The Dad

Long time reader, first time poster...

2003 996 C4 Cabriolet with 89k mi, I purchased 14k/2 years ago. Love the car generally, but the flex bugs me a little. Yes, minor compared to other convertibles I've driven, and open-air driving is certainly worth the tradeoff (especially in the Bay Area, where I can put the top down 9 months out of the year). But still annoying.

Thoughts on upgrades that might help? Sway bars, perhaps? And if so, what brand?

I don't track it, FWIW. This is for street (preferably twisty mountain roads).

(For the record, I did a few searches before posting, but didn't see any relevant discussion here.)

Thanks in advance.

Schnell Gelb

Do you really mean chassis flex or do you mean soft/worn suspension ? Similar but different cause/solution. At 90k miles, a careful inspection of the suspension components may be a good idea?

Slakker

Roll cage does wonders for rigidity. :P

extanker

dude just drive the car..........and do not put a roll cage in the car..............unbelievable advise

rockhouse66

My cab has a front strut bar in it but it came that way from a PO so I don't know what it drives like without it. I don't notice the chassis flex and I have a lot of really good mountain roads. I also have the M030 sway bars so that could be a factor in the feel of the car as well.

The Dad

Thanks for the input so far.

I think that the roll cage suggestion was tongue-in-cheek.

A suspension inspection might be a good idea indeed. I'm probably getting the clutch renewed (and IMS upgrade installed), so it'll be going into the shop and I'll ask them to look. But they noted wear in (and replaced) the CV boots 4000 miles ago, and I suspect they'd have looked at the suspension while they were in there.

Assuming that there's no suspension wear issue to resolve, though, any thoughts? A little research suggests that conventional wisdom discounts strut bars, but that could be my misinterpretation.

5CHN3LL

I don't know if a solution exists for 996 cabs. I know the feeling - chassis flex for C4 Corvettes is horrendous. The roof panel is structural and the car suffers when it is out; many of us use an empty targa frame or an aftermarket brace to stiffen the chassis. Some ragged-out Vettes get so sloppy that the targa panel can't be reinstalled unless the car is parked on flat ground.

I don't think there are sufficient hard points for the 996 to do something comparable to the Corvette-style braces. I'm not sure the hardtop is supposed to be structural when it's installed, and I wouldn't expect the mount points to be robust enough to carry significant load.

My 986 was fairly stiff for a Cabriolet, but it was nowhere as stiff as my C4 Coupe - not even close. It would flex (and even creak) pulling into driveway aprons, whereas my C4 coupe will pop a wheel off the ground going into almost any driveway. It is ridiculously rigid. I know there are strut braces/trusses for the 996, but I don't know of any aftermarket product designed to reduce/eliminate chassis flex/twisting.

Boomvang

I have noticed more flex than I like in my '02, I would say on a par with a Miata, and not half as stiff as an S2000. I doubt sway bars would help, I would think the flex has its roots in the fact that the Cab was not designed from the beginning as a drop top, and suffers a loss of ridgity from absence of the coupes top. I believe that some have had some success with adjusting the door catches, the floppy doors are the thing that really bugs me. I will address this in the future, but need to source some new catch screws, as the top one is stripped, more than likely from a previous attempt to adjust using a torx wrench rather than a double square.

Slakker

The default suspension is pretty loose so there may be more there to gain than you think. I just from KW V3 coilovers and GT3 sway bars back to stock suspension. For daily driving, I love it. Grips good enough on the on ramps and I can go down roads at 60 that I had to slow down to 20 on. It almost feels like a 4x4 and since they graded my road to the soil and haven't gotten the asphalt back down its a good thing.

But I did 3 sessions on a track a few weeks ago and was very frustrated. It wasn't near as fun with stock suspension.

So yes, I think upgrading the shocks and the sway bars will give you a more rigid feel and definitely help it grip better. While you may still feel some twist in the chassis, the stiffer suspension should make up for it.

The Dad

It's not. Actually, when I have the hardtop on, I notice the flex even more, because it rubs against the windshield frame. Some silicone lubricant helps the sounds.

5CHN3LL

Bummer, although it's not really a surprise. If you've ever had a car (like a Corvette, or an old Camaro with t-tops) where the panel(s) are structural, you know what a pain in the butt it is to remove/replace 'em.

Sounds to me like you are already resigned to the fact that the flex you're describing (the top shifting when cornering or when you load opposite corners) isn't going to be completely solved with suspension adjustments...but if you can learn to live with it, it's still an incredibly capable platform. Just a little twisty (and maybe squeaky as it ages)...

Schnell Gelb

If the chasiss is too flexible for your liking, stiffer than stock suspension would be a bad idea.
Can you describe the exact situation you notice the flex? Railroad crossing for example?
I a thinking maybe just new shocks/struts after 90k miles? Not rock hard Konis ,just equivalent to OEM.

The Dad

Yeah. I'm really not even talking about top-up - I don't really expect that. I'm talking top down. But loading opposite corners is a good description.

Could be, especially if what I'm hearing is the suspension. I'll see.

Thanks, all. Apologies for my ignorance.

Vancouver996

The cab has a reinforced chassis , the series two cab is even stiffer than the early chassis .
My first check would be the suspension and all the bushes .

TheMystro

The 996 Cab is pretty stiff as Cabs go. They are very respectable compared to their Ferrari counter parts. I question the age of the suspension if that's not giving you a false sense of what you are feeling. The open top motoring is a trade off. The coupe is always the "no compromise' option that is hard to duplicate with any open top sports car.