The 24 Hours of Lemons Forums → Lemons Tech → Anti-sway bar
Our civic needs a stiffer anti-sway bar. I've been told that I basically can't make it too stiff in the back. I'm thinking we need to go look underneath some large vehicles in the pull-a-part to find something reasonably narrow that we fab some brackets for. Any ideas as to what we should look under?
The Escort sedan uses a 13mm bar I believe.
The Escort wagon uses a 21mm...I can't remember.
Anyway, find one off a wagon or something.
Ours was bolt-on for $50.
KT
Think outside the box, this is Lemons
http://ef-honda.com/main/viewtopic.php?t=38169
2 rear sway bars! Your thinking is right, the rear can't be stiff enough on a FWD car.
The gnomes have done that to their metro. I think it's pretty clever but... we have an '88 civic sedan and the rear bar is about as big around as my pinky. Maybe we could put six of them back there.
Trekkor is right about the Escort wagon rear bar being thicker. We snagged one since it's a direct fit for our Protege, and we're running it in addition to the stock one. It'll take you 5 minutes TOPS to get it off the wagon at a pull-a-part. Ours was $11 and some change for front and rear.
Not sure how it would fit, but the 1997+ Escort front bar is 1" in diameter. It'll likely take you hours to remove unless you find one with the front taken all apart. It's quite buried.
Here's what we ended up with:
It's the front sway bar from a Jeep TJ. We were going to put it underneath, but didn't couldn't find a place to put it. Read slightly more here:
http://www.perpetualdownforce.com/2010/01/sway-bar.html
I get a red X.
Fixed. Thanks for the heads-up.
Awesome! I love it!
Ghetto bar. Love it!
great solution. i hope those "endlinks" hold up.
That is beyond awesome. I can't see the judges even asking about budget on such a creative installation!
Do you really think that you needed that much bar?
I'm considering making my own bar. Either with strait tube and flat arms (like this)
...or just getting larger diameter rod and bending it into something resembling the stock bar shape. Any suggestions for material choice? 4130 plus heat treat is what that blingy purple one above is made from.
Here's what we ended up with:
That is rad.
The judges won't even see that!
KT
I'm considering making my own bar. Either with strait tube and flat arms (like this)
http://www.kokeln.com/images/swaybars_004.jpg
...or just getting larger diameter rod and bending it into something resembling the stock bar shape. Any suggestions for material choice? 4130 plus heat treat is what that blingy purple one above is made from.
Think about this. there are sprint car torsion bars that can be found on ebay. They come in a range of rates. We usually use anywhere from 950lb to 1025lbs on our sprint cars. They can be found very cheap. They have splines on the end so you need the arms also but you can put together a complete sway bar for about $50. The sway bars are hallow so they are alot lighter than a factory sway bar. Just do an ebay search for sprint car torsion bars and sprint car arms. The front and rear arms and bars are the same spline. Its just that the rear arms on a sprint car have bends in them which would get your pick-up points farther out. You would just need to drill holes in the ends of the arms for turnbuckles or links to attach to your a- arms or whatever. The sprint car torsion bars only come in 2 lengths. 29" and 30". Here's what im talking about.
http://cgi.ebay.com/ebaymotors/Sprint-C … arQ5fParts
http://cgi.ebay.com/ebaymotors/Sprint-C … arQ5fParts
great solution. i hope those "endlinks" hold up.
The tiny looking bent bits are actually the stock Jeep endlinks, so they should (in theory) hold up. We welded them to some scrap tubing we had that fit around them almost perfectly. The bottom ends of the tubes are welded to the end of the Integra endlinks.
Do you really think that you needed that much bar?
We were told we wanted as much as we could get. I think we got it.
The judges won't even see that!
This way we can claim it's part of the cage.
RobL wrote:Do you really think that you needed that much bar?
We were told we wanted as much as we could get. I think we got it.
you sure did. but remember this isn't autoX, so the car doesn't need to be as loose as it does in that setting. make sure you test it out before you go wailing into turn 1 at CMP. 
If the end link, i.e. moment arm is long enough, almost any steel rod or thick wall tube will do, even mild steel, especially if your car is lowered and has limited suspension travel.
Too much rear bar will cause oversteer. Like they said, test it well before the race.
I've calculated the rear bar as contributing 160lb/in at the wheel. The longer arms on the bar and the .5 motion ratio help lower the rate. The stock bar was about 1/10 of that.
I was told 1000lb/in at the wheel but it was an off-the-cuff answer from someone with experience with bigger cars.
At this point we'll be doing well to even have the car put together before the race. We'll take a couple of spins around the block, but give us some clearance on the first stint! Fortunately it's pretty easy to disconnect the link.
I've calculated the rear bar as contributing 160lb/in at the wheel.
show your work, or it didn't happen
Those end links aren't gonna hold up. You're going to get upwards of 200 lbs of force through those (possibly MUCH higher in transients), and as you turn different directions, it will cycle that force from tension to compression and back. If they're as bent as they look in that picture, they're going to fold eventually. Replace them with this stuff:
http://www.mcmaster.com/#rod-ends/=5j50ox
http://www.mcmaster.com/#threaded-rods- … ds/=5j51h8
http://www.mcmaster.com/#threaded-rods- … ds/=5j51kq
And I'm pretty sure you should have one bushing above the bar and one bushing below the bar (I know this from painful experience - it's a long story but it ends with a wheel falling off).
+1 for what everyone else said about oversteer. Too much rear bar tends to cause unpredictable, uncontrollable snap oversteer in mid-corner - the "Oh my god how did I get backwards?" type of oversteer. Overdoing it is a recipe for disaster on a track. You definitely want to test it.
Other than that, excellent installation.
Jeez. You guys are harsh. Here's the calcs:
I'm not too worried about the links. They look pretty scrawny in the pic, but those were the same links with the same bends that were on the jeep. I'm sure the jeep sees much higher deflection than our Civic rear end. They're made of .5" diameter rod.
I was writing about how those calculations aren't right and your motion ratio calcs looked wrong... until I figured out it was calculations for the swaybar. You forgot that the swaybar is attached to a spring on the other end, not a rigid point. It's essentially transferring spring rate from one side to the other, while absorbing some of that rate in the bar. I'm sure that if I had enough time to spend on it, I could nuke out something that would approximate how it works, but it would be a much bigger spreadsheet and not worth nearly the amount of time it would take.
And I think your calculations are squaring and square-rooting stuff a lot of places they shouldn't. A spring rate of 622 lbs/in with a motion ratio of about 0.5 should result in a wheel rate around 311lbs/in, not 162.
When it comes to swaybars, analysis is generally more work than its worth. Just test it and make sure the car handles ok.
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