Front spring rate increase:

More under steer; increase in proportional weight transfer to the front when rear wheel rate is not increased; reduces front traction when rear rate is not changed.

Usable adjustment: 150-600 lbs/in

Symptoms of too much adjustment: terminal under steer; front of car hops in corners; excessive wheel spin on inside front tire on FF cars.



Front spring rate decrease:

Less under steer; decreases proportional weight transfer to the front when rear wheel rate is not increased; increases front traction when rear rate is not changed.

Usable adjustment: 150-600 lbs/in

Symptoms of to much adjustment: Too much over steer; over steer then under steer if spring is so soft that the car bottoms out on lean, car bottoms out excessively with a jolting ride.



Rear spring rate increase:

More over steer; increase in proportional weight transfer to the rear when front wheel rate is not increased; increases rear traction when front rate is not changed.

Usable range: 100-600 lbs/in

Symptoms of too much adjustment: too much over steer; sidestep hop in corners; twitchy; pretty scary.



Rear spring rate decrease:

Less over steer: decreases proportional weight transfer to the rear when front wheel rate is not changed; increases rear traction when front rate is not changed

Usable range: 100-600 lbs/in

Symptoms of too much adjustment: car under steers; if way to soft car under steers then over steers as car bottoms out on lean; car bottoms out excessively with a jolting ride.



Front anti-roll bar stiffer: more under steer

Usable range: none to 1.25 inches in diameter

Symptoms of to much adjustment: terminal under steer; lifts inside front tire off the ground witch can cause massive wheel spin on FF cars; also not good for most effective tire usage as inside tire is now doing nothing.



Front anti-roll bar softer: less under steer

Usable range: none to 1.25 inches in diameter

Symptoms of to much adjustment: overstate scary; more like fun



Rear anti-roll bar stiffer: more over steer

Usable range: none to 1 inch in diameter

Symptoms of too much adjustment: Big-time over steer. Can cause inside rear tire to lift off the ground.



Rear anti-roll bar softer: less over steer

Usable range: none to 1 inch in diameter

Symptoms of to much adjustment: under steer; slow and boring



Front tire pressure higher: less under steer by reducing slip angels on most tires

Usable adjustment: up to 55psi hot

Symptoms of too much adjustment: no traction- tire crowned so more under steer; adds wheel spin in FF cars; jarring ride; center of tire wears out



Front tire pressure lower: more under steer by increasing slip angles on most tires

Usable adjustment: not less then 20psi

Symptoms of too much adjustment: edges of tire wear quickly because tire is folding over; feels mushy; tires chunk because low pressure means heat build up.



Rear tire pressure higher: less over steer by reducing slip angles on most tires

Usable range: up to 45psi hot

Symptoms of too much adjustment: no traction—tire is crowned so more over steer; bad wheel spin on FR cars; jarring ride; center of tire wears out.



Rear tire pressure lower: more over steer by incresing slip angles on most tires.

Usable range: not less then 20psi

Symptoms of too much adjustment: edges of tire wear quickly because tire is folding over; feels mushy; tires chunk because low pressure means heat build up



More negative camber front: less under steer because of better lateral traction as tread is flatter on the ground under side load.

Usable range: up to 3.5 degrees negative

Symptoms of too much adjustment: poor braking; car is road crown sensitive; twitchy; front tires wear on inside edge



More negative camber rear: less over steer because of better lateral traction as tread is flatter on the ground under side load. More rear grip

Usable range: up to 2.5 degrees negative

Symptoms of too much adjustment: more over steer; car feels twitchy in back; tires wear out on inside edge; less breakaway warning when limit is exceeded.



Ride height to low (typical beginner mistake): car is twitchy with unpredictable dynamics. Bump steer make you life miserable.

Usable range: usually 1.5-2.0 inches lower then stock unless car has been modified to go lower.

Symptoms of too much adjustment: everything that could possibly go wrong: sudden over/under steer; twitchy due to bump steer; very harsh ride; premature tire wear.



Toe in – front: car is stable going straight. Turn in is average

Usable range: 0-1/8th inch

Symptoms of too much adjustment: car has slow twitchiness under braking; feels odd; kills outside edge of tires



Toe out – front: Car turns in well; works pretty well on FF car as they tend to toe-in under load.

