2020 Corvette

[Le Français]

As ugly as the interior is, I defy someone to find a better handling sreet/track car for the money than the C5 Z. The setup and power were fantastically balanced for a front engine rwd car. These things were the last ones you could take to the track, throw some stickies and a helmet on, change to an aggressive pad, and go hunting. I got mine used in 07 and put 175K on it and only had to add oil and gas. Still gets 34 mpg on the highways in 6th at 1800 rpm.

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Very nice. I almost got one recently. Did you find the driver’s seat to be up to the task of holding you in place on the track, or did you swap it out?

[Bucky]

These things were the last ones you could take to the track, throw some stickies and a helmet on, change to an aggressive pad, and go hunting.

I’m not quite sure what you mean, or why a C6 or C7 can’t do the same.

Agree about the value. Beautiful car TOTS.

[TOTS]

Very nice. I almost got one recently. Did you find the driver’s seat to be up to the task of holding you in place on the track, or did you swap it out?

I can’t remember if I read it on Corvette forum or Z06 vettes, but there was a thread about unzipping the seat covers and moving some of the padding from behind the side supports to inside them. The frame of the seat seems to be a fiberglass core with a lot of foam on the front with a little behind it for padding. I just bulked up the padding in front and it hugs your sides tighter, providing more support. Caveat emptor; it’s only a long-term solution for thinner dudes. Big guys need big seats.

[TAZ]

Love the look of it, but its a Lottery win car for me unfortunately.

[JRB]

A C8 at the Tx2k event in Houston last week ran a bottom 12 at 118 in the 1/4. Same car with some N2O immediately broke an axle and had to be towed away. It'll be interesting to see how these cars respond to mods, but a 118mph trap for a base pkg is promising.

The C5 Z06 is a lot of car, but C5's aren't aging well as a whole, so I'd be very careful to scrutinize any potential C5 buys. There are a lot of 'C5 problems' with the interior, power seat, window seals, etc.

For the $, personally, I say C6 Z06 or 08+ C6 Z51.
If one wants a cheaper fun car, an 03-04 C5 Z51 can be found for $12-14k if you shop around, and I think that's money well saved vs a $20-22k C5 Z06.

[Bucky]

For the $, personally, I say C6 Z06 or 08+ C6 Z51.

I was seriously considering trading my C6 Grand Sport for a C6 Z06. Even had a perfect one lined up, but it was bought out from under me. Then I wondered why the 7.0 L had been dropped from the lineup. Did some research and found they had some issues.

What prompted my curiosity was many years back, we did a 400 small block build for a friends Z-28. Because the bore was so big, there was no room for coolant to circulate between the cylinders. The engine ate head gaskets and was an overheating nightmare.

The 6.2 has a great track record thus far, and can be pretty impressive like the C7 ZR-1 at 755 HP.

[JRB]

I was seriously considering trading my C6 Grand Sport for a C6 Z06. Even had a perfect one lined up, but it was bought out from under me. Then I wondered why the 7.0 L had been dropped from the lineup. Did some research and found they had some issues.

What prompted my curiosity was many years back, we did a 400 small block build for a friends Z-28. Because the bore was so big, there was no room for coolant to circulate between the cylinders. The engine ate head gaskets and was an overheating nightmare.

The 6.2 has a great track record thus far, and can be pretty impressive like the C7 ZR-1 at 755 HP.

The Z06's chassis advantages to include all the CF and other nice parts (that the Grand Sport mostly got too) are what really makes the car special. It's hardly just a hot engine. Now, if you wanted more HP to scratch the itch I'd just modify the Grand Sport's native LS3 and live happily ever after. East Coast Supercharging makes a fantastic Novi 1500 SC kit and combined with catted long tube headers will make ~575-700whp depending on how frisky you go with the pulley combo, and that's a pretty damn nice power level for a C6 Corvette.
Needless to say, if one is wanting to go 'all motor' then the C6 Z06 is the premier choice. Heads/cam/longtubes/intake etc can crest 650whp but it takes a lot more money than going SC, and rowdy cams sound wonderful but kick highway mileage in the nuts no matter how good your tuning is.

Ultimately, though, it was emissions and CAFE regulations that killed the 7.0L, not cooling. The LS7 cooling circuit and construction could not be much more different than a 400SBC and still be a watercooled pushrod 16v V8, so I'd disagree strongly with that comparison, too.

Yes, there's a handful of things to address with the LS7, but it's hard to find an early model that hasn't had those sorted out already, and the later ones (08+) had much fewer problems. Other LS's have their finicky issues too. But a lot of LS7 stuff is the upgrade most other Gen 3/Gen 4 LS's go to.
Beyond that, the stock LS7 longblock is good to go for ~650whp on an SC or nitrous without any fuss, and can nudge toward 1000 with rods/pistons and sleeves. From there the AL block is the weakness and going to a narrower bore such as an LS3 block doesn't buy you much leeway but that combo can carry you over 1000whp. For crazy shit, especially on nitrous or big turbo setups, going to an LSX iron block and LSX heads is pretty much necessary for the block strength and additional head stud per hole, since 1000+whp loves to lift heads and crack mains on AL stuff even with exotic L19 or CA625 head studs.

