DIY rear anti-sway bar upgrade for 2009-2011 Genesis

[scottdk]

Here is a little DIY guide to replacing a rear anti-sway bar on a Hyundai Genesis Sedan. I really think that this is a project that most semi-handy people can accomplish. It wasn't very hard. Note - The 2012 Genesis Sedan uses the same sway bars in all of their models i.e. V6, 4.6, 5.0, 5.0 R Spec according to my service department, which means the part # for all models is the same. The 2009-2011 use a smaller rear anti-sway bar vs. the 2012 so I decided to put the 2012 bar in my car. The Genesis sedan understeers, especially at the vehicles limit, which is typical of a large sedan. A larger sway-bar would decrease the amount of understeer in most vehicles. The 2009 sway bar is MUCH heavier than the 2012's. The new sway bar is very light in comparison.

The new sway bar comes with the 2 bushings and 2 brackets already attached. Cost of the new sway bar with tax was $142. Dealer previously quoted $152 + Tax, but when I came to pick the part up they said they'd give a discount. Don't know why, and I didn't argue

Here is my version of the steps neccasary to install the rear sway bar:

1st - Safety 1st! Put the car on jackstands! Also, make sure to remove the rear wheels off the car, otherwise you'll find that it is near impossible to remove the old bar and install the new one. Trust me, I learned the hard way until I had the amazing idea to remove the rear wheels.

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2012 sway bar

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2009 and 2012 bars

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Here is a shot of the OEM sway bar while still on the vehicle. It sits directly behind the spare tire storage space.

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This is the sway bar bracket and bushing. Each bracket (one on each side of the sway bar) has 2 bolts to remove.

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This pic shows the sway bar linkage nut, which is basically a nut/washer. Remove 1 nut from each side of sway bar linkage.

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To install the bar to the linkage you will need to apply a lot of pressure to get the bar to sit on the linkage thread

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I used an adjustable plyers to assist, which made it much easier. There is a metal plate on the bottom of the linkage - put the plyers under that plate and press bar down hard in order to reach the plyers and squeeze it closer together and put bar into thread.

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Here is a different shot of the linkage all connected.

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Here is the new sway bar fully installed on the car. New sway bar has the BLUE sticker

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I will post driving reviews once I get some wheel time with the new sway bar.

 

[waveman]

Not that I'll ever do this myself, but your guide and pics are excellent, so thanks for posting. Will be interested to read about your driving impression, too.

 

[scottdk]

Not that I'll ever do this myself, but your guide and pics are excellent, so thanks for posting. Will be interested to read about your driving impression, too.

Thanks for the kind words I actually thought my pics and explanations are a little lacking compared to other DIY threads on here, but I was in a hurry due to my wife I figure people can ask questions and I'll respond with more details if needed.

 

[EXBMWGUY]

Not that I'll ever do this myself, but your guide and pics are excellent, so thanks for posting. Will be interested to read about your driving impression, too.

I agree. You are nearing the TJPark DIY standard endorsed by the SAE and, I am sure, the CIA.

 

[scottdk]

I think it's important for me decide what my expectations are from this change, and I'm actually not expecting to really notice much difference if any, but hopefully when pushed hard I'll notice the difference. Hopefully this weekend I get some drive time to find out.

Either way, most importantly I had fun working on the car, and finally got to tinker with the Genesis again.

 

[Rich10]

A larger sway-bar would decrease the amount of understeer in most vehicles. The 2009 sway bar is MUCH heavier than the 2012's. The new sway bar is very light in comparison.


I will post driving reviews once I get some wheel time with the new sway bar.

If the 2009 bar is heavier than the 2012 bar, the 2009 bar might be solid and the 2012 bar might be hollow.

From my perspective, the most important question would be whether the new bar noticeably decreases body roll while cornering.

 

[scottdk]

If the 2009 bar is heavier than the 2012 bar, the 2009 bar might be solid and the 2012 bar might be hollow.

That was my guess also. Hopefully the new one being a larger diameter can make up being hollow.

 

[scottdk]

I had some time driving the Genesis around over the weekend with the new sway bar. At 1st, it was hard to even notice any difference vs. the stock bar. After putting driving all weekend on fun back country roads and getting to drive the car a little harder, I can feel the difference. The difference is minimal at best, but does make the car more enjoyable to drive due to the car inspiring more driver confidence than before. The best example is that I think the car is a little more predictable when taking a sharp corner. The car used to understeer under this condition normally, which is a little scary since the car isn't turning where you have the front wheels aimed. Now the car is able to track a tighter line when hard cornering. I noticed I was able to use the throttle more while in the turn. If I tried this prior to the sway bar change I'd just push myself more into the edge of the road or ditch.

