Presto

i have the eibach sways and they do NOT go under the exhaust

scotty_g

iTrader: (3)

How about this: Put the hotchkis rear on with the stillen front bar. Two thick bars should take care of your body roll Would that work?

scotty_g

iTrader: (3)

Nobody likes my idea?!?

1cleanG

iTrader: (53)

bump bump as requested by a few members

JSolo

iTrader: (14)

Some eibach information. Some of this is already known/posted. Spring rates were not. Take this info with a grain of salt. For example, front OE is spec'd at 362 lbs/in, while the stillen specs indicate 560 lbs/in (540 lbs/in rear for oe according to stillen). Which is correct??? Those better in the known can chime and to clarify if the standard rwd models use different spring rate bars than the Sport models.

Another issue I have with the stillen specs involves their own specs (or lack thereof). The front bar appears to be 2 hole adjustable, while 3 holes in the rear. Reading the specs @ http://www.stillen.com/product_files...5~appnotes.txt suggests the front is 5 way adjustable (but they only list one spring rate for their bar), and rear only shows rates for 2 holes. Very confusing.

I did have a nice chat with someone from stillen sales this afternoon. The gentleman was well informed in general suspension concepts, but when pressed for actual data, reiterated the same information as in the file above. He had no explanation for the discrepancies. At least eibach is consistent

Eibach Data
http://performance-suspension.eibach...g35g37_ark.pdf

FRoNT:
oE bar: 26.5 mm (1.04 in) tubular
oE measured bar rate: 63 N/mm (362 lbs/in)
oE bar weight: 3.06 kg (6.7 lbs)

Eibach bar: 32mm (1.25 in) tubular and adjustable
Eibach measured bar rate: 2 position adjustable
P1 = 128 N/mm (730 lbs/in)
P2 = 158 N/mm (900 lbs/in)

Eibach bar weight: 5.8 kg (12.8 lbs)


Rear:
oE bar: 24.3 mm (0.96 in) tubular
oE measured bar rate: 69 N/mm (394 lbs/in)
oE bar weight: 2.04 kg (4.5 lbs)

Eibach bar: 29mm (1.1 in) tubular and adjustable
Eibach measured bar rate: 3 position adjustable

P1 = 110 N/mm (627 lbs/in)
P2 = 130 N/mm (741 lbs/in)
P3 = 151 N/mm (860 lbs/in)

Eibach bar weight: 4.9 kg (10.8 lbs)

1cleanG

iTrader: (53)

Yeah, I'd highly recommend Eibach when it comes to the three choices.

apexi350z

iTrader: (1)

So the verdict is: Eibach > Hotchkis > Stillen > OEM?

I'm in thinking about getting swaybars, just want to get the best one.. I have Swift Springs installed, with factory shocks. If I get the Eibach swaybar, which setting/hole to use for good daily driving, and occasionally track? Soft for the front, and Middle hole for the rear? Would that be good to start with?

thanks!

dal1307

iTrader: (1)

Anti-sway bars should be used to dial in under/over steer in your suspension, not to make it stiffer. You should select the springs/coilovers that provide the stiffness you desire then add adjustable anti-sway bars to dial in the under/over steer. The stiffest bar is not necessarily the "Best" bar. You want multiple adjustment options that cover a range of stiffness to handle the spring rates you are running. Different driving conditions (i.e. street, autocross, road course, drift) require different adjustments of the bars to get the best balance of under/over steer to meet the demands of the conditions and the driving style of the driver. Weight of the bars is also a secondary consideration.

JSolo

iTrader: (14)

I thought by definition anti sway bars reduce sway. Isn't the under/over steer is a by product of this reduction?

dal1307

iTrader: (1)

There is a lot of good information floating around on suspension tuning. Here is a small sampling related to sway bars (anti-roll bars).

