I recently bought my wife a 96 Z28 A4 and the handling is a bit wierd to me.

Before I tell you what it's doing, let me tell you what I've been used to. My 94 Z has welded in triangulated subframe connectors, a strut tower brace, stif shocks and stock springs cut to slightly lower the car. It is EXTREMELY stiff and has no squeaks or rattles.

Her car seems to have what I can only descrtibe as a cowl shake at about 20-40 MPH. Feels like the front of the car is being rocked side to side. The car actually feels like it's twisting. It dosen't do it all the time and is mild (wife dosn't even notice it). It seems to be most noticable over bumps or in turns. It's most obvious with the top down.

The car has brand new tires (did it with the old ones too) and I've checked everything in the front end and it's all good with no obvious play.

The reason I was wondering if it was a convertible thing was today I was driving a frineds 2000 Mustang vert with the top down and although it wasn't as bad, it did the same thing.

Any ideas

Re'

 

My '95 and '99 TA vert does not do that, maybe a little shake if hitting a good bump while cornering at 35-40mph but doesn't seem to be any more than any other car.
Make sure the extra "X" brace is on the bottom, it connects the 2 sides of the tunnel together and ties it to the transmission crossmember.
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On my '95 I installed weld in SFCs and a strut tower brace and it firmed up the whole car, but it did not do what you are describing before that.

 

I used to hate the way my car was before SFC's. My vert would twist like crazy if I didnt take a speed bump with each set of wheels hitting at the same time, or I could feel and hear it twist when going in a driveway at an angle. My strut brace and kenny brown SFC's fixed it for me.

 

Holy cow! I was just about to write about MY experience with flexing, shaking, and general looseness! I have always loved and supported American cars, and have wanted a convertible pony-car since my '67 Camaro convertible. And I LOVE the look and design of f-body convertibles and spent TEN YEARS dreaming and reading every issue ever published on f-bodies --- issues of C&D and R&T (especially the Sports & GT Guides) about how WONDERFUL convertible F-bodies were -- almost "no cowl-shake", etc.

I am coming from owning a series of durable, reliable Toyotas ---and I was in the process of selling my showroom-condition 62,000 mile '85 Supra, which, despite its low mileage has a definite flex and groan that comes from its b-pillar gowing over bumps or when it is jacked-up. I was just about to sell it to buy a sweet, one-owner, very-rare-color, 90,000-mile '95 Formula convert here in "pothole-free" SoCal, when I took the Formula for an extended drive and found THAT IT FEELS LIKE IT IS FALLING APART, depite looking absolutely mint on the outside and inside and running perfectly. I literally could not tell if the tie-rods were falling off and the engine mounts and shocks broken. In addition, there was a grindy-groan -- like bad brakes, but not just when braking --- when you slowed down, coming perhaps from the leaking rear dif. I am wondering if that that advice about the "X"-brace being missing may be something to check --- I did not see one on my planned-purchase.

I have not driven an American convertible in TWENTY YEARS (with one exception that I'll mention in a second...), but I am SURE that the flexible old '69 GTO convertible I once owned ---while shaking itself like crazy over ruts and railroad tracks -- was no worse than this f-body! I recently drove a 2006 Mustang convertible rental for a week around some great curvy and bumpy roads in NorCal, and found it TIGHT AS A DRUM with the small exception a some very distant, minimal, opposite-corner quivering. I have HATED squeaky, transmission-slipping Fords for my entire life, but after a week with this 'Stang, I was ready to buy one --- it was not only amazingly tight, but handled well, moved like a banshee for a V-6 (15.5-sec 1/4 in C&D), and was FUN TO DRIVE AROUND BUMPY CORNERS ------ this '95 Formula was not, and in fact only began to be somewhat "normal" on a silky-smooth, straight highway. Even my '69 L-48 Caprice hardtop was tighter and smoother than this Formula, with 220,000 miles on its frame and body (they used boxed convertible frames...)

Can a 4th-gen F-body convertible REALLY feel this sh*tty after just 90,000 miles on Southern Californian roads...?????? I "courted" this car's owner for a month to get it (already got him to spend $500 on repairs) and wanted it SO BADLY, but just walked away after driving it.

