Vetracr

The trouble making days of my youth are behind me so I'm not out to start a ruckus. Its just an enquiring enginering mind can sit quietly for just so long before you have to start asking questions. I've read many kudo's on this forum for the RD camber brace. My engineering mind can no longer be quiet. Just how, in enginering terms does the RD camber brace improve chassis stiffness?

No broad brush, it worked for me answers please. I'd like an engineering explanation. As a degreed auto engineer with a lot of experience buliding race cars, I just don't get it. From what I've seen, the brace has only a single bolt attachment on each K member dog bone. A single bolt attachment cannot effectively transfer torsion. The RD brace can only efficiently transfer horizontal loads between the upper control arms but most of the horizontal cornering loads are carried by the LCA's.

The key to improved performance is to be able to increase the torsional stiffness of the chassis, not the ability to transfer a horizontal load from one side of the chassis to the other.

I'm open minded and if I'm wrong I'll be the first to admit it. I'd just like someone to explain to me HOW, in real measurable engineering terms, the RD camber brace improves chassis torsional stiffness.

Forget the enginering. Has anyone ever tested the increase in torsional stiffness of a C4 chassis with the RD camber brace installed?

I'm willing to listen to a real engineering explanation or to see real data. Hey, if you can convince me it works, I'll buy one for my 93.



Larry

JrRifleCoach

As I see the design intent, the brace maintains the distance between the upper control arm foundations. Thus maintaining (to some degree) the camber. I have noticed the cars enhanced stability across a rough surface during normal street driving. I don't see how the RD camber brace improves chassis torsional stiffness.

Perfusion

Since I don't want to just post a "it worked for me", I'll just

Mr Mojo

I don't have one, but by the name of the thing, "Camber Brace" I have to assume that it keeps the camber in check. I don't know how much of a difference it makes or if the upper part where it attaches moves much under cornering without it.

I do know that the Cross Frame will help stiffen up the chassis since it bolts into the same place the convertible X brace does and the Cross Bar and the roll bar will definitely help stiffen up the car as well as the targa truss.

I'm sure Dave will chime in with an answer.

1991Z07

I'm just making a WAG here, but I am guessing that it works like the tower braces for the C3's and also for most of the unibody cars with struts.

Since the C4 frame has so many welds in it, the vertical stability of the frame is "suspect" and the camber brace steadies the flex of the frame under load.

Just an educated (electrical) engineering guess there...

Redeasysport

You hit it on the head. The front rails can flex the Camber Brace stops the twist.Same thing the tower braces do.I have some crappy roads here in Ohio and on the twisty ones my car would hop sideways before the brace I can feel the difference on the same roads with a before and after drive.

On related note I took My Crossframe off to get some tranny work done and I did not remember how much cowl shake I had before. I do now and it stinks with the top off steering wheel never stops shaking on any slightly bumpy road.Can't wait to get it back on.

STEVEN13

http://forums.corvetteforum.com/show....php?t=1155769

Read this thread. I questioned if it worked also.

Steven

USAsOnlyWay

Steven,
what did you end up doing?

tempest

although i am another to attest to the difference the Camber Brace's effectiveness, i do not think it stiffens the frame (i.e. the rails) itself, but rather the front crossmember.

R-D Racing's website has pretty good illustrations of the front crossmember.

http://www.r-dracing.com/Camber-brace.htm

if you look at the front crossmember, the suspension just mounts on two "plates" that stick up perpendicular from it. figuratively, it's like an open shoebox. the Camber Brace effectively closes up the shoebox, stiffening it.

the frame does not contribute to the stiffness of the front crossmember because it is only bolted on to the frame, and only in a few places. if the crossmember was welded to the frame rails into one piece, i think the Camber Brace would not be nearly as effective.

stiffening the front crossmember stiffens the overall chassis rigidity.

that's the best explanation i can provide without whipping out numbers.

95wht6spd

I have one and it makes a big difference. It boxes in the front frame, and maintains suspesion geometery/alignement in corners etc. makes the car feel much more solid, and reduces cowl shake.

VenkmanP

Better yet, do a search and read the 100s of other threads on the subject.

And for the finite element analysis, you might want to post on the SAE forum.

