Thread: does anyone have chassis braces?

To me, there isn't any huge weak point directly under the car. It's a pretty solid unibody and has frame rails in the middle.

Having no rocker panels doesnt help as that is somewhat part of it's strength.

Also when you lift these cars off the ground you can open any door without a problem. All three that we've had don't body flex that much.

On older cars like the miata or fox body mustang, bracing is an absolute must.

I've never seen any or heard of the need to brace the uni body on these. There are a few guys on here autocrossing these things, and at least one guy running in the 24 hours of lemmons. So if there were any, someone should chime in. Good luck with your search.

I do recall some other body braces I remember seeing years ago.

Maybe its because of my own experiences, but if I were to go about stiffening a W-body... a cage would be my choice. However adding that is infinitely more difficult than adding rigidity to the torque box area with fabbed sheetmetal braces or square tubing like is popular on Mustangs (aka "subframe connectors"). Those tubular braces in the pic look like a joke to me, sorry. But if you gotta add weight, doing it down low is best for performance. Until you get confident and roll it. Seriously, the unisides and roof structure area are really smushy on these cars. Door frames and front / rear glass provide much of the strength. A lot of flex happens in the roof, just open the sunroof cover and listen as you drive!

If there is one thing this front-drive car needs, it is active traction control. Under the hood of my test car was a supercharged version of G.M.'s hoary 3.8-liter V-6. A pushrod engine with two valves per cylinder, the 3800 Series motor has been updated this year with electronic throttle control. Like all two-valve pushrod engines, this one produces peak torque at lower engine speeds (280 pounds-feet at 3600 r.p.m.), but tends to labor at higher revs. In contrast, the car's import competitors use modern, overhead-cam, multivalve engines -- many of them with variable valve timing for smoother, more flexible power delivery.

Between the Grand Prix's peaky power plant and the touchy feel of its e-throttle, the car lacks composure. Step on the gas too hard (it doesn't feel too hard) and the front tires squeal like pigs under a gate. Then the traction control kicks in, smothering engine power. The car bogs down. It's ugly.

On my test car, the co-conspirators in this rude behavior were 17-inch Michelin Energy tires, which do not offer nearly enough grip for a 280-horsepower front-drive car. Another weak link is the suspension tuning. Essentially, the front strut suspension is stiff while the rear suspension is very soft. In racing this is called the car's ''setup'' and it dictates whether the car understeers (that is, tends to go straight as the wheel is turned) or oversteers (that is, turns freely). Most cars have a degree of understeer engineered into them for safety's sake, so they are not overly twitchy and hard to drive.

But when it comes to understeer, a little goes a long way, and the Grand Prix goes round the bend. Under acceleration, the car's weight shifts ponderously rearward, lightening the load on the front tires and provoking them to spin. This is especially bothersome while cornering. If you pick up the throttle, whatever bite the front tires have begins to wash out and the car refuses to answer to the helm. You don't have to be challenging a twisting back road to feel this; it happens in mall parking lots.

Also, the car has significant body roll and bounding oscillations over rough roads. This is the kind of excitement Pontiac drivers don't need.

If you are searching for the G.M. renaissance, don't bother to look under the hood. The steel body stampings are spot-welded and bolted together as they have been for ages, it seems, with large gaps at the flanges and exposed sharp edges that will eat up a mechanic's hands. G.M. did invest in larger machines so that the door-frame stamping is now a single piece running from the front fenders to the rear ones -- an improvement that greatly enhances chassis stiffness and solidity.

http://www.nytimes.com/2003/08/03/au...-cladding.html

Before you worry about a tiny bit of unibody flex. You have close to 2000$ to spend just fixing the suspension