Effect of sway bars after suspension lowering
 

What is the effect if you have stiffer springs (lowering), and stiffer shocks, but you kept the stock sway bar?

In particular, what does it mean when one enters corners at speeds? perhaps encounter some bumps and cracks on the road surface.

I just made this upgrade.

Big difference, all the energy that went into rolling the car, before it turned, is now going directly into turning it. Also, the new bars, with grease, seem to have provided a lot more fluid (no sticktion) motion. Definitely make the upgrade.

Thanks 04green for the feedback. I'm looking for more of an explanation of whats going on and all that. I know sways affect body roll, and they work together with the shocks and springs to reduce roll. But there must be disadvantages associated with having really stiff roll bars too.

So I am wondering now that springs/shocks already stiffen the ride, if I leave stock roll bars and not upgrade it, what advantages and disadvantages if I do that?

The main issue with roll bars is they connect wheels on opposite sides (duh) which means as you go up with bar size/thickness, you have a less-independent suspension. A bump on the right causes the left wheel to react as well. There's no one best solution, only compromises leaning one way or another.

Springs are not going to affect the sway bar directly. Springs are up and down, sway bar is side to side....

so what can stiffer sway bars do for a car that's lowered with springs and stiffer shocks? What advantage/disadvantages and under what driving conditions, track/street.

It's all related one way or another. Approximately: stiffer springs --> softer bars for a similar perceived reduction in body roll. Lowering by very much is generally a bad idea in any case, assuming one wants handling and not ricer bling points.

A stiffer sway bar will make a car handle better...Simple as that.

Can you go in more detail? That's a very generic statement. If stiffer sway bars make the car handle better, then at what point does it become too stiff that handling is no good? You see what I mean by when I say generic statement? Cause we all know that being infinitely stiffer is essentially having no suspension mechanism then that isn't going to work very well.

I'm looking for some detailed answers here, with respect to street driving and track driving.

There are many threads about suspension geometry and how roll stiffness is effected and etc etc...I'm not going into detail.

Buy a Progressive Tech sway, or the Hotchkis sway and you will notice a huge difference over stock. As far as how to make your car faster...Do some testing with different setups...

your daily driving will become a little more rough, but your track days will thank you...

It's not a generic statement, it's a general statement. What you want is an easy, simple answer (spoon-fed). Get and study a couple of good books on suspension engineering/tuning. Read some portion of the several hundred posts on the subject in the forum. If you're paying attention, you'll discover the only simple answer is "It depends ....".

The generic statement is: Search!

To the preceeding poster: If stiffer is always better, then why have any suspension at all? (Hint: what does 'handling' mean when the tires aren't in contact with the ground?)

HiFlite999,

I wrote specifically that I am looking for some detail answers here, so I'm definitely not here for "an easy, simple answer (spoon-fed). You have misunderstood me.

I am here looking for answers to questions, and you are here to flame me and educate me on how to learn. If you don't know the answers or you don't want to tell me the answers, you don't have to respond to this thread at all. On top of that, I know after this response, this is going to turn into another flame-war response thread going back and forth about opinions, so beyond this reply, I'm just going to ignore what you say because it's not helpful.

You have yourself a good day.

http://auto.howstuffworks.com/question432.htm

http://grassrootsmotorsports.com/articles/lean-less/

In a nutshell...

Springs, effect how hard it is to move a corner of the car up and down.

Shocks effect transitions, stiffer shocks, less rapid transitions, front to back, side to side, one wheel up or down.

Sways do that for roll. Think of them as special heavier springs that only work for roll (side to side) and not front to back. It all gets to how completely you load a wheel when you are turn. I did not notice any rougher rider when I upgraded mine. I did notice immediately that the turn-in was more precise. I expect, based on limited testing, I have a LOT more stability at the track. If you add adjustable sways, you get options for adjusting over and under steer over an above tire pressure. That is a plus. For more than that, get a copy of the Going Faster book. There is a great section on sways, problem is you have to read the rest of the book to understand. I also think I got a benefit in reduced stick-tion.

I replaced my shocks because they were worn out, I did springs because I had the shocks out. I have a feeling that, dollar for dollar, the sways are a better upgrade than shocks and springs, but that is just a feeling. I made my changes to a suspension with 80,000 miles on it...

Did any of this help? It is not an easy question. There are several religious camps out there. I think that means there are several valid ideas...

Good luck.

Thanks, these last two replies are very helpful.

I think you mean a stiffer shock setting. Assuming you are asking the "what if" question because your contemplating this buying decision, here is what I think you're going to experience. There is some missing information here but I think you'll understand where I'm headed.

Assuming you have increased your cars grip potential with either stickier or larger contact surface tire, you will find that using the existing stock bar but increasing to a firmer spring (and you offered lowered as well) you'll find a nice performance improvement. About the worse thing that could happen is that you have a really sticky tire (like an R compound) and let's also pretend you know how to drive it well, you'll probably get a ton of body roll AND you may run out of suspension travel/find interference. This depends again on how low the springs are, how much grip and how well you can tap into the tires potential grip.

The shocks won't really influence things as most people might think IMHO. Largely because about 99% of the people out there do not know how to operate them correctly.

