Let's have a look at suspension tuning concepts. I may be wrong but I don't care, someone will correct me.
Race car or simply race bred.
Mechanical Grip Basics
Mechanical grip is that dictated by vehicle weight through suspension and tyres.
This is sometimes hard to understand because there are so many variables.
FD3s has 50:50 weight balance so that takes one thing out of the equation.
So I will briefly cover Suspension and Tyres
Suspension geometry:
The FD3s is set at a predetermined ride height and geometry is designed to allow suspension components to move (quite a long way) to achieve best balance and grip over a regular normal (often bumpy) road. As conditions change and environments around the world have different requirements, a balance is chosen. The conponents of the FD3s suspension allow for free movement like fluidity and are quite "adjustable" from the factory.
Damping and Springs
Dampers and springs on a normal FD work, don't they? Yes they do... quite well in fact.
A common crazy idea is that stiffer springs and harder dampers = better handling. Well there two trains of thought on this one. I'll come to that later.
Tyre Grip:
Everyone knows that tyres make a huge difference in handling, stopping and traction. But matching tyres to the suspension is key in developing a fine handling car. Semi Slicks and stock suspension aren't going to be too successful. Or are they? The answer is... that depends.
So the standard car is the best setup from the factory for everyday driving and practical use. It is very effective point to point on the FD3s target road... "Winding Road" US Spec models may differ slightly in this regard.
Aerodynamic Grip
Aero dynamic grip changes things a lot. Stick a gt-wing on a standard FD, set it to max angle and go fast. Watch the antics. Ass down front up. No turn in, but good rear traction. Adding 30kg or more of rear down force means something else must change as with all modifications and this is where the issues start.
Stock or modified.
Watch these videos of a stock FD3s and then decide if you feel you want to change the factory settings.
Type 6 2000/12 Rx7 RS RZ
Review & Type 5 1999 Rx7
Review
If you aren't going to modify your car. And quite frankly the factory FD3s is VERY GOOD. 1.04 at Tsukuba TC2000 is awesome. Stop now and feel satisfied. I would.
If you are ready to modify... read on, but you may by the end be going back to stock.
The above car is a Bilstein suspension tuner's private car. Experts know best. Ask. I am no expert.
First consider the target road. Circuit or Rough Stuff. I'll use the extremes as ways to think of tuning.
Go Kart theory or Baja Desert Racer.
Circuit and Go karts. Designed with NO suspension travel, tyres and chassis flex do all the work and they handle well. Often used in analagies for superb handling.
Desert Bumps and the Baja Racer.
Going fast on a bumpy rocky sandy who knows what kind of "road" means LONG LONG LONG suspension travel that soaks it all up.
So which way do you go, how far do you go?
Balance is the key.
Changing something like tyres will effect braking, bushings, roll bar settings, dampers and spring rates and more. But most people don't notice as they never drive 10/10ths. you would be surprised how fast a pro can drive YOUR car.
Lets look at some case studies.
Targa Tasmania rally spec.
Most of these cars are fast. Slightly boost up machines with semi-slick tyres, upgraded brakes and dampers without aero. The ride height and suspension is allowed to use the full length of travel over many types of terrain. Often soft springs around 6~8kg are used to soak bumps and still keep grip at a maximum. Chassis roll is of no real concern as mechanical grip is kept high.
Japan Time Attack.
Smooth racetrack road surface. Semi-slick very soft compound tyres, suspension is super stiff, roll bars very stiff, aerodynamic aids are everywhere creating more demands on tyre and suspension. Sometimes damping spring rates are 22kg and more. Turn in with 265 tyre size on the front and the entire contact patch tuned to be used with about 3degrees of camber at Tsukuba. Rears are getting to 295 with a widebody car and this had completely changed everything. It's not an FD3s from the factory, thats for sure.
So putting a set of JDM 18Kg Tein Super Racing dampers on a cheaply tyred street car is laughable. They aren't designed for that. Just because they are expensive, doesn't mean they are the best. They are the best however only if you change the rest of your car to match them.
For a Clubman style track day.
Here is a list of things to consider what might upset the factory balance.
Front bumper and splitter,
Rear wing or GT-Wing. maybe a Rear diffusser
high grip radial tyres.
Coil over suspension for adjustability. (yes, you need to know how to adjust it)
Spring Rates,
Damper setting,
Ride height,
Stabiliser bars,
Alignment,
Bushings,
Brake pads
etc
etc
etc
and don't forget DRIVING LESSONS
Be careful about emulating the touge masters. If that's not where you drive, these cars are very targeted to that course. Are they the fastest street car? Gunsai is a closed course. If there is a big dip in the road at a T-Junction and it rips your splitter right off when you go around it at 100kph, they are hardly the best.
Think... more... before...
Russ.
