CAINCA

Hello,

My name is Chris and I bought a 2020 C8 about a month ago. I keep a "build" thread on Grassroots Motorsports Forum. I've started a few threads here asking specific questions but I think I'll just move to a build type thread here too. Since the focus of my questions will be technical and/or track related I've put it here in the C8 Tech/Performance forum.

I'm going to copy and paste a bunch of posts in here to start:

I was really interested in the C8 Corvette when they first came out but after building one on Chevy's website I came to the conclusion that they were out of my price range. So, instead I bought another car that I had drooled over since they came out, a 2011 Porsche Cayman base with PDK, in May 2022. It also fulfilled a childhood dream to own a Porsche someday. It's been the best car I've ever owned, but it has some downsides. It's a bit underpowered by today's standards, it's noisy and it rides a bit rough. I thought long and hard about buying a newer Cayman S or GTS but I could never find one that had all of the options I wanted for a price I was comfortable paying for what is essentially a toy. In the background I've been looking at C8s. Last week a car that checked all the boxes and then some popped up about 5 miles from my childhood home near LA. I called the dealer on Friday and bought a plane ticket. Saturday morning (3/2/24) I flew down and bought the car.

The requirements were 2LT, Z51, Magnetic Ride, front lift, GT2 seats in Rapid Blue with a black interior. In addition this car has bunch of things that I would have had a hard time justifying but really liked: Trident wheels, carbon fiber grill, interior trim, mirror caps, engine appearance package, Red engine cover, Tension Blue seat belts. There were $28k in options. It's a one owner car with just 12k miles (~4k a year). It's been serviced at the dealer from day one. Apparently, the owner just bought this car as a interim while he waited for his Z06 allotment.

So here she is:






On Sunday (3/4/24) we took a 75 mile drive down the Big Sur coastline to Napenthe for a late lunch. It was raining the whole way home. At one point I managed to get the rear end to kick out on a tight hairpin while in "Weather" mode. The Mrs was not impressed. Lol!

CAINCA

I plan to drive this car into the ground so I bought a 5/60 bumper to bumper warranty. I was putting about 1k miles a month on my Cayman.



I'm also planning to track it a few times a year so I've been putting a list of things I'll need for track days. I've purchased or ordered the following.

OEM Brake cooling kit. Purchased from someone on CorvetteForum.

Tow hooks. I found a set of ACS Composites on FB.

Motive pressure bleeder cap, brake pin socket, Lisle brake Spreader, 22mm lug socket from Amazon.

Jackpoint jack stands. They are on back order but I found a set of four on the PCA classifieds.

Race Ramps Trak-Jax (3" to get the jack under the car).

Wheels I purchased a set of stock silver 5 double spoke wheels for $450 off FB.

Tires: The CR-S V2 isn't available in a 305/30/20 right now. Their entire shipment got refused at the port and sent back so it's probably going to be a while until they get any more in. I decided to go with 265/35/19 and 325/30/20. I've always run a little wider tire than stock and it sounds like others have run this combination.

Brake Pads: I've found a few posts about the Cobalt Racing XR2 brake pads and they sound like what I'm after. They are similar to Ferodo DS1.11s, PFC 01 or Pagid DS14s. I ordered a set to try out.

Brake Rotors: I found a lightly used set of GiroDisc 2 piece rotors from someone on CorvetteForum..

PPF. I wound up having the entire car PPFed after my Cayman experience. I got a full front track package and wound up with a 1/8" square chip on the top of one of the rear fenders.

I had the local Chevy dealer change the DCT filter and add the two extra quarts of fluid.

CAINCA

The only option that I didn't like on this car was the body colored rear spoiler. To me it didn't balance the the CF front grill inserts and mirror caps. I found a couple pictures of C8s with an exposed CF duck tail spoiler that I really liked. It's unique and more subtle than the CF high wing spoilers than most guys go with. I found a shop selling one that had been ordered by a customer and then the guy totaled his car before it arrived. They basically sold it to me for their cost.

CAINCA

We had a little club drive at work on Saturday (3/14/24):

CAINCA

A couple more beauty shots:

CAINCA

Thursday(4/424) I had the track alignment done. Afterward the shop asked if I had it aligned before because the numbers were all over the place. I'm not sure why it was so far out of spec but I'll have to keep an eye on it.



