General Setup Tips

Keep in mind always that if you ever (EVER!) want to race, rally, or
autox your car, you should understand the rules about what you can do
and what you can't. In most cases, you will be limited in the mods you
can do. If you think that the possibility that you may get serious about
a motorsport might exist, then be careful. It's easy to get addicted to
automotive competition.

In this case, I think alignment of the MR2 can be done well and still be
legal per the strict SCCA soloII rulebook. For the most part, this car
doesn't need much help. It handles well from the factory. It did in
91/92 have a couple of quirks. To some extent, this actually works in
our favor.

The 91/92 car had two major problems. One we can call the snap
oversteer. Obviously the car being midengined will tend to oversteer
(where the back end wants to lead) more, but this car tends to have a
radical rear tire "toe out" upon correction of a spin. This snapping
effect can be a bad thing. Typically you will spin. This impacts your
autox times because you become worried about spinning. Obviously,
spinning when you didn't expect it on the street is a bad thing.

The other problem this car has (without LSD) is the tendency to smoke
the inside rear wheel tire when exiting a turn. When you come out of a
turn hard, you unweight the inside tire and power then transfers to
spinning this tire. You make smoke and make BFG happy, but you don't go
faster. Being able to apply lots of power early coming out of a turn
should be the strong point of this car and it's torque. Every second of
lost acceleration here is compounded by the length of the straight you
are now on.

So, we need to solve these two "problems". As it turns out, SCCA lets us
do certain things, and one of those things is that we can do whatever we
want with the FRONT sway bar. Okay, so cool. A fatter front bar does two
main things. It induces more understeer, which removes some of the
oversteer. This doesn't mean the car will not whip, but it will be more
predictable. A little understeer is good as you can intentionally create
oversteer with throttle/brakes/steering. The bar also stiffens the car
so that when you power out of turns, flex is reduced and the inside rear
wheel stays planted and you get to use all your torque.

But which bar? There are (AFAIK) 3 bars you can buy. I threw out the
first option, which is an imported GAB adjustable for $600. Then there
is the Suspension Techhiques (ST) bar. This is around $170. Then there
is the TRD bar, which is also close to $170.

I did the calcs on this a few years back, and I am relying on memory
here, but I think the ST bar is almost 100% stiffer than the stock bar.
The TRD bar is hollow and appears to be about 25-30% stiffer. I tried
using the full ST bar for one year and gave up on it. I didn't like the
amount of understeer I had. I also didn't have my car well setup as far
as alignment though, so I think now I could have dialed out some of
that, but I was clueless.

Some drivers do like the full ST bar. It is nice for the higher speed
stuff, where you want more understeer, but the slower the turn, the more
the car will push. So I decided I wanted a bar that was 80% more stiff.
I had my ST bar machined. Some folks have welded in a smaller section.
Some folks have created custom end links with adjustment so that you can
extend the swaybar arms and thereby "soften" it.
 

Now that car doesn't spin the driving tires and has a lot less
oversteer. What else can we do?

Adjustable shocks. I have the Tokico Illuminas all around. They are 5
way adjustable. Some folks like the Konis and a few use the GABs. I
don't think it's that important, but adjustable shocks are nice to be
able to dial in softer or stiffer ends of your car.

Alignment settings. I put 1/8" toe in per side on the rear. This removes
a lot of oversteer, and I think it helps that sudden whip toe in
condition. After setting the rear toe, I don't spin as easily, and I can
quite often catch the spin. Try to get as much negative camber as you
can (should be 1.5 degrees per rim minimum).

On the front, caster may be set from stock to full (I went full).
Install Toyota suppplied crash bolts to get more negative camber. Hard
core autoxers may want more that 2.5 degrees negative. Street only may
want about 2 degrees. I do get more inside wear on my fronts with 2.7
degrees negative, but I get a lot less outside tire wear, so it isn't
too bad.

I like about 1/8" toe out on the fronts. This isn't a big deal. I had my
car accidently set wrong to 1/8" toe in on the front for 7 months last
year. I think it slowed me down a bit, but not too much. The Toe in
created lots more push coming out of corners (but it may have gone into
the corners faster). The toe OUT means I can come out of the corners
quicker.

Side note: You can also change your air filter, muffler, tires, fluids,
ignitions plugs and wires.

That is the extent of the allowed alignments things I would do to stay
legal in SCCA autox. Now, the next question, should you get strut tower
braces, lowered springs, and a 12 diameter muffler tip? 8)

Depends. In autox, this moves you into Street Prepared (or Improved
Street) where the cars are pretty fast. I am not sure that these mods
will make you go much faster around corners.

If you autox, you will need another set of rims anyways, use your stock
rims for autox and get some bigger rims for street so that you can look
PHAT when you are in your ride. I run 15" rims for street and 14" rims
for autox. The smaller rims let you put down the power better in corners
anyways (even if the trend is to get bigger diameter rims).

One of the net effects of my alignment is that I have a lot more wear on
my front tires. Previously, I wore out my back tires at 9k miles and my
fronts seemed to last forever. The good news now is that my fronts are
wearing out at 9k miles also. 8)

Randy Chase
'91 MR2 N/A (Nology Wires, triple ground plugs, Nology ground straps,
Koni adjustable shocks, modified Suspention Techniques swaybar, upgraded
front end links, Schroth Rallye 3 point harness, new rubber boots, Ken
Farrel shift boot (oh..soo..soft), Twos-r-us hitch (soon), Supertrapp 4"
glasspak muffler, brand spanking new tranny, trick alignment, Toyota
crash bolts, K&n filter, Redline MT-90 fluid and Waterwetter, Motul
brake fluid, Carbotech Mean Green pads rear, new clutch, 3 sets of rims,
and Toyos, BFGs, Kumhos, and Hoosier tires, Calif Car Cover, more
go-fast stickers than anyone should ever own)