C6 Grandsport suspension questions: Which eccentric bolts are for camber/caster?
#1
Drifting
Thread Starter
C6 Grandsport suspension questions: Which eccentric bolts are for camber/caster?
Hey all,
For the last couple of months I've been researching and experimenting with adjusting the alignment on my C6 Grandsport. So far I've been successful in adjusting from side to side and front to rear but I still have some questions about he independent components.
My Questions:
- Which Eccentric represents Caster and which Camber?
- How many degrees of change does the hash marks on each bolt represent?
Why does toe change when Camber/Caster is adjusted?
My Experiences:
- The first time I made any adjustments it was brutal took me several hours on multiple days. Now it takes about 1-1.5 hours and most of that is setup.
- I try to tighten my eccentrics to 80 ft-lbs not sure if this is proper, but they don't move and so far no bolts have stretched.
- Small rotational changes at the bolts make for big degree changes at the wheel, so I learned do be very careful.
- My car has F55 suspension so I use a 3-5 mile loop near my apartment to make sure everything is settled before I take new measurements.
Last edited by truth.b; 12-16-2015 at 08:48 PM.
#2
Drifting
I can't say that I remember which eccentric is which, but for sure the nuts need to be torqued to spec or they will loosen on track. For a C5 torque spec is:
125 ft-lb on front eccentric nuts
107 ft-lb rear control arm (front)
71 ft-lb rear control arm (rear)
C6 is probably similar
125 ft-lb on front eccentric nuts
107 ft-lb rear control arm (front)
71 ft-lb rear control arm (rear)
C6 is probably similar
#3
Melting Slicks
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Both eccentrics affect both camber and caster... the one most in line with the bottom ball joint affects camber more than caster and vice-versa.
Toe change occurs because the bottom of the spindle moves in and out with cam/cas adjust, but the tie rod length remains unchanged until adjusted separately.
Unknown whether the hash marks actually represent anything...
After having done around 1,000 alignments professionally, I respect anyone willing to undertake one at home. Make sure your surface is level, and your gauges are accurate. And if you are measuring directly from the rims, make sure they aren't bent. Tire pressures are also important.
Good Luck!
Toe change occurs because the bottom of the spindle moves in and out with cam/cas adjust, but the tie rod length remains unchanged until adjusted separately.
Unknown whether the hash marks actually represent anything...
After having done around 1,000 alignments professionally, I respect anyone willing to undertake one at home. Make sure your surface is level, and your gauges are accurate. And if you are measuring directly from the rims, make sure they aren't bent. Tire pressures are also important.
Good Luck!
#4
Drifting
Thread Starter
I can't say that I remember which eccentric is which, but for sure the nuts need to be torqued to spec or they will loosen on track. For a C5 torque spec is:
125 ft-lb on front eccentric nuts
107 ft-lb rear control arm (front)
71 ft-lb rear control arm (rear)
C6 is probably similar
125 ft-lb on front eccentric nuts
107 ft-lb rear control arm (front)
71 ft-lb rear control arm (rear)
C6 is probably similar
Thanks for the numbers. 125 ft-lb is a big number and I don't know if I would be able to pull that off while laying on my back with my current jacks and stand setup. 80 ft-lbs is pretty difficult but I manage and so far no slippage.
Both eccentrics affect both camber and caster... the one most in line with the bottom ball joint affects camber more than caster and vice-versa.
Toe change occurs because the bottom of the spindle moves in and out with cam/cas adjust, but the tie rod length remains unchanged until adjusted separately.
Unknown whether the hash marks actually represent anything...
After having done around 1,000 alignments professionally, I respect anyone willing to undertake one at home. Make sure your surface is level, and your gauges are accurate. And if you are measuring directly from the rims, make sure they aren't bent. Tire pressures are also important.
Good Luck!
Toe change occurs because the bottom of the spindle moves in and out with cam/cas adjust, but the tie rod length remains unchanged until adjusted separately.
Unknown whether the hash marks actually represent anything...
After having done around 1,000 alignments professionally, I respect anyone willing to undertake one at home. Make sure your surface is level, and your gauges are accurate. And if you are measuring directly from the rims, make sure they aren't bent. Tire pressures are also important.
Good Luck!
#6
Drifting
Both eccentrics do both, they work in tandem. Almost impossible to get numbers to repeat using cams due to the play in the system.
Anytime you move any arm mount point in or out you are changing toe. Alignment 101 !!!
It is an absolute PITA to do home alignments using the cams. They are only used for production use to make it easy on a rack where you can watch the numbers change. I do not know anyone that has given any attention to the marks as the cams normally have more play in the cradle than mark changes.
Replacing the cams with camber blocks, & using shims at the top along with studs makes it very easy and repeatable for a hobbyist.
Anytime you move any arm mount point in or out you are changing toe. Alignment 101 !!!
It is an absolute PITA to do home alignments using the cams. They are only used for production use to make it easy on a rack where you can watch the numbers change. I do not know anyone that has given any attention to the marks as the cams normally have more play in the cradle than mark changes.
Replacing the cams with camber blocks, & using shims at the top along with studs makes it very easy and repeatable for a hobbyist.
Last edited by blkbrd69; 12-17-2015 at 08:39 PM.
#7
Drifting
I wonder if I hit even 80 ft-lb on ramps. I ended up going to a friend with an oil change pit. Even then it was tough getting to 125. It's really hard to get leverage with a torque wrench vertical.