Don't expect a big change from just changing out a sway bar, but if you're looking to spice things up a bit I think this is a good start since it's inexpensive to purchase the new sway bar kit and install easily yourself. If you're wanting more improved handling than this, buy an R Spec or go race go carts.

 

[genesis 45]

Hello, i have been away from the forum for a long time.....i was part of the original group who had problems with the 2009 suspension...i bought one of the first 2009 sedan models in southern california...i was the first person to get the new part numbers for the shocks and springs when hyundai made the first changes....i gave this info to the forum and some members also made the changes of the shocks and springs as i did........i was happy with the improvement but it still seemed like it could be better,,,,, i just put the 2012 rear sway bar on ny car and the ride is sooooooooooooooo much better in the back end.......i was thinking of trading the car in but i am so glad i tried the sway bar which was only 159 bucks......it amazing what a small change can do for the ride comfort of this car... The new sway bar makes a huge difference for those who have and early 2009 model.....later

 

[radicaltimes]

Sway bars are for cornering,They are for control of body lean during cornering. I don't see how they have any effect on the ride.I changed my C5 corvettes to the C6 Z06 sway bars for less lean during cornering. Ride is not changed. Some times changes seem to make a change even though it hasn't.

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[genesis 45]

Im not sure why it did but i can tell you the ride is less jittery and it handles potholes and un even pavement much better.....ive dine a lot of driving over the same roads to tesy it out and it is much better........ive had this car or almost 4 yrs and my son who sits in the back seat immeditaly noticed the difference........my brother is a professional mech. And he thinks the new sway bar is poss more flexible over the bumps, since the bar is lighter and hollowed out........later

 

[scottdk]

More info From Wikipedia

Main functions
Anti-roll bars provide two main functions. The first function is the reduction of body lean. The reduction of body lean is dependent on the total roll stiffness of the vehicle. Increasing the total roll stiffness of a vehicle does not change the steady state total load (weight) transfer from the inside wheels to the outside wheels, it only reduces body lean. The total lateral load transfer is determined by the CG height and track width.

The other function of anti-roll bars is to tune the handling balance of a car. Understeer or oversteer behavior can be tuned out by changing the proportion of the total roll stiffness that comes from the front and rear axles. Increasing the proportion of roll stiffness at the front will increase the proportion of the total load transfer that the front axle reacts and decrease the proportion that the rear axle reacts. In general this will cause the outer front wheel to run at a comparatively higher slip angle, and the outer rear wheel to run at a comparatively lower slip angle, which is an understeer effect. Increasing the proportion of roll stiffness at the rear axle will have the opposite effect and decrease understeer.

Drawbacks

Because an anti-roll bar connects wheels on the opposite sides of the vehicle together, the bar will transmit the force of one-wheel bumps to the opposite wheel. On rough or broken pavement, anti-roll bars can produce jarring, side-to-side body motions (a "waddling" sensation), which increase in severity with the diameter and stiffness of the sway bars. Excessive roll stiffness, typically achieved by configuring an anti-roll bar too aggressively, will cause the inside wheels to lift off the ground during very hard cornering. This can be used to advantage: many front wheel drive production cars will lift a wheel when cornering hard, in order to overload the other wheel on the axle, limiting understeer.

 

[mikec]

A couple things to add on the sway bar operation:
1: for folks that aren't familiar with the suspension parts, the sway bar is a wide "U" shaped piece that connects one wheel with its twin on the other side of the car. The ends of the "U" attach to the arms that go up/down with the wheels; the center portion of the "U" has bushings attached to the vehicle chassis. To picture this better, stand with your arms straight out, then bend your elbows in 90 degrees and make fists (almost as if you were about to grab a pair of ski poles). Your fists represent the attachment links to the wheel hubs, your shoulders are where the bar attaches to the vehicle chassis. Now move your hands up/down together (rotating your elbows) while imagining your forearms were rotating too... that's basically a sway bar motion when the two wheels hit a common bump like a speed bump. Ideally the bar moves with no resistance in the chassis bushings. Next, move your hands out of sync - one up, one down. If your arms were connected between your shoulders you'd feel the spring tension building. That's what a anti-sway bar does when the wheels move differently. Car body lean in corners makes one wheel go up and the other go down; the anti-sway bar stiffness fights this, limiting the total lean (roll) angle.