Usable range: 0-1/4 inch

Symptoms of too much adjustment: Car is really twitchy under braking; car wanders on straight road; kills inside edge of tire



Toe in – rear: car is less likely to over steer when the throttle is lifted

Usable range: 0-1/8th inch

Symptoms of too much adjustment: weird, slow, rocking movement in back; feels slow but still unstable; wears outside edge of tires.



Toe out – rear: Helps car rotate useful in low speed and slalom courses; very common on FF pro rally cars.

Usable range: 0-1/8th inch

Symptoms of too much adjustment: not to good for street driving; causes lift throttle over steer; makes violent side to side rocking motions in the rear; tie wears on inside more.



Positive front caster: helps stability; suspension will get more negative camber when turning; reducing positive caster reduces steering effort. (Negative caster is not usable)

Usable range: 4-9 degrees positive

Symptoms of too much adjustment: can increase under steer especially in cars with wide low-profile tires. Can increase steering effort.



Single adjustable shock stiffer: Better turn in; better transient response; causes slower onset of over/under steer by slowing weight transfer depending on what end of the car is adjusted.

Symptoms of too much adjustment: suspension becomes unresponsive; ride gets harsh; car skips over bumps, loosing traction; Causes a big delay in weight transfer resulting in strange handling like under steer then late corner stage over steer.



Single adjustable shock softer: slower transient response; quicker onset of over/under steer

Symptoms of too much adjustment: car oscillates due to under dampened spring motion, like a boat. Car gets twitchy in turns. Feels unstable.









Have fun tuning your suspention. Use Toe and Camber to your advantage! Even Tire pressure helps.





__________________

velocity.isfaster.com

great posting thanx

Here is my set up, so far I love it. Still can not compare to S13-14 and Hachies but the bigest improvement were the springs and camber plates.



350lb. front springs.

275lb. rear springs.

1.5 degree negative camber in rear.

2.5 negative camber in front.

0 static toe front and rear.

Inner ball joint shimmed 6 mm.

Tokico non adjustable struts.

Sport brake pads in rear and cheapie front brake pads.

Open diff.

Stock toe bushings.

Stock sway bars.

140 RWHP NA motor.



I could use more power at thins point. Planning to run a 4 port carbed NA.

someone should sticky this...

although my alignment changes all the time......hehee here is my basic setup





Cusco coilovers 8kilo frt 7kilo Rr.

Camber adjust pillow ball uppers set to max camber

1 deg of toe in on the front

about 2deg of toe in on the rear

Camber adjust rod set to near maximum in the rear

Mazda Speed Diff set to 10kilo initial tourque

Toe control canceler bushings

Rigid diff mount

Front and rear tower bars

roll cage

30mm over fenders

9j panasport G7 rims

Falken Azenis 235-40-17 tires

Project mu HC Titan Kai brake pads

350hp Turbo engine

And remember as far as rims and tires go the smaller the rim the less HP it takes to spin it and the less inertia(sp) it has..because most the weight of a rim is on the out side around the diameter of it.



also as far as tires go if you have more of a square side wall it has a higher limit before it breaks away but has a sharper edge ie it breaks away more quickley/unpredicatbly..but if its rounder, then it has more predicatable breakaway qualaties...(got this from an F1 tire guy)

Wow. Good information. https://www.nopistons.com/forums/pub...IR#>/happy.png

awesome post man

driftaholic: Whats your setup? Great post too!

LOL, I got a stickey sweet! https://www.nopistons.com/forums/pub...#>/biggrin.png



My suspention work is far from done but this is what I have



-HKS Hypermax D Coilovers 8k/7k spring rate

-Dampening is on the softer side 3 of 15 points front and rear

-Camber front is set to max rear is not yet ajustable, but FC's gain a lot of camber when lowered

-1 deg total toe in in the front, thinking about more. rear still has TOE STEER! ICK

-Suspention techniques Swaybars the front is ajustable 3ways mine is on the softest.

-Tire pressire is 40psi



This setup has provided me with a well balanced car, it will understeer as easy as it will oversteer. caution the amount of camber in the front makes it very easy to lock up front brakes just prior to turn in, after turn in you can give more brake effort.