Stiffer Front Sway Bar??

[invader166]

Hi guys, just wondering if there would be any kind of improvement or worsening in handling if one were to increase the front sway bar stiffness.

Don't know much about this phenomena, but since stiffening the rear creates oversteer, then stiffening the front would create more understeer, no?

However, I do recall Garm/cali yaris mentioning that a stiffer front sway bar reduces body-roll a lot, which would definitly help!

So, question is: Is it worth spending some cash on a Tanabe unit like this:

http://www.ebay.com/itm/Tanabe-TSB121F-Sustec-Stabilizer-Front-fit-Toyota-Yaris-14-/131235764119?fits=Model%3AYaris&hash=item1e8e42d797:g:CEgAAOSw7I5TuqGC&vxp=mtr

Or am I better off not touching it and leaving things as they are?

[Bluevitz-rs]

Do you have a rear one added yet?

[MUSKOKA800]

Adding a rear anti-sway bar will decrease understeer. Perhaps a far to stiff/thick bar may put you into an over-steer situation but this is unlikely. Go with an aftermarket rear bar to balance the handling by lessening your understeer. Stiffening the front will cause increase understeer. Some have even talked of disconnecting a front bar end link to reduce understeer how ever I've not read any results.

[CoryM]

So, question is: Is it worth spending some cash on a Tanabe unit... Or am I better off not touching it and leaving things as they are?

That depends on what you are doing, and what you intend to change on your car. I recently installed a larger front bar on my car. I have delayed posting results as I still don't have it set-up properly.

The reason I went for the front bar is because I autoX my car regularly in Stock class. Meaning I am on stock, soft springs. Soft springs, high COG, and no camber-gain makes it very hard to keep rubber flat on the pavement. In my case, with -2.8° Camber, the biggest problem is keeping the inside tire from spinning (and still outside edge wear on the outside tire). I often have only 3 of 8" of rubber on the pavement in the inside tire in corners.... that sucks. See attached pic.

So staying within Stock class rules I tried a larger front swaybar. It allowed me to drop front tire pressures by 7psi and still have the same edge wear. Like this, it is about the same at autoX before the bar, except it is much faster through the slaloms. Where I notice increased understeer the most is when you are moving too slowly to rotate the rear, and then trying to accelerate out of it. Otherwise the car turns into the corner, just the briefest bit of understeer and then the rear rotates and it works fine.

So long story short, at autoX in Stock class, so far I think it is faster with the larger front bar. If you were doing track-days, or on stiffer springs, or just casual street driving.... probably not. Again, I still don't have enough time with the new bar yet to try all setups.

For reference my car is:
-09 5dr
-2.8° Camber up front
-tokiko blue struts
-TRD rear bar
-Tanabe front bar
-205/50r15 NT01s (or all-seasons when too cold)
-lighter rims

http://www.yarisworld.com/forums/attachment.php?attachmentid=51321&d=1373426042

[invader166]

Thanks for the reply everyone!

My goal is the reduce body roll and under-steer through corners as much as I can without using coil-overs since this is my daily driver. I don't plan on using my car for any competitions, events or track days yet. ...at least not for a long, long time.

(Someday I hope to. It's been a dream of mine for a while, but for now I have go-karts. :tongue:)

I haven't done any major suspension work at the moment. (does a front strut bar count?) For now, I'm just weighing in on my options and bouncing some ideas around, hence my question about a larger front sway-bar.

So far, I'm planning on installing a set of MI lowering springs along with new aftermarket shocks and struts. I also have an 22mm adjustable rear sway-bar that I'll be installing during that job. I'm also exploring the possibility of using wheel spacers but I'm hesitant about that since it's a DD vehicle.

@MUSKOKA800: Interesting idea with disconnecting an end-link. Now I'm curious to find out if that really would improve things. (or make them worse, since I know Toyota doesn't like to add things that increase the cost of their vehicles unless they have no other choice lol)

@CoryM Awesome!! I had no idea someone was actually using a set-up like that competitively. I'd love to see if it really does make an improvement on your run times.

