toe, camber, castor? basic alignment question?

[rainmonkey]

Hello,

I'm installing some coils, and I'd like to know what would be advisable for a good compromise between autocross and the like, and weekend driving (not a daily driver, car is mostly just used on weekends for pleasure).

I'm under the impression that most people run only a couple degrees of camber on the front and rear. I've received recommendations for -2* front, -1.5* rear.

Regarding toe... I'm a little more lost. Some people say 0/0 front/rear is good, but I also read that toe is used to make the car a little more stable even when just using it on the highway (non spirited/track stuff).

I guess that at the end of the day, I'd like to have the car be more of a "jack of all trades, master of none" rather than specialize and severely impact performance (or comfort/safety/wear) in one environment or another.

I know this is a loaded question, but any help and suggestions are most welcome.


Thank you!

[CSG Mike]

What's your driving experience? Do you want a "align and forget" conservative setting, or are you willing to re-align based on data you collect?

I've aligned my S2k probably around 40-50 times over the past few years...

[rainmonkey]

Originally Posted by CSG Mike

What's your driving experience? Do you want a "align and forget" conservative setting, or are you willing to re-align based on data you collect?

I've aligned my S2k probably around 40-50 times over the past few years...

Driving experience... Driven for a while, first rwd. Not much in the way of enthusiast driving tho. I've done one autocross event and will be going to a few more this summer.
Given that, I think a conservative set and forget would be a good starting point. Then if/when I figure out which direction to specialize in (or acquire more funds) I can make new adjustments.

[CSG Mike]

Originally Posted by rainmonkey

Driving experience... Driven for a while, first rwd. Not much in the way of enthusiast driving tho. I've done one autocross event and will be going to a few more this summer.
Given that, I think a conservative set and forget would be a good starting point. Then if/when I figure out which direction to specialize in (or acquire more funds) I can make new adjustments.

Do you feel the car is overly loose, or prone to spinning out? How would you like to change the car's behavior from what it does now? What modifications do you have? Have you added the parts necessary to perform a full alignment? If not, toe will be the only adjustment you have front/rear without finding a specialty shop that can mess with tolerances.

[rainmonkey]

I spun out a few times because I was probably going to fast. I experienced understeer because I would turn in late. I have no other modifications to the suspension, coils will be the first. I have the fortune auto 500s and that allows for camber adjustments at least up front. According to ft86speedfactory, the drop which I intend (1-1.5 inches) will result in roughly -1.5* or so camber in the rear. This, I am amenable to.

As for what I want to change... I always felt like I was on the verge of running through the cone boundaries. Probably mostly from understeer although this feeling may be attributed to my only having driven awd and fwd cars before. I believe some of the oversteer will be rectified by the greater increase in spring rates relative to that of the rear.

My currently I would default to just 0/0 toe front and rear. Although I've read that stock setup does have some toe.

I appreciate the help, good sir.

[CSG Mike]

a 1.5ish drop will result in closer to -2 to camber in the rear in our experience.

Based on your feedback, try this.

-2 camber front/rear.
1/32 total toe-in front, 1/32" total toe-in rear. (the toe gives a teeny bit of freeway/dd stability)

Caster to preference.

[wparsons]

Nothing against Mike's suggestions since they look like a really good starting point and he has WAY more experience than I do, but it sounds like the most valuable thing the OP can do is get more seat time.

If it's pushing because you're turning in too hot or too late then camber or toe isn't going to fix it. Camber should be set based to maximize the contact patch in corners and toe can help set how the car turns in and rotates. If you give it rear toe out to rotate more because you're entering turns too fast you'll end up with something that rotates way too much at a proper entry speed.

[rainmonkey]

Originally Posted by wparsons

Nothing against Mike's suggestions since they look like a really good starting point and he has WAY more experience than I do, but it sounds like the most valuable thing the OP can do is get more seat time.

If it's pushing because you're turning in too hot or too late then camber or toe isn't going to fix it. Camber should be set based to maximize the contact patch in corners and toe can help set how the car turns in and rotates. If you give it rear toe out to rotate more because you're entering turns too fast you'll end up with something that rotates way too much at a proper entry speed.

