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Steering box brace - any good?

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If competition driving or you like to throw your car around corners, some say that the car sub frame flexes and you can actually feel it. I doubt most drivers could tell the difference but if you want maximum assurance that the steering box is stable and your steering is going where you want it, then this is the thing to have.



Here are two more items that play on car owners insecurities that they don't have a race car handling vehicle.


Strut brace




Engine torque strap.


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The steering box brace is more for structural integrity. Cracks can occur in the steering box area and the brace just helps keep this flex at bay, which keeps the cracks from forming.


The strut tower brace is a whole 'nother thing. The brace allows the suspension to do its job more effectively. Think of it like this: would you rather have your chassis do the flexing or your suspension? On race cars, to be competitive, car owners spend a lot of time on suspension tuning. If your chassis is part of the suspension (which it should not be), the flex is hard if not impossible to account for. Bracing added to known flexible areas of the chassis eliminate chassis flex from the suspension equation, allowing your suspension tuning to be more effective. A good roll cage is also a form of brace.


On 510's with rear coil over conversions, it's also a good idea to strengthen the tie between the two rear shock towers, as now the loading is at the tip of the shock towers, where it was not designed to be.


The engine brace is only needed on engines that have super soft engine mounts. Both of my Volvos (a 1971 145 and a 2003 V70 T5R) had them stock. Early MGb's had them stock also. I would never use solid mounts on an engine brace though, as you see in Mike's pic.


These things are cheap and look cool (if done right) so I say go for it. Can't hurt.

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Big power engines, or driving abuse can rip stock type engine mounts apart.

Solid engine mounts can induce block flex on some engines, like my 6-cyl Toyota.

Some people use a stiff poly donut with a bolt through it, but this allows forward/back, and side to side movement, so not an answer either.


Found these in Japan, made by Kazama.

They allow some movement, and sound deadening, but can take 1000 HP without failing.




People like XM, and others in this country copy the design.

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If the rumor I read is correct, they are suspension bushings from the Toyota AE86, pressed into the steel tubes that are welded together.


But back to the original subject........

I remember observing the steering box on my son's first 510 move around, and had to brace it.

So yeah, any type of performance driving, especially with sticky tires, I sure would brace it.

Nice that someone offers a kit to do it  :)

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If you like to throw your car around corners,

if you want maximum assurance that the steering box is stable and your steering is going where you want it, then this is the thing to have.

∆thats why.

The steering has never been great, so a small brace makes a big difference.

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I'd recommend having a box brace over not having one IF you run fat stick front tires. As for a strut brace it is not recommended or used by Troy Ermish who holds lap records at Laguna, Willow, and Sonoma with his 510. The firewall is a massive lateral sheer brace that is only a few inches away from the strut towers. The only force exerted on the top of the tower is directly upward from the tension of the spring and shock. All of the torsional forces are exerted at the bottom crossmember and through the TC rods. If you are running race slicks you might experience some body flex, but it would twist the body not move one strut independent of the other. There is no lateral stabilization provided from a rod with hinged connection points at the top of the tower. If you want to eliminate body flex use a 6 point roll cage.  

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I disagree. They do minimize flex in the front end. And since they are cheap and easy to build, and don't weigh a lot or get in the way too much, I would build one (or buy one). But as stated, they are only really needed on a competition car.


As per Troy's car, it has been braced with other tubing welded to the body, so that's not a very straightforward comparison.

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A Pre-load brace makes the car very stiff.


A good setup for strut towers is a triangle with tunable braces. 


image of a BRZ rigid brace without turnbuckles. The concept is sound. 




There are other more permanent ways to stiffen flex points on a car. For everyday driving these types of items really aren't needed though.

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The 510 unibody is far more rigid than body on frame cars of the same era. 70s big block Mustangs for instance had a V brace from the top of the firewall to the shock towers, but no cross brace. The stang was a body on frame design though so it needs it. Think about it, the 510 body is a welded together steel box. If the entire body was flexing significantly (enough to alter suspension tuning) in corners, the body would fall apart. 






Look how close the brace is to the super rigid firewall. Given that the brace is up so high, I just don't see any g force geometry that would flex the top of the strut towers together in a corner. if anything, one would rise relative to the other, but a flimsy little hinged rod way up there isn't going to help.