Tuning advice
Just like spring rate, you want to run as soft an ARB as possible while maintaining sufficient control of the car and body roll and the proper handling balance. Softer settings lead to more compliance and more grip on that end of the car. They also tend to be slower responding and easier to drive, but stiffer settings can be more stable and faster responding.
Front:
(1) Stiffer: Will increase overall car stability (reduces roll) and shift the car’s balance toward UNDERsteer (push), thus allowing the driver to be more aggressive with the steering. The compromise can be on bumps and/or braking. A stiffer front bar will reduce compliance, so when one tire hits a bump the entire front axle will be affected through a loss of overall grip.
(2) Softer: Allows more roll and will shift the cars balance toward OVERsteer (or less UNDERsteer.) And the front will improve in compliance, which improves performance in brake zones and over bumps.
Rear:
(1) Stiffer: As you add throttle through the corner while the steering wheel is still turned, the rear anti‐roll bar becomes very effective. Stiffening the bar supports the rear and shifts the balance to less UNDERsteer at corner exit. Again, the compromise is in compliance; a possible SNAP or FLAT OVERsteer may result if rear anti‐roll bar is TOO stiff.
(2) Softer: Allows more roll at the back of the car, which will be most evident at corner exit. If the bar is TOO soft, the car will exhibit exit OVERsteer. In this case, compared to a rear bar that is TOO stiff, the exit OVERsteer condition will be more gradual instead of a snap, hence the phrase “roll OVERsteer.”
Interactions
The roll control effects of an anti-roll bar or sway bar are similar to the effect of changing spring rate (in effect an ARB is just a special kind of torsion spring), thus the roll stiffness of the ARB is often traded back forth between spring rate to determine the optimum compromise. Stiff front anti-roll bars can also lead to increased front inside front tire lockup under braking.

"What does a sway bar do?"
1. We know it keeps the car more level. So what? Limiting the lean of
the body is good because it means that when you take a quick set into
a turn, that the body isn't still moving sideways after the tires at their
limits. Otherwise you turn in quickly, the tires grip, then the body finally finishes
leaning, when it stops, the tires loose grip. This is especially noticable in most
cars in the slalom where you lean one way then the other and so forth.

2. It limits camber changes. The camber is the angle that the tire leans in or out at the top
relative to the chassis of the car. The camber directly impacts the angle at which the tire
cross section meets the road and thus controls lateral grip. As the suspension compresses
the camber angle generally changes relative to the chassis. With a normal Macpherson
strut that hasn't been lowered, the camber goes from positive to more negative as the
lower A arm swings out straight, and then back to positive as it swings up. That swing
up into positive camber is BAD. At that point the chassis is already leaned over so the
tire may be starting to roll onto its sidewall. Changing the camber even more positive
just just nasty. A big sway bar will prevent the body roll in the first place, and
prevent the suspension compression on the outside which causes the positive camber
change relative to the chassis.

3. Transfer lateral grip from one end of the car to the other.
This one is a real trick to understand, but racers exploit this EVERY time they go
on the track. Their spring rates are often so high, the cars so low, and their
suspension travel so little, that the whole camber and body lean problem is already
a non-issue. The car doesn't lean much with 500 lb springs. They use their bars
to change the balance of the car. Here's the simple rules first.
A big bar on the front, increases rear lateral and motive traction.
A big bar on the rear, increases front lateral and motive traction.
The applications. If the car is understeering, decrease front bar size, or increase
rear bar size. This increases front lateral grip and decreases rear lateral grip
giving the car a more neutral to oversteer feel. Reverse the process for
too much oversteer.
I mentioned motive grip. That's the neat one. Let's say your RWD car is handling ok, but
everytime you get into a corner hard and get on the gas the rear inside tire breaks loose
and spins. You can't accelerate out of the turn. You can go around the turn quite
quickly, but you can't accelerate out, and the guy with traction hooks up and
passes you halfway down the next straight because he came out of the turn going 3-4mph faster.
The reason you're losing the traction at the inside rear, is usually because the rear bar is too big.
As the rear outside suspension compresses, it's actually causing the rear inside suspension to
compress as well (because the bar couples the sides.. remember where we started), and that
decreases the weight on the rear inside tire.
First thing. Decrease size of rear bar. That decouples the sides a bit, let's the inside tire press
down on the road more and thus not spin when you're on the gas.