Agreed, more seat time is always better. However since I've already acquired coils, I might as well set them up in a way that will help me right?

I wanted a base point to build on that won't overcompensate for anything I'm messing up. I think that's what @CSG Mike's set up is.

How would you do things?

[wheelhaus]

Considering the fact, between the two twins, that everyone perceives the BRZ to be somewhere between slight understeer to neutral, I wouldn't change too much. a car that understeers slightly is more stable and easier to drive nearer it's limit. A car that oversteers more readily may feel faster, but you may be fighting yourself too much. -2° front camber sounds aggressive to me with coils, but I'm no autocross guru so it may work great.

To elaborate on what's happening- When the tire is loaded heavily under lateral load, the sidewall flexes and the contact patch rolls onto it's outer shoulder. Adding negative camber will tilt the tire inward to help keep the contact patch fat and square when the tire is under load. Too aggressive and it can hurt tire wear, braking, and accel since the contact patch is more of a triangle, where it leans on the inner shoulder too much for everything but heavy cornering.

Both CSGmike and wparsons have good tips. Seat time will help you learn how to manage the car's weight. Entering a corner has everything to do with how you enter the corner. (that's some insight, eh?) Just mashing throttle, slamming the brakes, and yanking the wheel are no way to go fast. Coilovers will make everything a bit stiffer and more responsive, especially weight transition, which affects tire loading. Tire loading affects tire temperature. So does pressure. And alignment. There's a lot of variables, especially for a rookie. If you make changes, try to do one thing at a time and pay attention to what happens differently on course. Keep notes! It'll help you remember what you did under what conditions and will help build your knowledge by having references to your own experiences.

[rainmonkey]

The handling characteristics that everyone perceives for the BRZ vs FRS are derived from the spring rates and shocks(or whatever the other pieces are). By changing to coils, that pretty much goes away doesn't it?

[wparsons]

Originally Posted by rainmonkey

Agreed, more seat time is always better. However since I've already acquired coils, I might as well set them up in a way that will help me right?

I wanted a base point to build on that won't overcompensate for anything I'm messing up. I think that's what @CSG Mike's set up is.

How would you do things?

Like I said, Mike's suggestion sounds like a good baseline. My whole point was to not go overly aggressive with the toe settings trying to make it rotate easier at the limit until you have more seat time.

They're kinda separate thoughts. Get a good baseline alignment, spend lots of time driving and get tips from more experienced drivers to see if you're over driving or trying to enter corners way too hot before messing with things to make it rotate more at the limit.

As for camber and tire wear, that's a myth except in extreme cases. -3* won't hurt the tires at all on the street, but having more toe will definitely be noticeable with tire wear and even fuel economy. Proper camber for how you drive will actually improve tire wear since you're using more of the contact patch.

[CSG Mike]

Originally Posted by rainmonkey

The handling characteristics that everyone perceives for the BRZ vs FRS are derived from the spring rates and shocks(or whatever the other pieces are). By changing to coils, that pretty much goes away doesn't it?

Correct.

I think the "rear happy" aspect comes from the fast that the majority of FRS owners are first time RWD owners, and the rear comes out when they're not used to it. The press stuff probably contributes to the perception too.

As for wparson's toe suggestion: The BRZ comes with almost 0 toe in the rear, whereas most FR-S seem to have around 5/32" toe-in. IMO, that's to compensate for the chosen stock spring rates. Numbers based on measurements taken by my alignment shop.

[koevasi]

I have a set of tein flex coils and had the car lowered 1.5 inches front and rear. Rear camber came out to 2.0-2.1. Changed the front camber settings to match the rears. Slight toe in at the back, none at the front. Just go from here. Sounds like you are still learning about the car and it's not a bad place to start. In any event there is never right or wrong when it comes to alignment settings. Just get enough parts (like the LCAs) to give your alignment guy the tools to play with all the variables.
Let us know how you get on with fortune autos. My tein flex has 7kg up front it's slightly too bumpy for my favourite driving roads and it appears it's not something that I can dial out with damping adjustments or alignment settings. For medium to fast(ish) street driving I think 6kg/mm at the front is as stiff as anyone would want to go - which interestingly is what KW and fortune auto have done.
Have fun!