BaylorCorvette

Spoke to a moderator and since CF doesn't have a specific "Build Thread" section I was told to post here. I plan to document my build as I go, the object is to document every pound of weight I add or remove from the car and to give feedback on what works and doesn't work for the road course.

I'm a recent Corvette convert, I picked up a '16 2LT Z51 M7 back at the end of February 2016. For the last few years I was in a '13 Camaro ZL1, the car was a fantastic touring car that I swore I would never get rid of with gobs of power and handled very good despite its two ton+ weight problem, or so I though until I drove a family members C7 Z51. At the time I was (and as I write this, am still currently) the Vice President of the Houston Camaro Club and we were having a road course / track event where I was able to take a family members C7 out for a spin and absolutely fell in love with it. I jokingly came into the pits saying I didn't even want to drive my Camaro any more. The only down side was the C7 was an A8 which I managed to overheat on the track in 15 minutes.

Fast forward about a year and one of our club sponsors was having a fire sale on all C7s on the lot (turned out it was the month the GS was revealed), they also gave me a killer deal on my ZL1, so I really couldn't pass up this offer. Knowing how quickly I overheated the A8 I knew I wanted to have a manul car. Problem was out of the 30+ C7s on the lot, only four were a manual. Two white, one shark grey and one torch red. My other requirments were that it needed to be a 2LT to get the heads up display, needed to have the PDR and also needed to have the Z51 option (had to have the dry sump!). So I ended up with a Torch Red C7 nearly three months to the day as I write this.

First impressions of the Corvette - it is very agile and light on its feet (remember I'm coming from a 4,200+ lbs. ZL1), couple that with the torque curve and light weight and it feels every bit as fast as my ~575 rwhp Camaro. However, once I opened it up on the highway and then on the straights at the track I could really tell the power loss in the high rpms. The Corvette actually has more driver head room & leg room than my Camaro as well, which is great because at 6'2" wearing a helmet I would be constantly rubbing my head on the roof of the Camaro, in the Corvette I do not have this problem. The interior is also fantastic, even though the ZL1 was the top of the line Camaro it still felt cheap in several areas, not so in the Corvette which is nice considering what I paid on my Corvette was only ~$2,000 more than what I paid for my ZL1 when it was new.

Track Feedback (updated on 5/27/16):

First track event was at a small one mile track called Grandsport Speedway where I tested a family members C7 and overheated the A8 a year ago. Despite being on different tires (Nitto NT01, 275x35x18 front, 305x30x19 rear) the back end of the car felt really loose, now the 305's came from my Camaro and the 275s were new, so I just figured it was the wear cycle difference between the two.

Second track event was a McLaren event at MSR Houston (~2.38 miles) where I got to test drive a 570S (Awesome Car!) and I did a couple sessions in the Corvette. The car again felt very loose but still on the same tires.

Third track event was at Texas World Speedway (~2.90 miles), this was a two day event and where I was able to really get a comparison against my ZL1 in terms of lap times. Long story short the back end was still really loose ( wanted to finish off these tires before new ones) so much so that I was surprisingly two seconds a lap slower than my Camaro, granted the Camaro had ~575 rwhp, suspension & aero upgrades. But I wasn't pleased.

Given how slippery the back end of the car felt I suspected something more was going on than just worn tires. I found a dealership that could adjust rear caster and made an appointment. I got the car readjusted and the caster zero'd out, hoping that would help. The car now had -2.0 camber front & back, zero'd out front toe, slight rear toe in and zero'd out rear caster.

Fourth track event was a private one day event back at MSR Houston. My God the difference having the correct rear caster setting is huge. The car was WAY more planted and I ended up shaving nearly 9 (NINE!) seconds off the lap. I was pushing the car pretty good until I corded my front passenger tire and had to call it a day.

So I can confirm that rear caster can make a huge difference. Mine came from the factory out of spec, I'd guess that most C7s that have the rear camber & toe adjusted (without looking at rear caster) would probably be ok. Definitely on the street but the caster issue will show up on the track when you're going into a turn and the car wants to come around on you.

