In motorsports events you'll never see anyone in a C4 convertible without a cage whose times are competitive unless it's a class for convertibles only or a class populated by poor drivers in coupes.

I've been thinking about this a lot the last few weeks, as I have both my C4 and C5 convertibles out for drives this time of year. Before my '96 LT4 convertible I had an '87 Z52 coupe. The Z52 had the convertible brace, and despite that I know well the unpredictable behavior of that car at the limit without its roof. I don't know why, but my '96 isn't unpredictable at all. I've got some extraordinary roads here and I'm not at all afraid of it through the twisties the way I was the '87. Maybe it's the F45, which is otherwise useless - can't say for sure, but they'd definitely cracked it by '96. And you don't need a cage for competition in a convertible - just get a hardtop. That's the stiffest stock configuration you'll ever get from a C4.

 

[MBDiagMan]

One of the best technical improvements of the C5 was the strong perimeter structure of the car. It is no surprise to me tha you find your C5's handling much more predictable than most ANY C4 top on OR off.