The C7's are doing pretty nicely, the C7 Z06's respond to basic mods like crazy - a SC overdrive crank pulley along with long tubes, an intake, and a tune will easily result in high 600's low 700's depending on the parts and the pump gas used. But that ~700-750whp range is just about maxing out the LT4's fuel system and adding more to a direct injection system gets interesting. The best combos I've seen actually add fuel rails with port injectors on top of the DI and that gets expensive between the hard parts and the tuning complications. A hell of a car, to be sure, but not one I'm sure is worth the cost difference vs getting a nice C6 Z06 and going to town on that.

As to the SBC - I've seen enough 377's (400 block with a 350 crank, a flat-track and dirt racer favorite) that sit on a 5500-6k rpm rev limiter for 15, 30 minutes at a time without any HG issues or cooling issues to know that there's no systemic problems with that block design. But building an SBC is a lot like building a 1911 in that all the parts must be the correct match for each other to get good results.
So I suspect your friend's Z28 engine combo was suffering from poor head gasket selection, poor block/head surface prep, re-using fatigued OE headbolts, poor water pump selection, too small/poor radiator configuration, insufficient airflow through the radiator (lack of a shroud, crappy fan selection, etc) a bad distributor/incorrectly set centrifugal/vacuum advance causing overly retarded ignition timing at low RPM (that will heat up an iron V8 FAST), or some combination of those problems.

[Bucky]

The Z06's chassis advantages to include all the CF and other nice parts (that the Grand Sport mostly got too) are what really makes the car special. It's hardly just a hot engine. Now, if you wanted more HP to scratch the itch I'd just modify the Grand Sport's native LS3 and live happily ever after. East Coast Supercharging makes a fantastic Novi 1500 SC kit and combined with catted long tube headers will make ~575-700whp depending on how frisky you go with the pulley combo, and that's a pretty damn nice power level for a C6 Corvette.
Needless to say, if one is wanting to go 'all motor' then the C6 Z06 is the premier choice. Heads/cam/longtubes/intake etc can crest 650whp but it takes a lot more money than going SC, and rowdy cams sound wonderful but kick highway mileage in the nuts no matter how good your tuning is.

Ultimately, though, it was emissions and CAFE regulations that killed the 7.0L, not cooling. The LS7 cooling circuit and construction could not be much more different than a 400SBC and still be a watercooled pushrod 16v V8, so I'd disagree strongly with that comparison, too.

Yes, there's a handful of things to address with the LS7, but it's hard to find an early model that hasn't had those sorted out already, and the later ones (08+) had much fewer problems. Other LS's have their finicky issues too. But a lot of LS7 stuff is the upgrade most other Gen 3/Gen 4 LS's go to.
Beyond that, the stock LS7 longblock is good to go for ~650whp on an SC or nitrous without any fuss, and can nudge toward 1000 with rods/pistons and sleeves. From there the AL block is the weakness and going to a narrower bore such as an LS3 block doesn't buy you much leeway but that combo can carry you over 1000whp. For crazy shit, especially on nitrous or big turbo setups, going to an LSX iron block and LSX heads is pretty much necessary for the block strength and additional head stud per hole, since 1000+whp loves to lift heads and crack mains on AL stuff even with exotic L19 or CA625 head studs.

The C7's are doing pretty nicely, the C7 Z06's respond to basic mods like crazy - a SC overdrive crank pulley along with long tubes, an intake, and a tune will easily result in high 600's low 700's depending on the parts and the pump gas used. But that ~700-750whp range is just about maxing out the LT4's fuel system and adding more to a direct injection system gets interesting. The best combos I've seen actually add fuel rails with port injectors on top of the DI and that gets expensive between the hard parts and the tuning complications. A hell of a car, to be sure, but not one I'm sure is worth the cost difference vs getting a nice C6 Z06 and going to town on that.

As to the SBC - I've seen enough 377's (400 block with a 350 crank, a flat-track and dirt racer favorite) that sit on a 5500-6k rpm rev limiter for 15, 30 minutes at a time without any HG issues or cooling issues to know that there's no systemic problems with that block design. But building an SBC is a lot like building a 1911 in that all the parts must be the correct match for each other to get good results.
So I suspect your friend's Z28 engine combo was suffering from poor head gasket selection, poor block/head surface prep, re-using fatigued OE headbolts, poor water pump selection, too small/poor radiator configuration, insufficient airflow through the radiator (lack of a shroud, crappy fan selection, etc) a bad distributor/incorrectly set centrifugal/vacuum advance causing overly retarded ignition timing at low RPM (that will heat up an iron V8 FAST), or some combination of those problems.

Good info, thanks. It was certain speculation about the 7.0 liter.

I’ll probably leave the GS stock, as it’s my everyday. Or, maybe an exhaust and mild tune. Not interested in going super charged. I’ve got that covered on my ‘19 Z06.