Here's a video from MSR Houston:



Current mods list. Last update: 6/1/16 -- THIS POST WILL BE KEPT UP-TO-DATE
Legend: Planned | Procured/Ordered | Installed

[*]Engine / Powertrain

• Z06 cooling upgrades:
  • Grille (23507619) (+0.0lbs)
  • Quarter panel vents (23373152) (0.5lbs)
  • 600-WATT radiator fan (23376530)
  • Secondary radiator (84037858)
• DeWitts C7 radiator; gen 2 (1139114M).
• Borla ATAK Dual Mode Exhaust System
• Headers (TBD)

[*]Handling

• LG Sway Bars
• LG End Links
• LG Coil Overs
• LG Drop Spindles

[*]Aero

• Custom Splitter
• Z06 Front Wheel Spats (+0.5lbs)
• C7 Carbon GTX Side Skirts (+7.0lbs)
• C7 Z07 Stage III Spoiler w/ Wicker (+10lbs)

[*]Tires / Wheels

• Nitto NT01 275/35/18 front (27 lbs), 305/30/19 rear (30.5 lbs)
• Cray Spider 18x9.5 front (21.5 lbs), 19x11 rear (23.5 lbs)

[*]Brakes

• Carbotech XP20 (front) (+0.0lbs)
• Carbotech XP12 (rear) (+0.0lbs)

[*]Net Weight Added/Removed From Vehicle

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Reserved For Pictures

Trading in '13 ZL1 for '16 C7 Z51
[IMG]https://cimg6.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/2000x1124/80-20160227_113103_1767f61e29ca5d6f132dbcca e3348ea2282f2e52.jpg[/IMG

Z06 Grill for better airflow to radiator and brakes


Z06 rear qtr ducts, GM claims it gets 15% more air to the Trans and Diff Cooler


Z06 wheel spats to help with wind deflection around the tires. With the OEM wheels it doesn't look great since the wheels are flush with the fender without the spats. But with the wider track wheels & tires I run it fills out the spats and looks a lot better.



Front straight at Grandsport, taking a friend out for hot laps


Front straight at MSR Houston


Just after tech in at Texas World Speedway


Getting my check ride for intermediate solo with a pack of Miatas behind me at Texas World.

billw4559

Could you mention the dealer or PM me?

Rooster OG

Congrats on the new ride!

I look forward to seeing the progress on your build. Have you put any thought into what kind of engine upgrades you might do?

X25

Nice to see you here, too. I'll also start up my build thread, and who knows, they might start a member journals section for us after all : )

EDIT:
Just created my own build journal:
https://www.corvetteforum.com/forums...ack-build.html

sycraft

great to hear, not to mention a ride in mine on the autocross... lol

BaylorCorvette

The dealer was Classic Chevrolet Sugar Land

Thanks! As far as engine upgrades nothing in the near term, but down the road probably just full exhaust and that's it. My ZL1 was at ~575 rwhp with intake, full exhaust, upper pulley and tune. The internals of the engine was completely stock and it was really reliable. I've seen/heard too many people with engine issues once they crack it open and mod it. The power is pretty good, top end is lacking and I'd like to have maybe another 50-75 rwhp but I'm definitely not complaining.

haha fingers crossed, I've lobbied for it.

Yup the autocross definitely peaked my interest and then when I got to drive one, it sealed the deal.

BaylorCorvette

Well I took the Corvette out for its maiden voyage yesterday in autocross. First time to autocross in the car, and ran on the stock run flats. The C7 Z51 runs in Super Street which includes C7 Z06s, C6 ZR1, Audi R8, current gen Vipers (non ACR), Shelby GT350R, Lotus Elise, Evora & exige, GT-R (2009-2011), and tons of Porsches. So I was a little skeptical that I'd be competitive. I went anyways, it poured rain in the morning but lucky for me by the time my group ran it had stopped and dried the track out for the most part.

