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Is it true that the lower rockers need to be removed for the attachment of the alignment equipment, making the track alignment (and reversal post track day) a pretty expensive proposition? No longer $150-$200? I was hoping to have my local shop undertake it.
the rear brake ducts have to be removed and the front splitter tray has to be unbolted and pulled down or removed. It take about 2.5 hours to do an alignment on a c8 on a hunter. If you remove the entire splitter tray( like it says in the book its 3.0 hours.
I took mine to a recommended alignment shop near me for the track alignment. I didn’t want to go quite all the way to the recommended specs so it would remain slightly streetable. They were able to get within half a degree of the full GM spec front and back pretty quickly without disconnecting anything so I had them do that. Was very pleased with how neutral it was on my first track day with it. Seems to have dialed out a little of the understeer on the street as well. Hasn’t been long enough to see how it affects tire wear but I’ve already mentally budgeted for tires as I plan to do 4-5 track days a year.
i ran the gm track alignment on the street for about a 2 years. I recently changed to a hybrid alignment of -1.5 front, -1.0 rear, and what ever the factory toe was. i did go with a little more caster on the front left to keep the tires from grabbing the crown on streets and high ways. I have not been doing as many track days and got tired of the "knock Knees" look on the street. It rides better and drives better with this set up. Its not going to be as quick on the track I already know. put about 5000 miles on the track alignment, the tires had no noticeable wear (not that I care).
Step #1 Below is the time consumption element from the techs perspective. I think my alignment was about $900 at the dealer to achieve track alignment. They do alot of the track alignments and they know what they are doing. Expensive so I have driven on the street without much issue. But then again I only get about 2000 miles on set of tires due to much track driving. I go beyond the GM recommended tire replacement intervals of two tanks of gas during track events requires a new set of tires. If I followed GM's track tire replacement suggestion, I would be replacing tires 2 times a day at a track event (once in the morning and once in the afternoon or every 100 to 200 miles.
WHEEL ALIGNMENT
1. The upper control arm to body washers on all four corners will need to be relocated from between the body and the control arm to between the head of the bolt and the control arm.
2. Adjust the lower control arm cam bolt position to achieve the following specifications. Note: After track use, reinstall washers between the body and the control arms. Reset to factory alignment.
TRACK PREPARATION FRONT (PER CORNER) REAR (PER CORNER) / Caster: +8.0 degrees / Camber: -3.0 degrees / Toe (total): 0.1 degrees toe in / Caster: 0 degrees / Camber: -2.5 degrees / Toe (total): 0.1 degrees toe in / Thrust Angle: 0 degrees
WARNING: Track/course loads wear tires both on the tread and internal to the tire. When driven in track/course conditions, even if tread is not worn down to the treadwear indicator, tires must be replaced after the equivalent of two tanks of fuel or approximately 160 km (100 mi).
Once AMT comes out with camber blocks for the lower control arms, and studs for the uppers, I’ll be running strings and doing this myself. This suspension is no different from c5, c6, c7. Upper and lower A arms.
Just have to set the caster with the gage on the rears.
My track alignment at the dealership was 250.00. 900.00 is steep but if u got what you wanted so be it. Those cam bolts make alignment so much more involved because moving one control arm affects more than just that control arm. Another benefit is the ability to make slight adjustments to the ride height in the rear to help with oversteer.
I will be able to paint pen the adjustments so it can be dialed in at the track. Can’t wait!
Yeah, for sure. I paid $160. My guy told me the car allows up to -2.5 deg in front and -2.0 deg in back with pretty simple adjustment and not taking anything apart. Seemed a no brainer to go with that and forego the time and expense for the additional 0.5 deg which I likely would never notice with my limited track experience anyhow.
I have Vossen HF-2’s with a very flush offset and it looks slightly knock kneed but not nearly as much as another C8 I saw at the track last month with stock wheels. Looks dorky as hell with the wheels tucked into the fenders so far AND lots of negative camber.
When Wheel Alignment is done on a C8 a Rear Caster tool is needed. Alignment Machines Can Not measure or Display Rear Caster so you will need this tool if Rear Camber is changed.
The reality is that what is good for the track is bad for the street, and vice-versa...
Any "compromise" in the middle ends up being lousy for both purposes...
If you want to have a "dual-use" street/rack car, you must make a set of difficult compromises, and decide what level of disappointment you can live with
Any "compromise" in the middle ends up being lousy for both purposes...
I have to disagree what that statement, at least as it relates to the C8 Z51. I drove mine for 3-4 months in the stock/street setting prior to the beginning of track season in late April. When the season started I had a hybrid setting, basically right in the middle of what GM recommends for track, I've not noticed any bad manners on the street and everyone who's driven the car both on the street and on the track to include some guys with quite a bit of racing experience have all said how balanced the car feels. In fact, the only bad thing I've heard has been that it feels heavier than they thought but that it still was pretty good for a stock suspensioned car.
After 2 actual track days at Nurburgring plus several touristen fahrten days, Three 30 minute sessions at Hockenheim and Six 30 minute sessions at RedBull Ring and no telling how many sprints through the Black Forrest this summer, my stock PS4S tires are just about done. They performed pretty well but I'll probably move to Cup2's next season.
Just had mine done last week to the GM recommended track specs. The alignment place I used only removed the rear brake ducts and partially lowered the front tray, which maybe added 5 minutes to the total time. They have done lots of C8s and other track/race cars and are meticulous about setting everything correctly, rolling the car, and resetting as necessary. $200 was it. After my track day this weekend, I may experiment with a "tweener" alignment, we'll see. I did not corner weight the car, but I probably will after this weekend. I can't believe anyone really needs to replace tires after 100 miles of track use, seems excessive given that Michelin makes top level tires that have proven to be track worthy for years. I am using dedicated track tires, so it doesn't matter for me since my street tires get to relax in the garage when I'm on the track.
How many miles did you get out of them? Did they wear evenly?
Not sure if this was directed to me but I'll try to give you an answer....I guestimate somewhere around 800/900 miles of track time between the ones I mentioned plus several thousand miles of everyday and forest driving. All in all, they have worn quite evenly, when I swap over to my other set of wheels, I'll snap a pic or two. On the street, the tires feel fine but at the last session on the Nurburgring and also at RedBull Ring, I could tell that they had definitely gone off a bit. Although I've certainly gotten faster, even though I'm still slow, the traction control was working a lot more these last two sessions than it had before in similar conditions.
When Wheel Alignment is done on a C8 a Rear Caster tool is needed. Alignment Machines Can Not measure or Display Rear Caster so you will need this tool if Rear Camber is changed.
GM Caster Tool and Pins need for a C8
I ain’t smart, but there is no caster adjustment on the rear suspension of the C8.
There is absolutely a caster adjustment on c8 and c7. If it’s too wrong the car drives like a$$. It can be adjusted by the bottom cam bolts front and rear.
There is absolutely a caster adjustment on c8 and c7. If it’s too wrong the car drives like a$$. It can be adjusted by the bottom cam bolts front and rear.
I’ve spent several hours the past couple of weeks working on alignment after replacing the coil overs and 3 hours today under the car with a Hunter laser alignment machine dialing in the camber , toe and front caster.
can you explain how caster is adjustable in the rear? Or why any car would want caster in the rear?
There is no adjustment of the upper a-arm, only the lower. Therefore there is no pivot point to create caster. I suppose you could “not”set the camber bolts the same on the lower a-arm and create a tinny tiny bit of caster, but the camber and toe would be totally whacked.
I’m not trying to argue. I just don’t see how it can be done and GM does not have a spec for rear caster on the C8 .
track alignment issues
