Mazda Chassis Tuning Instructions Manual

This document is released into the public domain and may be reproduced and distributed in its entir ety so long as all

t

r

r

credit to Jim Daniels remains. If you fi nd this guide hel pful please consider do nating a small fee via the links located a
http://www.specmiata.com.

Setup Guide and Chassis Tuning Tips

(

simple version)

By Jim Daniels

As promised the following is a walk through of how I setup my SM with a list of tuning tips I
use at the track. Many have theories, thoughts and ingrained ideas on setup and tuning.
I’m not trying to change any of that, I’m simply providing you with what I use on this type of
racecar. I hope that you use this guide as a source to further your racing program and setup
abilities. I welcome any suggestions you have, send them to me at [e-mail]
This guide will be placed in the FAQ section of the www.specmiata.com

web site.

.

Expect 6-8 hours the first time you do this yourself, sometimes longer depending on you
mechanical ability. This time estimate is AFTER you level your floor.

Tools and equipment needed to do setup at home:

• Level surface (absolutely level, use shims to achieve if needed)

• Scales, camber gauge, toe plates, string

• Normal tools and jack stands

• Maybe some 8’ sections of clear tube needed to level the workspace

Before you start, a few things need to be done to the car, a few assumptions hav e to be made
and a couple techniques explained.

1.) The sway bars need to be disconnected on one side (I like the left side).

2.) You need to find the center of the steering rack then lock down the column with a
pair of vice grips and a bungee cord. This would be a good time to adjust the
steering wheel adapter if it is off center from the rack’s center. I use my steering
wheel like a degree wheel to find the center. Then, I removed the hub and adjust
the splines until the “T” on my steering wheel is square.

3.) The tires need to be at “hot” pressures, 40 will do.

4.) The driver’s weight needs to be in the car at all times, I prefer a real person to sit
there the whole time. If not, try to divide up body weight for torso, legs etc…

5.) Do yourself a favor and make sure the suspension bolts, perch adjusters and
other hardware you will be adjusting are free, ready to adjust but not loose.

6.) In the rear sub-fame, driver’s side, just above the inboard lower b ushing mounts

you will see some holes cut by the factory. These holes are on both sides of the
sub-frame again just up from those lower bushings. Find the two holes that are in
alignment, one for the front of the sub-frame and one for the rear. Install a 3-4” bolt,
the size of the hole, with a jam nut holding it in place. Have the bolts extent outward
(front to the front and rear to the rear). These bolts establish the centerline of the ca
and will be used to square the car up in later steps (see Picture 1).

7.) I make the assumption that no parts are be nt and you hav e used your th umb to get
toe and camber where it looks ok. 2” of toe out or +3 camber on one wheel is what
I mean, correct that NOW by eye, do not spend too much time on it.

8.) After each setting adjustment, bounce the car in place STOP, roll it 8-10” back
then forward to where it was. NEVER, bounce again after you start rolling
forward and always end your bounce going up, not down on the car.

9.) You have a factory manual and know how to use it for finding out the pr ocedures
needed to make the setup adjustments.

10.) Empty all fuel and put one gallon back in.

11.) Using a fish scale, and after all prep is done, I measure the car’s resistance on a
flat surface. Record what it takes to just roll the car. Later, as you do
maintenance, compare the freshly prepared car to the after raced car. If you gain
resistance, look to see if there is a reason for that gain (brakes, fluid break down,
bearings etc…). Correct if you can keeping in mind that you might establish a new
resistance number after the car has seen the track and become seated in.

Regarding setup and especially for new builds this process below will not be v ery fun as you
will chase yourself narrowing the gap of the different settings. You will find out that when
you make a change to one setting, others may be altered. Be patient, the gap will lesson
until it is right.

It Begins

Step #1 (Ride Height)
Using the spring perches, adjust the ride height to 5-1\4” at the pinch weld on the bottom of

the car at the rocker panel (see Picture 2 & 3). It is normal for the LR to have more threads
showing on the bottom compensating for the driver’s weight. This will take sometime as you
get used to how the car moves on one corner while you adjust another. BE PATIENT, keep
going back and forth till it is near perfect. Remember this step, you will be back here again
many times. You will not be showing the same amount of threads corner to corner.
Remember, the floor where your car sits AND where you measure from needs to be level!!!

Step #2 (LR Toe and Camber)

We now need to square the car up so we can run through the first of several settings
adjustments. Remember those bolts I had you install, now is the time to use them. They
are used to measure the lower control arm on the dr iver’s side rear wheel verse the
centerline of the car. Using a telescopic measuring device, adjust the lower cam bolts unt il
the distance between the bolts you installed, front and rear, and the back of the outboard
bushing flange of the lower control arm are the same, front and rear (see picture 4). You
now have zero toe on that wheel and that wheel is pointing straight.

While doing this wheel, go ahead and make the camber -2. You are adjusting the cam
bolts anyway, this is what I like to do. Often, I do not have to touch this wheel again.
JUST REMEMBER, if you get out of whack, set this wheel again and go from there, keep
reading. Keeping this wheel square is vital to this process!!

Please Note: Steps #3 - #5 can be both time consuming and frustrating for the uninitiated.

r

f

Iron Canyon Motorsports has recently released an ICM Alignment System to assist in
“stringing” your Spec Miata. Visit http://www.ironcanyonmotorsports.co m for more
information.

Step #3 (LF Toe, Camber and Caster)

Time to get that kite string and jack stands out. Adjust 2 stands where they are slightly
above the center wheel hub height. Tie your string securely to the portion of the stands that
is adjustable. Now make final corrections so the string is level with the center line of the
wheel hubs and tight enough to not be drooping. Ok, the Miata is wider in the rear, this is a
pain. You should now have a string tied to the stands with it level with the hubs centerline
with the stands stretched out about 3’ past the front and rear wheels string tight. Basically,
you will see a string running along the side of your car connected to the stands. Move the
stands around until you have a 1” gap on the LR between the string and the wheel lip front
and rear of that wheel. Once this is done, you have aligned the string to the wheel that you
already aligned to the chassis, coming together for you now? As you set toe and make othe
adjustments, you will have to continue to square up the string to the LR wheel. BUT, after
we get further along, we will drop the string and use toe plates, stay with me.

Move to the front left wheel, measure from the string to the wheel lip, front and rear of the
wheel, and inline with the string. Since the rack is centered and locked down and you
have that 1” gap on the rear, you are looking at how far the toe is off verse the centerline o
the car. Adjust toe on the LF to zero. Of course, you will have to re-square your string
each time you roll the car.

While doing this corner, you are going to set your camber to -2, your caster to +3-5 (just make
sure the other side matches on caster later). Once the toe is zero, and the other settings are
correct, secure this corner but do not tighten all the way just yet.

Step #4 (RR Toe and Camber)
We now are going to move to the passenger side of the car. Dust off them toe plates, their

up now. Start by using your toe plates to get the RR to zero toe. While there, you guessed
it, set the camber to -2. Once you are done, move to the RF corner.

Remember, tighten to keep form moving only, no need to gorilla it at this point.
Step #5 (LF Toe, Camber and Caster)
Use the toe plates to match the left side, just like you did in the rear. Set the caster and

camber to match the left front.
At this point, the car is aligned with the centerline of the car, our ride height is set and our

settings are in basic form. I call this the pre-scale setup. Good for you, these cars are not
that corky, meaning not much chasing compared to other types of race cars.