My class included a Porsche GT3, Porsche Cayman, Lotus Elise and another C7. I was running on the stock run flats and managed to pull out a first place finish.

X25

Looks great! I'm happy to see that GM made sure the spring rates were up to the task for the Z51 w/ no MRC. I'm sending my Camaro to the dealer tomorrow, so I will probably receive my Corvette next week. Looking forward to trying it out. Now I need to find a way to finish up that break-in period ASAP.

BaylorCorvette

Well I just had a two day track event at Texas World Speedway. The entire weekend the temperature outside was in the mid to high 90s. Saturday went well, no issues, Sunday I was pushing it harder and ended up melting the AFM actuators. Just picked the car up from the dealership earlier today and it's fixed. The car never overheated or went into limp mode and I was pushing it pretty good for 20 minutes straight per session. The hottest the engine oil got was 273* and the engine 223* however the transmission got up to 306*

Anyways I'm pleased that the car didn't overheat in mid to high 90* temps. However it is discouraging that the AFM sensors melted and reading other people's feedback it seems like GM does not have a fix.

Here's a video from the weekend, not my fastest laps but I'm maneuvering through traffic so it makes it more interesting.

X25

Perhaps you'd adopt my fix if it works for me : p

I will take the muffler out tonight.

BaylorCorvette

I'm definitely going to have my eye on your fix!

sycraft

what does the muffle have to do with the AFM lifters, are you melting the NPP valves X25?

Chets LS3

whats the proposed fix?

X25

I mentioned it in another thread, too:
I've had very similar actuator valves on motorcycles. They all do work the same, and their design are usually very similar, too. The difference in this one is that motorcycle manufacturers always put the electric motor on a cool remote location, whereas GM did not see any need for such precaution.

Anyway, the actuator needs to have that spring-loaded valve resisting to it to successfully finish its init cycle, so you can't just leave it outside. However, you could easily cut the valve from its already existing welding points, and the ECU would be happy.

There can only be two issues with this:
(1) There might not be enough space to put the dangling actuator away; it's a very tightly packed car (which s actually causing the overheat issue by the way).
(2) Your acoustics will be impacted in V4 mode. I can live with that : )

In any case, I'm planning to do this next week, but I'm still working on putting in the miles for the first oil change. I've hit 300 miles today, and it's a long weekend : )

BaylorCorvette

Several things since I last updated this thread. I have relocated the AFM actuators by way of longer bolts and using washers as spacers. Doing this allows me to bolt the AFM actuator to the existing housing but the longer bolts and washers keep the actuator off the butterfly valve reducing/eliminating heat transfer. I've put 500 miles on the car since doing this, ~300 of which were track miles. No check engine light and no failure.

Now to the more fun stuff, I just spent two days at Texas World Speedway which is basically my home track. With my ZL1 that was making ~175 more rwhp and had aero and suspension mods as well, I clocked a best time of around 2:03 and that was on Nitto NT01 tires. My C7 had a best time of around 2:00.xx on Nitto NT01 tires (275 front, 305 rear). My goal this weekend was to break the two minute mark. Well Saturday I was clocking 2:00.xx-2:02.xx consistently, however the back end felt loose. Sunday rolls around and now the tires can only go about three laps before they have zero grip in the turns and it feels like I'm driving on ice. I couldn't get better then 2:04.xx times. I reviewed some PDR video with an instructor and he gave me some pointers, my lines were better but the tires were toast, which is absolutely nuts because this was only the second weekend on the Nitto NT01's!!! They had about 400 track miles before they become complete garbage. Frustrated I started to pack up and decided for the last session of the day I'd throw the OEM Pilot Super Sport Run Flats on and give it a whirl. Well I clocked two 1:58.xx back-to-back! I was SUPER STOKED! Especially since I was on narrower (245/285 as opposed to 275/305) tires and they were much less sticky. I think the NT01's fall off fast where as the Pilot Super Sports are a little more consistent through their life cycle. If I had brand new NT01's I would have maybe been in the 1:56.xx range.

