i have read on a few posts that sway bars and strut tower braces actaully dont have a signifigant effect on the handling/ stiffness of the car. is this bs? do they just have crap equipment? does the thickness of the bars equal more stiffness/less roll?

 

Sway bars have a dramatic affect on handling. Chassis stiffening bars like strut tower bars, C pillar bars, tie bars, etc. do not. The two are totally different in function.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MolecularIntegra &raquo;</TD></TR><TR><TD CLASS="quote">Sway bars have a dramatic affect on handling. Chassis stiffening bars like strut tower bars, C pillar bars, tie bars, etc. do not. The two are totally different in function.</TD></TR></TABLE>



A lot of the crappy chassis bars people are shelling out tons of cash for, mount to areas that have little to no lateral load transfered through.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MolecularIntegra &raquo;</TD></TR><TR><TD CLASS="quote">Sway bars have a dramatic affect on handling. Chassis stiffening bars like strut tower bars, C pillar bars, tie bars, etc. do not. The two are totally different in function.</TD></TR></TABLE>

i don't agree..... i have upper and lower front and rear tie bars on my civic and they make the car much more secure and less prone to flex....... think about it: the suspension used to be four separate shocks, and now they are tied together in the front and rear and squared off........... it's just basic physics. but, to each his own.

 

This thread is going to invite a few different opnions, the following is mine.

I think they both help out, the sway bar more that the strut tower bar but they both help.

Why would factory sports cars have strut tower bars if they were useless?

The sway bars tie both sides of the suspension together. In a hard turn the outside
suspension components are doing all the work. The sway bar distributes the work
between both sides and tries to keep the car level.

Yes the stiffer the sway bar the the less amount of body roll, but too stiff and then the wheels no longer work independently of each other.

A GOOD Strut tower bar will cut down on flexing you hear in hard turns caused by the body rolling. The more points that the strut tower bar connects to the better.
Lt strut tower + Rt strut tower + firewall/ trunk floor = triangle.
Triangles are strong.

If you want a really stiff chassis though you should look into cages, but if you are only driving on the street theres no need for that much modification.


Modified by 909 Civic at 3:31 PM 2/19/2004


Modified by 909 Civic at 3:33 PM 2/19/2004

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
i don't agree..... i have upper and lower front and rear tie bars on my civic and they make the car much more secure and less prone to flex....... think about it: the suspension used to be four separate shocks, and now they are tied together in the front and rear and squared off........... it's just basic physics. but, to each his own.
</TD></TR></TABLE>

The shocks are not lateral load bearing. We have double wishbone suspension, not MacPherson Struts. The lateral load is transfered through our upper control arms, not the shocks. Which is why bracing the UCA's is more beneficial than the shock hats themselves.

The rear suspension, the UCA doesn't even bolt near the shock towers. It bolts to the wheel well. Comptech has done testing that has shown there isn't really a need for a rear strut tower brace.

Lower Tie bar brace the subframe and where the LCA's connect to it.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
Why would factory sports cars have strut tower bars if they were useless?
</TD></TR></TABLE>

Lots of these sport cars have again, MacPherson stuts. In these cars, the shocks are lateral load bearing, so chassis flex in this area causes a bad result for dynamic camber.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
A GOOD Strut tower bar will cut down on flexing you hear in hard turns caused by the body rolling. The more points that the strut tower bar connects to the better.
Lt strut tower + Rt strut tower + firewall/ trunk floor = triangle.
Triangles are strong.
</TD></TR></TABLE>

If you are referring to the bars I think you are, those are cross braced, they are not an actual triangle. A triangle would require another bar running from the trunk floor back to one of the strut towers.

A good front stut bar can be beneficial, but the c-piller, rear strut bars, are just cash flushers.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by StyleTEG &raquo;</TD></TR><TR><TD CLASS="quote">
If you are referring to the bars I think you are, those are cross braced, they are not an actual triangle. A triangle would require another bar running from the trunk floor back to one of the strut towers.</TD></TR></TABLE>

I think this is what you are refering to



I was talking about this



and this




The load may be transfered through the ucas, but the ucas are mounted to the
to the same place the struts are. It is possible to fabricate a bar that would brace the ucas but it would just look like a modified strut tower bar.

Everything is tied together in unibody cars though, I just think the more cross bracing you have in our shells the better.

Good info man, thanx.

 

In the front they are yes, but wouldn't it be a better idea to brace the UCA's themselves?
In the rear the UCA's are attached to the wheel well, not the shock tower.