Speaking of which, I can’t imagine needing to juice that any more. Even under perfect conditions, it’s tough putting all of it to the ground.

It’s been way too long to remember the specifics of the 400 build. I know this guy didn’t have the patience or discipline to properly break it in, and every second behind the wheel was at wide open throttle. Also, nothing in the car was was upgraded, so a better cooling system may have helped. Still, a similarly built 350 faired way better.

[JRB]

Good info, thanks. It was certain speculation about the 7.0 liter.

I’ll probably leave the GS stock, as it’s my everyday. Or, maybe an exhaust and mild tune. Not interested in going super charged. I’ve got that covered on my ‘19 Z06.

Speaking of which, I can’t imagine needing to juice that any more. Even under perfect conditions, it’s tough putting all of it to the ground.

It’s been way too long to remember the specifics of the 400 build. I know this guy didn’t have the patience or discipline to properly break it in, and every second behind the wheel was at wide open throttle. Also, nothing in the car was was upgraded, so a better cooling system may have helped. Still, a similarly built 350 faired way better.

There's a lot of weirdness and myths and internet lore on the LS7's, that much is for sure.
Personally I have only observed the dreaded valve issue once out of probably 20 or 25 Z06's I've worked on in my life, and it was a 2007 model, which falls out of the common internet lore range of 2008-2011 cars being the worst affected. The fix was having the heads pulled and sorted out by Texas Speed where they got some nice new supporting parts and a nice CNC port job. That head work was about $1500 and ~10hrs labor if memory serves, we ended up installing longtube headers at the same time because it was really easy 'while we were in there'.

The rod issue is almost guaranteed to be a problem in the first 10k miles, so the majority of C6 Z06's out there have wildly exceeded this already or had the engine sorted out by warranty coverage. Beyond that it's just an awesome engine that loves to make power.

On your GS - catted 'green' long tube headers from Kooks, a good intake kit, and a tune is all you need. Honestly you'd need to go supercharged to get close to making the stock catback a meaningful restriction, and longtubes plus the stock catback make a great combo of snarly V8 noises without headache-inducing decibels or drone on the highway. Catted longtubes in particular are the best bet for this. After tuning you should see 40-60whp gain almost across the board with those changes, too.

You have a '19 Z06? That's a fantastic car! You're having traction problems, though, because those stock Goodyear all-seasons are more dangerous in dry weather with that stock ~550whp than proper R888R's or Pilot Sport Cups would be in the rain. My opinion, I am not a lawyer and all that, but I'm shocked so many OE's ship such powerful cars with such insufficient tires these days.

If there was ever a car that 100% transformed from just a set of proper tires, it's the C7 Z06. If you intend to use it as a summer fun car and not daily drive it or risk driving it in poor weather, I would strongly recommend a set of Pilot Sport Cups or R888R's. A good compromise though is the Michelin Pilot Super Sport or Michelin Pilot Sport 4S.

I'm spitballing a bit because I can't remember which of those tires are available in C7 Z06 sizing off the top of my head, but the takeaway is that a proper summer-only street legal motorsport tire is a fantastic improvement across the board for that car.

My hat's off to you, though - a C6 GS daily and a C7 Z06 garage beast is an absolutely fantastic pair of Vettes to own.

[Trigger]

My hat’s off to both JRB and Bucky. There is so much good car info in this thread. The signal-to-noise ratio is so much higher than the car forums.

But enough blowing sunshine. (So to speak)

Reference the earlier discussion on the C5 Vette being the best balanced/performing track car out there, it brings up an excellent point on this forum. What performance characteristics do you value most in a sports car? (Or pistol, or rifle, or whatever) I drove a C5 Z-06 Vette on the track for a session, but I’m by no means an authority. Awesome grip, great acceleration, heavy steering, heavy clutch, notchy shifting. Blisteringly quick. But the car’s limits were difficult to approach without overshooting, and spinning the car.

On the other hand, I’ve driven an e30 M3 (1988) on the track a few times, and it was amazing for different reasons. The easiest car to throttle steer I’ve ever driven. Back end brakes loose very progressively and well-behaved. Steering is telepathic. Engine note is wonderful. Vastly underpowered compared to the Vette. But so easy to gracefully dance around the track, the car makes you look smooth and skilled. On of the E30 M3s had a 1995 3 liter Euro motor and 6-speed transplant. Plus a Torsen diff and suspension upgrades. What a smooth and wonderful car to drive, but still slow compared to a Vette.

I’ve recently driven my wife’s new/used ‘17 Miata. What a hoot to drive! 2300 lbs. Underpowered, but still a great car with nice chassis balance and refined driving experience.

Which is best? Well it depends on what you value. Glock 19 or Sig 320? CZ P-07 or Shadow? Colt 6920 or DDm4v7? JP or GA Precision? BAT or Kelbly?

I guess I prefer the BMW handling traits over the Vette, but that does not mean I don’t look at the power of a C7 Z-06 without a certain amount of poorly-concealed lust. To each their own, celebrate diversity and all that. Or be like Jay Leno and own them both.