About 9 months ago I posted a video on my thoughts on which is the better car, C7Z vs C8Z, after owning the C8 after a month.
I have now owned the C8z about 10 months and have done about 8 track days and have progressed a good amount, gotten very close to my PB’s on the C7z. So here’s a follow up, now comparing both on track and my opinion as to which I think is the better track car:

 

C8 Z51 and C8 Z06 are about the same curb weight, and yet the MCS coilovers that worked just fine on Z51 were utterly insufficient on the C8 Z07 when I switched them over, despite having identical suspension geometry. I eventually switched to another set of coilovers meant for Z06, and it took me TWO more iterations of revalving to finally start liking the feeling of the rear end. I think it all has to do with the much taller CG the Z06 has at the rear, despite being about same curb weight, due to DOHC engine design.

You mentioned your brakes were getting into ice mode on C7Z all the time. Did you have exact same issues before installing the AP kit? on C7 Z06, the brake boosters of base and Z07 models are different, yet Essex racing doesn't know about it, and they developed their kit for 'one of them'. When I got my C7 Z07, I switched to J56 brakes, and immediately felt they were very spongy. I replaced the $100 brake booster to non-Z07 car version, and the issue was resolved.

I would love to do the similar change on C8 as well, but this time, it's the same brake booster with different 'program', which I cannot change : ( I ended up switching to Pagid RSL1E enduro pads to get to modulate them enough...

 

No I didn’t change the booster on the C7z. It was a base car with iron brakes so never really considered it, I thought that’s only needed if the came with CCB’s?

On the C8 I’m using Girodisk GP40’s and as long as I have smooth application the brakes do work better than on the C7 on stock or even AP’s.

I spoke to MCS about getting a 2 or 3 way setup done for me, they recommended that I “double” the factory spring rates and maybe add a bit more rear spring rate.
Is this correct?

 

C7 Z07 booster's boost is "less" than Z06/J56 booster. As such, if you had too much boost with AP kit, perhaps Z07 (CCB) spec would fix it. Anyway, I suppose you sold the car, so it doesn't matter.

I started with MCS' 200 / 220 N/mm front/rear setup, and it wasn't sufficient. With advice from MCS, I upped it to 240 / 280, and later to 260 / 320. The last one stabilized the rear, but I no longer had enough traction, and lost lap times. It doesn't need anything more than that original 200 / 220 (which is double OEM), but it needs aggressive low speed comp and rebound to support the rear, and it hasn't. I discussed this all in my build thread : )

 

New Z07 owner here (one track week end)...
Are you using those Pagid pads with CCB's or steel brakes?
I found my CCB's a bit of a "black box" on my first runs!
Thanks!

 

I'm using the smaller AP brakes (372mm / 355mm) to be able to fit the 18" wheels front and rear. My original CCB brakes are in brand new condition, collecting dust : ))