Tamago's guide to ultimate yaris handling

[at3GG]

.....yes....yes you do. But only if you report back to us!

[ddongbap]

Damn Loren.

You talking about how changing the toe just a little bit would get it to rotate better got me wet.

[Loren]

Originally Posted by ddongbap

Damn Loren.

You talking about how changing the toe just a little bit would get it to rotate better got me wet.

Yeah, I'm sexy like that. You should hear me talk about rev-matching and heel-toe downshifting.

[TheRealEnth]

LMAO thats sick

[markitect]

First off awesome writeup!!!!!!!!!!!

I have one question though, for those looking to stay in HS what shocks/struts work well with stock springs? Any side affects with that combination?

Most are designed to be paired with lowering springs so it seems like this would affect their range of motion (I need something that can go over potholes). Of course if anyone knows of reasonably priced adjustable ones let me know.

[Tamago]

Originally Posted by markitect

First off awesome writeup!!!!!!!!!!!

I have one question though, for those looking to stay in HS what shocks/struts work well with stock springs? Any side affects with that combination?

Most are designed to be paired with lowering springs so it seems like this would affect their range of motion (I need something that can go over potholes). Of course if anyone knows of reasonably priced adjustable ones let me know.

i would imagine that the TRD shocks would fair well with stock suspension, since TRD is for their mild 1"ish drop.

R comps will take you a lot further than shocks in HS though IMO

also, keep in mind, if you run a "shorter" shock with stock spring, you'll be compressing the stock spring beyond its original setting, thereby raising your static spring rate :D which isn't bad, but may get you kicked out of HS in a nationals environment. (not that an HS mini is gonna be scared of a yaris.......... )

[mikenacarato]

good thread! :)

[Loren]

Originally Posted by PK198105

don't forget however that changing your camber, toe in/out will affect the lifetime of your tires. Tamago you wrote so much im not sure you mentioned this (my fault probably i fat read your post)

Done properly, it won't necessarily affect the wear of your tires. In fact, depending on your driving style, it could IMPROVE your tire wear.

I'm running factory alignment in the rear (-0.9 camber, slight toe-in), and -2.5 camber in the front with very slight toe-in. My tire wear is very event all around. If I DIDN'T have all that front camber, my front tires would be wearing on the outside edges.

Excessive toe, especially when coupled with agressive camber will cause tire wear issues. But, with neutral toe settings, up to 3 degrees of camber is not a problem even on a daily-driven vehicle.

(trivia: The factory alignment on the rear of my Triumph is 3 degrees negative camber)

[Loren]

Originally Posted by PK198105

thanks for clarifying Loren. I just though since you're changing the vertical angle (camber) the contact patch will be offset to either side.

Well, it does, but it's just not enough to be a problem unless you combine it with too much toe.

Running 2 degrees of camber with mild toe settings and doing strictly highway miles might result in 2mm more wear on the inside of the tire vs the outside. Of course, if you do strictly highway driving, you don't NEED that much camber! If you have that much camber, it's probably because you do some mountain driving, or autocross, or track driving... and that performance driving is going to largely equalize the wear. You might still see maybe 1mm more wear on the inside vs. the outside... but who cares? That's close enough.

[SEVEN]

Originally Posted by Tamago

basic "autocross setup" springs... if you're gonna autocross, and you've installed lowering springs, please get a set of shocks that were built to be coupled with a lowering spring. stock struts and "lower" springs just don't fit into autocross land.[/size]

will tein s.techs and trd shocks work???

[Loren]

Originally Posted by SEVEN

will tein s.techs and trd shocks work???

What you'll eventually conclude with that setup and really think about it is that a) you don't have enough suspension travel so you bottom out both in hard turns and over bumps and b) the shocks don't sufficiently control the motion of the springs on rebound.

Will it "work"? Yes, but not if you want the car to handle as good as it could.

[SEVEN]

Are there TEIN shocks for yaris??? I can't find any ...

[cleong]

Cusco does make a front anti sway bar (part no. 900 311 A26). So its available for a price should you feel the need for it. As I cannot read Japanese I cannot say if it is stiffer than stock or not.

I found that running too much negative camber on skinny street tires reduces its off-the-line traction. It might not really hurt acceleration that much but it seems easier to get the tires to break loose.