Here's where it gets really tricky.
If decreasing the size of the rear bar doesn't help enough the next thing you do is
increase the size of the front bar. When the outside front compresses in a corner, it
causes the inside front to compress and may actually lift that tire completely off the
ground. The car is now sitting on 3 tires and guess where the weight that was on
the inside front goes? Outside front? Some of it. The rest goes to the inside rear
where we need more grip. The total weight of the car hasn't changed. It's just been
redistributed, and a sway bar at one end, actually transfered weight to the other
end of the car.

Anti-Roll /Sway Bars as discussed in the Suspension Upgrades page, can provide adjustable settings in the suspension set up. Especially useful in dialing out oversteer, or understeer handling characteristics and getting a better balanced car. They are the same effect as changing the springs, but their effects are only used in lateral cornering forces.

The reason this is so useful, is that you can make adjustment to front and rear independently with out affecting other suspension settings. Stiffer settings will reduce body roll, while softer settings will increase body roll. The relationship between the front and rear settings ( roll coupling), will also have a direct affect on the handling of the car. Like most suspension adjustments, it is best to take small incremental adjustments rather then going to one extreme to the other.

It is critical that the right Anti-Roll/Sway Bar is also selected to complement the other suspension components. I would suggest seeking profession advice on the overall suspension set as a whole and not just individual upgrades, when considering suspension adjustments.

It is generally accepted that it is better to reduce the settings, rather then increase them to get a better balanced car. Softer settings will make weight transfer more gradual, with less abrupt loading, bending into corners rather then darting into them. Great care needs to be taken with too soft a setting as well, if the car has a low center of gravity, a soft setting could result in the car bottoming out. Also camber settings ranges could be affected with a soft setting, where the tyre/ tire exceeds the optimum set up.

Having too stiff a setting could result in poor handling in tight corners, with the inside wheel lifting off the ground. Also if either of the two wheels linked on the axle are on different road surfaces (one wheel on track, other on the side of the track), having a stiff set up will result in imbalances being transmitted through the Anti-Roll/ Sway Bar to the other driven wheel.

•Understeer: reduce front or increase rear anti-roll/ sway bar settings.
•Oversteer: increase front or reduce rear anti-roll/ sway bar settings.

JSolo

iTrader: (14)

Thanks for the post. Will have to read that over several times to 'absorb' the content.

I haven't driven my car very hard yet. Even at what I'd consider moderate corner speeds, there does appear to be some understeer present. I guess a starting point, I'll start with the rear bar on the softest setting and OE front. Drive it for a few hundred miles, then try the middle hole. Who knows, I may be happy with this combination instead of going stiffer front & back.

Do you have a source/link for the above?

dal1307

iTrader: (1)

Here you go:

Car Suspension Tuning: geometry setting guide

How-to: Tune 101 for best suspension/handling: tune out under or oversteer - DSM Forums

How-to: Tune 101 for best suspension/handling: tune out under or oversteer - DSM Forums

anti-roll bar (sway bar) - iRacing.com Wiki

How sway bars work

http://www.google.com/url?sa=t&rct=j...nHqhw37F9PZqdw

This is a really interesting topic. The basics are fairly simple but after reading some of this stuff you can see why car designers and race teams need to spend a huge amount of effort on suspension design and tuning.

duck31905

think you could let me know as well?

Spartacus

Thanks for providing all the suspension information on swaybars, my question is my G is slammed with the tein S tech springs which has taken most of the roll out and still has a nice low ride.
Most of my driving is running canyons that require some hard braking and I don't want to loose any brake grip and I see that your using the Stillen's sways with Tein coil overs, I was thinking I needed the Eibach but now I'm more confused. Send me a PM if you any ideas that might help.
Thanks again for the post

Black Betty

iTrader: (60)

If you think dropping your car with springs got rid of a lot of body roll, wait until you install stiffer sways. Installing any of these sway bars won't realky hurt your everyday braking performance. They are exactly what you need for canyon runs.

I have Hotchkis but I think that any of them will work fairly well and are an improvement over stock.