Sway Bars..Do they really make a difference for a DD?
 

Like the title says, would I notice a big difference if I installed them on my car.

I was looking at the perrin one..

http://www.perrinperformance.com/p/2165

Also, could I just install just the front or rear one? Any suggestions would help

They can make a difference, and that is NOT the bar you want to add to the car. Just because one is available doesn't mean it's the right choice.

On an otherwise stock BRZ/FRS a larger rear bar will make the car more prone to spinning and will make the limited slip differential much less effective. Neither of those things are beneficial.

A larger front bar could benefit you depending on driving style, etc.

Thanks! Could you explain why the perrin bar is bad or not the right choice. Tirerack also sells front and rear ones with the prokit lowering springs for $455 or so. What makes one sway bar better than the other.

Sure they'll make a difference. The question is, do you need aftermarket sways for a dd?

This.

obviously there's a difference between need and want. i'm probably on the side of the OP as i too "want" some sort of sway or strut bar, but i plan on doing some autox next summer.

IF someone wants help, lets not ask his motive, but just help the person out! that's what we're all here for right?

Anyways, OP, i would take someone experienced to drive with you to see what your driving style is, then have them decide what type of "bar" you should purchase based on your driving style

I'm saying that for a mostly stock car you do not want or need a HUGE rear sway bar that happens to be a WRX/STI (forgive me for not knowing the difference) sway bar. Tuning a heavy AWD car with a lot of weight bias, and drive tires on the front end is a lot different than tuning a lightish RWD car with good balance.

In the end, I agree with the folks that say "drive it." Is there some handling problem you are trying to fix? The answer should be yes before you start bolting on suspension parts.

Do you feel the car has too much body roll? Because getting a set of sways first is just going to be about feel. They may help your handling a little bit if you've changed to stickier tires, but will likely hurt handling if you have the stock tires. I'm not convinced they are the way to go with this car early on in the suspension mod process.

On the nose-heavy, awd, understeering Imprezas, a rear sway is the #1 suspension mod to do. But on this car that is already so neutral and with so little body roll from the factory, I think by tying the left and right wheels together more will only hurt unless the spring rates are increased some as well. And even then, the increased rates could take care of the body roll on their own and retain left/right independence.

I'm doing springs before sways on this car. And they are going on in a couple days. I'll have a better idea about the spring vs. sway issue this weekend.

^ Agreed....swaybars are usually a good quick cheap first mod for Subarus, but for this car it's not quite the same. A big rear bar will cause handling issues on it's own. Front bars will be beneficial but it's important to look at the complete picture and think about what else you plan to do.

- Andrew

FWIW, one end link of the front sway bar on my RX-8 broke off (common problem). Probably was that way for months. Never noticed a difference in daily driving, not even after it was fixed.

I shall steer my mod bug urges towards a different path then.

LOL that doesnt sound too good

I think Perrin is being irresponsible suggesting that their big bars are FRZ suitable. Fitment isn't the only criteria.

... Must not start Perrin rant ...

Factory WRX (08+) rear sway bar fits our cars right? Looking for more oversteer.

We fitted a bigger rear bar on the BRZ in Japan, and a professional driver drove it back to back vs. the stock swaybar. On Tsukuba Circuit it was a second slower with the bigger rear bar. Too tail happy.

If you want to do something to the car, and you want to do swaybars - you have to do them front and rear at the same time. "Improving" only the front or rear doesn't make sense, this is a relatively rare case of a car that's very well balanced out of the box.

I want it "tail happy'. I like daily drifters!

Start with alignment then.

Sorry for dragging up an old thread, but do you happen to know what size rear bar they tested? :thanks:

Anyone who's not completely familiar with how a sway bar works (and various other suspension components) should really read this book, as it will help you a lot:

[ame="http://www.amazon.com/How-Make-Your-Car-Handle/dp/0912656468"]Amazon.com: How to Make Your Car Handle (9780912656465): Fred Puhn: Books[/ame]

http://ecx.images-amazon.com/images/...SH20_OU01_.jpg

The book was written in the 80's so it's not completely up-to-date but most of the principles are the same. It's also cool to see how much suspension has evolved over the past 100 years.

