Sway bars, braces, and too much tech!!!

[Dezoris]

There are many debates on whether strut braces (pictured below)

(comptech sport)
actually do any thing to a vehicles handling, or help in balancing suspension components. Well you know the claims

strut towerbars are the final part of the suspension tuning system for greater body rigidity and sharp handling. Improve suspension rigidity and accomodate vector changes during high-speed cornering. Increased rigidity of the stationary support portion of the suspension unit reduces unit fatigue caused by upward thrust. Create a superior suspension system featuring both durability and smooth operation.

Well that sums it up or does it?
Take a look at these




Ok now that you have visuals, lets explain.
The way suspension travels should be of no mystery to anyone.
You have a shock or strut connected to a tower mated to a coil spring, connecting to a control arm etc. What happens when you hit a bump?
The shocks/springs compress and rebound, putting stress on the shock towers, and under hard manuvers the frame may flex. So what is the obvious way to keep the frame from twisting, build a support beam from tower to tower. The frame needs to twist a bit, that is what it does. So why the need for a bar. Well see if you meet the criteria.
Strut bars are a good modification for the following people
1.)You have your vehicle lowered more than 1"
2.)You have sport springs or shocks
3.)have a tire profile of 45 or below
It is a good mod for those who have changed other suspension components that can effect the way the car handles.
Strut bars are not proven to provide any better lateral grip usually, but if your goal is to stiffen a frame that has has one of those 3 items done to cause more stress on it, then it may be worth your while. Stay away from bars with pivot points as pointed out above, they are virtually worthless, but cheap.
Bars to look at:
Nuespeed
Comptech Sport
Mugen
Sprint
Finally, adding those bars is a small piece in the puzzle, but, it is a piece.
Everything is working against keeping the tires glued to the ground. Strut braces if anything aid in keeping the tires planted or help them form being unglued in extreme cornering situations, or turboulent road conditions. Keeping the frame stiff, is the goal, a cheap way to do it is a strut bar, one w/o pivot points.

Tie Bars are a similar addition



The lower tie bar increases the strength of the subframe, and is manditory with sway bars over 19mm in thickness, primarily in Hondas, where the subframe, specifically the rear, is notorious for pull aways and tears. Most manufacturors are designing their sway bars to come with the complemented Lower tie bar, mainly, because, in Neuspeeds case, the sway bars were tearing the subframe from the welds. These cases caused companies like Neupeed to look at their products, and redesign them (brackets, assemblies etc) to work better with the stock frame. What the end user gets is something that Honda did not intend, a , more rigid frame, more suitable for fine tuning their already great suspension. The tie bar is not a modification that is really felt. It is yet another small piece in the suspension tuning process. Alone a tie bar is not really going to do anything, IMO, except maybe stabilize the pick up points, at higher speed manuvers, will you notice it, I'd say not. But when combined with the sway bars, they work wonderfully together, especially when mated to an adjustable shock spring combo that has been corner weighted.

For sway bars I am going to take a post from Texan whom I respect, and admire his knowledge, and in many regards should have my job here.

Texan's Sway Bar Tech Post
"SUSPENSION TUNING 101: sway bars

How do sway bars work, and how can you use them to tune your car’s suspension? Most performance people know that stiffer rear sway bars reduce the understeering tendencies of a vehicle, but if you ask them exactly why this is they generally draw a blank. Usually they know the results, but not the reasons behind chassis tuning. This article is intended to answer those questions as well as give readers a better understanding of what goes on in your suspension when you take a corner. First, let's get an understanding of what lateral weight transfer is, because this will help you understand exactly how sway bars work to tune the balance of the chassis.

Lateral weight transfer is a function of three things:

-overall weight of car
-height of the Cg (center of gravity)
-track width (this is the distance between the vertical centerlines of each tire on an axle, and many times track width is different on each axle)

So the first thing to notice here is that spring rate IS NOT a primary determinate in how much weight is transferred laterally on a car for a given amount of steering input. This is something many people have a hard time swallowing, but nevertheless it IS TRUE. All the springs do is determine how much the suspension will compress or expand due to this weight transfer.


