Hoping the track folks can chime in with what their ideal setup would be and if the below is a reasonable idea.

I'm looking for a car I can daily drive on smooth roads (5 mile commute). It does not need to be great on long trips, I have other cars for that. But be able to be driven to the track and then driven home, without trailer. I'm an above average driver, with a few years SCCA experience. In general I'm usually top few at a race. This would be for HPDE, and maybe some TT, but no real racing.

Here is what I'm thinking. What have I forgotten?
C7 Grand Sport - Thinking this over the Z06 as cooling is much better.I would eventually probably put a LS7 based motor in it, but for now I just want something reliable. Is this a good idea, or is Z06 better to start with and just do the LG cooling up front?
4pt rollbar and harness bar, race seats, etc... I'm ok daily driving this (have before)
18x11 and 18x12.5 wheels maybe sport cups, most likely a tire trailer with R7's
18" brake conversion probably along lines of what X25 did, race fluids, etc..
APR wing GT500 wing,splitter but has to be streetable, so will probably run wing at a shallow angle
DSC sport controller, with maybe tractive RT, but start with stock shocks.
LG swaybars
Headers, exhaust
Antigravity battery

What else is needed / recommended?

 

17 or newer M7 Z06 Z07. Just get the track alignment or something between street and track settings and you’re good to go. Many track days in high temps and no cooling issues. I sold my 15 A8 Z51 which would would go into limp mode. If your going to track the car get the manual transmission.

 

c7 GS. Intake, headers , tune to get up to 500 ish hp and make up some of the lack of grunt. Make sure to find one with comp seats or else you can’t do harness bar and harnesses without race seat. Yes to the wheels. Skip whatever brake changes you mentioned. All c7 brakes fit under 18 inch wheels. They are plenty good for a GS levels of horsepower. Skip ls7 based engine. You don’t need it. That’s just asking for trouble for no reason. If you want power, just go full bolt on and call it quits. Maybe cams. But you will now need oil coolers and bigger radiator. honestly I wouldn’t touch the engine for a long time. Battery is a waste of money until you start trying to shed weight which means carpet pull, race seat, etc.

are you a very fast driver? Skip aero till you’re at the limits of the car. If gs z07 the oem suspension goes far. If non z07 get the Lg sway bars. Go with coilovers if when you get aero.

point is, stock c7 GS and z06 are bonkers fast with just tires and brake pads. If you run a lot of fast courses and 911s are eating your lunch on the straights then spend the $ on another 75-100 whp

 

An M7 Z06 with the secondary radiator (2017+) will run with a 911 when the suspension is set up correctly and the intercooler is bled properly so the SC charge air stays cool. On most road courses the big issue isn't HP it is getting through the turns faster. I knocked 5 seconds off my lap time at VIR by getting through the uphill Esses and Turn 10 faster.

The C7 Z06 big disadvantage against the 911s is weight. My 15 with not quite a full tank of gas weighed in at 3565 lbs on a truck scale, a GS will be somewhere around 100 to 150 lbs lighter.. Added HP only helps recover acceleration lost to weight, it doesn't help turn the car or slow the car so reducing the weight helps across the board. On a fair number of tracks, you will see GSs running close laps with Z06s due to less weight, different gearing and maybe a little better balance to the car. At tracks like VIR, there are only two long straights where the extra HP of the Z06 helps and that is right at the end of the straights where it may have a few mph speed on the GS.

The C7 coupe halo bar performs very well in rollovers and a 4-point roll bar will protect the same area of the car so doesn't really provide any extra safety for the money spent. If you want true rollover protection then you need a cage which means at least an 8-point cage. If you want race seats go with a BK Harness Bar, Schroth belts, and AMT seat mounts. There are several good race seats that are comfortable when driving short distances on the street.

There is a company out of Ohio that has a hitch design for the C7 and you can definitely tow a tire trailer with the car.

Bill

 

Regarding Antigravity battery:
I've run into glitches and the car giving random errors whenever this battery started running low, or whenever I trickle-charged it. It might be limited to my case/car, but as soon as I switched to MegaLiFE battery (which also has a reserve and a resume button), I stopped running into issues.

Regarding LS7:
It'd be a nightmare to install a 4th gen engine into a car with 5th gen. Besides, LS7s fail during track use (controversial topic).

Regarding Z07:
If you get a Z07 version of either GS or Z06, you won't need to do much (besides that brake swap or switching rotors to iron from Girodisc or similar; it's needed for maintenance cost cut, not for clearance). With Z06/Z07, you'd not need DSC, either; the 2019+ calibration sold by GM for $350 would more than suffice in my opinion. It worked great for me.

Lap times:
With a proper setup (good alignment and tires), you can be full throttle pretty much everywhere you'd with a Z06, like you would on a GS. GS just cannot keep up at any track I've driven, despite the weight advantage. That said, a second or two per lap, though feeling like infinity during a race, is not that much of a difference when not directly compared. In my experience, Z06 is pretty well matched to GT3 RS, but GT2 RS is a second or so faster yet.

Headers, exhaust:
If not done right, you can start cooking stuff inside the engine bay. I'm also not sure which aftermarket cats are best for track use. OEM parts are pretty sturdy, but I think headers might eventually crack if you keep overheating your engine.

Z06 cooling:
It needs help. Even if you're not completely overheating, you'd run it very very hot if you push the car enough, and lose enough power to make you wonder why are you just not running a GS if you can't use the power anyway. LG cooling kit is great for the price. Running taller gears drastically help, but you'll leave time on the table, which is a big NO in my opinion. Yes, it has a lot of torque, but still this is not a diesel and will make more power in the higher RPM band.

Seats:
If you're tall, the OEM seats don't really work very well unless you recline the seats. AMT's seat mounts let you gain an inch or more with a good seat.

 

Ok so updated

Step 1
C7 Grand Sport
Brey Krause harness bar
18x11 and 18x12.5 wheels with Leroy hitch and I'll build a trailer
Girodisc rotors if Z07 package
LG swaybars
seats (actually already have these)

Step 2
Faircloth wing and splitter
DSC Controller (coilovers only if necessary)

Step 3
Heads / Cam
headers

So for the Z07 package, there are very few Grand Sports with Z07 packages for sale. Not impossible to find but close. How important is the Z07 package? Looks like stiffer springs, different swaybars, different shock valving, and of course the brakes. Anything else that makes that option really desirable?

 

tc tuning is different if you use tc. Maybe abs tuning.

Otherwise it’s all just parts

 

According to online parts stores the shocks are the same part number for the FE6/FE7 suspensions. With Mag Ride the difference is in the programming not the valving. Shock dampening varies with the resistance of the shock fluid which is controlled by the programming.

Bill

 

I think GS indeed uses same shocks (and softer front springs) on all versions including Z07.

Z06 uses stiffer front springs and different shocks.