Sway Bar Setup

[onliLX-i]

I have read a lot about sway bars on this site. I found the how to to be particurlarly interesting. I do disagree about the best stock bar setup though. The 87 LX has a medium front sway and no rear sway. The 89 LX-i has a thick front sway and a medium rear sway. In stock condition they both have the same understeer. The LX-i just corners flatter. Honda designed the cars with a common principal understeer for safety. Don't want grandma dealing with oversteer! The best way to get a FF car through a turn is to remove the front sway. Check it out. Read about sway bars here.
http://webhome.idirect.com/~sav/Upgrade/hondafaq.html#4.3
Of course this would result in a floppy car and maybe too much oversteer. My solution was this. Use a medium front sway bar and a medium rear sway bar. I have an 89 LX-i with an 87 LX front sway bar. The car has a tiny bit more body roll but it handles better this way. I have tried both setups. If you have a 3GEE with a medium front sway bar and no rear, like and 87 LX, install a stock rear sway from a junkyard and leave the front alone.

[cardoc33]

I have an 88 LXI with a stock front bar and a Vigor rear bar. It does corner flatter than with the stock rear bar, the balance moved rearward a bit. It needs more though. I would go with the S.T. rear bar.
After I installed the Vigor bar, I replaced the front rubber with urathane and that alone threw it back to what it was before the Vigor bar.
My recommendation would be to use the stock front LXI bar with urathane and the rear S.T. bar. That should give it enough rearward balance to rotate the car in the twisties.

[86AccordLxi]

I thought the vigor rear bar was bigger than the ST rear bar.

Alex

[onliLX-i]

I have never experimented with an aftermarket bar. Having a larger rear bar would accomplish the same objective. The front and rear bars have to be closer to even. Closer than they come stock.

[smufguy]

as everyone knows a sway bar is nothing but a torsion bar, just like the ones that hold up our trunk lids. under torsion, these bars act as a liner spring. I dont know what moron said that to eliminate understeer, you have to get rid of the front sway bar. There is a whole book that talks about suspension. There is a reason why every single car is designed with a bigger front sway bar and smaller rear sway bar....... to induce understeer. The rear tracks the front and rears over driving the front causes over steer. So in cars that are designed to have a predictable understeer, has either no or smaller rear sway bar. To eliminate understeer and have a neutral handling, you need to have the car weighed at four corners, have the right spring rate matched up to appropriate shocks. The bigger than stock sway bars are always hollow, if you know material dynamics, you will understand why a hollow sway bar is stiffer. The Top loading not only causes surface shear load, it also continues through the material to cause an opposite loading on the surface of the inside of the hollow tube. The direction of the inside shear load is opposite to the top loading and hence causes a reisistance to the load/torque that is applied to the bar, making the bar hard to load (loading of force).

How a car handles, flat or body roll, is induced by corner loading of centrifugal force on the shocks, and the loading is trasmitted thru the sway bars to keep the opposite tires in perfect geometry. Once the sway bar is gone, the loading method changes and causes what is called 'float'. Floating is often experienced as improper/inadequate feedback. So eliminating the front sway bar would be the stupidest thing that anyone could possibly do.

Simple fix for understeer is to have a stiffer than stock Rear sway bar, which is what a lot of aftermarket swaybars are.

[cardoc33]

I thought the vigor rear bar was bigger than the ST rear bar.

Alex

Nope. the ST bar is 15/16" and the vigor bar is smaller @ 16mm.

[AZmike]

The bigger than stock sway bars are always hollow, if you know material dynamics, you will understand why a hollow sway bar is stiffer.

A solid bar is stiffer than a hollow one, but a hollow bar is lighter for a given stiffness. While some aftermarket sway bars are hollow the majority are not.

[smufguy]

A solid bar is stiffer than a hollow one, but a hollow bar is lighter for a given stiffness. While some aftermarket sway bars are hollow the majority are not.

torsional resistance is greater on a hollow bar mike. its the mechanical property of material. unidirectrional stress has no resistance to shear load. 85 to 90% of the serious aftermarket swaybars are manufactured hollow. stock replacements are a different story tho.

