I found it to be quiet informative, and with his permission I'll share it with you. I have changed a couple of words just to make it slightly more relevant. All the information has been left intact.
To start with, let’s get the basics down pat: you’re building this vehicle for circuit work and a bit of drag racing, right? There is quite a bit you need to do in terms of
bracing (especially on a wagon) and weight reduction to get the car to perform as well as an early model GC8 with similar work done to it, or a light-weight GD. Afraid to say
you’ll probably never get anywhere near an Evo9. Sad, but at least Evo boys will forever be chasing GT2s and GT2s will always be chasing F1 cars who are chasing SR71s.
Paul, are you going to keep Le Ghetto Wagon registered? If not, then skip straight to roll cages and seam welding, rip out the side glass and put Perspex in, cut the side
intrusion bars out, gut the doors, and rip the hoodlining and dashboard out, leaving the cluster held to the steering column by massive hose clamps. You need to get out as much
weight as possible from high up in the car. However, if you just rip too much weight out of 1 area and leave it in others, you’ll end up with an imbalanced car that will handle
like turd. Unsprung weight (like wheels) is a good place to start, before moving onto plugging sunroofs, removing spoilers, ripping out the complete air conditioning and cruise
control systems, switching to non-ABS hubs and lines, ditching wipers, thinner glass, gutting trim (including dashboard) and putting lightweight carbon-backed seats in on
low-mount rails. Cutting the wiring loom down to the bare essentials is a very good idea because there is heaps of weight in wires, plugs and grommets that you can take out and
cover up with smaller rubber bungs.
One of the big problems with a car’s handling is that as energy moves around the vehicle it forces the geometry out of alignment, therefore impacting the wheel’s contact patch
with the road, and ipso facto, grip. One way to stop this is by installing a roll cage, and if I could seam-weld my car and put an integral roll cage in it I would because the
chassis stiffness you get is amazing. I would definitely get them done by a professional as they’re intricate pieces of work and things like conical strut top hats to add
strength, inch-on, inch-off welds, etc are all more technical than you’d think. You’ll have to wire-wheel every single body join on the car down to bare metal to get it ready
for the welding, as well, and this is a job that makes taking tar off the car look like a lazy stroll in the park. You need to work out right now how serious you want to go with
it, because once the car is together you’ll have to strip it back to a complete bare shell (eg: even remove the wiring looms) to get this work done.
Unfortunately, putting proper roll cages in street cars is now not possible due to changes by the RTA you are no longer allowed to have a caged street vehicle. You can brace
street cars using bolt-in pieces, but it is not as good as a proper welded-in effort that triangulates the bars around the frame. This is one reason a bolt-in bar I’ll talk
about later in this email is good, because it spreads the load and is braced off several different points.
If the wagon is to stay a street registered car it gets trickier to keep the chassis and geometry straight. Adjustable strut tops with pillow mounts/rose joints on the coilovers
is a must as it will let you get farking WICKED wheel alignments, plus if you got the adjustable alloy front control arms you can shim them for more castor. Going through and
removing every single old rubber bush with fresh poly stuff is 100% a good idea, and I’d definitely look for a 2.7 steering rack for your car and hook up a cooler for the power
steering. This will be tricky with a FMIC, though I have the V2 STI RA one mounted on its side behind my grille and on top of the FMIC core. Custom lines FTW. In the rear,
rose-jointed trailing arms would be wicked, or even just slamming some poly bushes into new arms (old arms have a habit of bending over time), and if the wags is mostly a track
car with little street use, you could step up to 25mm/25mm swaybars. A diff lock kit and subframe locking kit would both be worthwhile additions to stop movement in the rear
cradle but they do increase a hellish amount of diff noise into the car.
You mentioned Tein coilovers before, which models were you looking at? Reason I ask is because there are huge differences between the HA models and the RA/RS/etc top-shelf
models. Going Tein would also let you hook up EDFC (Electronic Damp Force Controller), which allows you to change damping rates in the car. Very handy when setting the car up
(which will take a while to do with all these mods). For struts I’d look for something with as big a piston diameter as possible, inverted design and as light in the strut as
possible. You might be shocked to learn that a coilover is normally heavier than a conventional strut. However, it is the pieces inside the coilover that it is important to
ensure are light as light parts respond quicker and in finer increments than big, dumb heavy ones. Circuit cars will need heavy (stiff) springs and strong shocks and they’ll
likely rattle your teeth out over any bumps or imperfections in the road surface, but that’s part of the game. You should definitely also budget for a roll centre adjuster
(sub-$300) as this means you can get the car lower without destroying your roll centres. This is something I am doing ASAP, and I’m also going to be looking for a new diff
cradle as the late model STis mount their lateral arms higher up, improving roll centres (and allowing them to go lower without chronic understeer).
In terms of chassis bracing you could get an H-brace to go under the front (though it makes it a PITA to work under there), as well as front and rear strut-top braces to hold
the floppy old wagon together in the bends. You’ll be putting a lot more stress through the frame of the car with sticky tyres and stiff suspension, so make sure your bracing is
up to scratch. This is where roll cages kick arse, but if you do want to keep it road registered then I’d look to Import Monster because there are all kinds of crazy braces on
there: bars to brace the crossmembers (F&R), to go between B-pillars along the floor, to triangulate the rear suspension links, etc. Fender braces are something both Rallyeee
and I are getting into as they’ll stop a lot of flex in the front-end, plus a brace to go between the rear strut towers that also fixes to the floor and base of the towers would
be the best way to go in that area. Getting a pair of crossed bars welded in with a strut brace to run across the top would also be good because let’s face it; you won’t be
carrying loads or people in this thing, so who cares? I’d personally try finding a bolt-in solution in case you crash it, then you can just unbolt the sucker.
You’ll need to keep tyres up to the car and we’re talking semi-slicks (RE55S), or at minimum really good quality rubber (RT615 Falkens). You should also learn about tyre heat
cycles to learn how to make full use of your semi-slicks and brakes. Track work will slaughter stock pads and rotors very easily through glazing and cracking (respectively) so
don’t go in under-prepared. Slotted rotors and fresh fluid every 3 months is required, and don’t be scared to go through at least 3L of Super DOT 4. Also, Lucas pads and Bendix
Ultimates are not track pads.Think more along the lines of the Elig jobbies GT Pumps are importing, or perhaps Ferodo DS2500.
Note: you’ll most likely need a winged/upgraded sump. ARC looks nice! And a surge tank and swirl pot would be a good addition to a track car IMO.
From a street car point of view, my car is designed to be set-up so that it can do a track day well, or with the suspension raised and the damping softened off, tarmac rally
work as well. This is my car’s set-up:
SUSPENSION: Buddy Club Racing Spec Damper coilovers (with pillow mount adjustable strut tops all 'round), STi RA 2.7 steering rack (with Whiteline bushes), STi RA front swaybar,
STi RA adjustable alloy front control arms, Perrin front end links, Whiteline adjustable 22mm rear swaybar, Whiteline solid C-links, Whiteline adjustable lateral control arms,
2007 STi Spec C trailing arms, Perrin subframe locking kit, Perrin diff lock kit
BRAKES 4-piston WRX front calipers, 294mm shitter rotors, Lucas pads, Goodridge braided lines, 2-piston WRX rear calipers, slotted DBA rotors to fit over 190mm handbrake
assembly, Goodridge braided lines, Cusco Master Cylinder Brace
Thank you to Marv for taking the time to put this together.
Cheers, Paul.