BODY ROLL
So why is body roll bad? Two reasons:
#1- it screws up the camber angle of the tires to the road
#2- it unsettles the driver

Next, you need to know that the principle way you control body roll is through spring rates. And here's where we encounter the problem of not being able to change the static spring rates between cornering maneuvers and just going straight. To show a quick example of this:
- Say the amount of body roll during a corner is 10 degrees for a spring rate of 500 lbs. If you wanted to halve this amount of roll, you would need to roughly double the spring rate to accomplish it. Now we already know that limiting body roll can improve handling (depending on circumstances and suspension setup), but running a spring that stiff will cause the car to be so bouncy that the tire will rarely be in good contact with the ground, unless the road is perfectly smooth. So how can we selectively increase spring rates only under cornering so that our straight line stability & tire to road contact is not compromised by really stiff springs? The sway bar is the answer.

Now it should be stated here what sway bars essentially do, even though I know you may already know this. What a sway bar does is counteract the action of body roll during cornering by transferring spring rate from the inside wheel to the outside wheel in a corner. This means that you don't actually get any added spring rate; you just subtract it from one side and add it to the other. This has the ultimate effect of transferring load from the inside tire to the outside, which has the visual effect of compressing the suspension on the inside of the turn and expanding the suspension on the outside of the turn (thus limiting body roll). This is good mainly because it smoothes the speed of weight transfer during quick transitions and also limits the camber change experienced at the corners of the car through suspension travel. And of course, using this concept one can dial in the amount of total loading on the outside tire by varying the effectiveness of the sway bar (stiffer bars equal more transfer). And the beauty of all this is that it mostly only occurs during cornering, so our straight line spring rates are not affected. Ok, so hopefully now you all understand this concept. This is the most important part though, so if anything is still fuzzy read this again until you get it. Also, here's an example of how this works:

-For this example we will use a sway bar with a roll stiffness of 250 lbs.
Left front static load: 1000lbs
Right front static load: 1000lbs

-lateral weight transfer in a right hand turn
Left front: + 500lbs
Right front: - 500lbs
Total weight transfer: 1000lbs

-load transfer of sway bar(which is 250 lbs):
Left front: +250lbs
Right front: -250lbs
Total weight transfer: 1000lbs

-total effective cornering load for this example:
Left front: 1000 + 750= 1750lbs
Right front: 1000 - 750= 250lbs

-without sway bar
Left front: 1000 + 500= 1500lbs
Right front: 1000 - 500= 500lbs

----------------------------------------------------------

Alright, now we are coming into the home stretch of this learning curve. You need to know that although you cannot control the total amount of lateral weight transfer during cornering (as I stated earlier), you CAN have some control over how it is distributed on each axle. Looking at the above example, you see that with or without the sway bar involved, total weight transfer change is always 1000 lbs. You can't change this amount, but you can re-distribute it along the axle. And this is a function of spring rates entirely, which we now know is best controlled during cornering through the use of sway bars.

So how does one control the balance of a car when armed with this knowledge? It's actually very simple at this point, if you understand that increasing tire loading adds to the total amount of traction available from it, but this relationship is NOT linear. The more load on the tire, the more traction available, but the amount of traction gained diminishes as load increases. So at first it's almost a direct "you add 250lbs of load, you get 250lbs of extra traction", but at 1000lbs of load, you might only get 800lbs of extra traction. Knowing this, look at the example I gave of the sway bar at work. Since it transfers load away from the inside tire, you lose traction there. Although it transfers this load to the outside tire, it is already quite loaded and therefore the 250lbs of load will not increase overall traction by 250lbs. More like maybe 150lbs. Now the inside tire, being much less loaded, could have gained more like 220lbs or traction from the 250lbs of load. So look at what we have in the end: although the outside tires already do most of the work, adding a sway bar actually lowers the total amount of traction available at this end of the car by increasing the difference in load distribution. And the stiffer that sway bar is, the more it will limit the total traction available at that end.