Thursday night I put the car up on four Jackpoint jack stands for the first time. That was pretty easy and took a lot of the stress out of jacking up the car. I installed the front Girodisc 2 piece rotors, Cobalt XR2 pads all around and the track tires/wheels. It took about 2 hours all in and I'm sure it will be quicker the next time. I took it out today and bedded the brakes. Cobalt says that it isn't necessary but I thought I'd take the belt and suspenders approach. They feel really good. I was able to hit 1.1G and managed to kick in ABS a few times on damp roads.



There were a couple other items that have been bugging me. First the rear hatch struts are tired and don't pop the lid enough to get your fingers under it. I replaced the lift struts with some from Paragon performance. The other thing that has been bugging me is the polished lower dash trim strips. Every once in a while the sun is in just the right spot and they absolutely blind me. Frickin Lasers! I looked around and found some real CF covers on eBay. They were fairly cheap and got decent reviews on the CorvetteForum. They were really easy to install and fit pretty well. There was one spot that they didn't quite cover so I hit it with a black Sharpie before I installed them. You wouldn't know it was there unless I showed you. They really cut the glare down and match the OEM CF bits really well.

Before:

After:


CF lower dash trim:



I got my Catalyst installed and fired up for the first time on Friday (4/5/24). I'm heading to Laguna Seca on Saturday 4/6/24). We'll see how this beast handles on the track.

CAINCA

I took the C8 to the track for the first time on Saturday. Holy smokes! This thing is a rocket ship. I was hitting 132mph at the end of the front straight. It cornered at basically the same speeds and was easily 10-15mph faster on every straight than the Cayman was. My fast time for the day was a 1:38.1 compared to a 1:44.07 PB in the Cayman.

I had a new experience this time. After the first couple sessions I started feeling vibrations at higher speeds. I asked the mobile tire guy to check the balance of the tires and they were all out. It turns out that these tires have so much grip and the car was braking so hard that they slipped on the wheels under hard braking. I had to up my tire pressures to help keep them from slipping. I was running 23/24 PSI cold - 30/31 PSI hot in the morning sessions. I moved up to 26/27 PSI cold - 34/36 PSI hot in the afternoon. That made the car a bit more lively, but it also allowed it to rotate a bit more. As I got more comfortable with the car I was getting slight on power over steer out of some of the corners. It was a hoot.

The only issue I had was that I was getting brake pulsing after a few laps. I would take a cool down lap and it would be good for another lap or two before it came back. I'm really hoping that it was coming from the stock rear rotors since the rear two piece rotors still haven't shown up.

I pulled the wheels/tires and brake pads off the car yesterday. The brake pads all look really good and the tires wore really evenly.



Here's the video from my best lap:

CAINCA

I used my Garmin Catalyst for the first time on Saturday. You can hear it coaching me in the video above. According to the Catalyst I should be able to put together a 1:37.XX lap if I just get all the pieces put together.

Note that there is no sound:

CAINCA

I punched my tire temps into the spreadsheet. I think I'm about 1 PSI over on all four corners.


The JackPoint jack stands worked out really well. It was pretty easy to get the car up on all four and it's super stable once you do.


The rear brake pads are retained with a pair of pins. They need to be tapped out of the caliper to remove the pads. I turned a punch with a dimple in the end to match the point on the pins. Then I noticed that it was hard to tap them back into place without occasionally whacking the caliper from behind so I turned a tool with a pocket to match the head of the pin. Much better.


I got one nice beauty shot while I was at the track.

CAINCA

So, now that I've thrown up a wall of text I'll point out the one issue I had on Saturday that I'm hoping to resolve before my next track day:
I was getting brake pulsing after a few laps. I would take a cool down lap and it would be good for another lap or two before it came back. I'm really hoping that it was coming from the stock rear rotors since the rear two piece rotors still haven't shown up.

I'm using the Colbalt XR2 brake pads. I have Girodisc two piece rotors F/R but I didn't receive the rears in time for this track day. I'm assuming that the rear rotors were overheating and warping. They were fine once they cooled off.

Anyone else running this combination? If so, are you getting this pulsing problem after a few laps?

