Island_Hopper

Like you, I have found the GM C8 track alignment to be a bit loose and I want to back off a bit. Is the -2.5/-2.1 what you are using on your C8 or is that your C7 settings? Also, do you know how much you can back off and still leave the suspension changes that are part of doing the track alignment in place? My initial thoughts had been to back off to -2/-2, but if you have had success with other settings I am happy to try that.

Rapidblux2

Finally 💥💥💥💥💥💥💥💥💥 someone besides me this says the advised track alignment is garbage “
🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗🤗 🤗🤗🤗
happy days are here again.

Rapidblux2

You will never have real entry speed with that set up EVER

Jacques Albrecht

When I first bought / drove my 2020 C8 Z51 w/MagRide I decided that the stock GM factory alignment was too squirrely so I had the dealer adjust to the GM recommended track alignment. The before and after alignment spec numbers are attached below as PDF sheet. Also, I switched to the BBS CI-R rims since they are lighter, stronger. slightly wider and have a greater off-set than the OEM. Click here for their website. I kept the very good, Michelin Pilot Sport 4 S summer tires, and have not had any adverse tire wear in ~7,000 miles of daily driving. No track driving yet.

B Stead

Most production sports cars are designed to reduce rear toe-in in bump to make a feel in ordinary driving. So the correct track set-up would be maximum rear toe-in within the recommended range. Or stiffer springs could limit bump travel and fix the problem.

And most production cars increase steering angle at the cornering limit to plow the front-end at the cornering limit. Fix that problem with stiffer suspension bushings and with smaller bump-stops. Or stiffer springs could limit bump travel and fix the problem.

The next issue is that lowering a car with less spring pre-load "... translates the use of the spring to a lower force range of the spring." Basically, don't lower the car with less spring pre-load but lower the car with shorter and stiffer springs. Or aftermarket coilovers usually have shorter shock-body lengths and then standard-diameter coilover springs that can be changed. I would guess that 1/2" lowering should have 30% stiffer springs at 1.3x, 1" lowering should have 100% stiffer springs at 2x, and 1.5" lowering should have 150% stiffer springs at 2.5x. But don't compare spring rates to the OEM rates of 217/263 because those are rates at the wheel and not the actual spring rates.

For tire tuning, I give links to tire manuals that include general principals:

www tirerack com/images/pdf/warranty/BFG_R1-R1S.pdf

www tirerack com/images/tires/tiretech/bfg_Gforce/bfGoodrich_gForce_R1_care.pdf

The links didn't work so try a web search for "goodrich g-force control manual".

theclutch

@Jacques Albrecht , from your PDF, it appears that the "before" settings in the rear were way off each other. Was this the alignment from the factory or have you had it aligned previously to getting the track alignment? I'm trying to figure out what was the "factory alignment" settings as I'm finding conflicting information everywhere.




Ultimately, I'm wondering if I can simply move the suspension washers in/out each time I go off/on the track. Moving the washers seems like a very easy job to do. Thanks in advance!

@savage , what suspension settings did you end up doing?

Jacques Albrecht

Ha, Ha, Ha "...the 'before' data sheet shows rear settings were way off..." well that explains why I thought the factory setting was not for me! Frankly, I never looked at the 'before' alignment sheet - I just assumed that the car came correctly aligned from the factory. But since I didn't like it and I'm more familiar w/driving a 911 Porsche I went ahead and paid my dealer ~$400 to give me a C8 track set-up. The 'after' sheet data PDF displays my current alignment and where I've been happily driving w/o any noticeable tire wear issues for ~7,000 miles.
Just came back from a one day 200+ mile trip and was quite pleased with how the car planted and responded at highway speeds. Your dealer could check and set-up your car to the OEM factory specs, under warranty (and also give you the data sheet). This would be a good starting point.
As far as simply switching the washers around - I don't think it's all that simple. Lastly, if you're going to track the car your tire wear (and brakes too) is going to be so high that there's no need to be concerned about minor street wear.

theclutch

Glad you like the track alignment. I, too, am more familiar with my 911. Frankly, I'm somewhat annoyed that I would have to bounce in and out of track alignment to go to the track. With the 911, I drive in and out with the same alignment and no worries about abnormal tire wear on the tire shoulders. But whatever, I'm enjoying the C8 regardless.