Here's the video of the two 1:58.xx runs. My C7 is bone stock with the exception of G-Loc R16 pads and DOT4 brake fluid.

X25

How were your trap speeds in comparison? Were they similar, or different? If not similar, heavier/wider tires might be having a toll on your acceleration. I'd hope not, though; this is not a Miata : )

Did you lose front tires, or rears, or seemingly both ends? 2 days out of set is just too low; I'm trying to understand what it might be. Are you ready to invest $5K to try out the 315 / 325 setup? : P I also wondering if your narrow wheels are hurting the tires.

If you'd like to experiment, you can try 295 / 325 Trofeo R tires; they're relatively affordable, too, but again, I'm not sure about your wheels, especially your front wheels.

BaylorCorvette

Similar trap speeds, I did the math based on tire size difference and it's only about 1.5 mph at around 140 mph, so the indicated speed difference on the videos is negligible.

Back end grip fell off REALLY fast, fronts remained more consistent. For reference I'm running 275/305 NT01s on 9.5" & 11.0" wheels. Like I had mentioned prior to this weekend I had only two days on the NT01's, which was in high 90* temps and I was pushing them hard for about 280-300 miles of track time. I just wonder if I heat cycled them out? Even so, that seems like they heat cycled out way too fast. This past Saturday they seemed decent, not great but they held up for 25 minute sessions. However on Sunday, after about 3 laps the backs were done. I even had an instructor ride with me to give me pointers and he mentioned a couple times how the tires fell off super fast. Now when I ran the 1:58.xx back to back I had picked up a few tips from other pros at this track. But lets say that was 1.5-2 seconds worth of improvement, that puts me at the 2:00.xx mark which is the best time I've ever ran on NT01's. I would think the NT01's would be worth a couple seconds over the Pilot Super Sports. My only other thought is that going to a different width threw the balance of the car off. However, you're a perfect example of really changing tire sizes from stock, granted you've massively changed the suspension too.

Going forward I'm probably going to move to slicks, buying scrubs is cheaper. In fact I've got six slicks sitting in my garage right now.

MerakiAutoworks

Love this build.. Needs some updates!

-Josh

X25

I almost immediately switched to T1 shocks, but I have to say, I've never been happy with the car's handling with wider tires and the stock springs, which are also meant to be used with the T1 shocks.

When I switched to 315/325s, it went much worse, and I lost quite a bit of confidence in handling with noticeably more squat, and rubbing fenders on all 4 corners. At that point, it became clear that I needed to switch to the coilovers. I have to say, perhaps the sway bars alone would fix it quite a bit, but I changed them all at the same time. The results was a massive improvement, and I wonder if you'd need something like that as well.

I am still not sure where my car currently stands against the Z07 suspension. I sure would love to find someone in my area with a GS/Z07 who also goes to track with it, so I could compare.

I am still not sure what happened with the NT01s. Did your NT01s last long on your ZL1? Your wheels are also wide enough, so that's not a problem, either. We'll see how long my tires last. In my experience with NT01s on the Miata (and my friend's experience on the BRZ), these tires keep their traction until they cord, and almost never heat cycle out. i don't have such an extensive experience on this car, though. I wonder if the size has something to do with it, but the fact that your rears were gone before the narrower fronts debunks that idea. I have to say, I was also not happy with 275/305s, and thought the rear needed more traction. Perhaps I had the very same issue, but just didn't know.

BaylorCorvette

Interesting that you say that, because even on fresh NT01's I thought the handling just wasn't there and perhaps like you suggested the spring and/or the sway bar may be the problem when going to more tire. I've got the LG front sway in my garage that I'll be installing soon, however the rear sway is staying OEM so I can stay eligible for stock class in SCCA. However, I'm thinking this time next year I'll be looking to order the LG coilovers.