CAINCA

I bought a set of four jackPoint jack stands with the low profile pads. If you jack at the rear point on the C8 you can lift that entire side off the ground. I thought it would be easy to slip the front stand into place, but since you're trying to get a 5/8" pin into a 11/16" hole it takes a bit of fiddling to get them in just the right spot. After using them a couple times I came up with the idea that a spring loaded pin that was a couple inches longer would be easier to get lined up in one shot. I designed these spring loaded pins and machined two of the top plates to match. The top plates were some of the cheapest, gummiest material I've ever had the displeasure of turning. Fortunately, the pins worked like a charm. I just slide them under the car, let the pin pop into the hole in the chassis and then lower the rear pad onto a jack stand.

gtpvette

I'm curious, did you cancel your caliper order??

CAINCA

Yes, I canceled my Z06 caliper order. I compared your measurement of the Z06 caliper to my Z51 calipers. From what I can see you'd need a 1/4" spacer to use the stock wheels. I'm not comfortable using a spacer that thick with the stock studs and I'm really not interested in using a 20mm bolt on spacer. The good news is that Ken at KNS had mentioned that he had a used AP racing kit available when I talked to him last week. It has used calipers but all of the other parts are new. So, after I canceled my Z06 order I called and made a deal with him for it.

In other news, I took my car into the dealer on Monday because I saw a buildup of grime and grit inside the rear wheels. It didn't seem like axle or CV grease, but it had oily feel to it. I thought it might just been rain combined with brake dust and road grime. The dealer called back and said that the transmission cover is leaking and there is a CSB to replace it. They are looking into how to cover it since it should still be under the powertrain warranty. I also asked them to check the AC system. I tried it out the other day when it was in the upper 70's and it didn't seem very cold. They checked it out and they think it's it's working as designed.

gtpvette

Sounds like you came out fine, just hope I hope I didn't steer you wrong with the measurement. I'll make sure I try the original wheels when I get mine mounted.

CAINCA

Apparently the transmission pans are on national back order. They said it could be up to a month before they can get one. I asked if I can drive it like it is and the service writer basically said “Well, I wouldn’t track it if that’s what you’re asking.”

CAINCA

I've been in a funk for the last couple weeks and having the C8 on time out isn't helping. Yesterday afternoon after work I watched TV for a bit, took a 3.5 mile walk with my wife, made dinner and then took the dog to the park. After all of that I decided that I needed some garage therapy to shake the funk off so I started installing the AP brake kit.



Overall it was pretty simple. Remove the stock caliper from the knuckle, remove the stock rotor, install the AP rotor, caliper bracket and caliper. Then the fun began. I tried to crack the brake line loose from the hard line. At first it wouldn't budge. After more force than I would have expected it finally cracked "loose", but it was still pretty stiff. I had to use a wrench all the way to the last thread (two flats at a time). Once I had it apart I looked at the nut. It didn't appear to have any thread lock on it, so maybe it's some kind of deformed nut? Ok, whatever. The line is dripping fluid. Let's just get this back together. I lined up the new SS brake line but it was really hard to get the threads started. I could only get it to thread about 1/2 turn with my fingers and worried that it might be cross threaded. I tried it a couple times with the same result. Paranoia started to set in and I worried that maybe I was sent the wrong lines, but no, the package said they were the correct ."C8 '20-'24". OK... Let's give this a shot. I used a wrench to tighten it up and thankfully, other than being stiff, it went together without a hitch. So, I have the passenger side installed. I'll do the driver's side tonight if I have time.

sowega

Great thread - nothing like garage time to sort it all out. I find that, if I say enough curse words at a repair/maintenance/tool/etc, then I don't feel like I have to say them to other people.

CAINCA

Thank you!

I find that having something that needs 100% of my attention for an hour or so is enough to clear my head. It usually doesn't work as well if I'm cursing. ;^)

X25

Regarding that brake line connection: those nuts are some kind of a soft metal, which I believe is by design to avoid leaks since it conforms, but it also means thread can easily get overtorqued or damaged/bruised a bit. After many years of going through this stress, I realized all I need to do is to CLEAN THE THREAD EVERY TIME I loosen these connections. Just get a flare nut thread maker/cleaner, and you'll be safe. Otherwise, sooner or later, luck runs out : )))

Here's what I have:

CAINCA

@X25 I started the driver’s side tonight. I struggled for a while but I couldn’t get the flare nut started on the SS line. Thankfully I was able to get the original line threaded and tightened up. The banjo bolt would thread into the SS line. I measured the bolt threads as 10x1.0 so I went ahead I ordered a metric thread file and a die. Unfortunately I won’t be able to get back to it for a couple days.