[onliLX-i]

This is how I see it. (I am not a physicist) Lats say I am going arround a left hand turn with stock sways. The inner tires, the left tires, are being slightly lifted by the swaybars in an attempt to keep the car level. If that force were to keep multiplying the left front tire would lift off the ground before the left rear causing the front to have 1 tire on the ground and the rear to have, lets say, 1.25 tires on the ground. Now the rear has more traction than the front and the front is losing tractoin, understeer. If you jack up the left or right side of our cars the front tire comes off the ground way before the rear tire comes off. NOW lets say we have even rate sway bars (taking into calculation front and rear weight diffrences). We take the left turn and now the front left has, lets say 1.25 wheels on the ground and the left rear also has 1.25 tires on the ground. Don't we have a balanced car now?

[Sabz5150]

I have an 88 LXI with a stock front bar and a Vigor rear bar. It does corner flatter than with the stock rear bar, the balance moved rearward a bit. It needs more though. I would go with the S.T. rear bar.
After I installed the Vigor bar, I replaced the front rubber with urathane and that alone threw it back to what it was before the Vigor bar.
My recommendation would be to use the stock front LXI bar with urathane and the rear S.T. bar. That should give it enough rearward balance to rotate the car in the twisties.

What year Vigor?

[AZmike]

torsional resistance is greater on a hollow bar mike. its the mechanical property of material. unidirectrional stress has no resistance to shear load.

What's your reference?

A solid cross section has a higher polar moment of inertia.
J=pi*(d^4)/32 for solid cross section
J=pi*(d_outer^4-d_inner^4)/32

For a shaft with a circular cross-section loaded in torsion:
Torque=(Polar MoI)*(Shear Modulus)/(length)*angular_deflection

A higher polar MoI means for a given torque there will be less deflection (stiffer). Please explain to me why this is not the case.

[corrected equation typo]

[onliLX-i]

We found a physicist!

[Vanilla Sky]

nope, an ME it seems.

let's invite all of the MEs in. someone find leia, too.

[onliLX-i]

ME? Material Engineer? (just a wild guess)

[Vanilla Sky]

mechanical

[smufguy]

the torsional deflection is measured in degrees as you know. and given by the equation (a re-written form of yours)

deg = T*L / (J*G)

T = torque
L = Length
J = K' = polar moment of inertia
G = Modulus of rigidity

so for the same trque and length, the deg is smaller if the denominator is larger. the denominator is directly related to J so in other words if the J is larger, then the deg is smaller.

for a crossection of 4 (and an inside of 1) the j for a solid bar is 1.57 and for a hollow bar its 25.034, which in other words is 16 times larger.

so my understanding is that the hollow ones yield a smaller deg of deflection.

also to note is that the aftermarket sway bars are a lot bigger than the normal stock ones and their thickness (or their hollow diameter) is often unknown.

[smufguy]

Okay i double checked my machine Component design book and found out that the equation that you gave for the Solid is wrong, should have been pi/32 * d^4 not d^2. So yes, for the same outside diameter of the hollow and the solid tubes, you are right, the solid will be stiffer. Which makes sense, but often the aftermarket bars are not the same stock size, which i did not mention in my previous statements as being the case. here is a small table of a torsion bar which is NOT a cantilever beam

http://img52.imageshack.us/img52/8247/untitled2qf.jpg (http://imageshack.us)

as anyone can see, the stiffness greatly increases with reduction in weight, for only a small increase in the overall diameter as compared to stock.



the torsional deflection is measured in degrees as you know. and given by the equation (a re-written form of yours)

deg = T*L / (J*G)

T = torque
L = Length
J = K' = polar moment of inertia
G = Modulus of rigidity

so for the same trque and length, the deg is smaller if the denominator is larger. the denominator is directly related to J so in other words if the J is larger, then the deg is smaller.

for a crossection of 4 (and an inside of 1) the j for a solid bar is 1.57 and for a hollow bar its 25.034, which in other words is 16 times larger.

so my understanding is that the hollow ones yield a smaller deg of deflection.

also to note is that the aftermarket sway bars are a lot bigger than the normal stock ones and their thickness (or their hollow diameter) is often unknown.

