Tips for lowering CG and the whole car... (Page 1 of 3)

It's all about control, man.  Cut the springs by an inch to get some of the ride height out of it and put GOOD SHOCKS on it.  Show up with fresh stiff coilover springs and the judges are going to grill you good, even if it is a Stanza wagon.  It's not worth the money.

Once you have control, the rest is easy.  Put a giant rear swaybar on the back, dial in as much camber as you can get in the front and put the widest tires you can reasonably fit on it.

Leave yourself enough suspension travel and softness to get over track curbing without upsetting the car.

Don't over-think (or over-spend on) your suspension.  You'll be pissed when the coolant hose that you didn't replace because you spent all your budget on springs blows out 2 hours into the race.

The thing about cutting springs is that you can't un-cut a spring.  So, if you're not sure how much to cut, cut less!  You can always cut again.

You can do the math (you need the wire diameter, the coil diameter and the number of coils, you can Google either the formula or a calculator to do it for you) and determine what your resulting spring rate will be (approximately).  Where things get muddy is in determining how much ride height you lose when you cut the spring.  Since the free length of the spring is shorter, but the spring rate is higher... it would be complicated to calculate.  Easier to just take a conservative guess and cut.  With as much ride height as you have, I'm sure you can safely cut an inch, which is why I suggested it.

Will the springs fall out under full droop?  Probably won't be an issue in the front.  If you have a typical beam axle rear, a short spring CAN fall out.  You'll have to be careful with that.  If you end up with a really short spring, you'll have to put some sort of a droop limiter to keep the spring from unseating.  You'll end up getting more wheel lift under cornering, but if a droop limiter lifts the wheel, the wheel obviously wasn't loaded, anyway.

Weight... yeah, I'm not sure what they'll allow you to cut out of a wagon these days.  Used to be you could cut the whole roof if you wanted to.  Maybe you still can if you leave the lower half intact for crash protection?  Better ask before you cut.

For CG, you can see if it's possible to easily change the angle of the steering column for a lower driving position.  Then get your driver weight as low and as far back as possible.

But, again, don't overthink it.  Your finish position is going to have more to do with RELIABILITY than anything else.  You should be under the hood making a list of all the things you need to replace and spares you need to carry.  Belts, hoses, distributor cap & rotor, brake and clutch master cylinders, and so on.  Trust me, you'll lose a LOT more laps even making a simple 30-minute repair than you'll ever gain by worrying about lightening the car or improving the CG!

I'd put the battery in the passenger footwell.  Less battery cable = less weight.  The battery requirements for such a tiny engine are very small, so there's not much weight there, not much need to worry about where it is... just don't add more to it than safety requirements dictate.

do like nascar and lower the body

solid suggestions on the tire/wheel combos. you should be able to get some 16x8s with some nice low-profile tires on them and decrease your total tire height. it'll stiffen up the response, increase handling, and moderately lower your ride height even with keeping the soft, old suspension; another bonus is tires and wheels are outside of budget constrains, so if you're super crazy and actually do want those BBS wheels, you won't get sweated in tech...however your fellow Lemons racers will wonder wtf you're doing with wheels that EACH CORNER will cost more than your cal valuation.

What serj said, except go with a shorter tire wheel combo in general.  the stanza is way underpowered, and way tall-geared, so a reduced rolling radius will give it it better gearing, at some expense of top speed.  But the top speed thing doesn't matter in this situation, because if the numbers are crunched, the top speed at redline in 5th gear is gonna be 148MPH, which the engine could never push.

The stock 185/70R14 is 24.3" tall, a 185/60R14 or 195/50R15 is 22.8", a change of 1.5",  and a lowering of 3/4".  A 195/60R14 will lower the car 1/2".  Those are about the shortest tires that will fit around the stock frt brakes.

A couple of things, from experience...