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Hitting the nail on the head. No one drives their car hard enough, nor can it be driven hard enough, to cause any flex attributed to the strut towers moving. Nor would anyone less than a race car driver driver know the difference in the first place. If the strut towers moved inward the hood would be pinched, outward, the gap would open up. Hood and fendres would buckle, no one ever sees or mentions this. Not that it doesn't move, just not in any amount that would be significant. 

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Think about it, the 510 body is a welded together steel box. If the entire body was flexing significantly (enough to alter suspension tuning) in corners, the body would fall apart. 



They do fall apart.


My first 510 street car was so torn up that it started popping spot welds and seams. It was so bad that we just threw it away and started over with a fresh shell. And no, it wasn't worn out from being crashed. Just driven too hard for too long.


I've seen my fair share of torn up 510 body tubs.

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Mixed up Mustang and Camaro. The frame rails bolt to a passenger box and the entire front and rear can be remover with a few bolts. Like most American cars of the time, Camaros flexed so much under power they'd lift one front tire. I will concede though, that is a hybrid and not full frame on, but is not a full unibody like a 510. The mustang's frame rails were also bolted on, but the bolts were welded up so they wouldn't back out.


Be honest now Stoffregen, was that 510 falling apart from hard cornering on the street, or were you doing "other things" with it? :rolleyes: I know I did with my first 510. I played Rally Car Driver on the washed out dirt roads behind our house in Rosarito Mexico, Speed bumps were a challenge not a deterrent, and got serious air off Tutus st. hill 1000 times in my old hood. Did that for three years straight in my bone stock 68 and nothing worse for ware. 

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Honestly? Ok, it was a high HP street car that I also used for track days. Not much dirt road action, but yes, it was in the dirt a few times at Sears Point. Hit a lot of curbs in the esses too.


But the tub was trashed.


Like I said earlier, it's not the only time I ever saw that.


A couple years ago I TIG stitch welded a 510 tub for a customer to help stiffen up the tub. I bet that helps for longevity too.

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I played Rally Car Driver on the washed out dirt roads behind our house in Rosarito Mexico, Speed bumps were a challenge not a deterrent, and got serious air... Did that for three years straight in my bone stock 68 and nothing worse for ware.


All the way to Bahia de los Angeles, over 1000 mi on that baja trip.

Seized a wheel bearing 2 days after I got home.

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My old low buck steering box fix was a Mazda RX4 reinforcing plate. It is about 1/4"" thick, mounts on the wheel side of the wall and fits perfectly. I suppose old RX4s are pretty rare now, but the plate was simply a flat piece. I made one for the Pink Car and welded it to the body. That car has seen a fair amount of use with no problems.


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So many things aside from the visible braces can be done to stiffen a chassis. 


Commuter cars isnt really the platform for this type of addition unless for your own visual pleasures. Street/Track car I would say is acceptable for function. 


A triangulare preload system is the superior addition for chassis flex without a safety cage. It just comes down to preference though. If you want it and feel all better having it. Then buy it and add the item.


No one is going to ridicule you for having it on your car. If they do then they are a hating asshole who might need to find a new meaning to his/her/it purpose on the forum or car scene.


Enjoy your car and build it however you want. Add the brace for looks or purpose. Then drive it. 

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Actually you be surprised at how much stiffening up a commuter car helps. Most race tracks are smooth and the chassis flex is loaded into the car progressively; it's bad because the car effectivily takes a set twice but you can almost drive around it or at least plan for it and negate some of the adverse effects. It's also identifiable in a race car whereas in a street car it may be effectiving your car in ways you hadn't imagined


Those humped out secitions in the left turn lane may jack the right front as much has 5-6 inches, that's a heck of a lot of twist put into to a car very rapidly. The symptoms may manifest themselves as scuttle shake or just simply ride quality that isn't what it should be. It's an order of magnitude; it may not be as bad as a old ladder frame pick up truck but it still may be there. Also take into consideration the effect flex (even minor amounts) has on dampers, you are trying to hit a moving target. Volvo 240s are built like tanks and touted for their crash worthiness, they also have an excellent ride and nice steering. The two are not unrelated.


So while that bracing may not make any noticeable change in the cars handling for most drivers, it may add to the comfort level and have secondary benefit of reduced driver fatigue. I wouldn't dismiss any bracing as a looks racy do nothing part until I tried them on varying surfaces. The parts may be doing nothing more than damping out certain frequencies, which does have a noticeable effect.


My .02

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