[Feuerstoss]

Alright... hm. I'll chime in a little bit, but I'm honestly not adding anything particularly new here... but I'll go ahead and lay this down in layman's terms.

With a car sensitive to understeer, like the 3G, stiffening the rear will help curb at least some of the problem, depending on the car. Conversely, stiffening the front will actually increase understeer. I'll admit I'm not very familiar with the 3G as it stands, but the LXi front swaybar seems a lot beefier than an LX front bar. As we all know, the DX/LX doesn't have a rear bar, and has a weaker front bar than the LXi. With the stock LXi setup, you would have a stiffer front bar, and a weaker rear bar. The reason for this is as previously stated; to give the car at least some amount of understeer. While understeer is pretty much detrimental to a performance driving standpoint, it is easier for an inexperienced or unprepared driver to handle. Most road vehicles are like this; even my GT-Four is set up wth a somewhat stiff front sway and a moderately weak rear sway, giving it understeer in contrast to a more neutral/slight oversteer balance you would want in an AWD sports car.

If you're getting serious with suspension tuning, just remember that a decent set of struts/springs(or coilovers) are probably one of the biggest benefits to great handling. Swaybars do provide a great bang for the buck; I picked up my LXi rear bar for less than $5 at the junkers. Personally, I'd believe that if you're going for the el cheapo junkyard warrior route, the LXi rear bar and the DX/LX front bar might be a decent combo. If you have a bit of money to spend, then the LXi front and a decent aftermarket bar would be a better choice.

Now, on a related question, maybe someone can answer me this. I picked up the LXi bar, bushings, bushing brackets(to the floorpan), endlinks, and all associated bolts. With a quick check on my car('88 LX), I couldn't find any mounting holes where the endlinks would fit. Am I just being blind, or will I have to drill holes in order to get this bar on? I know there's a how-to posted up, but the links to useful pics are dead, unfortunately. What do I do? :shrug:

[Vanilla Sky]

http://www.3geez.com/forum/showthread.php?t=105

this is one of the how-to articles that suffered the fate of a closed geocities account :S

no, you don't have to drill holes.

http://www.hondaautomotiveparts.com/auto/jsp/mws/catimgs/13sg70_j15.gif


hope that helps, man

[Feuerstoss]

Thanks a lot! Actually, the diagram should help quite a bit, I think. :thumbup:

[Feuerstoss]

Yes, it definately did help. All I can say is... wow. Anyone who has a carbed Accord and hasn't taken the time to throw on a rear sway bar needs to go out and do it immediately. I can't even begin to say how much better my car handles after I did it.

[b8er]

i dont mean to burn on you AZmike ( i think it was you ) but a if a solid bar is stiffer then why would driveshafts and race car frames be made from hollow tube, it was very tough for me to follow threw all that but i believe i understand what was happening and im pretty sure smufguy is correct

[Vanilla Sky]

weight. that's one of the more critical places to reduce weight, and a hollow driveshaft is plenty strong enough. when you start making more power, then you have a new shaft (or shafts) made.

[smufguy]

for the same weight, a hollow tube is stiffer than the solid one. but for the same diameter, then the solid one is stiffer. So yeah, AZmike was right and i was right, only cause we were talking about two different things :D.

[AZmike]

A solid bar is stiffer than a hollow one, but a hollow bar is lighter for a given stiffness.

A solid bar is stiffer for a given amount of space. A hollow bar is stiffer for a given weight. Weight is almost always a higher priority than space in a car (expect for fasteners and other highly stressed components) so most parts are hollow. I never said that solid bars are better.

[onliLX-i]

Thanks for the support. I knew my setup produced less understeer!