Setting ride height

[Blue Streak 21]

I need a little help. I'm trying to set the ride height to the spec's in the manual. Here's what I've done so far.
I started by putting the nuts on collars in the same position as they were with the old springs. This was roughly in the center of the threaded length of the collar. I knew this would not be correct since the new stiffer springs would compress less under the weight of the car, but I figured I could adjust from this point.
I took the car off of the jack stands and found that the height was 5 1/2" up front and 6" in the rear. I need to drop the car 2" on all four corners to get it to the spec height.
So my question is do I compressed the springs further to drop the ride height, or do I release some of the compression? Rotating the nut is a Bi&$# in the confines of the wheel wells, so I want to do it right the first time.
My thinking is that by compressing the spring, I'm shortening the overall length of the shock and should be dropping the ride height. Maybe I'm thinking about it backwards. Can you tell I'm confused????
Help.

[Cobra4B]

Subscribed.

[Blue Streak 21]

I solved my problem with a little trial and error. It seems that compressing the spring increases the length of the shock, and thus raises the ride height of the car. Counterintuative.
After one round of going the wrong way with the car height, I reduced the compression on the springs and tried again. Success!!!
The new starting position for the nut on the threaded shock collar is just barely compressing the spring. This is for 550#'ers up front and 350#'ers in the rear. One turn on the nut to hold the springs in place was all I used. I dropped the car to the ground and I was with in a 1/4" up front, and 1/2" in the rear. I went with 3 3/4" up front and 4 1/4" in the rear.
Final adjustments were made with the car on the ground, and 200 lbs of balast in the driver seat. I bounced the chassis some, and the values seemed to hold pretty consistent.
Good to go to alignment.

[Cobra4B]

^ Awesome... I'll be doing this soon and might have to bug you

[Blue Streak 21]

Originally Posted by Cobra4B

^ Awesome... I'll be doing this soon and might have to bug you

No problemo. If you get stuck, just e-mail or post questions.

[Blue Streak 21]

A friend brought over his alignment measurement tools yesterday. Each corner of the car measured up differently. The camber ranged from -3.7 degrees on the LF to +0.1 on the RR. Toe was just as inconsistent. I was not able to measure caster, but it looks to be way off too. After I corner weight, the car will go get a professional alignment at a Firestone shop I have used for several years. They give a life time alignment for about $150. My Z06 has been aligned by these guys for over three years. Pretty good deal.
I also decided to reposition the A-arm. I don't like the funky angle it's sitting at. I think it adds caster in big doses. I loosened the mounting bolts and adjusted the longitudnal cross brace to be in line with the chassis member right above it. A couple of pictures that I've seen of the GTS cars have the A-arm aligned this way. I positioned the center of each bolt 1 3/8" away from the vertical attaching point. No real reason for selecting this distance other than it allows for adjustment in either direction. This is not fully centered in the adjustment range, but it's gotta be better than having the rear bolt jammed up against the inside of it's range of motion.

[panoz302]

Blue streak
you are 100% correct in moving the arms, way too much caster, as John will eventually pipe in this was done to tighten up the steering for the school. I changed it, reset my ride height, re squared the rear end, re set the camber and the caster. I will post my specs. I also corner balanced the car. I been getting my specs from Chris Riley, Riley Motorsports, he is an east coast panoz dealers, he has been running a gts in scca for a few years.

[Cobra4B]

^ I'd love some pics and a proper spec sheet so I can re-do my car and have something to go by.

[panoz302]

cobra go to wirewheels.com wb site look at the gts pics, those cars have the upper arm rear sec parallel with the frame , mine was not, plus the camber bolts where removed to further adjustthe caster too much. THe school cars where intentionally set this way according to the school guys, and I was told John L. did this for them as the engineer. I also went over this with my shop, John Gilmerveen (sp) SAE suspension guy. yada yada.

[Cobra4B]

Picture? I'm trying to undersand how adjusting the angle of the A-arm in relation to the chassis affects caster.

[Cobra4B]

Ahhhhh I get it... just looked at the pictures from wirewheel.com and see what you mean about the A-arm being parallel to the chassis. That moves the upper ball joint forward or rearward adjusting caster.

[Blue Streak 21]

Originally Posted by panoz302

Blue streak
you are 100% correct in moving the arms, way too much caster, as John will eventually pipe in this was done to tighten up the steering for the school. I changed it, reset my ride height, re squared the rear end, re set the camber and the caster. I will post my specs. I also corner balanced the car. I been getting my specs from Chris Riley, Riley Motorsports, he is an east coast panoz dealers, he has been running a gts in scca for a few years.

Panoz32;
What spec's does Chris say would work best for the car on a tight track, where the fastest corner speed is in the high 80's, and most "fast" corners are 70's? My home track is Sandia Motor Speedway, and is a 14 turn, 1.6 mile track. It has two hairpins (30 mph), a carousel (55 mph), and a middle 60 mph turn at the end of the front straight. There are no S's, and most corners are constant radius turns, no increasing or decreasing radius corners.
I've been given the following general spec's:
-2.75 degrees camber
6 degrees caster
1/16 toe out
My plan is to have the car aligned to these spec's unless I hear good reasons from experienced racers to do something else. Currently the car is nonwhere close to these numbers, so an alignment is definetly required.

[Cobra4B]

Any reason the turning radius is so low in these cars? From what is marked as center I can turn the wheel to the right just under 1 full turn (about 330 degrees) and to the left 3/4ths of a turn (240 degrees or so).

Not sure you could ever auto-x one of these.

[Blue Streak 21]

Originally Posted by Cobra4B

Any reason the turning radius is so low in these cars? From what is marked as center I can turn the wheel to the right just under 1 full turn (about 330 degrees) and to the left 3/4ths of a turn (240 degrees or so).

Not sure you could ever auto-x one of these.

Brian;
My manual says that the rack and pinion should be 3 turns lock to lock with a 15:1 steering ratio.
My car allows one full turn to the right and 1 1/4 turn to the left.
I guess I'll find out about auto-X in a week and a half. As that will be the first event I plan on taking the car to. The course is the first 6 turns of our road course and then a few additional cones in the hot pit area. Maybe I'll have to throttle steer to get through tight corners.

[Cobra4B]

^ What controls that? I'm going to go check mine lock to lock... brb.