GD Alignment advice

mike-tracy said:

There's some threads on the subject, such as this one:

camber settings with pictures

Seeing as how I'm bout to get my car aligned for this season and I've never had any aggressive camber settings, id like to see what you all are set to and how it appears on the car. I'll be doing timed laps and autox.

www.rs25.com

I'm not a suspension guru, but I do a lot of reading. I'd encourage you to do the same, search for "camber setup" or similar terms to find threads like the above.

What do you think, @2pot?

Click to expand...

Road car, GD-wise:
Alignment: start with zero front toe.

If steering is subsequently twitchy - too responsive to steering inputs, use front toe-out: negative 0deg 03mins (0.06deg or 1/64" or 0.4mm) per side,
To quicken turn-in, use front toe-in: positive 0deg 03mins (0.06deg, 1/64" or 0.4mm) per side - may adversely effect mid-corner and corner exit.

You can increase/equalise the front caster by slacking the 2 bolts on the rear lower control arm bushing and prying the bush forward and outward. Aluminium arms - flipping the pin that holds the lower control arm rear bush and/or adding a spacer will also increase caster.

Rear toe-in: 0deg 03mins (0.06deg, 1/64" or 0.4mm) rear positive toe-in, per side = running a rear slip-angle gives instantaneous response to steering inputs, high-speed stability and more stability under high-speed braking.
The rear toe adjusters often rust solid (a UK link of parts required):
Subaru Impreza Turbo Rear Lateral Link Inner Toe in Adjust Bolt Kit

Front camber: negative 1deg 45mins - 2 deg (1.75deg - 2 deg), per side using off-set Whiteline or Pedders front top mounts - the Pedders seem to be more long lasting, at the moment. I wouldn't use this much front negative camber, if a lot of freeway use.
Or, max out the negative adjustment, with a normal front top mount.

Front strut 2 x lower bolts 175N/m (129lb/ft).

The rear camber isn't technically adjustable, but there is play in the lower strut bolt holes - slack, pry and push to equalise:
Rear negative 1deg 15mins -1deg 30mins (1.25 deg - 1.5 deg) per side. You can minimise the rear camber, before adjustment, by torquing the strut bolts when the rear suspension is in full droop.

2 x rear lower bolts 197N/m (145lb/ft).
I don't like rear aftermarket camber bolts - due to their reduction in torque setting.

Slack off the roll bar bush clamps/bolts, front and rear, before installing/torquing any new suspension into place.
Make sure the full weight of the car is back on its suspension, before re-attaching the roll bar - otherwise the ride height may be held up, or be uneven.
A bent drop-link will also cause uneven ride-heights.

If changing struts/springs, see if you can get a deal, where you take the car back after 500miles of driving (as the bushes and struts settle to their new positions) to get the alignment checked/adjusted for free.
Have a FULL tank of fuel (or put 100lb/50kg of weight in the boot), for the initial alignment and the re-check . Half a tank of fuel add 50lb/25kg etc.

Road tyre pressures (check before alignment):
Start with minimum 33psi front, 28psi rear
Maximum: 36psi front, 34psi rear.
Keep the rear pressure 2, 3, 4 or 5psi lower than the front.
Increase the rear tyre pressure to increase oversteer/manage understeer.