So, to make a really long post short (again, sorry), what we end up with is the knowledge that weight transfer ultimately lowers the total amount of traction available at each end of the car. This is why the more we can limit total weight transfer (by increasing track, lowering the Cg height, or lowering overall vehicle weight) the more total traction will be available. But for the purposes of this post, we are explaining how sway bar sizing (which directly reflects it's roll stiffness amount) cures an unbalanced car. If a car is understeering, it's because the rear end has more total traction than the front. If you put a big sway bar on the rear suspension to limit the total amount of traction available there (by maximizing the amount of load transfer to the outside wheel), you can dial it in to match the front suspension's total available traction. And when we get really smart, we start to match the front & rear bars to one another to achieve the best balance through the largest possible range of suspension movement."
'99 Prelude SH ..."Ambition is a poor excuse for not having enough sense to be lazy." -Steven Wright

Any questions?

[Oinac]

Hey Dezoris,

I also got a couple of things from Texan (or Bampf ) about these things... anyway I got one quick question... if you look at the 1999-2000 SIs strut bars compared to the lower trim (EX, HX, DX) you can notice that the bars connect to the points around the shock...

For example,


Now if you look at the Mugen or Comptech Sport one, which you also posted:

You notice that the points where it connects to the chassis is NOT around the shocks but NEXT to them... it is clearly noticeable by where the holes are in the strut bars...

Now for my question:
Which area is better for strut bar placing??? And what advantage/disadvantage does this have over the other area?

[SilverY2KCivic]

As fo the OEM Si bar, from what it looks like, it deosn't attach directly to the struts themselves, like a pivot point bar does (that attaches to the strut to body connecting bolts) where as the Si bar appears to me to connect to the body of the car, or am I missing something there?

[Oinac]

that's the point I'm trying to make SilverY2K... to make it more clear here's the pic of the Mugen Bar... notice the difference in mounting points between the Neuspeed one and the Mugen one...

[Dezoris]

Originally posted by Oinac
that's the point I'm trying to make SilverY2K... to make it more clear here's the pic of the Mugen Bar... notice the difference in mounting points between the Neuspeed one and the Mugen one...

These of course are the best, mainly because of the mounting point, and also because they are not sharing the shock mount nuts. You can get into the tecnical side of the actual frame and how the size and length of the bar effect it, but to be honest,

the concept is the same the solid bar, does not pivot. You will not notice, and real diiference between the neupspeed and the 300+ Mugen shock bar.

And one step further and better is the shock tower brace, connecting to the firewall as well, you will start to see these on the newer Hondas.

[madtownhonda]

Originally posted by Oinac
that's the point I'm trying to make SilverY2K... to make it more clear here's the pic of the Mugen Bar... notice the difference in mounting points between the Neuspeed one and the Mugen one...

if your wondering about the mugen bar, the mounting bracket attaches around the damper bolts and also bolts up where the factory tower bar does

[Oinac]

Originally posted by madtownhonda


if your wondering about the mugen bar, the mounting bracket attaches around the damper bolts and also bolts up where the factory tower bar does

*sniff* they redesigned the mugen bar... i have the updated one which i posted before (only connects to where OEM goes) ... here's the old mugen bar... RIP...

[piscorpio]

Holy crap! Is my sway bar going to tear off, or is it safe being exactly 19mm and not more?? Now Im worried about it, and if I get a lower tie bar, Im afraid it may not fit right with the sway bar, what should I do?

[Dezoris]

Originally posted by piscorpio
Holy crap! Is my sway bar going to tear off, or is it safe being exactly 19mm and not more?? Now Im worried about it, and if I get a lower tie bar, Im afraid it may not fit right with the sway bar, what should I do?

The ST bars are not know for tear problems. A tie bar should fit fine.
with their bracket design.

[piscorpio]

Thanks again man, I think Ill still get that lower tie bar (at least now Im a little more confident it will fit).....now you got me all paranoid!
You know, when I had to drill the holes for the brackets, they were right by the factory spec holes. I remember thinking to myself, I wonder if this is going to weaken the frame here? It just seems like the two sets of holes were a little too close, is that essentially the cause of the problem, or is it just a matter of the frame not being built to take the extra abuse of an oversized sway bar?

Heres another question that just came to mind. With all the stiffer springs, strut bars and sway bars, is this putting more strain on other suspension components? Will it wear down bushings and bearings? Could it even cause damage to major parts like control arms, trailing arms, etc.?