Switching the front washers look super simple; 4 easy access bolts per corner. It will likely take me 10 min each with the proper tools. For the back, looks like I need to remove the wheel liner to access one of the 4 bolts. That one looks more involved.

I am thinking of a "compromise" setup where I put -2.0* front and -1.5* rear. This is from the street setup of -0.5* front and -0.5* rear.

exia92

Hey! Wanted to revive this thread to check if you’ve continued with your modified alignment or have found another that works for better for both Street and Track use?

theclutch

I ended up splitting the track setting in half aiming for -1.5 camber front and -1.25 rear.

This is what my alignment came to with roughly 3400 miles.

Before Front: Camber -0.8, -0.4; Caster 7.2, 7.4; Toe 0.07, 0.12
After Front: Camber -1.5, -1.4; Caster 7.2, 7.4; Toe 0.03, 0.02
Before Rear: Camber -0.6, -0.7; Toe -0.04, 0.11
After Rear: Camber -1.3, -1.3; Toe 0.00, -0.04

I have about 2000 miles on this setup now with 1 day track event. The front tire did not "roll" over the edges with "only" 1.5 degree camber. I'm keeping that setup as I believe for me it's a good enough compromise. I don't see any unusual front or rear tire wear. I am staying with this setup all year round unless I discover something new.

However, what I did notice was that when driving after the alignment, I feel the rear shimmy a little when I hit some dips (not bumps) on the street. It wasn't there prior to the alignment. It's weird. Car handles great in turns and currently has more grip than I have ***** to find the limit. But what's more disturbing is that when I was looking into this issue, I found a different one. See here:

https://www.corvetteforum.com/forums...ear-wheel.html

Bottom line, the car drives so well that this was more of a cosmetic issue that only OCD people like me would find.

bhvrdr

Your toe was WAY the heck off from factory. Way way off. Your front tires likely wouldn't have lasted 5k miles

zrracer

A couple of things;
sometime newbies want track tires and race alignment and any other stuff they can think off.
IMHO it's best to stay on street tires and street align if you a relatively new. With the stock set up
the tires will scream at the driver. With track tires race setting it won't happen and possibly induce over steer.
newbies should keep their heads up, watch the flags and enjoy.

exia92

Appreciate the update! I’ll most likely give your alignment once I get more experienced with the car. Question, did you get this alignment done at a dealership or at a specialized Corvette shop?

@zrracer - Your opinion is valid and made me re-think about when I’m targeting to have my car aligned to a more aggressive setting. I’ll do it once I’m more familiar with the car and after a few track days under my belt.

theclutch

I had mine done at the dealer MacMulkin since they obviously have sold more C8s (at least last year) than anyone else in the world and arguably would have more experience on them than anyone else. Had it not been them, I would have taken it to a specialty race shop that has the specific Corvette alignment tools that's needed to do the rears (I forget what it's called and what it's for).

Helderjspedrosa

Hi All, I have sent my c8 for a track alignment on a Chevy dealer and went I pick it up I have washers in my cup holder, i asked the mechanic why the washers are there? I thought they need to be relocated and not removed on the control arm but he said no.
My question is do they supposed to be removed or relocated? and if relocated how could he have done a proper alignment? thank you all in advanced.
Also any YouTube video that actually show the all process of the track alignment?

NoMatter

^ I agree. But very curious of what it was set at without them. There’s a big range when the washer is on the inside and outside. But haven’t heard what range with them completely off.

Jacques Albrecht

Did you receive the alignment data sheet from your dealer's mechanic showing you where it is now set? If not then ask for it so that you know just what adjustment was done to your wheels. Also, how much did they charge you? The track alignment takes about four hours labor...
FYI - I've attached the GM factory track spec sheet as a PDF doc.

theclutch

Well.... that's a FAIL! Your mechanic is super wrong. But at least he didn't throw the washers in the garbage! They are supposed to be RELOCATED as per the user manual. Do a search on Youtube yourself and you'll see what you're looking for.

c5racr1

you are running -2.0mm front and -4.0mm rear?

c5racr1

it’s not a big deal as long as you have the washers. The reason they were relocated was to keep track of the washers when the track alignment goes back to a street alignment. The relocation doesn’t do anything as far as alignment goes.