Alignment question

[puckaveli]

I have a 2000 Subaru Impreza and when the car was stock and I would get alingments I would put 200lbs in the drivers seat to simulate my weight being in the car. In my younger less experienced days some serious road racers told me to do it at several track days I did. I have done lots of suspension mods to my car and haven't put the weight in the seat the last couple alingments and was wondering if it matters really. Plus now with all the mods and heavier springs would 200lbs have less effect?

List of my suspension mods in case it helps:
Aluminium control arms
ALK comfort
20mm front sway bar
WL solid endlinks front & back
adjustable rear sway bar-set at 24mm
hardened sway bar mounts front and rear
STi lateral links and trailing arms
Tein Flex coilovers 336lb front 280 rear
Cusco rear strut tower brace
rear camber bolts

Thanks for your time.

[Peter]

G'day Puckaveli,

If your vehicle was an all out track car, then I suggest that adding driver weight may be necessary. In such applications, you would also be setting up the corner rates to suit particular corners etc.

At the moment you have a combined spring rate in excess of 1200 lb/inch. Applying a motion ratio of around 0.9 still results in a high rate at the wheel. After correctly setting the ride heights, the weights you are referring to may have little effect on actual alignment settings. The best way of evaluating this is to have an alignment performed, record all the readings, then jump in to the drivers seat and take another set of readings- any variation on camber etc can be noted. I suggest that this may be insignificant.

Peter
peter@whiteline.com.au

[puckaveli]

Thanks Paul. I daily drive but I gymkahna (auto-x) twice a month, track day once a month, and rally 5 times a year, so it's pretty multipurpose. I been wanting to corner weight my car but no tuners in my area have the right scales. I'll try your method next alingment. I have the car lowered 1" (see pic below)

Another question - fact or fiction? I have heard from various sources say when lowering a GC Impreza that it doesn't have any effect on alingment settings if it's less than 1 1/2" drop from stock. I raise and lower my car 2" between summer & winter. 1" above stock in the winter for rally and ground clearance and 1" below stock in the summer.

And yet another question, since I haven't corner weighted my car I'm not sure if moving the battery to the trunk would help or hurt the balance. Any thoughts or experience with this?

I hope you don't mind me posting the pic, if it's not allowed just say so and i'll take it down.
http://www.filefarmer.com/puckaveli/Pics/ESM5.jpg

[Peter]

Altering the ride height will alter your alignment - particularly toe and camber.

As your car is mainly used for daily street use I would tend to leave the battery where is.

Remember that it it all about the tyre contact patch. The larger the patch the higher the grip - alignment is therefore critical to maximise grip.

Cheers
Peter