Tokico Reds, Blues, or Front swaybar for HS autoX?

[CoryM]

Hey guys,

Hoping for some input from those with more experience. Car is HS legal and currently has: 205/50r15 NT01s, rear TRD bar, front camber bolts (and a seat belt harness for safety reasons of course. The fact that it also hold my butt solid in the seat has nothing to do with it.....). The Yaris is mostly used in the winter autoX series and runs on Kumho 4X when too wet/cold for the NT01s (say 5 out of 7 events).

So, would you upgrade the front swaybar or struts first? I know usually a bigger front bar will cause more understeer, but I am wondering if reducing the body roll would actually reduce the understeer due to the increased contact patch of the inside front tire.

In terms of struts for this car do you think the Reds are worth the extra cost over the Blues? On a stock sprung car I have no idea. If I get the Reds I will likely tune it to whatever works best on average at autoX and leave it there. Too lazy to be crawling around the car :tongue:

And, can someone please confirm that adjustable shocks are legal for Stock class?

Thanks for any input.
Cory

[7:34pm]

Nice to see another Yaris from BC autocrossing! What rims are you on?

Subscribing to this thread.

[CrankyOldMan]

With all the changes coming to stock I would wait until they finalize the allowances before spending any money.

[cali yaris]

I am wondering if reducing the body roll would actually reduce the understeer due to the increased contact patch of the inside front tire.

It will, it works really well on the Yaris.

If I get the Reds I will likely tune it to whatever works best on average at autoX and leave it there.

The adjustability is critical, and the Reds have a very wide range of adjustment, from softer than Blues to more stiff than Blues.

[xnamerxx]

Hey guys,

Hoping for some input from those with more experience. Car is HS legal and currently has: 205/50r15 NT01s, rear TRD bar, front camber bolts (and a seat belt harness for safety reasons of course. The fact that it also hold my butt solid in the seat has nothing to do with it.....). The Yaris is mostly used in the winter autoX series and runs on Kumho 4X when too wet/cold for the NT01s (say 5 out of 7 events).

So, would you upgrade the front swaybar or struts first? I know usually a bigger front bar will cause more understeer, but I am wondering if reducing the body roll would actually reduce the understeer due to the increased contact patch of the inside front tire.

In terms of struts for this car do you think the Reds are worth the extra cost over the Blues? On a stock sprung car I have no idea. If I get the Reds I will likely tune it to whatever works best on average at autoX and leave it there. Too lazy to be crawling around the car :tongue:

And, can someone please confirm that adjustable shocks are legal for Stock class?

Thanks for any input.
Cory


Yes adjustable shocks are legal in stock. If your trying to gain huge amounts of time you'll likely not see much with either set of shocks but the reds are probably the faster of the two.

In theory the bigger front bar might cause corner exit understeer on sweepers but make the car behave better transitionally, but it will likely increase corner exit inside spin as well since more load from the inside tire will transfer to the outside tire.

[TheRealEnth]

I have had blues for over 80k miles now. They work great for the autox. It all depends on how serious you want to tune. I honestly think better tires and better experience shaves off most seconds.

And oh yeah it does reduce understeer a lot like CaliYaris noted. My car tends to oversteer a tiny bit.

[CoryM]

Thanks for the input guys.

7:34pm- You must run with VCMC? I've only been to one of their events. Rims are currently konig heliums and aren't actually legal for HS. The NT01s are my daily summer tires and I am too lazy to bolt on my other rims.

CrankyOldMan- Good info. I didn't know about them. Looks like it probably won't affect my strut choice, but good to know.

cali yaris- Thanks. Expect at least a swaybar order soon.

xnamerxx- I think the problem with conventional swaybar theory is that it's from performance cars; Not soft sprung economy cars. After seeing those pictures I figure reducing the roll and increasing the contact patch of the inside tire will make a pretty big change for the better.

TheRealEnth- Good info. Thanks. I'm running R-comps already and refuse to run Hoosiers because I know I will never go back. Already hate driving on all-seasons. I also get one set of Nittos per year for very cheap so better tires are out. :wink:

Cheers.

[cali yaris]

refuse to run Hoosiers because I know I will never go back.

:smile:

[xnamerxx]

Thanks for the input guys.

xnamerxx- I think the problem with conventional swaybar theory is that it's from performance cars; Not soft sprung economy cars. After seeing those pictures I figure reducing the roll and increasing the contact patch of the inside tire will make a pretty big change for the better.


All swaybars are is a dynamic spring that reacts in roll only.

Going to a bigger swaybar will reduce roll since it resists roll motion, but when you reduce load on the inside tire from accelerating the inside from will have dramatically less load since it will be transferred to the outside rear.

I think of load like this.

No motion sitting static
[720][720]
[380][380]

Forward acceleration no steering
[640][640]
[460][460]

Braking
[900][900]
[200][200]

Left hand turn accelerating, this is where the swaybar starts to do what its designed to do. The stock bar on my car provides around 160lbs of resistance. Going to a bigger front bar will reduce load to the inside wheel which is also the drive wheel. Shown crudely below. As you can see you have a 2-3" contact patch with only 460/lb of load on the drive wheel.
[460][730]
[400][610]

From the pictures what you're seeing is dynamic camber loss under extension. It doesn't help the fact you're inside rear is picking up transferring more load to the outside front, which if you look carefully at the picture is deflecting really really badly and probably overloading from what I guessing.

Being your car is Mcpherson you really fix the contact patch issue on the inside front without reducing body roll a significant amount which bars aren't really gonna fix.