Also, holy smokes!!! That photo is totally crazy! You're on 3 wheels!! Is there no way you can get some down-force on that car?!

[tmontague]

Don't stiffen the front bar then until you have sufficiently stiffened up the rear or you'll get excess under steer as stated above. First start with the TRD rear sway bar or even go with a thicker diameter one made by (I can't remember, maybe Whiteline?). The MI springs are great at reducing body roll and keeping your DD smooth and still comfortable. That being said, they have soft rear springs relative to the fronts so they will increase understeer unless you have the rear sway bar.

I have never had my MI springs installed without the rear sway bar so I can't comment on how bad the understeer was without the sway bar.

[CoryM]

@CoryM Awesome!! I had no idea someone was actually using a set-up like that competitively. I'd love to see if it really does make an improvement on your run times.

Also, holy smokes!!! That photo is totally crazy! You're on 3 wheels!! Is there no way you can get some down-force on that car?!

I will keep you posted as I dial in the swaybar, and try different things. Rear swaybar is the first handling mod you want to do. I only run the TRD bar because then I can use two swaybars in Stock class. If you want to run in STF class any swaybar is legal, and stiffer springs is the next step. They will reduce the roll, and not cause any more understeer. The front swaybar is literally the last part I've put on my car in an attempt to make it handle better. It's not something you should go for first as it does have some negative effects (understeer).

There's no reason to wait to race your car... I AutoXed mine totally stock except for alignment for 2yrs and had a lot of fun. Bring yours out and have fun; you won't find a better way to improve your driving and learn about what mods actually work. It's fairly cheap too.

Three wheels (tripodding) is pretty common at autoX. It's due to the rear swaybar. Downforce isn't viable as the speeds aren't high enough. Probably only doing 70kph in that picture.

Disconnecting the swaybar does work for some cars (especially in the rain). I'm almost certain that the stock Yaris springs are too soft for it to be faster in any situation though. Typically you need stiffer springs to get away with it.

Cheers.

[rabbito]

i have aftermarket performance oem replacement(i think kyb sr or red ones etc. will be fine too)..shock and spring set dropped 1.5 front and 1.4 rear..from 185/60/15 stock dunlop to 195/50/15 hankook tires(v2 series)..i added front tower strut and rear sway bar...

omg..it corners like a champ..im also regreting right now, should have spent a little more money and got the hankook rs3 sticky tires...but i dont regret about getting none coilovers, cars light enough to corner like a champ! :)

pro: corners good..no more nose dive..go through traffic like a champ [emoji16]

con: i am going 5km on the bump..scraping my bumper when i go down hill in the parking lot..sometimes slams rear sway bar on the bump if i go too fast...smh [emoji24]
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[CoryM]

Bit of an update after this weekends autoX: I think with my setup, and at autoX, the front swaybar is a good investment. It would still be basically the last thing I would put on the car though.

Pros:
-screams through the slaloms etc now
-was able to reduce tire pressures
-was able to reduce neg. camber to -2.5° (car brakes much better now because of it)
-more contact patch on the drive wheel in corners (still waiting for a good picture to prove that though)

Cons:
-cost
-understeers a hair more on launch, and occasionally on turn-in (but turns to oversteer immediately)

Basically I can be on the gas sooner, and on the brakes later. That's a win to me.

Cheers.

[invader166]

Bit of an update after this weekends autoX: I think with my setup, and at autoX, the front swaybar is a good investment. It would still be basically the last thing I would put on the car though.

Pros:
-screams through the slaloms etc now
-was able to reduce tire pressures
-was able to reduce neg. camber to -2.5° (car brakes much better now because of it)
-more contact patch on the drive wheel in corners (still waiting for a good picture to prove that though)

Cons:
-cost
-understeers a hair more on launch, and occasionally on turn-in (but turns to oversteer immediately)

Basically I can be on the gas sooner, and on the brakes later. That's a win to me.

Cheers.

Awesome! Glad to hear you've happy and have had good results with it. I bet with a rear sway-bar, that initial under-steer would be virtually eliminated. Great stuff! :thumbsup: