Agreed with 7thgear entirely. Suspension tuning really is a black art.

You'll see lots of guys on the forums here going to crazy lengths to get precision handling; high spring rates, sway bars, crazy alignment settings. The reality is, these guys are track guys. They race on a frequent basis, whether competitively or not, and their cars are set up as such.

It sounds like you're just a normal guy, looking to have fun with his FR-S, like most of us out there. And honestly, the car is really well set up for this from the factory. Your best bet may be to enjoy the car thoroughly for the time being, and perhaps then start with a mild performance alignment to extract a bit more out of it when you're ready :)

Ithink I forget the recover case...

I actually hav both, hah. But it seems like How to Make Your Car Handle has more inset pictures in it. So I read that, hah.:party0030:

What do you mean by that? I was trying to say that drift cars need crazy levels of grip to maintain control of the car at all times. Someone more into the drift crowd please chime in if I'm wrong but I don't think those cars are ever set up to oversteer at all. It's all initiated by the driver. They give those cars crazy front end grip so they can always get the cars pointed back in the right direction more easily.

Again, I don't know drift cars at all, and I'm probably digging myself a hole here :P

I meant u r correct. Drift car need some grip to recover. :cheers:

You should seek the advise of a good alignment shop that specializes in suspension/alignment settings for track cars (or aggressive street use).

Unless you know what you are talking about, the only real way to benefit from alignment settings is to have someone set the car up according to how you drive. What works for others may or may not work for you, because some like to have a twitchy setup (see: BRZ guys trying to make their cars "slide easier" like a FRS), while others may prefer a bit more understeer at initial turn-in (myself).

When I set up my car previously for drift, I used a very reputable alignment shop in Los Angeles (West End Alignment), and asked Darin to set the car up for whatever road course I was going to run. It's not the extreme angle stuff others run, but it worked great and handling was never an issue for me.

Bottom line: don't figure out alignment settings on your own (or even with advice of others) if you don't know what changes in toe in/out, positive/negative caster, or positive/negative camber mean for the driver at turn in, mid-corner, turn exit, throttle, braking, etc etc.

Just leave the settings to someone that has experience setting up FR cars, and leave the driving to you to figure out.

-alex

IANASG: I am not a suspension guru

That said, even the suspension gurus will tell you, it's much easier to make a car handle worse than it is to make it better. This car is very tossable from the factory, even the "more" understeery BRZ.

Before you spend money on suspension changes (or even tires), see if there is some kind of Law Enforcement Driving School near you that will allow civilians to take classes. There used to be one in East TX (not sure if still there) that taught all the low/high speed low/high traction evasive/pursuit driving. It covered skid correction, but first you had to learn how to get there. Sounds like that would be perfect for you.

Now we're getting into those messy details.

Fow what actually happens in a corner, you have to take the weight distribution, weight transfer, camber curves, and other things into account.

If we step up one level of simplification with our cars:
The front gets more negative camber because there are more things trying to push it positive. There's more weight up front, the steering angle makes it go positive, and if you're lowered without roll-center adjusters the suspension compressing adds more positive camber.

The rear is designed to gain *negative* camber as the suspension compresses, so that's helping you counteract the body roll. And the rear doesn't have to deal with steering angle either.

Also, you have to take into account that while we're talking negative camber like -3 degrees, at the limit the body is rolling MORE than that. You're still seeing positive camber even after all the negative camber we're putting on the car. So once you see more body roll than the rear can compensate for, the front has more grip. The reason why you don't see MASSIVE amounts of negative camber on anything short of a dedicated race car is because you lose straight-line grip which hurts braking and acceleration.

SCCA Regions will also offer similar courses. Really though, go to an AutoX! There is nothing better than AutoX to teach you how your car behaves at the limit.

Also a good idea. Auto-X is cheaper, I forget about it.

I just thought about the LE training stuff first because you get wet courses, and are encouraged to learn general hooliganism. Sounds like that's what the OP is interested in.

You have to go a long way into bump before you stop gaining negative camber. So far that the LCA becomes perpendicular to the line of action of the strut.

Other FR cars with double wishbone front suspensions have optimal setups with more front camber, it is the norm for FR cars, as roll stiffness is biased to the front to allow the rears to get better drive traction on corner exit. Struts may need a little more static camber, but not necessarily a tremendous amount more.

Model I made of the FR-S front suspension (from link to geometry I found on this site, accuracy not validated, but not too dissimilar from my 240Z strut models) has it gaining negative camber at the rate of 0.6 degrees per inch of bump travel from static. At 3" of bump travel, it's still gaining 0.3 degrees per inch of travel. Camber gain doesn't stop until 4" of bump, at which point it's gained 1.45 degrees.

To the OP, at the camber levels you're talking about (-1.5/-2), more is going to pretty much be better for ultimate lateral grip, up to something on the order of 3 degrees.

Really, anything in the ~2-2.5 degree range is going to be OK for a street/track/autoX compromise setup.

I'm having trouble picturing how a MacPherson strut design can be gaining Negative camber after the LCA passes horizontal. Once above horizontal, the LCA is effectively shorter so it should be pulling the strut inwards, tilting it towards positive. And as the strut shortens, this should increase in rate.

I drew this a while back while ZDan was helping to explain why a MacStrut isn't exactly a 1:1 motion ratio, but it also shows camber effects.


http://i1283.photobucket.com/albums/...ps35169005.jpg

The discussion is in the 'Ask RCE and CSG Mike suspension question tag-team' thread.

here ya go... a buddy of mine made this a long time ago.



http://i5.photobucket.com/albums/y16...herson_001.gif