2: So what can go wrong? If the chassis bushings are too tight, the bar can't rotate when both wheels go up/down in sync... so the anti-sway bar ends up acting like a regular suspension spring, making the total up/down spring stiffness higher than intended. That makes the ride more jittery AND it is extra spring stiffness that the shock absorber (which is really best described as a damper assembly) has to fight - and it could overwhelm the shocks leading to up/down vibrations in the suspension. Think of it this way: ever have a car with worn shocks? What happens - you hit a bounce and the vehicle oscillates up/down for longer time because the shocks are too weak to fight the mass of the vehicle on the springs. Well, stiffening the springs - via too-tight anti-sway bar bushings - makes the total spring stiffness higher which is the same as a shock wearing out.

3: the anti-sway bar connects to the wheels of the vehicle through "end links" which are just long bolts, spacers, and rubber bushings. Why? Go back to holding your arms out again with your fists oriented vertically still (still holding the ski poles). Rotate one fist one arm up/down again and watch the path of your hand in the air: notice it's an arc? It doesn't move perfectly straight up-and-down. In fact, most suspension parts have this arc motion... which is why suspensions have several parts moving together to try to cancel as much of this arc motion as possible. Anyway, if the anti-sway bar is to connect to the wheel stuff it can't be moving in this arc (forward/aft motion must be eliminated) so it is connected to the wheel hub via short links that can flex a bit at each end. These links absorb the forward/aft motion. If the bushings on either end of these links are too tight that will restrict their ability to absorb the fore/aft motion... causing the anti-sway bar to bind/jam a bit. Ergo more stiffness in the suspension again. Ideally these "end links" and their bushings have a little softness to them right away, this lets the wheels move up/down individually over small bumps without putting any twist into the anti-sway bar... but when the wheel motions get larger the anti-sway bar then comes into play, doing its job. This initial softness in the response is part of the generic suspension term "compliance" which is what really isolates the vehicle from buzzy road vibrations. A super-sports car, or any race vehicle, has almost no compliance at all - so the anti-sway bar works instantly to control body lean BUT such vehicles typically have buzzy rides where you feel every crack in the pavement.

I wonder if the improved ride noticed by the OP might simply be due to the original anti-sway bar having too-tight bushings or too tight end link bushings. Sometime in the next few months, when time allows, I'll look at my car and check all those bushings. Mine is an early 2009 with the "worst" suspension yet back seat riders have praised my car. I do notice the rear wheels "thump" more than the front wheels over small pavement irregularities (like thick crosswalk paint!) so maybe I can improve that a bit.

mike c.

 

[STREETS]

Did you have your exhaust system modified? The pipes are welded behind the mufflers.

 

[scottdk]

Did you have your exhaust system modified? The pipes are welded behind the mufflers.

http://www.genesisowners.com/hyundai-genesis-forum/showthread.php?t=2378

Yes sir

 

[STREETS]

The MagnaFlows sure rust more than stock exhaust.

 

[scottdk]

The MagnaFlows sure rust more than stock exhaust.

Yup. Any OEM exhaust will outlast the car usually, which is why it is so expensive to have replaced if exhaust damage occurs due to accident etc. The aftermarket vendors sell SS exhaust, but at a fraction of the quality.

 

[Rey]

I have modified Hyundai sway bars be replacing the soft OEM bushings with Energy Suspension poly bushings. I did this to my late model 2009 (with factory improved suspension). I noticed a slight but material difference. The car cornered a bit flatter. Ride and bump compliance did not seem all that much different. The harder bushings will transmit more noise, but not a lot. This is a lot cheaper/easier than replacing a sway bar. The hardest part is removing the OEM bushings as they are pressed into place in their brackets.

As for OEM sway bar bushings being too tight, I think that is virtually impossible with the fairly precise fit of bushings to bracket. The bracket tightens metal-to-metal. There is no squishing of the bushing.

 

[jnc2000]

as soon as someone launches a full front camber and rear 3 piece kit you can be this along with the coil overs will be on my short list.

http://www.kspec.com/list.php?ac_id=192&ai_id=2413

 

[TimeOut]

I'm interested in this DIY. Do you guys have the Part Number of R-spec Sway Bar?