Suspension and chassis tuning is a black art. You really don't want to just bolt parts onto your car without knowing how they will affect performance, especially considering the time and effort the Subaru and Toyota engineers put into making this car handle so great from the factory.

Only add a bar to correct a handling issue YOU have with your car.

Before you do that:

1. Be sure you are on a set of tires you are going to stick with.
2. Get your alignment checked and set up the way you need.
3. Then address your issues with your car

It was a 20mm solid bar.

To me they are the single most cost-effective improvement you can make to the handling on any car. People go crazy with their opinions on size, hallow/solid, etc. Just get something stiffer and eliminate the body roll, you will have a much better handling feel. If you want to understand optimizing the chassis/suspension or track set-up then do some research. Just dropping sway bars in will make you smile.

Also people over emphasis the wheel/tire combo. Of course having a stiffer suspension will isolate the performance of the tires. However, with sway bars it allows a more efficient transfer of weight in cornering. If you read people's posts on here you will get the impression you will fly off the road and crash by adding sway bars, this is not the case.

That being said, you will understand the limits of the tires clearer so you will then understand you will want better tires.

Wow, no wonder it was tail happy! Thanks for clarifying.

funny. I went the other way. I removed my rear bar.

CG is so low in this car, the bars don't do a ton of work. Dampers and alignment got the rear where I wanted it without the sway bar in the back. And that is on a 255 RS3, so I've got more grip than the average FR-S too.

It all depends on how stiff your springs are too. Too stiff of a bar on light springs can make things happen (like three wheeling) that you might not want, and too light of a bar (or no bar) on light springs will definitely increase body roll.

Sway bars basically give roll stiffness without increasing bump stiffness.

I have Tein H Tech springs, would going to a Strano 22mm bar or Whiteline 20mm bar up front be an upgrade? the spring rate in the front is pretty soft and i was thinking a larger/stiffer front bar would effectively stiffen the front end but maybe somebody can point me in the right direction.

what do you mean by "stiffen." what is it your trying to accomplish? less side to side roll?, less forward pitch?, less oversteer?, less understeer?

Bingo!

In the simplest terms, a stiff front bar will increase understeer and a stiff rear bar will increase oversteer, it isn't just a stiffer is better solution.

Adding more swaybar decreases the independence of the linked points; many people have gone to a bigger bar for autocross and changed back to a smaller or stock bar at a later point in time citing the increased suspension independence was much more enjoyable on the street.
In a gross way, yes. On a car like the Impreza, a bigger rear bar WITH a bigger front bar often performed better than just a bigger rear bar. Balance is important in sway bar sizing. The bigger rear bar in that application certainly made the rear livelier, but the stiffer front didn't INDUCE understeer like you'd expect. As I said, the two ends must be considered together.

Increasing understeer is the same as reducing oversteer, and vice versa. It doesn't mean the car actually pushes/understeers necessarily, just that it's more likely to than before. It's definitely a balance, which is why adjustable bars are handy so you can fine tune them based on your car, ride height, spring rates, etc.

here are the rules:

It's also important to remember that following that chart to decrease understeer or oversteer may or may not make the car faster. Case in point, adding a larger front sway bar to the BRZ/FRS may add a little at the limit understeer, but will increase overall grip.

- Andrew

of course!!!

That goes without saying

100% valid, its not by any means the bible, just a good set of basics to often test and see what needs to be done vs what can be done to remedy any given 'condition', I like to keep it in the back of me skull

Agreed! One thing that I always see is people trying so hard to decrease understeer and increase oversteer without thinking about anything else. This isn't a 2003 WRX!

- Andrew

That was exactly what I was trying to say a few posts up, thanks!

Daily driver, no track kind of guy?

No

Save your $$

Less body roll would be the main goal i suppose, i definitely don't want more oversteer which i why i plan to leave the rear bar alone.

Would a larger/stiffer front bar increase grip and decrease body roll is what i am really asking.

in basic theory thats what it would do. but its effectiveness will probably vary depending on what springs and tires you are using in conjunction. if you havent done those yet, that would be the best place to start of course. if you already have springs and tires and still want less body roll, then a front bar could be good for you. you could also look into bushing kits. there seems to be a replacement for every bushing on this car. consult with your prefered vendor for specifics on what bushings might help. gl