The first pic, and the last pic, are not for hondas. Those are for 240's.

 

First pic honda, second pic mitsu, and the last pic is a 240 i believe. (I also own a 240sx, but thats a whole different monster and crowd.)

Never said they were for hondas, just talked bout different strut tower designs.

I know where the components are located, replaced them when I installed my
camber kits.

These threads are not for "I know more than you" posts. They are meant to be like a clearing house for info amongst us honda guys.

Keep on tuning

 

The UCAs are not easily accessible in the rear unfortunately. That is where most of the load is coming in, but it is still beneficial to brace the chassis at another point as opposed to not at all. I don't know how to describe it in words. It was demonstrated to me with a cardboard box and some mock up braces. Even though the load comes in at a certain point, it travels throughout the chassis. So you stop the chassis from twisting by bracing an accessible area.

Take for instance a roll cage. It isn't bolted to the UCAs, yet it has a profound impact on the stiffness of the chassis. As do floor bars etc. One of the best places to brace is the B pillars at the seat belt mounting bolts. Unfortunately this is not very streetable.

Though I agree that companies like EM Racing have released a ridiculous array of bars and I just wonder why not get a roll cage.

Swaybars are one of the most effective modifications you can make to your street car. The effect of chassis bracing by comparison is small. How swaybars were described in this thread is incorrect. What a swaybar does is subtract traction from you inside tire and add it to your outside tire where it is needed. You can see that if your swaybar is too thick/stiff, you will take too much traction from the inside tire. 1mm difference in thickness between two swaybars is significant.

 

Oh yeah ever notice how the front Comptech bar doesn't bolt to the UCA mounts?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shaundrake &raquo;</TD></TR><TR><TD CLASS="quote">The UCAs are not easily accessible in the rear unfortunately. That is where most of the load is coming in, but it is still beneficial to brace the chassis at another point as opposed to not at all. I don't know how to describe it in words. It was demonstrated to me with a cardboard box and some mock up braces. Even though the load comes in at a certain point, it travels throughout the chassis. So you stop the chassis from twisting by bracing an accessible area.
</TD></TR></TABLE>

Yes forces can travel, but a flimsy cardboard box isn't really a good example of a car in motion.

I still don't see any structural advantage to bracing the strut tower independantly. Incorperated into a proper cage, you might see some increased rear traction due to reduced flex, but even then it would be near impossible to measure.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
How swaybars were described in this thread is incorrect. What a swaybar does is subtract traction from you inside tire and add it to your outside tire where it is needed.
</TD></TR></TABLE>

That is not what sway bars do. Sway bars, or the other term "Anti-roll" bars, do just as they sound. They increase your spring rates, but only in a turn. They take out body roll, hence "anti-roll". This allows you to run streetable spring rates and still handle body roll effectively. Some consider them a way to dynamicly increase spring rates.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
When one side of the suspension compresses, the lever arm moves downward causing entire the sway bar to twist so the lever arm on the opposite side also attempts to move the same direction and compress it's own side as well. This resistance to movement increases the spring rate of your suspension when cornering. When both sides of the suspension are equal, the sway bar will have no effect. Here is a chopped down and simplified diagram of how the sway bar works.
</TD></TR></TABLE>

I am confused as to why you would want more traction on the outside tires, especially considering the technically fastest way around a track is using all available traction equally.

 

You talk like you know something, and then you make some really strange comments and it makes me wonder if maybe you should finish whatever article you were reading to get your info. The strange comments I'm referring to are <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">I am confused as to why you would want more traction on the outside tires</TD></TR></TABLE> and where you said my summation was wrong but then go on with an explanation that I totally agree with.

I had a lot of difficulty in my early reading because most of the honda/acura handling books and magazines use the same borrowed info. They all use a very dumbed-down explanation that isn't totally accurate. The articles I read online in various honda FAQ threads were all very technical but didn't tell you how to apply the concepts. My instructor had a lot to say but I didn't take him seriously since his experience was with old bombers on a circle track. I kept skipping over the books that had BMWs, Porsches etc on the cover but later this is where I got my basic understanding, and then I went back to the material I read earlier in order to focus on the differences between what I had learned about RWD and Macpherson strut designs with FWD and a double wishbone suspension (and with an open mind for what the bomber-man was saying). A lot of experimenting on GT3 helped too At first just skim over the math and physics and focus on the concepts and applications. After you've mastered that and had some real life experience with it, go back over the physics if you're still interested. That stuff doesn't matter to most of us since we aren't the ones designing car suspensions or aftermarket parts. Oh, and don't go to your local beat down library, you can find a number of titles at mall stores like Borders and Barnes and Nobles that don't mind if you sit and read for hours right in the aisle.

