I'm considering a camber brace in hopes of stiffining up the flex that I'm experiencing when I remove the top on my LT4 cpe. Any here with one and was it worth the expense? Was there a notable improvement in flex with the top off?

 

I think what you need is the x brace the is used on the vert. I believe the camber brace will only help the front suspension under loads.
The reason I mention the x brace is I had a 95 coupe and it flexed to the point of distraction with the roof panel off. It is the reason I bought a vert the next year. It is much stiffer than the coupe with the panel off. The x brace is an OEM part.

 

Camber brace isn't going to do anything related to the top being out.

With that being said... I have one in my track car and it is a very noticable gain.

 

You can have the camber brace, the X Brace, the cross bar and once you remove the targa it is going to flex.

Do I like I did with my Vert, get used to it and call it "The Titanic". Ask a Vert owner, that is the mother of all flexes and they have the X-Frame from factory.

They sell a roof frame to be installed on the targa bolt holes and I heard it works well.

 

Targa Tuss Bar will take the flex right out.

 

ProStreet Customs AFSB

Get this, it looks better than the R-D Targa Truss. Tom is top notch!!! I bought one last summer for my 85 and its a HUGE difference. Way tighter than with the glass top. I ended up having to send mine back to Tom for a few adjustments, which he made with no problems and sent back. Very quality piece, this is my first recommendation for coupe owners. I use it for racing as well.

 

If you decide to go with the RD Racing Targa Truss, let me know. I'll make you a great deal on one. Sorry didn't see your post till now

 

What kind of "improvement" are you looking for? Seems like a waste of money to me...

The car was designed to be driven with the top off, it's certainly not unsafe.

 

The car was also "designed for" 205 hp (originally) but many people understandibly want more. What people are looking for here is increased chassis/frame rigidity...espceially when the top is off. What they "gain" from that is the preception of better ride quality and handling...which is a big deal to many (myself included). Properly increasing frame stiffness will reduce;
*Cowl/windshield/steering colulmn shake
*Rattles
*Sharp impact (bump) perception
*Front and rear "skip" over sharp bumps
*Noise

A car with a stiff, solid frame is more pleasurable to drive than one with an "undampened spring" as a structure.

EIDT: I also agree with those above who said that the Camber Brace won't help the top-off flexing issue. The camber brace isn't addressing that part of the car!

 

Come on, comparing HP numbers to a camber brace is NOT the same thing. HP actually makes a car accelerate faster - this is a measurable gain. Using math. A camber brace makes the car "feel" better. Feel can not be quantified. In fact, I'd wager (and have many times, actually) that the performance in a quantifiable way (i.e. on a track) would be worse with a CB. C4's push, and stiffening the front without other mods will only make that condition worse.

The difference here is perception of improvement vs. actual improvement. I drove my car for years on the street with the top on and off, and while I noticed a bit of shimmy on rough roads (this is Detroit, after all.) it was certainly never a problem. It's a C4. If adding a steel bar somewhere actually got rid of the rattles then they'd sell a lot more of them.

It's not my business because it's not my money, but OP asked for opinions and mine is that this is an unecessary modification.

 

I have a camber brace for sale right now in the parts section. $120+Shippping from 44224.

I can't use it due to my superchager. It helped top down cornering in my vert. I cld feel the difference

 

Scaryfast,
ALL modifications are unnecessary. HP improvements "feel good" too. Right? Isn't that why many people do them? And how many people do "HP improving" mods... that don't REALLY improve HP. And yet they still come on here and claim how much better their car FEELS (not track or dyno data)? How often do you see that, on here?? A LOT!



WRONG! The frame stiffening CAN be measured using objective numbers.."Math" as you call it. Both in frequency and bending resistance. You can measure the frame's stiffness bending laterally, longitudinally, and measure the torque/degree of twisting stiffness. Unfortuntely, almost nobody does that, but the fact is, it's IS measurable and objective.


I'd wager against you. The camber brace isn't increasing rolling resistance (like a sway bar) which DOES add to "push". The camber brace's claim to fame is adding structure to MAINTAIN front end geometry, under loads; camber (mostly), caster (to a lesser extent), so that your tires maintain the geometry that you set them at.

Does it help? I'm skeptical, even though I bought and installed one. I PERCEIVED no improvement, though I didn't take the time to test it objectively. IMO, this particular part is a waste of money, and certainly, it won't help the OP in his mission of improving stiffness in the midsection of the car...as I stated clearly, in post #9, when I said...