[Loren]

Originally Posted by cleong

Cusco does make a front anti sway bar (part no. 900 311 A26). So its available for a price should you feel the need for it. As I cannot read Japanese I cannot say if it is stiffer than stock or not.

The last thing you want on a FWD car is a larger front swaybar. It would just require you to stiffen the rear that much more to reach something close to "neutral" rather than "obscene understeer".

The only reason Cusco makes it is because people who don't know any better WILL buy it... not because anyone really needs it.

[ChinoCharles]

Bravo Tamago.

[cleong]

We can't be certain of that fact which is why I stated the bar was available but can't speak for its effects. If it would make the car understeer worse like you say it would, then if you took the front anti roll bar off, would it cure the understeer without having to fit a rear anti roll bar?

I think it is possible that a correct front anti roll bar would reduce front roll, and optimize the tire contact patch in the corners, because too much roll unloads the inside tires. I'm not saying the Cusco would do it, because I've never tried it, but it is a tuning option that should be tried before being written off.

[Loren]

Originally Posted by cleong

We can't be certain of that fact which is why I stated the bar was available but can't speak for its effects. If it would make the car understeer worse like you say it would, then if you took the front anti roll bar off, would it cure the understeer without having to fit a rear anti roll bar?

Yes, we can be certain that fitting a stiffer front swaybar (with no other changes) will make the car understeer more. That's just simple suspension physics at work. That's just the way it is.

And, yes, removing the front swaybar would probably make the car understeer less (it's been done on some FWD cars with success), but while it might have higher cornering limits, the steering would feel very "sloppy" and it wouldn't be enjoyable to drive. One absolute truth about suspension tuning: It's always a compromise.

I think it is possible that a correct front anti roll bar would reduce front roll, and optimize the tire contact patch in the corners, because too much roll unloads the inside tires.

Body roll is not the "evil" that so many people think it is. Look at some of the best handling cars in the world... a Lotus Elise, for example... lots of body roll. Even purpose built race cars have some body roll in as much as their suspension moves. (look at an F1 car full-on in a corner, the outside is compressed visibly more than the outside) Body roll isn't bad. It's a by-product of weight transfer. What you want is control of that roll (good damping), and balance of the weight transfer (spring rates and sway bar rates).

If eliminating all body roll was the answer, every race car and high-end performance car would have NO body roll. Eliminating more body roll (with a larger front swaybar) at the expense of moving the handling balance of the car further in the wrong direction is no solution.

This whole discussion is much like arguing about lowering springs with ricers. They think that "lower is better" no matter what... and "stiffer and flatter" is better no matter what. It's simply not true.

I'm not saying the Cusco would do it, because I've never tried it, but it is a tuning option that should be tried before being written off.

I've not tried it on a Yaris, but most of my suspension tuning knowledge does come from experience. One of the first suspension mods I did to my Saturn when I started autocrossing was to put a bigger front swaybar on it. Same reason everyone else wants to: to get rid of the body roll. I then spent the next 3 years finding ways to eliminate the understeer that it caused. I was stubborn and refused to remove the front bar that I'd spent good money on, which would have solved the problem instantly. (as a side note, the Saturn S-Series cars had two swaybar options, the twin cam front bar was larger than the single cam bar... and the twin cam had a rear bar whereas the single cam had none... the hot ticket is simply putting the smaller front bar onto a twin cam car!) To balance the larger front bar, I ended up having to put a rear bar on that was so stiff that it actually BENT the stock rear end link mounts.

Wanna play with what removing the front swaybar would do? It's easy, just remove an end link on one side. The other side will hold the bar in place and keep it from flopping around, but with one side disconnected, the bar will have no effect. Very simple experiment. Somebody do it and report back. (maybe I'll do it when I have time)

If you have a stiff coilover suspension, you might get away without the front swaybar. I tuned the suspension on my old Miata with really stiff springs and NO swaybars. People thought I was nuts, but I wanted to prove that it could be done. It took really stiff front springs to get it to feel right, of course.

[Tamago]

Originally Posted by PK198105

don't forget however that changing your camber, toe in/out will affect the lifetime of your tires. Tamago you wrote so much im not sure you mentioned this (my fault probably i fat read your post)

yes, it will.. absolutely.

this guide is to help those who are interested in handling, before tire longevity, etc etc.