Using a model demonstration is a million times better than reading a paragraph and trying to visualize it all in your head.

I wish I could take you for a drive in my car and maybe we could do a strut bar "taste test". Sure, the performance increase is small, but I'm not willing to give it up.

I chose the front Neuspeed bar over the Comptech bar since the Neuspeed bolts to the upper control arms.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shaundrake &raquo;</TD></TR><TR><TD CLASS="quote">You talk like you know something, and then you make some really strange comments and it makes me wonder if maybe you should finish whatever article you were reading to get your info. The strange comments I'm referring to are and where you said my summation was wrong but then go on with an explanation that I totally agree with.</TD></TR></TABLE>

Your comments are borderline insulting, there is no need to stoop to that level. And I am not sure what you are hoping to gain by your paragraph talking about your teachers?

You say that all a sway bar does is transfer traction from the inside tires to the outside tires.

This is not correct. It does not "transfer traction".

If you agree with what I posted, then you should understand your error. A swaybar takes out body roll, and like springs it alters how the suspension manages load transfer. By your definition all springs do is transfer traction from tire to tire, this is inaccurate. Done properly, the springs/sway bars will equally distribute the load between the two tires (front/rear). This way no tire is overloaded, and you don't over/under steer.

Looking specifically at traction "transferring", singling out a tires Coefficient of Friction. A tires peak CF comes at a specific slip angle. Most graphs I have seen for street tires, looks like a bell curve (CF at a given slip angle). For a swaybar to TRANSFER Traction from inside to outside, it would have to increase or decrease the slip angle of the inside tire to the outside tire, depending on what slip angle it currently was operating at, and the same for the outside tire. Can there be instances where the swaybar does in fact decrease the slip angle of the inside tire, and increase the outside where you end up with the inside with less traction and the outside more? Yes, absolutely. But a sway bar only operates one way, and it could just as easily change the slip angles for the worse as well. I could go into tractive force and download, but I don't think its necessary.

Yes, a cardboard box can be a model to show an idea. But to figure that if a card board box flexes in one area and it effects another, would be the same as a car is not accurate. I could make a model showing that flex causes the car to crack in half, does that mean if you don't get a strut bar your car will crack? no.

Just in case it isn't clear, I do beleive in the use of a front strut tower brace. Since you can directly brace the UCA, and the front suspension/tires are actually being used to change the yaw of the car. However, I feel the rear strut tower brace is worthless.

 

I'm not sure anyone's quite hit the nail on the head re: sway bars here (or if they have, I didn't see it).

A sway bar reduces body roll by tieing the two sides of the suspension together. So when the outside corner compresses in a corner, the sway bar compresses the inside corner suspension as well.

As far as weight transfer goes, the result (from side to side) is that weight that would normally be placed on the inside tire ends up on the outside tire. Since the amount of friction available to a tire compared to the amount of weight placed on it is a case of diminishing returns, the end result is less traction available on that end of the car. This is why you tune for more oversteer by using a larger rear bar.

The second effect of a stiffer sway bar is that that end of the car w/ more roll stiffness (front or back) will now support more of the car's weight. So using the example of a larger rear bar on a previously understeering vehicle, even though you're reducing traction at the rear by putting more weight on the outside tire, at the same time you're pulling some weight off the front. So in theory, the total amount of available traction will increase. Combined with a more balanced handling vehicle (and a driver that can handle the new attitude), the car will be faster through the corners.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
Since the amount of friction available to a tire compared to the amount of weight placed on it is a case of diminishing returns, the end result is less traction available on that end of the car. This is why you tune for more oversteer by using a larger rear bar.
</TD></TR></TABLE>

This is not necessarily true.

While yes, as you increase download onto a tire the CF does drop. However you also have to consider tractive force. Tractive force in fact increases as download increases.

While you might have a CF of 1.75 at 200lbs of download, this results in 340lbs of tractive force. (1.75 x 200lbs)

However, if you look at a tire a 400lbs with a CF of only 1.35. This results in a tractive force of 540lbs (1.35 x 400lbs).

Of course its a rate of diminishing returns at some point the loss in CF is going to result in less traction, and that is where you start overloading the tire and loosing grip all together.

So it is quite possible for the swaybar to increase or decrease traction on the outside tire, depending on many different factors.