 

What I was hoping to correct with the brace is the very sloppy feel my car has with the top off. First time I drove it with top off over a bumpy road I thought my front end was going to drop off. My LT4 feels solid with the top on and I really dont hear any of the rattles that many experience, however remove the top and it feels crpaay, perhaps not handles different. It feels like a 50 year old pick up truck with a bad suspension. I was hoping camber brace would do the job but targa truss or top on seems like the options that will provide best results. Thanks for all the input.

 

If your car feels that sloppy, it could be what you are comparing it to, meaning another vehicle you had or have driven.

Or since the c4 is not a new car anymore, so it is possible that the bushings and or other suspension parts are wearing out or already wore out which can make a huge difference.

 

I was comparing same car roof off, roof on. The difference is very obvious. My car with roof on feels very solid no sign of flex at all. Roof off totally different story

 

Tom you make some excellent points. The difference is feel versus performance improvement. I am willing to pay for performance, not for feel. Maybe I am alone in this belief. I have spent a LOT of money over the years on products that other people liked only to find out that they do not perform as advertised. I would simply spare others that grief. I have no vendetta against RD or other vendors, but I do have a vendetta against BS parts that are supposed to make your car "better" that simply do not.

I have done no testing with the camber brace. But I see little reason to do so other than to settle this argument once and for all. The logic they profess is that by keeping the two "strut towers" (for lack of a better term) fixed you improve handling. What? That makes no sense for two reasons: Data taken by others on this board shows that the tower flex is negligible. Not a problem in need of fixing. And secondly, if the suspension is designed correctly this is irrelevant. The point is to maximize contact patch in a corner. This can be accomplished with camber settings and spring/shock combinations. How does tying my left front to my right front achieve this by itself?

You are correct, frame stiffness can be measured. But do you really profess that the camber brace actually increases the stiffness of the C4 frame?

As stated, I have not tested one myself. But what I have done is research. I've read, I've designed, I've talked to people with a lot more experience racing C4's than I have (which is a good many successful years). Never once has anyone pointed to this as a point to work on in our cars.

Gotta run, this is good discussion but I'm headed to the track so I'll check back Monday...




BTW, I'll take your bet, just send me a CB and the terms. I'll do back to back testing, same day, same car, same driver. If you're right I'll post all over the CF about how wrong I was, plus any personal wager we agree on. I've made this offer 100 times and to date, no takers.

Oh, and lastly, it's not polite to say things like "WRONG!" on a public forum. It's much more agreeable to say things like "have you considered", or "my experience shows something else." Keeps these little chats from becoming confrontational and getting shut down by the mods.

 

Ain't that a fact. But installing a hardtop made a world of difference on my '94 'vert. My seat-of-the-pants flexometer says about a 75% reduction. It's pretty dramatic. So much so that I'm thinking of fabricating a roll/reinforcing bar that would bolt to the same mounting pads as the hardtop for summer convertible use when the hardtop comes off. What I don't know is whether the extra stiffening provided by the hardtop comes mostly from the incorporated roll bar or from connecting the windshield to the rest of the body. The fact that t-top owners report a lot of flex with the top off argues for the latter, but then they don't have the X-frame either.

 

i think it comes from connecting the windshield to the frame.

The reason how I know this is because I have a 6 point roll bar on my 93 vert. Welded to the frame in 6 places. Even w/ non-removable diagonal sidebars. It did not improve chasis stiffness like I hoped for.

The only thing not connected is the windshield to the frame...

 

You know they saw this defect at the factory and they rolled them out anyway.

 

Yeah, they probably declared it "within acceptable parameters" since there wasn't much they could do about it. The sad truth is that (in my experience) pretty much every convertible suffers from some level of cowl shake. I put a strut tower brace on a Nissan 240SX 'vert and it helped but did not eliminate the problem.

Even my '05 Solara convertible has some degree of shake, in spite of the fact that it was designed from the ground up as a convertible rather than as a modification of the basic coupe design (prior to '05 Solara convertibles were actually coupes sent to a shop in Socal for modification). Toyota doesn't offer the Solara 'vert any more, so maybe they had too many complaints for a problem they could not solve. I don't mind it; it's a hell of a lot less shaky than the ragtop Corvette -- about the same as the 'Vette with hardtop on, in fact.