Here is a great way to think about sway bars or anti-roll bars. As a general rule, racing in the rain or in poor grip conditions in an RX-8 (and most any other rear wheel drive car), you want a slllloooow transition from side to side. I like to share with people this: think about walking on ice or walking on a slippery surface. This is done will sllllow steps and placing your foot gently onto the slippery surface. This is the same for rain. Smaller (or no) roll bars will require a car to roll more (%) and take longer to do this (like the step you take on the ice). This slowly plants the left side of the car when making a turn to the right. BIG, HEAVY swaybars will more instantly transition weight to the outside tire. On a rain, wet or slippery surface this will have the car instantly load the outside when the wheel is turned. This would feel like instant turn-in.

The hot ticket is to run as less spring, shock and bar that you can and still make the car work. The opposite of this is to overburden the tire and to more easily upset the car as it navigates bumps, turns, curbs, etc.

Hope that helps.

Eric is a smart fella.

I'm going for bling factor mostly, but I will be adjusting my ride height and Agency Power sway bar for track use.
I wonder why when I went back to stock suspension for the winter it felt like the rear of the car was all over the place, on the snow/ice/cold roads of course (I don't have DSC). Someone suggested that I take the rear sway right off, so I did, and my car handles very good now?
When I put my coilovers back on I will put my stock rear sway bar back on.
The aftermarket front sway bar seemed to tighten up my turning.
Sorry I can't help with anymore technical answers.

I've a couple thoughts for you...

..with stiffer springs, you'll have less roll, and esp if you lower some, you'll have even less roll still...as you're COG if lower.

..with less roll for the same lateral force, the up/down deflection of your swaybar will also be less, and so a stock bar will have even less effect than when using stock springs.

..although less sway bar effect may be satisfactory as you aren't rolling as much with stiffer springs anyway, a stiffer bar will help regain the amount of effect the swaybar makes, just doing it with less defection. The goal of 'going faster' means the best balance between spring siffness, shocks resistance, and bar stiffness is one of those things that W.E. warriors and racers alike ponder and work at perfecting through theory first, and trial and error afterwards.

The difficulties in doing that process mean it's hard to tell when you get it right exactly... but you generally know when you get better...track times ... that is :yesnod:

That rear sway bar thing you experienced? ---- read my post again and it will make sense. By removing your rear bar you are now "stepping slowly" on to the ice with your rear outside tire and this does not all of a sudden throw a ton of weight on this outside rear tire when you turn the car. This makes the car less likely to have an "instant weight burden" which generally leads to a spin or some undesirable consequence.

With our race cars when we KNOW it's going to rain for an event or a race, we will reduce both our front and rear spring rates by about 100 to 150 lbs (depending on what tire we were running). We also disconnect both the front and rear bars. We also stand the tire up (run less negative camber) because the car has poor traction and the car doesn't "roll" much so therefore you can run less camber and get a better contact patch.

IF I were to drive our race car in the snow here in Indiana I would do what I suggest above: Take the bars off, run a low spring rate, run very little camber and run a good snow tire. This would allow the car to be nice and lazy (like when you need to walk on ice and not brake your azzz).

Have you ever seen a corvette or a mustang in the snow? All over the place? Firm bars and springs contribute to their more instantaneous wheel spin when cornering.

Great post. I especially like that you are running data acq----the unfair advantage

Thanks Eric, I totally get it now.
Seems like I have done the right thing.
I disconnected the sway, put the soft stock springs in and got an alignment when I put the winters on. (now I know why the mechanic told me he "squared out" my tires for the winter).

btw, It really made a difference and I drive like a pro in the snow.

yes, I met Eric a few times at Mosport for his races. Thanks Eric, that does make sense.

I currently have the Bilstein B8 shocks on Eibach prokit springs. I am contemplating a stiffer roll-bar, and hence why this thread exists. I'm trying to find out what advantages/disadvantages I would have if I do get some upgraded roll bars.

In relation to what you said, before when I had my stock suspension setup, in the winter on snow, it is easier to control, perhaps this is what you are talking about regarding slow transitions.

Then, I upgraded the springs ONLY, and noticed the car became twitchier at the limits and sometimes occasional crashing at high speeds over bumps; this is quite possibly the mismatch of spring rates with stock shocks.

Then, I added the Bilstein B8 shocks and everything dialed in nicely and the bumps are all absorbed much better with no more crashing. On a "test" corner, I was also able to gain an extra 10km/h without understeering.

However, I feel there is still more room for improvement, and why I turn to sway bars now. I can't modify suspension mount points but I don't think a 1" drop will warrant such a huge difference for a modest daily driven car. The biggest problem I have now is that the rear seems really soft.

At the exit of the turn whenever I want to full throttle out of the corner, the rear end slips out into an oversteer situation, it seems to lack grip. Can you give me some of your racing advice and comment on why that is occuring and whether sway bars will help?

^^^ I have noticed the rear end thing a little as well... I think my Tein S.Techs are starting to SAG as I have noticed my car sits lower than usual with friends and without friends in the car. I need to probably buy some new springs here soon but Id like to know the answer to this question as well...

Footman, what are your alignment settings? Most people find that they need a bit more negative camber in the front than the rear, at least on typical street setups. Toe-out on the rear can also cause corner-exit oversteer, as can cornerweighting issues, although those conditions are not as likely as simply needing a bit more negative rear camber in the rear.