We cut the springs on our Volvo Amazon.  Coils at each corner.  It was super easy- the hardest part is calculating how much to cut off.  I think we ended up cutting a LOT off- lowered the car like 2 inches.  A stock Amazon has more ground clearance thana lot of SUVs these days!  As has been previously mentioned, if you are bad at math or intellectually lazy, simply cut one coil off each one and see what happens.  If you're worried about losing a spring, nylon webbing from ratchet straps can be used as a limiter.  Make sure you use the most obnoxious colored ones you can find.  Pink and neon green seem to work the best.  ;-)

To cut the spring- use a dremel tool with one of those neat, new cutoff wheels that will cut through anything.  They have a quick-change mechanism on them, too.  Lowes sells the whole kit for $20.  After cutting the coil off, dress the cut edge- you don't want it sharp. Then take a map gas or acetalyne torch and heat the spring between 1/3 to 2/3 of a coil around from where you cut.  BEFORE the spring glows red, quickly turn it upside down and press down- this will close the end of the spring the way its supposed to be.  DON'T heat the metal so hot it glows- if you do you will lose the temper of the steel.  If you didn't heat it enough, you won't be able to close the spring end, heat it some more.  Glowing red is like 800F, so if you want to get really scientific, a temperature probe or IR temp reader can tell you when you are close.

After closing the spring end, take a bench grinder and take the shield off one of the wheels.  Press the now-closed end of the spring in towards the spinning stone to grind the closed end flat.  Voila!  A lowered spring. 

Don't ever quench the spring in water or oil- let it air cool.  Quenching can also alter the steel properties in undesireable (for a spring, anyway) ways.

It really is easy to do, and the learning curve is fast.  The first one might take you an hour, but by spring #4 you'll be doing it in 30 minutes or less. 

As for tires- the larger your wheel/ tire the greater your unsprung weight.  Also, bigger tires and wheels cost more- and while that money doesn't count against your $500, it still has to come out of your pocket.  Finally, low profile tires are, in my opinion, overrated unless you are a really, really good driver.  Fatter sidewalls are more durable, forgiving, and easier to drive.  A car with low profile tires will have a higher limit of adhesion, but at that limit will break away much more quickly than a car with higher profile tires.  Again, the goal is to keep your car on the track, not turn wicked fast record setting laps (which, in a nissan wagon, you ain't gonna do anyway)

Wow. Awesome - will cut front springs as directed.

The rear suspension is torsion bar - if this is anything like Porsche 924/944 torsion bars, I should be good. The bottom of the car (including all suspension parts) is super-rusty, though. I'm afraid I'll break something if I touch it

We already got a set of 240SX wheels with some OK tires on them - I think those are the best value, as I paid $100 for the set. I think we'll buy another set or two and mount something nice and new on one of them, keeping the other set(s) as spares.

I could, indeed, buy $2000 worth of wheels/tires, but that'll be the detrimental to my life and limb.

Forgot to mention, steel wheels are much more forgiving than aluminum.  You can bend a steel wheel, and it'll still hold a bead.  Or you can bash it back out.  And they are cheap.  Yes, they weigh more but when you run over that muffler, suddenly those 1.5 second faster laps don't seem to matter too much.

We cut one full coil in the front and two coils in the rear.
Really good feel and ride height.

With the car jacked up, I cut the springs in place without removing them from the car with a sawzall. No heat treatment, just cut and go!

Also found a bigger junkyard rear sway bar from an Escort wagon.

Everything else is left alone.
Smooth and reliable.

KT

We may cut a coil on our car's rear. It handles well mainly because it the car light and has 205's for tires, but it looks like a rally car. But in front, which uses transverse leaf springs, we have to try something else, either fab a shackle to let the spring ends hang lower than the A-arm, or put a double-bow in it by putting a block of metal in the center.

But, we have bigger problems to deal with, including engine temps and the new 2" helmet clearance rule.

Droop limiter = chain

Put the car on jack stands all the way around. Then jack up the suspension until the spring is held in place with no load. Attach a chain to something on the upper part of the suspension and something on the lower part, like a u-bolt with an extra nut and washer. You could also run a bolt through the upper and lower hats of the spring mount and run the chain around the outside of the spring. This only has to carry the weight of the suspension and wheel so it doesn't need to be super beefy. But make sure the chain is not going to interferer with anything when slack. make sure it won't take out your brake lines or get jammed up on a tab or ????

Droop limiter= clamped spring ends

If you go a step further on wheel size and drop down to 13", your gearing will improve, you'll lower the car a bit more, and reduce your unsprung weight.
The Stanza is 4X4.5" bolt pattern, correct?  Very common with the Mini Stock guys and those wheels are pretty cheap.
A full set of 13X7 Bart or Aero wheels with 215/50/R13 Sumitomos will run you somewhere between $400-$450.