If this Formula is typical of a 90,000-mile f-body, than it is NO WONDER the prices on '94-97 f-bodies ---- including the convertibles --- are dropping like bricks out here...


P.S.... I'm also sorry to those of you who have to live with the the plastic interior -- especially the sqeaky-creaky console lid!

 

I think some of the flex feel may be because the top is down and you get the feeling its flexing from the windshield moving in front of you when going over bumps. When there is a top over you, you don't get that same sensation. If the body was flexing everytime you went over a speed bump, the car would be a rattle can after 20k miles.....just look at or drive some of the 3rd gen cars
I can jack my 4th gen verts up at any one of the 4 corners at the jacking positions and the door will open and close fine, even before SFCs....try that on my 3rd gen TTA and the doors will not close due to body flex.

 

I'm not really sure what the car is doing. It just feels wierd and NOT what I'm used to from my 94 t-top car. I was expecting the twisting as nearly all verts do this.

I know I can build a quality subframe connector to stop this but the car is my wifes and she dosn't want it modified. She threw a fit when I installed the Delteq, plus I really don't want to mess with this car, just fix what breaks.

Guess I'l put it on a lift and look around.

 

hehe, I can relate to that..wife didn't want me jacking with her '95 TA...and now look at it in my sig She didn't want the heads/cam...but now she says "this is bad azz"

 

I could also jack up my 4th gen vert by 1 corner and have the doors open and close perfectly, before I installed the SFCs. I couldnt say the same for a couple hard top 3rd gens I owned.

My vert now has SFCs and a STB. It feels pretty good, but it still doesn't feel as solid as some of the more expensive luxury convertibles, but what the heck... it doesn't cost nearly as much as those cars either. You gotta pay to play.

 

Sounds very odd.... the only "twist" I have ever noticed was when I went over a huge speed bump diagonally. Not really a twist then, just a small creak sound from the rear- hell that may have been from the suspension itself vice the body.

I have never noticed any sort of twisting in the cowl area and mine is rock steady at any speed- granted I don't have many miles racked up though.

 

After watching a buddy take his 30th SS convertible to mid 8's/160+mpg, I have complete respect for the 4th Gen convertibles. But the car had SFC's almost from the day he bought it new. I was truely amazed by the beating that thing took.

 

BTW, I hope no one thinks I was being disrespectful here --this is a great site and I wouldn't be looking for an f-body convert if I hadn't wanted one for so long... I was just really surprised -- actually kind of shocked --- at how loose they are after so few miles, and am still wondering if they are all like that. It also makes me hesitate to ever consider paying even more for a much-lower-mileage LS-1.

 

Hmm, I've found that the 3rd gens are tighter than the 4th gens. Go figure.

 

I also live in tulsa OK, which has hte worst roads in the country.. And like I said about the twisting, I'm like you and I nit-pick things like that constantly and I only noticed it when going in angled in a steep driveway. The speed bumps only made it flex at slow speeds with going over it one wheel at a time. I'm sure it'd be totally adequate for anyone else but after every thing I nit-picked, the trianglulated SFC's stopped it all. You also shouldn't base your buying decisions on jsut that after only 300 dollars installed will fix it.

 

GM says the chasis of the 4th gen is 25% stiffer than that of the 3rd. I remember reading that back in 1992 when the 4th gen was released.

 

You guys want to feel cowl shake, you need to drive a C4 vette. My 97 vert. is like a coupe in comparison.
I too have experianced a similar shake from time to time. Usually on Monday morning after it's sat in the garage all weekend. In my case I believe it's caused by realitively soft performance tire that get flat spotted or slightly out of round from sitting to long. I've had this problem on other cars (coupes) also. Usually after a few miles it goes away, which is one way to tell it's the tires.
I've had many different convertible over the years and these modern verts. are way, way better.

f-body fan,
Either this 95 is particularly bad or your way to picky for a vert. In this case it sounds like the car has been beat on a lot more then it looks.