Gary04Z06

It not suppose to increase the chassis stiffness. The Cross Frame and S/T Frame support do that. The Camber Brace simply ties the upper a-arms together keeping the wheels "flatter" during spirited driving. Read the product discription before rambling off how does it work, I don't see how it works.......And yes, it does perform as advertised. If I get another C4, it will have a Camber Brace.
http://www.r-dracing.com/Camber-brace.htm

AORoads

As a auto non-engineer responding to one who is, my question is:

why ask this here? Why not ask it of R-D since what you want is the "engineering" explanation?

There are engineers here, or at least they say they are, but it seems as if not that many are auto engineers, as you are.

Maybe you could bring in the discussion by asking/printing the R-D response (s)---that'd be really helpful to all of us as well.

Thanks in advance.

STEVEN13

I don't think I will get the camber-brace. The cross-frame looks like it works (verts came from the factory with an x-brace). I will spend my money on this.

Steven

P.S. Right now I am trying to finish installing upper/lower ball joints for a time trial event w/EMRA 9/11 @Pocono.

steve40th

I put mine on at some high mileage, around 125 k. It definitely made my suspension "stiffer" I have the base spring, ZO7 sway bars and 275 front and 315 rears. These pieces make the car ride rougher, but with the camber on it makes it stiffer. How do I know, my steering wheel SOTP feelings have changed. I am no autocrosser, but I will and have pushes my car to the limits quite often on real world roads, and then I put the S/T frame in, WOW, then the roof bar as I like takeing the roof off. WIth tthe roof bar RD racing makes, its a whole new world, now I can thouroughly enjoy the Vette. I have have driven low mileage cars of the same type and suspension set ups, ie ZO7 40th, Z51 Grand SPorts( I think that is there adjustable) and they feel good, and with age they will get better. SO in a long term high mileage car it really makes a big difference because there is a lot more slop in the car, and Daves products fix/bandaid allot of GM's design flaws.
My suspension has urethane bushings everywhere in the suspension , rear diff bat wing, etc etc ecept front A Arms, so my car really shows via the mileage I have and have had it that these products work, especially the camber brace.

CentralCoaster

I have one on my 85, didn't notice a difference, drive the car real hard on mtn roads, don't race it legitimately.



I don't believe it work just because everyone says so. Theory says yes, it helps maintain camber when the front is loaded evenly (ie, braking in a straight line). When it's loaded on one side in a turn? Who knows. Vertically, the front end with brace becomes a 4 sided box, which doesn't have any triangulation.

I'd like to know how much flex occurs to begin with. I could quantify this by bolting some metal to each tower in such a way that they move in and out, (rubbing against or marring eachother). Then after beating the hell out of the car on a racetrack, measure the relative movement, or how long the scratches are.

Corvette Kid

I'm far from a structual engineer but I do know this. Anytime you triangulate something, you strengthen it.

Slalom4me

(Before I continue, I'd just like to remind people that we are talking
about a $200-250 purchase. One that has been endorsed by countless
satisfied customers.)

FEA is out of reach for some. Force drawings might tax recollection
of various school subjects. Before/after torsional tests are a minor pita.

But anyone can use styrene, balsa or even cardboard to mock up
a representation of the C4 front end. Source the materials with
a trip to the hobby store or into the cupboard.

The C-B is not triangulating, it is adding a fourth side to create a
rectangle.

If the rectangle consisted of tubes with heim joints at each end, there
would not be much rigidity to the shape.

On the other hand, if the rectangle consisted of two '[' shaped pieces
where:
- the long sides are formed of substantial tubing,
- the short sides are formed of heavy rectangular bar stock,
- the corners formed by the intersection of tubing and bar stock are
welded
- the two 'c' shapes are joined together by bolted lap joints in the
middle of the short sides formed by the bar stock.

Like this: [] (rotate image 90º)

Then I believe you would find that you had created a fairly sturdy
object. You would have also modeled what the C-B does to the
region around the C4 K-member.

Furthermore, although I have yet to hear about anybody doing so.
I know of no reason why the C-B couldn't be triangulated.

Like this: [/]

.

Slalom4me

C-Bs weigh about 9-10 lbs and can be removed in a matter of minutes.
Why not take it off, go out for a rip and evaluate whether to reinstall
or sell it?

.

Daffy

I would have to believe that this product will be more effective on the 88-96 cars where the upper control arm mounting is higher than on the 84-87 cars