Caster / Camber/ Toe

OK so I'm trying to come up with a alignment setting for the POSIV (1994). Car serves multiple purposes but Autocross is the main reason I own it. ;)

Here is what I am thinking on alignment settings if I'm wrong please educate me!

• Caster - +5 deg (both sides the same)
• Camber - 1.5 deg Front & 1.0 deg rear seems to a good place for a stock ride height car.
• Toe - Help! **

** Toe seems to have a few variable I've seen folks recomend both positive toe & negative toe.

Can someone 'splain to me what the affect of each would be??

Currently I based on my garage measurements the caster is messed up but I don't have a caster gauge, and 1.0 degree camber on the front and 0.5 degree on the rear, & negative toe front and rear.

TIA!

IIRC the old common Stock class wisdom on a Miata went something like this:

• Caster – run as little static caster as possible (this allows you to maximize static camber at the expense of dynamic camber gain. I don’t necessarily agree with this approach, but it was the prevailing wisdom when I ran in C Stock).
  
• Front camber – Max you can get.
  
• Rear camber – Front setting plus minus another half degree, give or take. Example: the front has -1.0, set the rear at -1.5.
  
• Toe – a little toe out up front will help the car turn in quicker, at the expense of making it a bit more darty at high speeds, like the freeway. A little toe-in at the rear to help put the power down better coming off the corner. More toe will cause accelerated tire wear in daily driving (toe has a much greater impact on tire wear than camber, contrary to popular belief), so keep these numbers reasonable, probably no more than an 1/8” total at either end?

I've been trying to figure out where to start with my alignment as well and the only thing that I've read that's different from what Iain posted is the MAX the front caster, but to give up caster in order to even out the front camber.

Right now I am running:

Front
Camber -2*
Caster 3.5*
Toe .2* out

Rear
Camber -2*
Toe .1* in

On Monoflex's with FM sway bars (full stiff front, full soft rear) and rears 2-3psi lower than fronts (205 Dunlop Star Spec). Car is VERY neutral and lots of grip. I am thinking about upping the front camber to -2.5* to see if can dial in a little more.

With FM spring and whites I ran:
Front:
Camber -2*
Caster 4*
Toe .3 out
Rear:
Camber -1.5*
Toe .2 in

Ran stock rear sway bar.

Funny you should ask, since I am getting my car aligned on Wednesday afternoon, now that I have new alignment bolts installed. I am going with...

Front:
Max Castor
1/8 Tow out
-2.3 Camber

Rear:
1/8 Tow in
-2.5 Camber

Quote:

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Originally Posted by goofygrin

I've been trying to figure out where to start with my alignment as well and the only thing that I've read that's different from what Iain posted is the MAX the front caster, but to give up caster in order to even out the front camber.

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Sean, that's always been my opinion as well. I run over 9 degrees of caster on the RX-8. I never believed in giving up caster to maximize static camber.

Like I said, I'm just regurgitating what the tribal knowledge was 3.5 years ago when I last set up a a Stock class Miata.

POS Racing.... You have ABS you don't need any caster. You don't care what it drives like on the highway.
Running street tires you will want some toe-in in the rear. If you don't have the bigger front bar yet get it.
Night and day difference. The key to the Miata is to have the rear planted and your foot on the gas.

Quote:

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Originally Posted by general default

POS Racing.... You have ABS you don't need any caster. You don't care what it drives like on the highway.
Running street tires you will want some toe-in in the rear. If you don't have the bigger front bar yet get it.
Night and day difference. The key to the Miata is to have the rear planted and your foot on the gas.

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Have any numbers you'd like to share general? ::Banana::

Quote:

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Originally Posted by sammm

Have any numbers you'd like to share general? ::Banana::

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Don't share them with Sammmm he never bought a car from you! ;-)

As your codriver, I should have already suggested a phone call to Mr. Default. Sorry. Another communication flop.

The numbers I think about are based on R-comp tires. Pyrometer test are the correct way to get the most from the tires. There can be other factors.

What are the condition of the bump stops? Are they new or old and shot? Do the shocks control transient maneuvers. These items make a difference in amount of body role the car has and how much bumps upset the car. The amount of time to transition the car and take a set.

As stated earlier generally you will want to max out front camber at the sacrifice of caster. Camber does not need to be the same on both sides. Nor does the caster. But you will want the caster to be fairly close to each other within a few 10ths.

The side that has more camber will just turn better than the other side. So your car will be better than the other guy that just made their car equal assuming the same number of turns in both directions. Remember this is a sport were you are looking for 10th's of a second per corner.

The rear camber is debated a lot and has changed over the years as tire designs have changed. At one time the idea was to max out the rear camber and you did that by getting the car to sit as low as possible in the rear. One of the reasons people use to degas shocks.

My idea on rear camber is to go until you notice acceleration issues due to camber. This would show up more on the bus lot but can be noticed at PMS.
Then you back off from that setting. My guess is you will end up between -2 and -1.5 in the rear. I don't have experience with the new Dunlop tire so this is a guess on my part.

You choice can also be determined by your style of driving. The amount of stager between the front and rear is more a feel that gives you confidence.

Again all this is based on stock rules and a front bar. CSP, STS or any other class and it is a completely different settings.

Miata_Racer might be a good person to ask also as he has run more of the current tires with the NA.

Good stuff I appreciate everyones input! :clap:

Quote:

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Originally Posted by POS Racing

Good stuff I appreciate everyones input! :clap:

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So, will you be offering alignment services in your garage, AJ Racing?

Bumpasaurs!

I'm going to Pro-Tuning Performance tomorrow to let them work their magic on the POSIV!

I'm interested in what you cool kids now think is a good setting for a ES miata!

TIA!

I'm running as close to Icehawk's numbers as BAM! could get my car. It has been a while since I have had it checked.

^Same here, Icehawk. Only it wasn't BAM and the guy was a moron. I watched the numbers though and they were pretty close. I love the way it drives on the street but haven't autocrossed the miata much. Surprising it doesn't eat tires as bad as I thought. It's been awhile since getting it aligned though.

I went to Pro-Tuning Performance yesterday worked with Forrest and got the POSIV all dialed in and ready to smack some cones!
::ConeDOWN
Forrest took the time to go over the specs and he helped me come up with a "Cheater Spec" for the POSIV! ;)

I highly recommend them top notch opperation!

Plus the shop was clean and organized which I always see as a plus! :clap: